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Bernhard P, Haener D and Frey O (2024), "Detection of Railway Track Anomalies Using Interferometric Time Series of TerraSAR-X Satellite Radar Data", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 17, pp. 11750-11760. Institute of Electrical and Electronics Engineers (IEEE).
BibTeX:
@article{bernhardHaenerFreyJSTARS2024DetectionOfRailwayTrackAnomaliesByPSIWithTerraSARX,
  author = {Bernhard, Philipp and Haener, David and Frey, Othmar},
  title = {Detection of Railway Track Anomalies Using Interferometric Time Series of TerraSAR-X Satellite Radar Data},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers (IEEE)},
  year = {2024},
  volume = {17},
  pages = {11750--11760},
  doi = {10.1109/jstars.2024.3405019}
}
Bertone A, Jones N, Mair V, Scotti R, Strozzi T and Brardinoni F (2024), "A climate-driven, altitudinal transition in rock glacier dynamics detected through integration of geomorphological mapping and synthetic aperture radar interferometry (InSAR)-based kinematics", Cryosphere. Vol. 18(5), pp. 2335-2356. Copernicus Publications.
Abstract: In dry southwestern South Tyrol, Italy, rock glaciers are dominant landforms of the high-mountain cryosphere. Their spatial distribution and degree of activity hold critical information on the current state of discontinuous permafrost and consequently on the response potential to climate warming. Traditional geomorphologic mapping, however, owing to the qualitative expert-based nature, typically displays a high degree of uncertainty and variability among operators with respect to the dynamic classification of intact (permafrost-bearing) and relict (permafrost-devoid) rock glaciers. This limits the reliability of geomorphologic rock glacier inventories for basic and applied purposes. To address this limitation, (i) we conduct a systematic evaluation of the improvements that synthetic aperture radar interferometry (InSAR) can afford to the detection and dynamic classification of rock glaciers and (ii) build an integrated inventory that combines the strengths of geomorphologic-and InSAR-based approaches. To exploit fully InSAR-based information towards a better understanding of the topo-climatic conditions that sustain creeping permafrost, we further explore how velocity and the spatial distribution of moving areas (MAs) within rock glaciers may vary as a function of simple topographic variables known to exert first-order controls on incoming solar radiation, such as elevation and aspect. Starting from a geomorphologic inventory (nCombining double low line789), we characterize the kinematics of InSAR-based MAs and the relevant hosting rock glaciers on 36 Sentinel-1 interferograms in the 2018-2019 period. With respect to the original inventory, InSAR analysis allowed us to identify 14 previously undetected rock glaciers. Further, it confirmed that 246 (76g%) landforms, originally interpreted as intact, do exhibit detectable movement (i.e., ≥1gcmgyr-1) and that 270 (60g%) of the relict labeled counterparts do not, whereas 144 (18g%) were kinematically undefined due to decorrelation. Most importantly, InSAR proved critical for reclassifying 121 (15g%) rock glaciers, clarifying that 41 (13g%) of those interpreted as being intact do not exhibit detectable movement and that 80 (17g%) of the original relict ones do move. Reclassification (i) allowed us to identify a cluster of intact rock glaciers below 2000ga.s.l. associated with positive mean annual air temperature (MAAT), and (ii) by increasing the altitudinal overlap between intact and relict rock glaciers, it depicts a broad transition belt in the aspect-elevation space, which varies from 50gm on west-facing slopes to 500gm on easterly ones. This finding deteriorates the significance of elevation and aspect as topographic proxies for modeling permafrost occurrence and highlights the importance of using InSAR to inform such models. From a process-oriented standpoint, InSAR information proves fundamental for imaging how this altitudinal transition manifests through changing rates and styles of rock glacier surface deformation. Specifically, we find that, as rock glaciers move faster, an increasingly larger proportion of their surface becomes kinematically involved (i.e., percent MA cover) and that this proportion increases with elevation up to 2600-2800gm, beyond which an inflection occurs and consistent average values are attained. Considering that the inflection falls between the-1 and-2g°C MAAT-the lower boundary for discontinuous permafrost-and is independent of slope gradient, we conclude that this altitudinal pattern represents a geomorphic signature: The dynamic expression of increasing permafrost distribution, from sporadic to discontinuous. © 2024 Copernicus Publications. All rights reserved.
BibTeX:
@article{Bertone2024,
  author = {Bertone, A. and Jones, N. and Mair, V. and Scotti, R. and Strozzi, T. and Brardinoni, F.},
  title = {A climate-driven, altitudinal transition in rock glacier dynamics detected through integration of geomorphological mapping and synthetic aperture radar interferometry (InSAR)-based kinematics},
  journal = {Cryosphere},
  publisher = {Copernicus Publications},
  year = {2024},
  volume = {18},
  number = {5},
  pages = {2335-2356},
  doi = {10.5194/tc-18-2335-2024}
}
Brangers I, Marshall H-P, De Lannoy G, Dunmire D, Mätzler C and Lievens H (2024), "Tower-based C-band radar measurements of an alpine snowpack", Cryosphere. Vol. 18(7), pp. 3177-3193. Copernicus Publications.
Abstract: To better understand the interactions between C-band radar waves and snow, a tower-based experiment was set up in the Idaho Rocky Mountains for the period of 2021-2023. The experiment objective was to improve understanding of the sensitivity of Sentinel-1 C-band backscatter radar signals to snow. The data were collected in the time domain to measure the backscatter profile from the various snowpack and ground surface layers. The data show that scattering is present throughout the snow volume, although it is limited for low snow densities. Contrasting layer interfaces, ice features and metamorphic snow can have considerable impact on the backscatter signal. During snowmelt periods, wet snow absorbs the signal, and the soil backscatter becomes negligible. A comparison of the vertically integrated tower radar data with Sentinel-1 data shows that both systems have similar temporal behavior, and both feature an increase in backscatter during the dry-snow period in 2021-2022, even during weeks of nearly constant snow depth, likely due to morphological changes in the snowpack. The results demonstrate that C-band radar is sensitive to the dominant seasonal patterns in snow accumulation but that changes in microstructure, stratigraphy, melt-freeze cycles and snow wetness may complicate satellite-based snow depth retrievals. © Copyright:
BibTeX:
@article{Brangers2024,
  author = {Brangers, I. and Marshall, H.-P. and De Lannoy, G. and Dunmire, D. and Mätzler, C. and Lievens, H.},
  title = {Tower-based C-band radar measurements of an alpine snowpack},
  journal = {Cryosphere},
  publisher = {Copernicus Publications},
  year = {2024},
  volume = {18},
  number = {7},
  pages = {3177-3193},
  doi = {10.5194/tc-18-3177-2024}
}
Deeb E, Meehan T, Hoppinen Z, Werner C, Frey O, Forster R and LeWinter A (2024), "Use of mobile L-Band interferometric synthetic aperture radar observations to inform snow property estimation", In EGU General Assembly 2024, EGUsphere. , pp. EGU24-22452. Copernicus.
BibTeX:
@conference{Deeb2024,
  author = {Deeb, Elias and Meehan, Tate and Hoppinen, Zach and Werner, Charles and Frey, Othmar and Forster, Richard and LeWinter, Adam},
  title = {Use of mobile L-Band interferometric synthetic aperture radar observations to inform snow property estimation},
  booktitle = {EGU General Assembly 2024, EGUsphere},
  publisher = {Copernicus},
  year = {2024},
  pages = {EGU24-22452},
  note = {EGU General Assembly 2024; Conference Location: Vienna, Austria; Conference Date: April 14-19, 2024; Poster presented on April 19, 2024},
  doi = {10.3929/ethz-b-000700486}
}
Dong W, Mitchard E, Santoro M, Chen M and Wheeler C (2024), "A new circa 2007 biomass map for China differs significantly from existing maps", Scientific Data. Vol. 11(1) Nature Research.
Abstract: The forest area of China is the fifth largest of any country, and unlike in many other countries, in recent decades its area has been increasing. However, there are substantial differences in estimates of the amount of carbon this forest contains, ranging from 3.92 to 17.02 Pg C for circa 2007. This makes it unclear how the changes in China’s forest area contribute to the global carbon cycle. We generate a circa 2007 aboveground biomass (AGB) map at a resolution of 50 m using optical, radar and LiDAR satellite data. Our estimates of total carbon stored in the forest in China was 9.52 Pg C, with an average forest AGB of 104 Mg ha−1. Compared with three existing AGB maps, our AGB map showed better correlation with a distributed set of forest inventory plots. In addition, our high resolution AGB map provided more details on spatial distribution of forest AGB, and is likely to help understand the carbon storage changes in China’s forest. © The Author(s) 2024.
BibTeX:
@article{Dong2024,
  author = {Dong, W. and Mitchard, E.T.A. and Santoro, M. and Chen, M. and Wheeler, C.E.},
  title = {A new circa 2007 biomass map for China differs significantly from existing maps},
  journal = {Scientific Data},
  publisher = {Nature Research},
  year = {2024},
  volume = {11},
  number = {1},
  doi = {10.1038/s41597-024-03092-8}
}
Fransson J, Börnberg D, Holmström A, Lazo J, Löve W, Nilsson M, Salo J, Santoro M, Sertel E, Soomro S, Wallerman J, Ünsalan C and Zarins J (2024), "Applying Machine Learning for Forest Attribute Mapping in Latvia - Sharing Insights from the Swedish Approach", International Geoscience and Remote Sensing Symposium (IGARSS). , pp. 5320-5323. Institute of Electrical and Electronics Engineers Inc..
Abstract: In this study, a novel approach to map forest attributes has been investigated for boreal forests in Sweden. The methodology relies on machine learning, utilizing a combination of remote sensing data and field data for both training and evaluating the proposed models. To ensure the accuracy in estimating forest attributes at any given time, the approach incorporates a broad range of available remote sensing data including airborne laser scanning (ALS) data, weekly satellite data from Sentinel-1 and Sentinel-2, and global forest map data. However, in this study focus has been on utilizing ALS data. The field data utilized in the study are derived from the Swedish National Forest Inventory and encompass measurements of key forest variables such as above-ground biomass, stem volume, basal area-weighted mean tree height, basal area-weighted mean diameter at breast height, and basal area. The potential of exporting knowledge gained from mapping Sweden to other forested landscapes such as in Latvia, using model updating with limited reference data from the new targeted area will be the next step to investigate. Here, data from Sweden were used to take the first steps towards developing a mapping methodology. The results demonstrate a promising potential of the proposed approach that will showcase new possibilities to share knowledge of updated forest mapping using the increasing flow of high-precision remote sensing data. © 2024 IEEE.
BibTeX:
@conference{Fransson2024,
  author = {Fransson, J.E.S. and Börnberg, D. and Holmström, A. and Lazo, J.F. and Löve, W. and Nilsson, M. and Salo, J. and Santoro, M. and Sertel, E. and Soomro, S. and Wallerman, J. and Ünsalan, C. and Zarins, J.},
  title = {Applying Machine Learning for Forest Attribute Mapping in Latvia - Sharing Insights from the Swedish Approach},
  journal = {International Geoscience and Remote Sensing Symposium (IGARSS)},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2024},
  pages = {5320-5323},
  doi = {10.1109/IGARSS53475.2024.10641620}
}
Frey O, Werner C and Caduff R (2024), "Dual-frequency high-resolution mobile mapping of ground motion of the Brinzauls landslide in Switzerland with a car-based interferometric SAR system at L- and Ku-band", In EGU General Assembly 2024, EGUsphere., March, 2024. , pp. EGU24-17107. Copernicus.
Abstract: Geohazards related to ground motion are widespread in mountainous regions. Time series of spaceborne SAR data are commonly used to retrieve maps of ground motion with extensive spatial coverage. However, there are situations where terrestrial radar systems are more suitable or even necessary for measuring ground motion. Such situations include slopes facing north or south, where the line of sight of current space-based SAR systems is nearly perpendicular to the prevalent direction of ground motion; slopes that lie in radar shadow or layover for current spaceborne SAR geometries; fast-moving landslides requiring shorter interferometric measurement intervals; and cases demanding higher spatial resolution or higher frequencies (e.g., Ku-band) with better sensitivity to line-of-sight motion.Terrestrial stationary radar/SAR systems, typically operating at Ku- or X-band, have been employed for many years to address these challenges. However, their limited synthetic aperture (or antenna size in the case of real-aperture radars) result in a constant angular resolution in the azimuth direction, leading to a reduced spatial azimuth resolution with increasing distance.Monitoring a landslide from a moving car or a UAV with a longer synthetic aperture allows using lower frequencies such as L-band, offering good spatial resolution at the meter level. Aperture synthesis from a car or UAV at higher frequencies (e.g., Ku-band) with smaller radar antennas can significantly improve the azimuth resolution to sub-meter or even decimeter level compared to stationary terrestrial radar systems which typically have azimuth resolutions in the order of 10m and more at range distances of several kilometers.In our previous work, we had demonstrated mobile mapping of ground motion using a compact repeat-pass L-band interferometric SAR system on a car and a UAV. Recently, a Ku-band SAR system (a modified version of the Gamma Portable Radar Interferometer (GPRI)) was added to the car-borne InSAR measurement setup. The new configuration allows simultaneous data acquisitions at both frequencies during repeat-pass SAR measurements while driving along a road.Frequency diversity proves to be advantageous in mountainous areas with varying land cover and motion processes with different velocities and scales. In this contribution, we present recent results from car-borne mobile mapping campaigns in the Swiss Alps showcasing the dual-frequency car-borne SAR setup (Gamma L-band SAR and modified GPRI at Ku-band). In particular, we present ground motion measurements of the Brinzauls landslide in Switzerland taken in fall 2023 at both frequencies, Ku- and L-band, and at different time intervals. The case study strikingly shows the complementary properties of the two frequencies in terms of sensitivity to motion and temporal decorrelation. The unprecedented high-resolution SAR imagery and interferograms obtained with the car-borne Ku-band SAR (decimeter-level azimuth resolution) allows discriminating different bodies of the landslide moving at different velocities in detail.
BibTeX:
@conference{Frey2024,
  author = {Frey, Othmar and Werner, Charles and Caduff, Rafael},
  title = {Dual-frequency high-resolution mobile mapping of ground motion of the Brinzauls landslide in Switzerland with a car-based interferometric SAR system at L- and Ku-band},
  booktitle = {EGU General Assembly 2024, EGUsphere},
  publisher = {Copernicus},
  year = {2024},
  pages = {EGU24-17107},
  note = {EGU General Assembly 2024; Conference Location: Vienna, Austria; Conference Date: April 14-19, 2024; Conference lecture held on April 16, 2024.},
  doi = {10.5194/egusphere-egu24-17107}
}
Frey O, Werner C and Caduff R (2024), "Simultaneous Car-Borne SAR Imaging at L-Band and Ku-Band for DInSAR-Based Mobile Mapping of Ground Motion in Alpine Terrain", In Proc. of EUSAR 2024 - 15th European Conference on Synthetic Aperture Radar. Munich, Germany, April, 2024. , pp. 1259-1264.
Abstract: In this contribution, we present high-resolution car-borne DInSAR imagery of a fast-moving landslide, simultaneously acquired at Ku-band and L-band. Recently, we have developed and implemented a car-borne and UAV-borne DInSAR end-to-end system at L-band also including INS/GNSS-based navigation, SAR focusing, and interferometric processing. Using this L-band SAR system we have demonstrated car-borne and UAV-borne measurements of ground motion at various sites. We then enhanced the car-based setup by adding a Ku-band SAR system alongside the Gamma L-Band SAR. In October 2023, we revisited the Brinzauls landslide in Switzerland, where we acquired high-resolution car-borne repeat-pass DInSAR data at Ku-band and L-band. This active landslide consists of various compartments with different kinematic behavior and with different land cover. Our car-borne DInSAR imagery obtained at Ku-band and L-band provides critical information at high spatial resolution to localize and distinguish landslide compartments moving at different velocities for a more detailed mapping of geological-kinematic features within the landslide.
BibTeX:
@inproceedings{freyEtAlEUSAR2024CarborneDInSARBrinzaulsKuAndLBand,
  author = {Othmar Frey and Charles Werner and Rafael Caduff},
  title = {Simultaneous Car-Borne SAR Imaging at L-Band and Ku-Band for DInSAR-Based Mobile Mapping of Ground Motion in Alpine Terrain},
  booktitle = {Proc. of EUSAR 2024 - 15th European Conference on Synthetic Aperture Radar},
  year = {2024},
  pages = {1259-1264},
  url = {https://www.gamma-rs.ch/uploads/media/freyEtAlEUSAR2024CarborneDInSARBrinzaulsKuAndLBand.pdf}
}
Frey O, Wiesmann A, Werner C, Caduff R, Löwe H and Jaggi M (2024), "High-resolution snow parameter/structure retrieval from tower-based radar time series of seasonal snow obtained with the ESA SnowScat and the ESA Wideband Scatterometer in SAR tomographic profiling mode", In EGU General Assembly 2024, EGUsphere. , pp. EGU24-17561. Copernicus.
BibTeX:
@conference{Frey2024a,
  author = {Frey, Othmar and Wiesmann, Andreas and Werner, Charles and Caduff, Rafael and Löwe, Henning and Jaggi, Matthias},
  title = {High-resolution snow parameter/structure retrieval from tower-based radar time series of seasonal snow obtained with the ESA SnowScat and the ESA Wideband Scatterometer in SAR tomographic profiling mode},
  booktitle = {EGU General Assembly 2024, EGUsphere},
  publisher = {Copernicus},
  year = {2024},
  pages = {EGU24-17561},
  note = {EGU General Assembly 2024; Conference Location: Vienna, Austria; Conference Date: April 14-19, 2024; Conference lecture held on April 19, 2024},
  doi = {10.5194/egusphere-egu24-17561}
}
Heimpel M, Hajnsek I and Frey O (2024), "Altitude-Adaptive Coregistration for Differential SAR Tomography", In Proc. of EUSAR 2024 - 15th European Conference on Synthetic Aperture Radar. Munich, Germany, April, 2024. , pp. 757-762.
BibTeX:
@inproceedings{heimpelHajnsekFreyEUSAR2024TomoHeightDependentCoregMountainousAreas,
  author = {Magnus Heimpel and Irena Hajnsek and Othmar Frey},
  title = {Altitude-Adaptive Coregistration for Differential SAR Tomography},
  booktitle = {Proc. of EUSAR 2024 - 15th European Conference on Synthetic Aperture Radar},
  year = {2024},
  pages = {757-762}
}
Holmberg M, Lemmetyinen J, Schwank M, Kontu A, Rautiainen K, Merkouriadi I and Tamminen J (2024), "Retrieval of ground, snow, and forest parameters from space borne passive L band observations. A case study over Sodankylä, Finland", Remote Sensing of Environment. Vol. 306 Elsevier Inc..
Abstract: Previous studies have indicated and shown the feasibility of retrieving snow density from ground based passive microwave measurements at the L band (1–2 GHz) from theoretical and experimental viewpoints. This paper expands the previous studies by presenting a case study of the retrieval problem with space borne brightness temperature measurements from the SMOS satellite over Sodankylä, Finland. To successfully retrieve snow density, also ground and forest parameters were included to the retrieval process. The retrieved variables were validated against in-situ ground, snow, and forest measurements made around the Sodankylä area over 12 winters from 2010 to 2022. A Bayesian framework was used to account for and quantify the uncertainties associated with the retrieval process. The results show good agreement between the retrieved ground and forest variables with the respective reference values. The snow density retrievals were seen to suffer from multiple sources of geophysical noise. However, the monthly average bulk snow density was successfully retrieved under stable midwinter conditions. The best agreement with the in-situ measurements was found for February, with a bias of -0.4 kg/m3, an unbiased root mean square difference of 12.2 kg/m3, and a correlation coefficient of 0.75. © 2024 The Author(s)
BibTeX:
@article{Holmberg2024,
  author = {Holmberg, M. and Lemmetyinen, J. and Schwank, M. and Kontu, A. and Rautiainen, K. and Merkouriadi, I. and Tamminen, J.},
  title = {Retrieval of ground, snow, and forest parameters from space borne passive L band observations. A case study over Sodankylä, Finland},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2024},
  volume = {306},
  doi = {10.1016/j.rse.2024.114143}
}
Hong S-H, Werner C and Lee S-K (2024), "ALOS-2 Stripmap + ScanSAR MTInSAR for Ground Subsidence Monitoring", IEEE Geoscience and Remote Sensing Letters. Vol. 21, pp. 1-5. Institute of Electrical and Electronics Engineers Inc..
Abstract: L-Band data from the PALSAR-2 instrument on the ALOS-2 satellite have been collected globally following the basic observation plan. The sparse archive of either Stripmap or ScanSAR mode data is often an obstacle to obtain an adequately sampled interferometric phase history for applying multitemporal synthetic aperture radar interferometry (MTInSAR). In this study, we evaluate the feasibility of ALOS-2 Stripmap + ScanSAR MTInSAR, using both acquisition modes, to enhance the small baseline subset (SBAS) network by filling temporal gaps. We combined 11 Stripmap and 21 ScanSAR acquisitions during 2015-2020 to monitor ground subsidence in Busan, South Korea. This improved the observation frequency, thereby reducing errors due to geometric and temporal decorrelation. Due to the differences in the azimuth spectral patterns, common-band filtering was not performed when processing the Stripmap + ScanSAR dataset. The subsidence pattern of the surface deformation time series derived from each acquisition mode appeared similar. Although the mean coherence of the Stripmap + ScanSAR (0.77) interferometric pairs was slightly lower than that of the Stripmap (0.83) and ScanSAR (0.84) only pairs, the standard deviation of the coherence in the Stripmap + ScanSAR dataset was the lowest. The mean difference in the displacement rate among the three datasets was 0.1 cm/year, with a standard deviation of 0.3-0.4 cm/year. The means of the standard deviation of the deformation, proportional to the residual phase in the time-series deformation of the Stripmap, ScanSAR, and Stripmap + ScanSAR dataset, were 0.7, 0.9, and 0.8 cm, respectively. The results show that the ALOS-2 Stripmap + ScanSAR SBAS applications provide a useful method to increase the frequency of observations and reduce errors in the deformation time series. © 2004-2012 IEEE.
BibTeX:
@article{Hong2024,
  author = {Hong, S.-H. and Werner, C. and Lee, S.-K.},
  title = {ALOS-2 Stripmap + ScanSAR MTInSAR for Ground Subsidence Monitoring},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2024},
  volume = {21},
  pages = {1-5},
  doi = {10.1109/LGRS.2023.3349302}
}
Hunka N, Duncanson L, Armston J, Dubayah R, Healey S, Santoro M, May P, Araza A, Bourgoin C, Montesano P, Neigh C, Grantham H, Potapov P, Turubanova S, Tyukavina A, Richter J, Harris N, Urbazaev M, Pascual A, Suarez D, Herold M, Poulter B, Wilson S, Grassi G, Federici S, Sanz M and Melo J (2024), "Intergovernmental Panel on Climate Change (IPCC) Tier 1 forest biomass estimates from Earth Observation", Scientific Data. Vol. 11(1) Nature Research.
BibTeX:
@article{Hunka2024,
  author = {Hunka, N. and Duncanson, L. and Armston, J. and Dubayah, R. and Healey, S.P. and Santoro, M. and May, P. and Araza, A. and Bourgoin, C. and Montesano, P.M. and Neigh, C.S.R. and Grantham, H. and Potapov, P. and Turubanova, S. and Tyukavina, A. and Richter, J. and Harris, N. and Urbazaev, M. and Pascual, A. and Suarez, D.R. and Herold, M. and Poulter, B. and Wilson, S.N. and Grassi, G. and Federici, S. and Sanz, M.J. and Melo, J.},
  title = {Intergovernmental Panel on Climate Change (IPCC) Tier 1 forest biomass estimates from Earth Observation},
  journal = {Scientific Data},
  publisher = {Nature Research},
  year = {2024},
  volume = {11},
  number = {1},
  doi = {10.1038/s41597-024-03930-9}
}
Izumi Y, Nico G, Frey O, Baffelli S, Hajnsek I and Sato M (2024), "Kriging-Based Atmospheric Phase Screen Compensation Incorporating Time-Series Similarity in Ground-Based Radar Interferometry", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 17, pp. 17626-17636. Institute of Electrical and Electronics Engineers (IEEE).
Abstract: Accuracy of radar interferometry is often hindered by the atmospheric phase screen (APS). To address this limitation, the geostatistical approach known as Kriging has been employed to predict APS from sparse observations for compensation purposes. In this article, we propose an enhanced Kriging approach to achieve more accurate APS predictions in ground-based radar interferometry applications. Specifically, the Kriging system is augmented with a time-series measure through correlation analysis, effectively leveraging spatio-temporal information for APS prediction. The validity of the introduced Kriging method in the APS compensation framework was tested with Ku-band ground-based radar datasets collected over two different mountainous sites. A comparison of this method with simple Kriging (SK) reveals a noticeable improvement in APS prediction accuracy and temporal phase stability.
BibTeX:
@article{izumiNicoFreyBaffelliHajnsekMotoyukiJSTARS2024KrigingBasedAtmosphericCompensationInGBInterferometry,
  author = {Izumi, Yuta and Nico, Giovanni and Frey, Othmar and Baffelli, Simone and Hajnsek, Irena and Sato, Motoyuki},
  title = {Kriging-Based Atmospheric Phase Screen Compensation Incorporating Time-Series Similarity in Ground-Based Radar Interferometry},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers (IEEE)},
  year = {2024},
  volume = {17},
  pages = {17626--17636},
  doi = {10.1109/jstars.2024.3469158}
}
Kneib M, Dehecq A, Brun F, Karbou F, Charrier L, Leinss S, Wagnon P and Maussion F (2024), "Mapping and characterization of avalanches on mountain glaciers with Sentinel-1 satellite imagery", Cryosphere. Vol. 18(6), pp. 2809-2830. Copernicus Publications.
Abstract: Avalanches are important contributors to the mass balance of glaciers located in mountain ranges with steep topographies. Avalanches result in localized over-accumulation that is seldom accounted for in glacier models due to the difficulty of quantifying this contribution, let alone the occurrence of avalanches in these remote regions. Here, we developed an approach to semi-automatically map avalanche deposits over long time periods and at scales of multiple glaciers, utilizing imagery from Sentinel-1 synthetic aperture radar (SAR). This approach performs particularly well for scenes acquired in winter and in the morning but can also be used to identify avalanche events throughout the year. We applied this method to map 16 302 avalanche deposits over a period of 5 years at a 6 to 12 d interval over the Mt Blanc massif (European Alps), the Everest (central Himalaya) region, and the Hispar (Karakoram) region. These three survey areas are all characterized by steep mountain slopes but also present contrasting climatic characteristics. Our results enable the identification of avalanche hotspots on these glaciers and allow us to quantify the avalanche activity and its spatio-temporal variability across the three regions. The avalanche deposits are preferentially located at lower elevations relative to the hypsometry of the glacierized catchments and are also constrained to a smaller elevation range at the Asian sites, where they have a limited influence on their extensive debris-covered tongues. Avalanche events coincide with solid precipitation events, which explains the high avalanche activity in winter in the Mt Blanc massif and during the monsoon in the Everest region. However, there is also a time lag of 1–2 months, visible especially in the Everest region, between the precipitation and avalanche events, indicative of some snow retention on the mountain headwalls. This study therefore provides critical insights into these mass redistribution processes and tools to account for their influence on glacier mass balance. © Author(s) 2024.
BibTeX:
@article{Kneib2024,
  author = {Kneib, M. and Dehecq, A. and Brun, F. and Karbou, F. and Charrier, L. and Leinss, S. and Wagnon, P. and Maussion, F.},
  title = {Mapping and characterization of avalanches on mountain glaciers with Sentinel-1 satellite imagery},
  journal = {Cryosphere},
  publisher = {Copernicus Publications},
  year = {2024},
  volume = {18},
  number = {6},
  pages = {2809-2830},
  doi = {10.5194/tc-18-2809-2024}
}
Kumawat D, Ebtehaj A, Schwank M, Li X and Wigneron J-P (2024), "Global estimates of L-band vegetation optical depth and soil permittivity of snow-covered boreal forests and permafrost landscape using SMAP satellite data", Remote Sensing of Environment., May, 2024. Vol. 306(114145), pp. 1-17. Elsevier BV.
BibTeX:
@article{kumawat2024global,
  author = {Kumawat, Divya and Ebtehaj, Ardeshir and Schwank, Mike and Li, Xiaojun and Wigneron, Jean-Pierre},
  title = {Global estimates of L-band vegetation optical depth and soil permittivity of snow-covered boreal forests and permafrost landscape using SMAP satellite data},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier BV},
  year = {2024},
  volume = {306},
  number = {114145},
  pages = {1-17},
  doi = {10.1016/j.rse.2024.114145}
}
Manconi A, Jones N, Loew S, Strozzi T, Caduff R and Wegmueller U (2024), "Monitoring surface deformation with spaceborne radar interferometry in landslide complexes: insights from the Brienz/Brinzauls slope instability, Swiss Alps", Landslides. Vol. 21(10), pp. 2519-2533. Springer Science and Business Media Deutschland GmbH.
Abstract: We performed an extensive analysis of C-band SAR datasets provided by the European Space Agency (ESA) satellites ERS-1/2, Envisat ASAR, and Sentinel-1 in the period 1992–2020 aiming at reconstructing the multi-decadal spatial and temporal evolution of the surface displacements at the Brienz/Brinzauls landslide complex, located in canton Graubünden (Switzerland). To this end, we analyzed about 1000 SAR images by applying differential interferometry (InSAR), multitemporal stacking, and persistent scatterer interferometry (PSI) approaches. Moreover, we jointly considered digital image correlation (DIC) on high-resolution multi-temporal digital terrain models (DTM) generated from airborne surveys and InSAR results to compute 3-D surface deformation fields. The extensive network of GNSS stations across the Brienz landslide complex allowed us to extensively validate the deformation results obtained in our remote sensing analyses. Here, we illustrate the limitations occurring when relying on InSAR and/or PSI measurements for the analysis and interpretation of complex landslide scenarios, especially in cases of relevant spatial and temporal heterogeneities of the deformation field. The joint use of InSAR and DIC can deliver a better picture of the evolution of the deformation field, however, not for all displacement components. Since InSAR, PSI and DIC measurements are nowadays routinely used in the framework of local investigations, as well as in regional, national, and/or continental monitoring programs, our results are of major importance for users aiming at a comprehensive understanding of these datasets in landslide scenarios. © The Author(s) 2024.
BibTeX:
@article{Manconi2024,
  author = {Manconi, A. and Jones, N. and Loew, S. and Strozzi, T. and Caduff, R. and Wegmueller, U.},
  title = {Monitoring surface deformation with spaceborne radar interferometry in landslide complexes: insights from the Brienz/Brinzauls slope instability, Swiss Alps},
  journal = {Landslides},
  publisher = {Springer Science and Business Media Deutschland GmbH},
  year = {2024},
  volume = {21},
  number = {10},
  pages = {2519-2533},
  doi = {10.1007/s10346-024-02291-z}
}
Nitze I, Van der Sluijs J, Barth S, Bernhard P, Huang L, Kizyakov A, Lara M, Nesterova N, Runge A, Veremeeva A, Ward Jones M, Witharana C, Xia Z and Liljedahl A (2024), "A Labeling Intercomparison of Retrogressive Thaw Slumps by a Diverse Group of Domain Experts", Permafrost and Periglacial Processes. John Wiley and Sons Ltd.
Abstract: Deep-learning (DL) models have become increasingly beneficial for the detection of retrogressive thaw slumps (RTS) in the permafrost domain. However, comparing accuracy metrics is challenging due to unstandardized labeling guidelines. To address this, we conducted an experiment with 12 international domain experts from a broad range of scientific backgrounds. Using 3 m PlanetScope multispectral imagery, they digitized RTS footprints in two sites. We evaluated label uncertainty by comparing manually outlined RTS labels using Intersection-over-Union (IoU) and F1 metrics. At the Canadian Peel Plateau site, we see good agreement, particularly in the active parts of RTS. Differences were observed in the interpretation of the debris tongue and the stable vegetated sections of RTS. At the Russian Bykovsky site, we observed a larger mismatch. Here, the same differences were documented, but several participants mistakenly identified non-RTS features. This emphasizes the importance of site-specific knowledge for reliable label creation. The experiment highlights the need for standardized labeling procedures and definition of their scientific purpose. The most similar expert labels outperformed the accuracy metrics reported in the literature, highlighting human labeling capabilities with proper training, site knowledge, and clear guidelines. These findings lay the groundwork for DL-based RTS monitoring in the pan-Arctic. © 2024 The Author(s). Permafrost and Periglacial Processes published by John Wiley & Sons Ltd.
BibTeX:
@article{Nitze2024,
  author = {Nitze, I. and Van der Sluijs, J. and Barth, S. and Bernhard, P. and Huang, L. and Kizyakov, A. and Lara, M. and Nesterova, N. and Runge, A. and Veremeeva, A. and Ward Jones, M. and Witharana, C. and Xia, Z. and Liljedahl, A.},
  title = {A Labeling Intercomparison of Retrogressive Thaw Slumps by a Diverse Group of Domain Experts},
  journal = {Permafrost and Periglacial Processes},
  publisher = {John Wiley and Sons Ltd},
  year = {2024},
  doi = {10.1002/ppp.2249}
}
Santoro M, Cartus O, Antropov O and Miettinen J (2024), "Estimation of Forest Growing Stock Volume with Synthetic Aperture Radar: A Comparison of Model-Fitting Methods", Remote Sensing. Vol. 16(21)
Abstract: Satellite-based estimation of forest variables including forest biomass relies on model-based approaches since forest biomass cannot be directly measured from space. Such models require ground reference data to adapt to the local forest structure and acquired satellite data. For wide-area mapping, such reference data are too sparse to train the biomass retrieval model and approaches for calibrating that are independent from training data are sought. In this study, we compare the performance of one such calibration approach with the traditional regression modelling using reference measurements. The performance was evaluated at four sites representative of the major forest biomes in Europe focusing on growing stock volume (GSV) prediction from time series of C-band Sentinel-1 and Advanced Land Observing Satellite Phased Array L-band Synthetic Aperture Radar (ALOS-2 PALSAR-2) backscatter measurements. The retrieval model was based on a Water Cloud Model (WCM) and integrated two forest structural functions. The WCM trained with plot inventory GSV values or calibrated with the aid of auxiliary data products correctly reproduced the trend between SAR backscatter and GSV measurements across all sites. The WCM-predicted backscatter was within the range of measurements for a given GSV level with average model residuals being smaller than the range of the observations. The accuracy of the GSV estimated with the calibrated WCM was close to the accuracy obtained with the trained WCM. The difference in terms of root mean square error (RMSE) was less than 5% units. This study demonstrates that it is possible to predict biomass without providing reference measurements for model training provided that the modelling scheme is physically based and the calibration is well set and understood.
BibTeX:
@article{rs16214079,
  author = {Santoro, Maurizio and Cartus, Oliver and Antropov, Oleg and Miettinen, Jukka},
  title = {Estimation of Forest Growing Stock Volume with Synthetic Aperture Radar: A Comparison of Model-Fitting Methods},
  journal = {Remote Sensing},
  year = {2024},
  volume = {16},
  number = {21},
  url = {https://www.mdpi.com/2072-4292/16/21/4079},
  doi = {10.3390/rs16214079}
}
Santoro M, Cartus O, Quegan S, Kay H, Lucas R, Araza A, Herold M, Labriere N, Chave J, Rosenqvist A, Tadono T, Kobayashi K, Kellndorfer J, Avitabile V, Brown H, Carreiras J, Campbell M, Cavlovic J, Bispo P, Gilani H, Khan M, Kumar A, Lewis S, Liang J, Mitchard E, Pacheco-Pascagaza A, Phillips O, Ryan C, Saikia P, Schepaschenko D, Sukhdeo H, Verbeeck H, Vieilledent G, Wijaya A, Willcock S and Seifert F (2024), "Design and performance of the Climate Change Initiative Biomass global retrieval algorithm", Science of Remote Sensing. Vol. 10 Elsevier B.V..
BibTeX:
@article{Santoro2024,
  author = {Santoro, M. and Cartus, O. and Quegan, S. and Kay, H. and Lucas, R.M. and Araza, A. and Herold, M. and Labriere, N. and Chave, J. and Rosenqvist, A. and Tadono, T. and Kobayashi, K. and Kellndorfer, J. and Avitabile, V. and Brown, H. and Carreiras, J. and Campbell, M.J. and Cavlovic, J. and Bispo, P.D.C. and Gilani, H. and Khan, M.L. and Kumar, A. and Lewis, S.L. and Liang, J. and Mitchard, E.T.A. and Pacheco-Pascagaza, A.M. and Phillips, O.L. and Ryan, C.M. and Saikia, P. and Schepaschenko, D. and Sukhdeo, H. and Verbeeck, H. and Vieilledent, G. and Wijaya, A. and Willcock, S. and Seifert, F.M.},
  title = {Design and performance of the Climate Change Initiative Biomass global retrieval algorithm},
  journal = {Science of Remote Sensing},
  publisher = {Elsevier B.V.},
  year = {2024},
  volume = {10},
  doi = {10.1016/j.srs.2024.100169}
}
Schmid L, Medic T, Frey O and Wieser A (2024), "Target-based georeferencing of terrestrial radar images using TLS point clouds and multi-modal corner reflectors in geomonitoring applications", ISPRS Open Journal of Photogrammetry and Remote Sensing., August, 2024. Vol. 13, pp. 100074. Elsevier BV.
Abstract: Terrestrial Radar Interferometry (TRI) is widely adopted in geomonitoring applications due to its capability to precisely observe surface displacements along the line of sight, among other key characteristics. As its deployment grows, TRI is also increasingly used to monitor smaller and more dispersed geological phenomena, where the challenge is their precise localization in 3d space if the pose of the radar interferometer is not known beforehand. To tackle this challenge, we introduce a semi-automatic target-based georeferencing method for precisely aligning TRI data with 3d point clouds obtained using long-range Terrestrial Laser Scanning (TLS). To facilitate this, we developed a multi-modal corner reflector (mmCR) that serves as a common reference point recognizable by both technologies, and we accompanied it with a semi-automatic data-processing pipeline, including the algorithms for precise center estimation. Experimental validation demonstrated that the corner reflector can be localized within the TLS data with a precision of 3-5 cm and within the TRI data with 1-2 dm. The targets were deployed in a realistic geomonitoring scenario to evaluate the implemented workflow and the achievable quality of georeferencing. The post-georeferencing mapping uncertainty was found to be on a decimeter level, matching the state-of-the-art results using dedicated targets and achieving more than an order of magnitude lower uncertainty than the existing data-driven approaches. In contrast to the existing target-based approaches, our results were achieved without laborious visual data inspection and manual target detection and on significantly larger distances, surpassing 2 kilometers. The use of the developed mmCR and its associated data-processing pipeline extends beyond precise georeferencing of TRI imagery to TLS point clouds, allowing for alternatively georeferencing using total stations, mapping quality evaluation as well as on-site testing and calibrating TRI systems within the application environment.
BibTeX:
@article{schmidMedicFreyWieserISPRS2024GeoreferencingOfTRIUsingTLSPointCloudsAndMultimodalCornerReflectors,
  author = {Lorenz Schmid and Tomislav Medic and Othmar Frey and Andreas Wieser},
  title = {Target-based georeferencing of terrestrial radar images using TLS point clouds and multi-modal corner reflectors in geomonitoring applications},
  journal = {ISPRS Open Journal of Photogrammetry and Remote Sensing},
  publisher = {Elsevier BV},
  year = {2024},
  volume = {13},
  pages = {100074},
  url = {https://www.sciencedirect.com/science/article/pii/S2667393224000188},
  doi = {10.1016/j.ophoto.2024.100074}
}
Schwank M, Zhou Y, Mialon A, Richaume P, Kerr Y and Mätzler C (2024), "Temperature dependence of L-band vegetation optical depth over the boreal forest from 2011 to 2022", Remote Sensing of Environment. Vol. 315 Elsevier Inc..
BibTeX:
@article{Schwank2024a,
  author = {Schwank, M. and Zhou, Y. and Mialon, A. and Richaume, P. and Kerr, Y. and Mätzler, C.},
  title = {Temperature dependence of L-band vegetation optical depth over the boreal forest from 2011 to 2022},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2024},
  volume = {315},
  doi = {10.1016/j.rse.2024.114470}
}
Shehaj E, Frey O, Moeller G, Strozzi T, Geiger A and Rothacher M (2024), "On the consistency of tropospheric delays over mountainous terrain retrieved from Persistent Scatterer Interferometry, GNSS and Numerical Weather Prediction models", IEEE Trans. Geosci. Remote Sens.. Vol. 62(4101018), pp. 1-18. Institute of Electrical and Electronics Engineers (IEEE).
Abstract: The tropospheric refraction along the signal path is the same for GNSS and radar interferometry. However, different observation geometries, spatio-temporal sampling, signal processing methods, as well as signal wavelengths yield rather complementary measurements. The origin of this research is the question whether tropospheric delays retrieved at GNSS permanent stations can support PSI processing for the retrieval of surface displacement in mountainous terrain, which is challenging because of spatial gaps due to radar layovers, shadowing and temporal decorrelation in combination with strong variations of water vapor. We analyze maps of tropospheric path delays obtained by collocation of GNSS-estimated delays and by PSI processing of an interferometric stack of Cosmo SkyMed X-band SAR data in a mountainous region in the Valais, Switzerland. We aim to assess the consistency and differences among the datasets to better understand their ability for sensing small-scale structures in the lower atmosphere. In addition, we compare them with maps of tropospheric path delays derived from COSMO-2 numerical weather model (NWM) data. We investigate several factors affecting the interpolation of the GNSS zenith delays to the locations of the persistent scatterers, such as assumptions in the collocation, network size and resolution. We assessed meteorological parameters of the NWM to find potential correlations between specific meteorological conditions and different levels of (dis)agreement of delay maps; a clear correlation was not found. We found that the delays estimated from collocated GNSS measurements and PSI tend to have a different dependency on the terrain altitude. The PSI-derived path delays obtained from the X-band SAR data stack capture small-scale spatial variations also visible in NWM delay maps, whereas, at a larger scale, mismatches are found. It appears that the current GNSS network in the mountainous area of the Valais is not dense enough to capture strongly varying tropospheric refraction. We can conclude that denser networks (with a resolution of 5-10 km) in the InSAR footprint region and a careful choice of the assumptions in our interpolation method would make GNSS more suitable for helping PSI processing.
BibTeX:
@article{shehajFreyMoellerStrozziGeigerRothacherTGRS2023ConsistencyOfTroposphericDelaysFromPSIandGNSSandNWP,
  author = {Shehaj, Endrit and Frey, Othmar and Moeller, Gregor and Strozzi, Tazio and Geiger, Alain and Rothacher, Markus},
  title = {On the consistency of tropospheric delays over mountainous terrain retrieved from Persistent Scatterer Interferometry, GNSS and Numerical Weather Prediction models},
  journal = {IEEE Trans. Geosci. Remote Sens.},
  publisher = {Institute of Electrical and Electronics Engineers (IEEE)},
  year = {2024},
  volume = {62},
  number = {4101018},
  pages = {1-18},
  doi = {10.1109/TGRS.2023.3344277}
}
Shukla S, Wouters B, Picard G, Wever N, Izeboud M, Husman S, Kausch T, Veldhuijsen S, Matzler C and Lhermitte S (2024), "Large Variability in Dominant Scattering From Sentinel-1 SAR in East Antarctica: Challenges and Opportunities", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 17, pp. 14380-14393. Institute of Electrical and Electronics Engineers Inc..
Abstract: Assessing the Surface Mass Balance (SMB) of the Antarctic Ice Sheet is crucial for understanding its response to climate change. Synthetic Aperture Radar observations from Sentinel-1 provide the potential to monitor the variability of SMB processes through changes in the scattering response of near-surface and internal snow layers. However, the interplay between several factors, such as accumulation, wind erosion, deposition, and melt, complicates the interpretation of scattering changes of the microwave signal. Additionally, lack of reliable ground truth measurements of the snow surface limits our capability to associate the SMB processes with dominant scattering mechanism. In this study, we aim to quantify the dominant scattering in Sentinel-1 signal and evaluate the scattering changes in drifting snow-dominated regions of East Antarctica. We introduce a scattering indicator, alpha -textscat,varepsilon , derived from scattering-type and entropy descriptors, providing a measure between volume and pure scattering. By relating the field measurements to alpha -textscat,varepsilon , we establish that the evolution of dominant scattering in the presence of snowdrift is complex. First, alpha -textscat,varepsilon strongly correlates with surface roughness (R^2=0.92, RMSE =2^circ). Spatially variable erosion patterns significantly increase the roughness and result in a strong affinity towards pure scattering despite net accumulation. Second, high surface densities also tend to influence pure scattering; however, the effect is dependent on the accumulation rate. With more accumulation, we observe an increasing dominance of volume scattering from internal snow layers. Long-term trends in alpha -textscat,varepsilon (2017/2023) further suggest that it is challenging to address the causes behind the scattering source based on a single snow surface process. We thus demonstrate the potential and limitations of alpha -textscat,varepsilon to infer the variability in dominant scattering from changes in surface processes. © 2008-2012 IEEE.
BibTeX:
@article{Shukla2024,
  author = {Shukla, S. and Wouters, B. and Picard, G. and Wever, N. and Izeboud, M. and Husman, S.D.R. and Kausch, T. and Veldhuijsen, S. and Matzler, C. and Lhermitte, S.},
  title = {Large Variability in Dominant Scattering From Sentinel-1 SAR in East Antarctica: Challenges and Opportunities},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2024},
  volume = {17},
  pages = {14380-14393},
  doi = {10.1109/JSTARS.2024.3438233}
}
Stefko M, Bernhard P, Frey O and Hajnsek I (2024), "Polarimetric analysis of bi-seasonal monostatic and bistatic radar observations of a glacier accumulation zone at Ku-band", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 17, pp. 9706-9727.
Abstract: We present ground-based Ku-band radar observations of the snow cover on top of the Great Aletsch Glacier carried out over two observation periods, in August 2021 and in March 2022. The observations were carried out with the combined mono/bistatic version of KAPRI, a full-polarimetric radar system, and revealed substantial differences between the scattering behaviour of the snow cover between the two seasons. We analyze the spatial and temporal behaviour of parameters including temporal decorrelation, the scattering entropy, the mean polarimetric alpha angle, and the co- and cross-polarized phase differences. The results indicate that snow cover decorrelates at Ku-band on the timescales of 4-12 hours in winter and summer, which has implications for repeat-pass methods with long temporal baselines. The analysis of the co-polarized phase difference in winter indicates that the parameter is prone to phase wrapping. In summer, its value exhibits smooth spatial trend and a strong sensitivity to changes in incidence angle and liquid water content. The bistatic cross-polarized phase difference also acquires a non-zero value, indicating the presence of non-reciprocal scattering, which has implications for possible calibration procedures of bistatic systems. The presented results aim to serve as a reference for snow scattering behaviour at Ku-band, which can aid planning of future data acquisition campaigns and satellite missions.
BibTeX:
@article{stefkoBernhardFreyHajnsekJSTARS2024PolAnalysisGfMonoAndBistaticRadarObsOfGlacierAtKuBand,
  author = {Stefko, Marcel and Bernhard, Philipp and Frey, Othmar and Hajnsek, Irena},
  title = {Polarimetric analysis of bi-seasonal monostatic and bistatic radar observations of a glacier accumulation zone at Ku-band},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  year = {2024},
  volume = {17},
  pages = {9706-9727},
  doi = {10.1109/JSTARS.2024.3374051}
}
Strozzi T, Jones N, Caduff R and Wegmüller U (2024), "L-Band DInSAR Surface Motion Products in Alpine Regions with SAOCOM", In IGARSS 2024 - 2024 IEEE International Geoscience and Remote Sensing Symposium., July, 2024. , pp. 10740-10743.
Abstract: The Alps are prone to a variety of slope deformations. Precise information on the surface displacement of these phenomena is important to analyse and interpret the associated hazard potential. Satellite SAR interferometry is an attractive technology for monitoring surface deformation in large areas, and is now entering an advanced operational phase triggered by the increasing availability of satellite data, in particular Sentinel-1. However, C-band sensors have limited performance in vegetated areas and for comparatively large movement rates (e.g., a few cm/year). In these cases, L-band satellites can complement the high-frequency systems. Here we evaluate the performance of the Argentinian L-band SAOCOM mission for monitoring slope deformation in Alpine regions using standard differential interferograms and time series analysis. Despite the limited number of SAOCOM acquisitions to date and the much larger orbital tube of SAOCOM compared to other current SAR satellite missions, we were able to demonstrate the excellent performance of the Argentinian L-band mission in three different cases. With regular acquisitions every 16 to 32 days and the open distribution policy, SAOCOM can soon be established as an operational and efficient tool for the systematic monitoring of surface movements in Alpine regions, complementing the nationwide maps of land deformation developed based on the regular acquisitions of Sentinel-1 data since 2014.
BibTeX:
@inproceedings{10642327,
  author = {Strozzi, Tazio and Jones, Nina and Caduff, Rafael and Wegmüller, Urs},
  title = {L-Band DInSAR Surface Motion Products in Alpine Regions with SAOCOM},
  booktitle = {IGARSS 2024 - 2024 IEEE International Geoscience and Remote Sensing Symposium},
  year = {2024},
  pages = {10740-10743},
  doi = {10.1109/IGARSS53475.2024.10642327}
}
Wegmüller U, Magnard C and Frey O (2024), "Assessment of Hongtu-1 Multi-Static X-Band SAR Constellation Interferometry", Remote Sensing., September, 2024. Vol. 16(19), pp. 3600. MDPI AG.
Abstract: In 2023, the Chinese company PIESAT launched the multi-static X-band SAR constellation Hongtu-1 (HT1). HT1 consists of the active monostatic SAR sensor HT1-A and the three additional passive SAR receivers HT1-B, HT1-C and HT1-D. The passive sensors are arranged as a cartwheel in a circle around the active sensor. For our SAR interferometric investigation, we were able to use a multi-static HT1 recording. After a brief introduction of HT1, we describe the processing performed. Based on the phases of the six single-pass interferometric pairs, we calculated height differences relative to the Copernicus DEM. Larger deviations were observed mainly for mining areas and for forest areas. Thanks to the simultaneous acquisition of the interferometric pairs, the high spatial resolution and the good signal quality, the necessary processing was relatively easy to perform. Besides the interferometric phase, we also investigated possible applications of multi-static coherence. Forest can be recognized by its reduced single-pass coherence values. Based on our results, we expect that the multi-static HT1 coherence and its dependence on the interferometric baseline can be used to estimate parameters such as forest biomass.
BibTeX:
@article{wegmullerMagnardFreyMdpiRS2024Hongtu1MultistaticXBandInSAR,
  author = {Wegmüller, Urs and Magnard, Christophe and Frey, Othmar},
  title = {Assessment of Hongtu-1 Multi-Static X-Band SAR Constellation Interferometry},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2024},
  volume = {16},
  number = {19},
  pages = {3600},
  url = {https://www.mdpi.com/2072-4292/16/19/3600},
  doi = {10.3390/rs16193600}
}
Wegmüller U, Magnard C, Strozzi T, Caduff R and Jones N (2024), "Landslide velocity mapping using ALOS-2 PALSAR-2 ScanSAR data", Procedia Computer Science. Vol. 239, pp. 2278-2285. Elsevier B.V..
Abstract: This work discusses landslide velocity mapping in the Swiss Alps using ALOS-2 PALSAR-2 ScanSAR differential interferometry and interferometric time series analyses based on small data stacks of about 10 images over eight years. A wide area coverage is possible due to the 350km swath width of the ScanSAR data. In our processing sequence we resampled the sub-swath SLCs to a common spatial grid. The co-registered sub-swath SLCs were mosaiced into large co-registered mosaic SLCs. We then applied normal procedures also used for stripmap mode data to generate differential interferograms and conduct a Persistent Scatterer Interferometry (PSI) processing. The results obtained over the Swiss Alps provide a good spatial coverage, with line-of-sight displacement velocities also extracted for some landslides in forested areas. The future applicability of the technique is very promising with upcoming L-band SAR missions (NISAR, ROSE-L and PALSAR-3) that provide data of even better suitability - higher spatial resolution, shorter revisit time intervals, and free and open data access. © 2024 The Author(s). Published by Elsevier B.V.
BibTeX:
@conference{Wegmuller2024,
  author = {Wegmüller, U. and Magnard, C. and Strozzi, T. and Caduff, R. and Jones, N.},
  title = {Landslide velocity mapping using ALOS-2 PALSAR-2 ScanSAR data},
  journal = {Procedia Computer Science},
  publisher = {Elsevier B.V.},
  year = {2024},
  volume = {239},
  pages = {2278-2285},
  doi = {10.1016/j.procs.2024.06.419}
}
Wegmüller U, Werner C, Frey O and Magnard C (2024), "Estimation and Compensation of the Ionospheric Path Delay Phase in PALSAR-3 and NISAR-L Interferograms", Atmosphere., May, 2024. Vol. 15(6), pp. 632. MDPI AG.
Abstract: Spatial and temporal variation in the free electron concentration in the ionosphere affects SAR interferograms, in particular at low radar frequencies. In this work, the identification, estimation, and compensation of ionospheric path delay phases in PALSAR-3 and NISAR-L interferograms are discussed. Both of these L-band sensors simultaneously acquire SAR data in a main spectral band and in an additional, spectrally separated, narrower second band to support the mitigation of ionospheric path delays. The methods presented permit separating the dispersive and the non-dispersive phase terms based on the double-difference interferogram between the two available spectral bands and the differential interferogram of the main band. The applicability of the proposed methods is demonstrated using PALSAR-3-like data that were simulated based on PALSAR-2 SM1 mode data.
BibTeX:
@article{wegmullerEtAlAtmosphere2024EstimationOfIonosphericPathDelayPhaseInPALSAR3andNISARInterferograms,
  author = {Wegmüller, Urs and Werner, Charles and Frey, Othmar and Magnard, Christophe},
  title = {Estimation and Compensation of the Ionospheric Path Delay Phase in PALSAR-3 and NISAR-L Interferograms},
  journal = {Atmosphere},
  publisher = {MDPI AG},
  year = {2024},
  volume = {15},
  number = {6},
  pages = {632},
  doi = {10.3390/atmos15060632}
}
Zhao Z, Ciais P, Wigneron J-P, Santoro M, Brandt M, Kleinschroth F, Lewis S, Chave J, Fensholt R, Laporte N, Sonwa D, Saatchi S, Fan L, Yang H, Li X, Wang M, Zhu L, Xu Y, He J and Li W (2024), "Central African biomass carbon losses and gains during 2010-2019", One Earth. Vol. 7(3), pp. 506-519. Cell Press.
Abstract: Disturbance, vegetation productivity, and recovery are crucial for aboveground biomass carbon (AGC) dynamics. Here, we use multiple satellite-based datasets to analyze the drivers of AGC dynamics in Central Africa. During 2010–2019, deforestation induced a gross AGC loss of 102.2 ± 17.1 Tg C year−1, which was counterbalanced by an AGC increase of 116.9 ± 41.1 Tg C year−1, leading to a net gain of 14.6 ± 3.8 Tg C year−1. Compared to anthropogenic and soil factors, changes in climate-related factors (e.g., radiation) are more important for the non-deforestation AGC changes. A large AGC increase was found in the northern savannas. In moist forests, strong biomass recovery and growth largely compensated the carbon loss from deforestation and degradation. Considering the increasing resource demand due to rapid population growth, reconciling natural conservation and economic development in Central Africa remains challenging and depends on climate changes and country-specific social-economic conditions. © 2024 Elsevier Inc.
BibTeX:
@article{Zhao2024,
  author = {Zhao, Z. and Ciais, P. and Wigneron, J.-P. and Santoro, M. and Brandt, M. and Kleinschroth, F. and Lewis, S.L. and Chave, J. and Fensholt, R. and Laporte, N. and Sonwa, D.J. and Saatchi, S.S. and Fan, L. and Yang, H. and Li, X. and Wang, M. and Zhu, L. and Xu, Y. and He, J. and Li, W.},
  title = {Central African biomass carbon losses and gains during 2010-2019},
  journal = {One Earth},
  publisher = {Cell Press},
  year = {2024},
  volume = {7},
  number = {3},
  pages = {506-519},
  doi = {10.1016/j.oneear.2024.01.021}
}
Zhou Y, Schwank M, Kurum M, Houtz D, Zhao Q, Lang R, Mialon A and Drusch M (2024), "Microwave Emission Model for Layered Vegetation (MEMLV): An Exemplary Study for Coniferous Forests from P- to Ka-Band", IEEE Transactions on Geoscience and Remote Sensing. IEEE.
BibTeX:
@article{zhou2024microwave,
  author = {Zhou, Yiwen and Schwank, Mike and Kurum, Mehmet and Houtz, Derek and Zhao, Qianyi and Lang, Roger and Mialon, Arnaud and Drusch, Matthias},
  title = {Microwave Emission Model for Layered Vegetation (MEMLV): An Exemplary Study for Coniferous Forests from P- to Ka-Band},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {IEEE},
  year = {2024},
  note = {(Early Access)},
  doi = {10.1109/TGRS.2024.3491218}
}
Zwieback S, Liu L, Rouyet L, Short N and Strozzi T (2024), "Advances in InSAR Analysis of Permafrost Terrain", Permafrost and Periglacial Processes. Vol. 35(4), pp. 544-556. John Wiley and Sons Ltd.
Abstract: Differential interferometric synthetic aperture radar (InSAR) is a remote sensing technique for measuring surface displacements with precision down to millimeters, most commonly from satellites. In permafrost landscapes, InSAR measurements can provide valuable information on geomorphic processes and hazards, including thaw subsidence and frost heave, thermokarst, and permafrost creep. We first review recent progress in InSAR data availability, InSAR processing and uncertainty analysis methods relevant to permafrost studies. These technical advances have contributed to our understanding of surface deformation in flat and sloping terrain in polar and mountainous regions. We emphasize two emerging trends. First, InSAR increasingly enables insight into the mechanisms, controls, and drivers of permafrost landscape dynamics on subseasonal to decadal time scales. Second, InSAR observations in conjunction with models enable novel ways to infer subsurface parameters, such as near-surface ground ice content and active layer thickness. We anticipate that in the coming decade, InSAR will mature into a widely used operational tool for monitoring, modeling, and planning across rapidly changing permafrost landscapes. © 2024 His Majesty the King in Right of Canada and The Author(s). Permafrost and Periglacial Processes published by John Wiley & Sons Ltd. Reproduced with the permission of the Minister of Natural Resources of Canada.
BibTeX:
@article{Zwieback2024,
  author = {Zwieback, S. and Liu, L. and Rouyet, L. and Short, N. and Strozzi, T.},
  title = {Advances in InSAR Analysis of Permafrost Terrain},
  journal = {Permafrost and Periglacial Processes},
  publisher = {John Wiley and Sons Ltd},
  year = {2024},
  volume = {35},
  number = {4},
  pages = {544-556},
  doi = {10.1002/ppp.2248}
}
Araza A, Herold M, de Bruin S, Ciais P, Gibbs D, Harris N, Santoro M, Wigneron J-P, Yang H, Malaga N, Nesha K, Rodriguez-Veiga P, Brovkina O, Brown H, Chanev M, Dimitrov Z, Filchev L, Fridman J, Garcia M, Gikov A, Govaere L, Dimitrov P, Moradi F, Muelbert A, Novotny J, Pugh T, Schelhaas M-J, Schepaschenko D, Sterenczak K and Hein L (2023), "Past decade above-ground biomass change comparisons from four multi-temporal global maps", International Journal of Applied Earth Observation and Geoinformation. Vol. 118 Elsevier B.V..
Abstract: Above-ground biomass (AGB) is considered an essential climate variable that underpins our knowledge and information about the role of forests in mitigating climate change. The availability of satellite-based AGB and AGB change (AGB) products has increased in recent years. Here we assessed the past decade net AGB derived from four recent global multi-date AGB maps: ESA-CCI maps, WRI-Flux model, JPL time series, and SMOS-LVOD time series. Our assessments explore and use different reference data sources with biomass re-measurements within the past decade. The reference data comprise National Forest Inventory (NFI) plot data, local AGB maps from airborne LiDAR, and selected Forest Resource Assessment country data from countries with well-developed monitoring capacities. Map to reference data comparisons were performed at levels ranging from 100 m to 25 km spatial scale. The comparisons revealed that LiDAR data compared most reasonably with the maps, while the comparisons using NFI only showed some agreements at aggregation levels <10 km. Regardless of the aggregation level, AGB losses and gains according to the map comparisons were consistently smaller than the reference data. Map-map comparisons at 25 km highlighted that the maps consistently captured AGB losses in known deforestation hotspots. The comparisons also identified several carbon sink regions consistently detected by all maps. However, disagreement between maps is still large in key forest regions such as the Amazon basin. The overall AGB map cross-correlation between maps varied in the range 0.11 0.29 (r). Reported AGB magnitudes were largest in the high-resolution datasets including the CCI map differencing (stock change) and Flux model (gain-loss) methods, while they were smallest according to the coarser-resolution LVOD and JPL time series products, especially for AGB gains. Our results suggest that AGB assessed from current maps can be biased and any use of the estimates should take that into account. Currently, AGB reference data are sparse especially in the tropics but that deficit can be alleviated by upcoming LiDAR data networks in the context of Supersites and GEO-Trees.
BibTeX:
@article{Araza2023,
  author = {Araza, A. and Herold, M. and de Bruin, S. and Ciais, P. and Gibbs, D.A. and Harris, N. and Santoro, M. and Wigneron, J.-P. and Yang, H. and Malaga, N. and Nesha, K. and Rodriguez-Veiga, P. and Brovkina, O. and Brown, H.C.A. and Chanev, M. and Dimitrov, Z. and Filchev, L. and Fridman, J. and Garcia, M. and Gikov, A. and Govaere, L. and Dimitrov, P. and Moradi, F. and Muelbert, A.E. and Novotny, J. and Pugh, T.A.M. and Schelhaas, M.-J. and Schepaschenko, D. and Sterenczak, K. and Hein, L.},
  title = {Past decade above-ground biomass change comparisons from four multi-temporal global maps},
  journal = {International Journal of Applied Earth Observation and Geoinformation},
  publisher = {Elsevier B.V.},
  year = {2023},
  volume = {118},
  doi = {10.1016/j.jag.2023.103274}
}
Bartsch A, Strozzi T and Nitze I (2023), "Permafrost Monitoring from Space", Surveys in Geophysics. Vol. 44(5), pp. 1579-1613. Springer Science and Business Media B.V..
Abstract: Permafrost is a sub-ground phenomenon and therefore cannot be directly observed from space. It is an Essential Climate Variable and associated with climate tipping points. Multi-annual time series of permafrost ground temperatures can be, however, derived through modelling of the heat transfer between atmosphere and ground using landsurface temperature, snow- and landcover observations from space. Results show that the northern hemisphere permafrost ground temperatures have increased on average by about one degree Celsius since 2000. This is in line with trends of permafrost proxies observable from space: surface water extent has been decreasing across the Arctic; the landsurface is subsiding continuously in some regions indicating ground ice melt; hot summers triggered increased subsidence as well as thaw slumps; rock glaciers are accelerating in some mountain regions. The applicability of satellite data for permafrost proxy monitoring has been demonstrated mostly on a local to regional scale only. There is still a lack of consistency of acquisitions and of very high spatial resolution observations. Both are needed for implementation of circumpolar monitoring of lowland permafrost. In order to quantify the impacts of permafrost thaw on the carbon cycle, advancement in wetland and atmospheric greenhouse gas concentration monitoring from space is needed. © 2023, The Author(s).
BibTeX:
@article{Bartsch20231579,
  author = {Bartsch, A. and Strozzi, T. and Nitze, I.},
  title = {Permafrost Monitoring from Space},
  journal = {Surveys in Geophysics},
  publisher = {Springer Science and Business Media B.V.},
  year = {2023},
  volume = {44},
  number = {5},
  pages = {1579-1613},
  doi = {10.1007/s10712-023-09770-3}
}
Bernhard P, Haener D and Frey O (2023), "Persistent Scatterer Interferometry to Detect Railway Track Anomalies using TerraSAR-X Observations", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1838-1841. IEEE.
Abstract: This study investigates the potential of space-borne SyntheticAperture Radar Interferometry for efficient detection of trackanomalies using the Swiss Federal Railways (SBB) railway network as an example. The condition of the ballast substructure is crucial for track service life, and moisture accumulation is a primary cause of deterioration and can manifest itself by subsidence. Current operational methods for track condition assessment have limitations, and remote sensing techniques offer a promising alternative. Using a time-series of TerraSAR-X observations, we performed a persistent scatterer interferometry (PSI) analysis to estimate surface deformations and further analysed the deformation rates and variability along a 22 km track section in Switzerland. The study explores the hypothesis that the variability of PSI-derived deformation estimates along the railway track can be related to longitudinal height measurements from track geometry vehicles. When compared with chord-based measurements from SBB, our preliminary results showed a promising correlation,suggesting that the variability in deformation measurement scan indeed be linked to longitudinal height measurements obtained from track geometry vehicles. If proven effective, a satellite-based evaluation method could significantly reduce resources required for railway infrastructure maintenance.
BibTeX:
@inproceedings{bernhardHaenerFreyIGARSS2023PSIbasedDetectionOfRailwayTrackAnomalies,
  author = {Bernhard, Philipp and Haener, David and Frey, Othmar},
  title = {Persistent Scatterer Interferometry to Detect Railway Track Anomalies using TerraSAR-X Observations},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE},
  year = {2023},
  pages = {1838-1841},
  doi = {10.1109/IGARSS52108.2023.10283221}
}
Borlaf-Mena I, Garcia-Duro J, Santoro M, Villard L, Badea O and Tanase M (2023), "Seasonality and directionality effects on radar backscatter are key to identify mountain forest types with Sentinel-1 data", Remote Sensing of Environment. Vol. 296 Elsevier Inc..
Abstract: Systematic Sentinel-1 acquisitions provide an unprecedented stream of SAR data which allows to describe forest temporal dynamics in detail, a powerful tool for phenological studies and forest type classification. Several studies have explored the temporal variation of backscatter intensity in this context, but none considered that scattering directionality of canopies may vary. Said directionality is related to target-sensor geometry (incidence angle), forest height, and optical depth, associated with leaf dynamics. This study explicitly models backscatter dependance on incidence angle by fitting a regression model for each Sentinel-1 image and forest type. Residuals are accumulated across the time series and used to classify pixels into the most likely forest type using the smallest accumulated residual. This modelling and classification strategy has been applied over a North-South transect across the Carpathian Mountains, including forests with different physiognomies, from deciduous broadleaf forest, to mixed broadleaf-needleleaf and pure perennial needleleaf forests. These forests were classified with increasing detail, assessing the results against in-situ forest stand data and satellite-based land cover classification products (Copernicus Forest type layer). The accuracy of our classification was K > 0.8, OA > 90% when separating broadleaf from needleleaf forest types. The accuracy decreased (K > 0.6, OA > 79%) when also separating mixed forest types. Our results suggest that incorporating directional effects into classification models can improve SAR-based forest classification of temperate forest over mountainous terrain. Furthermore, models fitted between backscatter and incidence angle provide an estimate of n, a parameter related to optical depth that has been shown to vary with leaf dynamics. ncould be used to improve image normalization in studies aiming at the estimation of biomass, or to aid the estimation of fast-changing parameters such as leaf area index or leaf moisture content. © 2023 Elsevier Inc.
BibTeX:
@article{Borlaf-Mena2023,
  author = {Borlaf-Mena, I. and Garcia-Duro, J. and Santoro, M. and Villard, L. and Badea, O. and Tanase, M.A.},
  title = {Seasonality and directionality effects on radar backscatter are key to identify mountain forest types with Sentinel-1 data},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2023},
  volume = {296},
  doi = {10.1016/j.rse.2023.113728}
}
Brun F, King O, Reveillet M, Amory C, Planchot A, Berthier E, Dehecq A, Bolch T, Fourteau K, Brondex J, Dumont M, Mayer C, Leinss S, Hugonnet R and Wagnon P (2023), "Everest South Col Glacier did not thin during the period 1984-2017", Cryosphere. Vol. 17(8), pp. 3251-3268. Copernicus Publications.
Abstract: The South Col Glacier is a small body of ice and snow (approx. 0.2ĝ€¯km2) located at the very high elevation of 8000ĝ€¯mĝ€¯a.s.l. (above sea level) on the southern ridge of Mt. Everest. A recent study by proposed that South Col Glacier is rapidly losing mass. This is in contradiction to our comparison of two digital elevation models derived from aerial photographs taken in December 1984 and a stereo Pléiades satellite acquisition from March 2017, from which we estimate a mean elevation change of 0.01ĝ€¯±ĝ€¯0.05ĝ€¯mĝ€¯a-1. To reconcile these results, we investigate some aspects of the surface energy and mass balance of South Col Glacier. From satellite images and a simple model of snow compaction and erosion, we show that wind erosion has a major impact on the surface mass balance due to the strong seasonality in precipitation and wind and that it cannot be neglected. Additionally, we show that the melt amount predicted by a surface energy and mass balance model is very sensitive to the model structure and implementation. Contrary to previous findings, melt is likely not a dominant ablation process on this glacier, which remains mostly snow-covered during the monsoon. © Copyright:
BibTeX:
@article{Brun20233251,
  author = {Brun, F. and King, O. and Reveillet, M. and Amory, C. and Planchot, A. and Berthier, E. and Dehecq, A. and Bolch, T. and Fourteau, K. and Brondex, J. and Dumont, M. and Mayer, C. and Leinss, S. and Hugonnet, R. and Wagnon, P.},
  title = {Everest South Col Glacier did not thin during the period 1984-2017},
  journal = {Cryosphere},
  publisher = {Copernicus Publications},
  year = {2023},
  volume = {17},
  number = {8},
  pages = {3251-3268},
  doi = {10.5194/tc-17-3251-2023}
}
Deeb EJ, Meehan TG, O'Neel S, Keskinen Z, Werner C, Forster R, Frey O and LeWinter A (2023), "Investigations of ground-based mobile L-band InSAR phase response to the application of soil moisture on a high-desert grassland", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Pasadena, July, 2023. , pp. 2691-2692. IEEE.
Abstract: In an agricultural river valley in central Idaho, USA, weconducted a case study to investigate interferometric synthetic aperture (InSAR) coherence and phase response as an indication of soil moisture change. Throughout a 3-day observational campaign, repeated observations were acquired from a mobile vehicle with a multi-polarization L-band (1.6GHz) InSAR system, first prior to controlled irrigation and then during a dry-out period. Here, we present results that show the time series of coherence and phase in coordination with in-situ soil moisture observations at two depths over the three days of the controlled experiment. During the subsequent dry out period, the time series of interferometric coherence shows an immediate degradation of the signal with a subsequent improvement. The in-situ soil moisture observations highlight this transition of controlled irrigation to subsequent drying out of the soils. We anticipate future work to include investigation of the interferometric times series of phase change as it relates to quantitative changes in soil moisture.
BibTeX:
@inproceedings{deebEtAl2023CarborneLBandSARSoilMoisture,
  author = {Deeb, Elias J. and Meehan, Tate G. and O'Neel, Shad and Keskinen, Zachary and Werner, Charles and Forster, Richard and Frey, Othmar and LeWinter, Adam},
  title = {Investigations of ground-based mobile L-band InSAR phase response to the application of soil moisture on a high-desert grassland},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE},
  year = {2023},
  pages = {2691-2692},
  doi = {10.1109/IGARSS52108.2023.10282878}
}
Fan N, Santoro M, Besnard S, Cartus O, Koirala S and Carvalhais N (2023), "Implications of the steady-state assumption for the global vegetation carbon turnover", Environmental Research Letters. Vol. 18(10) Institute of Physics.
Abstract: Vegetation carbon turnover time (τ) is a central ecosystem property to quantify the global vegetation carbon dynamics. However, our understanding of vegetation dynamics is hampered by the lack of long-term observations of the changes in vegetation biomass. Here we challenge the steady state assumption of τ by using annual changes in vegetation biomass that derived from remote-sensing observations. We evaluate the changes in magnitude, spatial patterns, and uncertainties in vegetation carbon turnover times from 1992 to 2016. We found the robustness in the steady state assumption for forest ecosystems at large spatial scales, contrasting with local larger differences at the grid cell level between τ under steady state and τ under non-steady state conditions. The observation that terrestrial ecosystems are not in a steady state locally is deemed crucial when studying vegetation dynamics and the potential response of biomass to disturbance and climatic changes. © 2023 The Author(s). Published by IOP Publishing Ltd
BibTeX:
@article{Fan2023,
  author = {Fan, N. and Santoro, M. and Besnard, S. and Cartus, O. and Koirala, S. and Carvalhais, N.},
  title = {Implications of the steady-state assumption for the global vegetation carbon turnover},
  journal = {Environmental Research Letters},
  publisher = {Institute of Physics},
  year = {2023},
  volume = {18},
  number = {10},
  doi = {10.1088/1748-9326/acfb22}
}
Freihardt J and Frey O (2023), "Assessing riverbank erosion in Bangladesh using time series of Sentinel-1 radar imagery in the Google Earth Engine", Nat. Hazards Earth Syst. Sci.,. Vol. 23, pp. 751-770.
Abstract: Riverbank erosion occurs along many of the Earth's river systems, affecting riverine populations by destroying agricultural land and housing. In this study, we detected past events of riverbank erosion along the Jamuna River in Bangladesh using time series of Sentinel-1 satellite radar imagery, ground-range-detected (GRD) data with a 12 d revisit cycle, available in the Google Earth Engine (GEE). Eroded land is detected by performing a land cover classification and by detecting land cover changes from vegetated areas before the monsoon to sand or water after the monsoon. Further, settlements are detected as persistent scatterers and classified as eroded if they are located on eroded land. We found that with Sentinel-1 data, erosion locations can be determined already 1 month after the end of the monsoon and hence potentially earlier than using optical satellite images which depend on cloud-free daylight conditions. Further, we developed an interactive GEE-based online tool allowing the user to explore where riverbank erosion has destroyed land and settlements along the Jamuna in five monsoon seasons (2015-2019). The source code of our implementation is publicly available, providing the opportunity to reproduce the results, to adapt the algorithm and to transfer our results to assess riverbank erosion in other geographical settings.
BibTeX:
@article{freihardtFreyNHESS2023RiverbankErosionBangladeshSentinel1GoogleEarthEngine,
  author = {Freihardt, Jan and Frey, Othmar},
  title = {Assessing riverbank erosion in Bangladesh using time series of Sentinel-1 radar imagery in the Google Earth Engine},
  journal = {Nat. Hazards Earth Syst. Sci.,},
  year = {2023},
  volume = {23},
  pages = {751--770},
  url = {https://nhess.copernicus.org/articles/23/751/2023/},
  doi = {10.5194/nhess-23-751-2023}
}
Frey O, Werner C and Caduff R (2023), "Car-borne Mobile Mapping of Ground Motion by Means of Repeat-Pass SAR Interferometry: Case Studies and Application Development Based on L-Band and Ku-band SAR Data Acquisitions", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Pasadena, July, 2023. , pp. 1902-1905. IEEE.
Abstract: Ground-motion-related geohazards are omnipresent in alpine areas. Time series of spaceborne SAR data are routinely used to assess surface displacement with large coverage. However, there are also many cases and expositions for which terrestrial radar systems are more suitable to obtain measurements of ground motion. Observing a mountain slope from a moving car or a UAV and thereby spanning a much longer synthetic aperture allows using also lower frequencies, such as L-band, with good spatial resolution. In addition, if aperture synthesis using a mobile mapping SAR system is employed at higher frequencies, the azimuth resolution can also be further improved compared to the azimuth resolution of (quasi-) stationary radar system at larger range distances of several kilometers. In this contribution,we report case studies that we are conducting to further develop and consolidate ground motion mapping by means of our carborne DInSAR system as an operational application.
BibTeX:
@inproceedings{freyEtAlIGARSS2023CarborneLandKuBandDInSARForGroundMotion,
  author = {Frey, Othmar and Werner, Charles and Caduff, Rafael},
  title = {Car-borne Mobile Mapping of Ground Motion by Means of Repeat-Pass SAR Interferometry: Case Studies and Application Development Based on L-Band and Ku-band SAR Data Acquisitions},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE},
  year = {2023},
  pages = {1902-1905},
  url = {https://www.gamma-rs.ch/uploads/media/freyEtAlIGARSS2023CarborneLandKuBandDInSARForGroundMotion.pdf},
  doi = {10.1109/IGARSS52108.2023.10283211}
}
Frey O, Werner C and Caduff R (2023), "Concurrent Car-Borne Repeat-Pass SAR Interferometry at L-Band and Ku-Band For Mobile Mapping of Ground Motion on Alpine Valley Slopes", In ESA FRINGE 2023. Leeds, UK, September, 2023. ESA.
BibTeX:
@inproceedings{freyEtAlFRINGE2023,
  author = {Othmar Frey and Charles Werner and Rafael Caduff},
  title = {Concurrent Car-Borne Repeat-Pass SAR Interferometry at L-Band and Ku-Band For Mobile Mapping of Ground Motion on Alpine Valley Slopes},
  booktitle = {ESA FRINGE 2023},
  publisher = {ESA},
  year = {2023},
  url = {https://www.youtube.com/watch?v=uDMxIs-CIJI}
}
Frey O, Wiesmann A, Werner C, Caduff R, Löwe H and Jaggi M (2023), "Analyzing Time Series of Vertical Profiles of Seasonal Snow Measured by SAR Tomographic Profiling at L/S/C-Band, Ku-Band, and Ka-Band in Comparison With Snow Characterizations", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Pasadena, July, 2023. , pp. 754-757. IEEE.
Abstract: Time series of SAR tomographic profiling measurements of seasonal snow in the Swiss Alps were acquired with the tower-mounted ESA Wideband Scatterometer (WBScat) during an entire snow season as part of the ESA SnowLab campaign. The wide range of frequency bands (1-40 GHz)covered in combination with the depth-resolving capability of the tomographic SAR measurements provides new insights into relative change of location and intensity of radar backscatter within the snowpack during melting and refreezing cycles as a function of time and various parameters obtained by auxiliary measurements such as snow accumulation, snow mass (SWE), snow surface temperature, and liquid water content. It is found that at both, Ku-band and Ka-band, the tomographic profiles provide evidence of substantial backscatter at melt/freeze crust interfaces within the seasonal snowpack. Varying penetration depths and (re-)appearing backscattering layers can be observed throughout several cycles of snow melting and gradual refreezing.
BibTeX:
@inproceedings{freyEtAlIGARSS2023ESASCANSASWBScatAndSnowScatTomographyTimeSeries,
  author = {Frey, Othmar and Wiesmann, Andreas and Werner, Charles and Caduff, Rafael and Löwe, Henning and Jaggi, Matthias},
  title = {Analyzing Time Series of Vertical Profiles of Seasonal Snow Measured by SAR Tomographic Profiling at L/S/C-Band, Ku-Band, and Ka-Band in Comparison With Snow Characterizations},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE},
  year = {2023},
  pages = {754-757},
  doi = {10.1109/IGARSS52108.2023.10283023}
}
Frey O, Wiesmann A, Werner CL, Caduff R, Löwe H and Jaggi M (2023), "SAR Tomographic Profiling of Seasonal Alpine Snow at L/S/C-, X/Ku-, and Ka-Band Throughout Entire Snow Seasons Retrieved During the ESA SnowLab Campaigns 2016-2020", In ESA FRINGE 2023. Leeds, UK, September, 2023. ESA.
Abstract: High-level scientific objectives of large-scale / global radar-remote-sensing-based retrieval of snow mass include (Tsang et al. 2022) :
(1) quantification of the spatiotemporal variability of the amount of water stored as snow,
(2) retrieval of snow structure, and
(3) transfer of this information into numerical weather forecasting, hydrological forecasting,
and climate models.
Several spaceborne radar/SAR missions are being planned / realized in this context at a wide range of microwave frequencies --- CRISTAL (Ku/Ka), TSMM (dual Ku-band),
ROSE-L & NISAR (L) and prev. CoReH20 (X-/Ku), Hydroterra (C-band) with mission objectives around assessing snow parameters;
primarily snow mass / snow water equivalent and extent of snow cover.
Detailed knowledge is required on temporal evolution of radar-related parameters during a snow season, including:
penetration depths, backscattering contributions at different layers and frequencies.
These parameters play an essential role to retrieve temporal changes of snow
characteristics (snow mass / SWE (change), structural anisotropy, stratification).
For seasonal snow these relations are poorly / only partially understood.
Knowledge gaps addressed with SAR tomographic profiling as part of our ESA SnowLab experiments are:
to provide time series of high-resolution depth-resolved SAR imagery of seasonal snow of:
(1) backscatter, with the primary objective to identify (vertical) distribution of backscatter contributions
depending on snow-pack depth and condition/properties,
(2) temporal interferometric phase/coherence for selected periods, with the primary objective to identify layer-wise phase difference vs. Delta-SWE (for cold & dry-snow periods),
(3) copolar phase diff., with the primary objective to identify layer-wise anisotropy of snow microstructure.
BibTeX:
@inproceedings{freyEtAlFRINGE2023SnowSARTomography,
  author = {Othmar Frey and Andreas Wiesmann and Charles L. Werner and Rafael Caduff and Henning Löwe and Matthias Jaggi},
  title = {SAR Tomographic Profiling of Seasonal Alpine Snow at L/S/C-, X/Ku-, and Ka-Band Throughout Entire Snow Seasons Retrieved During the ESA SnowLab Campaigns 2016-2020},
  booktitle = {ESA FRINGE 2023},
  publisher = {ESA},
  year = {2023},
  url = {http://gamma-rs.ch/uploads/media/fringe2023_SnowScat_poster_freyEtAlFinal.pdf}
}
Holmberg M, Lemmetyinen J, Schwank M, Kontu A and Rautiainen K (2023), "Snow Density and Ground Permittivity Retrieval Problem with L-Band Satellite Radiometer Observations - Case Study from Sodankylä, Finland", In Proc. IEEE Int. Geosci. Remote Sens. Symp.., July, 2023. , pp. 21-23.
Abstract: Seasonal snow cover is an important environmental component, as its characteristics affect energy and gas exchange between ground and the atmosphere. The mass of seasonal snow cover, or Snow Water Equivalent (SWE), describes the available freshwater stored in snow. When present, snow cover affects the microwave signature of the scene and should therefore be considered in any microwave based remote sensing model and retrieval algorithm. Microwave remote sensing of snow and its properties has a long history, and in particular SWE has traditionally been retrieved by using passive microwave observations at 19 and 37 GHz [1] , [2] .
BibTeX:
@inproceedings{holmbergEtAl2023,
  author = {Holmberg, Manu and Lemmetyinen, Juha and Schwank, Mike and Kontu, Anna and Rautiainen, Kimmo},
  title = {Snow Density and Ground Permittivity Retrieval Problem with L-Band Satellite Radiometer Observations - Case Study from Sodankylä, Finland},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2023},
  pages = {21-23},
  doi = {10.1109/IGARSS52108.2023.10283299}
}
Horvath L, Kostelac F, Houtz D, Schwank M and Bolognesi C (2023), "Passive Microwave C-Band Radiometer Prototype for UAV Applications", In Proc. IEEE Int. Geosci. Remote Sens. Symp.., July, 2023. , pp. 4792-4795.
Abstract: The future of agriculture is moving towards a more technological and efficient way to produce food for the world’s population. One key resource for that is water. A radiometer design is introduced that will be used to determine the feasibility of an 800g C-Band (6.8 GHz) radiometer for fixed-wing UAVs, giving agronomists a new cutting-edge tool to measure soil and kernel moisture in cereal grain pods. Simulation tools and computer-aided optimization were used to develop multiple design iterations, which were manufactured and measured to assess the performance of the proposed radiometer. A custom HEMT LNA was designed using ADS EM co-simulation, resulting in a 10dB gain and 1dB noise figure. The proposed system design has a theoretical NEΔT of 0.28 K and a preliminary measured NEΔT of 0.535K at 36.9ms integration time, respectively.
BibTeX:
@inproceedings{horvatEtAl2023,
  author = {Horvath, Lars and Kostelac, Fran and Houtz, Derek and Schwank, Mike and Bolognesi, Colombo},
  title = {Passive Microwave C-Band Radiometer Prototype for UAV Applications},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2023},
  pages = {4792-4795},
  doi = {10.1109/IGARSS52108.2023.10282789}
}
Houtz D, Horvath L and Schwank M (2023), "Vehicle Mounted L-Band Radiometer for Remote Sensing of Turfgrass Soil Moisture", In Proc. IEEE Int. Geosci. Remote Sens. Symp.., July, 2023. , pp. 4824-4827.
Abstract: A second-generation portable L-band radiometer is presented for use in turfgrass management applications and golf course soil moisture mapping. The "turfRad" has been optimized for ease-of-use and for the conditions in operational turfgrass management. This is the first known use of a vehicle-mounted L-band radiometer for turfgrass soil moisture mapping for irrigation decision-making. Preliminary results, including dual-polarization brightness temperatures and retrieved soil moisture, are presented. The single-parameter soil moisture retrieval using the Tau-Omega emission model with constant vegetation optical depth is chosen due to the high level of vegetation uniformity in the fairway areas.
BibTeX:
@inproceedings{houtzEtAl2023,
  author = {Houtz, Derek and Horvath, Lars and Schwank, Mike},
  title = {Vehicle Mounted L-Band Radiometer for Remote Sensing of Turfgrass Soil Moisture},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2023},
  pages = {4824-4827},
  doi = {10.1109/IGARSS52108.2023.10281943}
}
Hunka N, Santoro M, Armston J, Dubayah R, McRoberts RE, Naesset E, Quegan S, Urbazaev M, Pascual A, May PB, Minor D, Leitold V, Basak P, Liang M, Melo J, Herold M, Malaga N, Wilson S, Montesinos PD, Arana A, Paiva REDLC, Ferrand J, Keoka S, Guerra-Hernandez J and Duncanson L (2023), "On the NASA GEDI and ESA CCI biomass maps: aligning for uptake in the UNFCCC global stocktake", Environmental Research Letters., nov, 2023. Vol. 18(12), pp. 124042. IOP Publishing.
Abstract: Earth Observation data are uniquely positioned to estimate forest aboveground biomass density (AGBD) in accordance with the United Nations Framework Convention on Climate Change (UNFCCC) principles of transparency, accuracy, completeness, consistency and comparability. However, the use of space-based AGBD maps for national-level reporting to the UNFCCC is nearly non-existent as of 2023, the end of the first global stocktake (GST). We conduct an evidence-based comparison of AGBD estimates from the NASA Global Ecosystem Dynamics Investigation and ESA Climate Change Initiative, describing differences between the products and National Forest Inventories (NFIs), and suggesting how science teams must align efforts to inform the next GST. Between the products, in the tropics, the largest differences in estimated AGBD are primarily in the Congolese lowlands and east/southeast Asia. Where NFI data were acquired (Peru, Mexico, Lao PDR and 30 regions of Spain), both products show strong correlation to NFI-estimated AGBD, with no systematic deviations. The AGBD-richest stratum of these, the Peruvian Amazon, is accurately estimated in both. These results are remarkably promising, and to support the operational use of AGB map products for policy reporting, we describe targeted ways to align products with Intergovernmental Panel on Climate Change (IPCC) guidelines. We recommend moving towards consistent statistical terminology, and aligning on a rigorous framework for uncertainty estimation, supported by the provision of open-science codes for large-area assessments that comprehensively report uncertainty. Further, we suggest the provision of objective and open-source guidance to integrate NFIs with multiple AGBD products, aiming to enhance the precision of national estimates. Finally, we describe and encourage the release of user-friendly product documentation, with tools that produce AGBD estimates directly applicable to the IPCC guideline methodologies. With these steps, space agencies can convey a comparable, reliable and consistent message on global biomass estimates to have actionable policy impact.
BibTeX:
@article{hunkaEtAl2023,
  author = {Neha Hunka and Maurizio Santoro and John Armston and Ralph Dubayah and Ronald E McRoberts and Erik Naesset and Shaun Quegan and Mikhail Urbazaev and Adrian Pascual and Paul B May and David Minor and Veronika Leitold and Paromita Basak and Mengyu Liang and Joana Melo and Martin Herold and Natalia Malaga and Sylvia Wilson and Patricia Duran Montesinos and Alexs Arana and Ricardo Ernesto De La Cruz Paiva and Jeremy Ferrand and Somphavy Keoka and Juan Guerra-Hernandez and Laura Duncanson},
  title = {On the NASA GEDI and ESA CCI biomass maps: aligning for uptake in the UNFCCC global stocktake},
  journal = {Environmental Research Letters},
  publisher = {IOP Publishing},
  year = {2023},
  volume = {18},
  number = {12},
  pages = {124042},
  url = {https://dx.doi.org/10.1088/1748-9326/ad0b60},
  doi = {10.1088/1748-9326/ad0b60}
}
Izumi Y, Sato M, Nico G, Frey O, Baffelli S and Hajnsek I (2023), "A Novel Atmospheric Phase Correction Based on Kriging Incorporating Temporal Phase Evolution for Ground-Based SAR", In Proc. Int. Asia-Pacific Conf. on Synthetic Aperture Radar (APSAR)., October, 2023. , pp. 1-4.
Abstract: In ground-based synthetic aperture radar (GBSAR) interferometry applications, the generated interferograms often suffer from propagation delay in the troposphere, known as atmospheric phase screen (APS). Kriging interpolation is one of the approaches that can predict the APS in interferograms. In this presentation, we propose a novel Kriging approach for more accurate predictions of APS in multi-temporal GB-SAR data. In the proposed method, the temporal atmospheric phase evolution at each pixel is taken into account in the Kriging. The proposed method is validated with a real GB-SAR dataset, showing improved results on the prediction accuracy of APS in the spatial domain.
BibTeX:
@inproceedings{izumiEtAlAPSAR2023AtmosphericPhaseCorrectionBasedOnKrigingWithTemporalPhaseEvolutionForGBSAR,
  author = {Yuta Izumi and Motoyuki Sato and Giovanni Nico and Othmar Frey and Simone Baffelli and Irena Hajnsek},
  title = {A Novel Atmospheric Phase Correction Based on Kriging Incorporating Temporal Phase Evolution for Ground-Based SAR},
  booktitle = {Proc. Int. Asia-Pacific Conf. on Synthetic Aperture Radar (APSAR)},
  year = {2023},
  pages = {1-4}
}
Jones N, Strozzi T, Rabatel A, Ducasse E and Mouginot J (2023), "Surface Instability Mapping in Alpine Paraglacial Environments Using Sentinel-1 DInSAR Techniques", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 16, pp. 19-37. Institute of Electrical and Electronics Engineers Inc..
Abstract: Current climate warming leads to widespread glacier shrinkage in high alpine terrains and associated changes in surface dynamics of deglacierized environments. In consequence, slope instabilities increasingly develop along retreating glaciers through debuttressing effects or degrading permafrost conditions. In the context of associated hazards to the local environment and infrastructure, a thorough analysis of slope instabilities is highly relevant. Affected regions are mostly inaccessible and cover large areas, therefore remote sensing techniques such as differential interferometric synthetic aperture radar (DInSAR) are valuable tools to monitor surface movements and assess their evolution. We apply standard and advanced DInSAR methods using Sentinel-1 SAR data from 2015 until late 2021 to map and classify slope instabilities in three glacierized regions in the European Alps. The final products include an inventory per region, with a total of 815 mapped slope instabilities, of which 38% move <3, 9% move 3-10, 42% move 10-30, and 11% move >30 cm/yr. An additional assessment of four landslides occurring along shrinking glaciers shows time series with recent accelerations in 2018/19. Validation of Sentinel-1 derived slope movement products is performed by comparison with shorter wavelength TerraSAR-X and optical Sentinel-2 derived data using offset tracking. Results clearly show the suitability of Sentinel-1 DInSAR methods to detect a range of slope movements in high alpine terrain, yet also highlight the limitations. We therefore recommend a combination of advanced Sentinel-1 DInSAR and Sentinel-2 offset tracking methods to develop a comprehensive inventory of alpine slope motion. © 2023 IEEE.
BibTeX:
@article{Jones202319,
  author = {Jones, N. and Strozzi, T. and Rabatel, A. and Ducasse, E. and Mouginot, J.},
  title = {Surface Instability Mapping in Alpine Paraglacial Environments Using Sentinel-1 DInSAR Techniques},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2023},
  volume = {16},
  pages = {19-37},
  doi = {10.1109/JSTARS.2023.3287285}
}
Kääb A, Bazilova V, Leclercq P, Mannerfelt E and Strozzi T (2023), "Global clustering of recent glacier surges from radar backscatter data, 2017-2022", Journal of Glaciology. Cambridge University Press.
Abstract: Using global Sentinel-1 radar backscatter data, we systematically map the locations of glaciers with surge-type activity during 2017-22. Patterns of pronounced increases or decreases in the strongest backscatter between two winter seasons often indicate large changes in glacier crevassing, which we treat here as a sign of surge-type activity. Validations against velocity time series, terminus advances and crevassing found in optical satellite images confirm the robustness of this approach. We find 115 surge-type events globally between 2017 and 2022, around 100 of which on glaciers already know as surge-type. Our data reveal a pronounced spatial clustering in three regions, (i) Karakoram, Pamirs and Western Kunlun Shan (∼50 surges), (ii) Svalbard (∼25) and (iii) Yukon/Alaska (∼9), with only a few other scattered surges elsewhere. This spatial clustering is significantly more pronounced than the overall global clustering of known surge-type glaciers. The 2017-22 clustering may point to climatic forcing of surge initiation.
BibTeX:
@article{Kaeaeb2023,
  author = {Kääb, A. and Bazilova, V. and Leclercq, P.W. and Mannerfelt, E.S. and Strozzi, T.},
  title = {Global clustering of recent glacier surges from radar backscatter data, 2017-2022},
  journal = {Journal of Glaciology},
  publisher = {Cambridge University Press},
  year = {2023},
  doi = {10.1017/jog.2023.35}
}
Kochtitzky W, Copland L, Van Wychen W, Hock R, Rounce D, Jiskoot H, Scambos T, Morlighem M, King M, Cha L, Gould L, Merrill P-M, Glazovsky A, Hugonnet R, Strozzi T, Noel B, Navarro F, Millan R, Dowdeswell J, Cook A, Dalton A, Khan S and Jania J (2023), "Progress toward globally complete frontal ablation estimates of marine-terminating glaciers", Annals of Glaciology. Cambridge University Press.
Abstract: Knowledge of frontal ablation from marine-terminating glaciers (i.e., mass lost at the calving face) is critical for constraining glacier mass balance, improving projections of mass change, and identifying the processes that govern frontal mass loss. Here, we discuss the challenges involved in computing frontal ablation and the unique issues pertaining to both glaciers and ice sheets. Frontal ablation estimates require numerous datasets, including glacier terminus area change, thickness, surface velocity, density, and climatic mass balance. Observations and models of these variables have improved over the past decade, but significant gaps and regional discrepancies remain, and better quantification of temporal variability in frontal ablation is needed. Despite major advances in satellite-derived large-scale datasets, large uncertainties remain with respect to ice thickness, depth-averaged velocities, and the bulk density of glacier ice close to calving termini or grounding lines. We suggest ways in which we can move toward globally complete frontal ablation estimates, highlighting areas where we need improved datasets and increased collaboration. © 2023 The Author(s). Published by Cambridge University Press on behalf of The International Glaciological Society.
BibTeX:
@article{Kochtitzky2023,
  author = {Kochtitzky, W. and Copland, L. and Van Wychen, W. and Hock, R. and Rounce, D.R. and Jiskoot, H. and Scambos, T.A. and Morlighem, M. and King, M. and Cha, L. and Gould, L. and Merrill, P.-M. and Glazovsky, A. and Hugonnet, R. and Strozzi, T. and Noel, B. and Navarro, F. and Millan, R. and Dowdeswell, J.A. and Cook, A. and Dalton, A. and Khan, S. and Jania, J.},
  title = {Progress toward globally complete frontal ablation estimates of marine-terminating glaciers},
  journal = {Annals of Glaciology},
  publisher = {Cambridge University Press},
  year = {2023},
  doi = {10.1017/aog.2023.35}
}
Lambiel C, Strozzi T, Paillex N, Vivero S and Jones N (2023), "Inventory and kinematics of active and transitional rock glaciers in the Southern Alps of New Zealand from Sentinel-1 InSAR", Arctic, Antarctic, and Alpine Research. Vol. 55(1) Taylor and Francis Ltd..
Abstract: In this study, we inventoried and mapped the active and transitional rock glaciers in the central part of the Southern Alps, New Zealand, using Sentinel-1 InSAR (interferometric synthetic aperture radar) data. We used forty-three interferograms acquired between 2015 and 2019 with time intervals between six days and two years along with orthoimage analyses. A total of 123 rock glaciers were identified, of which 40 are active; that is, displaying velocities higher than 10 cm/yr. The remaining landforms are considered transitional. Among the complete sample of rock glaciers inventoried, 9 may also be interpreted as debris-covered glacierets. The number of inventoried landforms is low compared to what is observed in other similar mountain ranges, such as the European Alps. We explain this by the reduced vertical extent of the periglacial belt and the generally steep topography often not favorable for rock glacier development. Additionally, the motion rates appear relatively low. We hypothesize that a mean annual air temperature at the rock glacier locations well above 0°C is the main reason for this. These conditions may have resulted in significant ground ice melt. Rock glaciers in the Southern Alps are thus in an inactivation phase, which is expressed by typical morphologies such as stable fronts. © 2023 The Author(s). Published with license by Taylor & Francis Group, LLC.
BibTeX:
@article{Lambiel2023,
  author = {Lambiel, C. and Strozzi, T. and Paillex, N. and Vivero, S. and Jones, N.},
  title = {Inventory and kinematics of active and transitional rock glaciers in the Southern Alps of New Zealand from Sentinel-1 InSAR},
  journal = {Arctic, Antarctic, and Alpine Research},
  publisher = {Taylor and Francis Ltd.},
  year = {2023},
  volume = {55},
  number = {1},
  doi = {10.1080/15230430.2023.2183999}
}
Lavalle M, Telli C, Pierdicca N, Khati U, Cartus O and Kellndorfer J (2023), "Model-Based Retrieval of Forest Parameters From Sentinel-1 Coherence and Backscatter Time Series", IEEE Geoscience and Remote Sensing Letters. Vol. 20 Institute of Electrical and Electronics Engineers Inc..
Abstract: This letter describes a model-based algorithm for estimating tree height and other bio-physical land parameters from time series of synthetic aperture radar (SAR) interferometric coherence and backscatter supported by sparse lidar data. The random-motion-over-ground model (RMoG) is extended to time series and revisited to capture the short- and long-term temporal coherence variability caused by motion of the scatterers and changes in the soil and canopy backscatter. The proposed retrieval algorithm estimates first the spatially slow-varying RMoG model parameters using sparse lidar data, and subsequently the spatially fast-varying model parameters such as tree height. The recently published global Sentinel-1 (S-1) interferometric coherence and backscatter data set and sparse spaceborne GEDI lidar data are used to illustrate the algorithm. Results obtained for a small region over Spain show that the temporal coherence and backscatter time series have the potential to be used for global, model-based land parameter estimation. © 2004-2012 IEEE.
BibTeX:
@article{Lavalle2023,
  author = {Lavalle, M. and Telli, C. and Pierdicca, N. and Khati, U. and Cartus, O. and Kellndorfer, J.},
  title = {Model-Based Retrieval of Forest Parameters From Sentinel-1 Coherence and Backscatter Time Series},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2023},
  volume = {20},
  doi = {10.1109/LGRS.2023.3239825}
}
Leinss S, Werner C and Wegmüller U (2023), "A pulse-to-pulse interferometry mode to map velocity fields over quickly decorrelating surfaces with the Gamma Portable Radar Interferometer (GPRI)", In ESA FRINGE 2023. Leeds, UK, September, 2023. ESA.
BibTeX:
@inproceedings{leinssEtAlFRINGE2023,
  author = {Silvan Leinss and Charles Werner and Urs Wegmüller},
  title = {A pulse-to-pulse interferometry mode to map velocity fields over quickly decorrelating surfaces with the Gamma Portable Radar Interferometer (GPRI)},
  booktitle = {ESA FRINGE 2023},
  publisher = {ESA},
  year = {2023},
  url = {http://gamma-rs.ch/uploads/media/poster_fringe2023-leinss.pdf}
}
Scheer J, Caduff R, How P, Marcer M, Strozzi T, Bartsch A and Ingeman-Nielsen T (2023), "Thaw-Season InSAR Surface Displacements and Frost Susceptibility Mapping to Support Community-Scale Planning in Ilulissat, West Greenland", Remote Sensing. Vol. 15(13) Multidisciplinary Digital Publishing Institute (MDPI).
Abstract: In permafrost regions, ground surface deformations induced by freezing and thawing threaten the integrity of the built environment. Mapping the frost susceptibility of the ground at a high spatial resolution is of practical importance for the construction and planning sectors. We processed Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) data from thawing seasons 2015 to 2019, acquired over the area of Ilulissat, West Greenland. We used a least-squares inversion scheme to retrieve the average seasonal displacement (S) and long-term deformation rate (R). We secondly investigated two different methods to extrapolate active layer thickness (ALT) measurements, based on their statistical relationship with remotely sensed surface characteristics. A generalized linear model (GLM) was first implemented, but the model was not able to fit the data and represent the ALT spatial variability over the entire study domain. ALT were alternatively averaged per vegetation class, using a land cover map derived by supervised classification of Sentinel-2 images. We finally estimated the active layer ice content and used it as a proxy to map the frost susceptibility of the ground at the community scale. Fine-grained sedimentary basins in Ilulissat were typically frost susceptible and subject to average seasonal downward displacements of 3 to 8 (Formula presented.). Areas following a subsiding trend of up to 2.6 (Formula presented.) were likely affected by permafrost degradation and melting of ground ice below the permafrost table. Our approach enabled us to identify frost-susceptible areas subject to severe seasonal deformations, to long-term subsidence induced by degrading permafrost, or to both. Used in combination with traditional site investigations, InSAR maps provide valuable information for risk management and community planning in the Arctic. © 2023 by the authors.
BibTeX:
@article{Scheer2023,
  author = {Scheer, J. and Caduff, R. and How, P. and Marcer, M. and Strozzi, T. and Bartsch, A. and Ingeman-Nielsen, T.},
  title = {Thaw-Season InSAR Surface Displacements and Frost Susceptibility Mapping to Support Community-Scale Planning in Ilulissat, West Greenland},
  journal = {Remote Sensing},
  publisher = {Multidisciplinary Digital Publishing Institute (MDPI)},
  year = {2023},
  volume = {15},
  number = {13},
  doi = {10.3390/rs15133310}
}
Stefko M, Bernhard P, Leinss S, Frey O and Hajnsek I (2023), "Bistatic Radar Measurements of Terrestrial Snow at Ku-Band - Phenomena, Models, and Opportunities", In Proc. IEEE Int. Geosci. Remote Sens. Symp.., July, 2023. , pp. 658-661. IEEE.
Abstract: We present the results of recent observations of terrestrial snow cover with KAPRI, a Ku-band polarimetric-interferometric radar system with bistatic capabilities. The bistatic configuration allows observation of phenomena which are not observable in the monostatic regime. Observations of polarization phase differences of snow cover on top of the Great Aletsch Glacier revealed that the behaviour of these parameters markedly varies between different times of year, as well as between the monostatic and bistatic acquisition modes. The bistatic capabilities of KAPRI were also recently used to characterize the coherent backscatter opposition effect (CBOE) in seasonal snow. We discuss the potential of such bistatic observations to observe quantities which are unobservable in the monostatic regime, and which could serve as new inputs for snow parameter retrieval methods.
BibTeX:
@inproceedings{stefkoBernhardLeinssFreyHajnsekIGARSS2023BistaticRadarMeasurementsOfTerrestrialSnowAtKuBand,
  author = {Stefko, Marcel and Bernhard, Philipp and Leinss, Silvan and Frey, Othmar and Hajnsek, Irena},
  title = {Bistatic Radar Measurements of Terrestrial Snow at Ku-Band - Phenomena, Models, and Opportunities},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE},
  year = {2023},
  pages = {658-661},
  doi = {10.1109/IGARSS52108.2023.10282423}
}
Strozzi T, Jones N, Leinss S, Wegmüller U, Boike J, Antonova S, Heim B, Grosse G, Westermann S, Kääb A and Bartsch A (2023), "Seasonal Thaw Displacement in Low-Land Permafrost Areas at L-, C- and X-Band", In ESA FRINGE 2023. Leeds, UK, September, 2023. ESA.
BibTeX:
@inproceedings{strozziEtAlFRINGE2023,
  author = {Tazio Strozzi and Nina Jones and Silvan Leinss and Urs Wegmüller and J. Boike and S. Antonova and B. Heim and G. Grosse and S. Westermann and A. Kääb and Annett Bartsch},
  title = {Seasonal Thaw Displacement in Low-Land Permafrost Areas at L-, C- and X-Band},
  booktitle = {ESA FRINGE 2023},
  publisher = {ESA},
  year = {2023},
  url = {http://gamma-rs.ch/uploads/media/FRINGE23_Strozzi_Poster_lowres.pdf}
}
Thyagarajan PL, Nies H, Frey O, Ender J and Ihrke I (2023), "SAR Tomography Reconstruction using ISTA and GLRT Techniques", In Proc. Int. Asia-Pacific Conf. on Synthetic Aperture Radar (APSAR).
Abstract: SAR Tomography (TomoSAR) leverages the utilization of multiple baselines to gather data about an area, enabling the acquisition of information not only in the range-azimuth direction but also in the elevation direction. This additional information in the elevation direction primarily consists of point scatterers, with one or more scatterers typically present within a single resolution cell. This research paper examines two distinct methodologies for detecting multiple scatterers in TomoSAR:the conventional Generalized Likelihood Ratio Test (GLRT)technique and a compressive sensing (CS) approach known as the Iterative Soft-Thresholding Algorithm (ISTA). The results are examined for a simulated case of two scatterers and a real case using the TerraSAR-X dataset.
BibTeX:
@inproceedings{thyagarajanEtAlAPSAR2023TomoGLRTandISTA,
  author = {Thyagarajan, Prithvi L. and Nies, Holger and Frey, Othmar and Ender, Joachim and Ihrke, Ivo},
  title = {SAR Tomography Reconstruction using ISTA and GLRT Techniques},
  booktitle = {Proc. Int. Asia-Pacific Conf. on Synthetic Aperture Radar (APSAR)},
  year = {2023}
}
Wegmüller U, Caduff R, Magnard C, Jones N and Strozzi T (2023), "ICEYE DInSAR and InSAR Time Series for Ground Displacement Mapping", In ESA FRINGE 2023. Leeds, UK, September, 2023. ESA.
BibTeX:
@inproceedings{wegmullerEtAlFRINGE2023,
  author = {Urs Wegmüller and Rafael Caduff and Christophe Magnard and Nina Jones and Tazio Strozzi},
  title = {ICEYE DInSAR and InSAR Time Series for Ground Displacement Mapping},
  booktitle = {ESA FRINGE 2023},
  publisher = {ESA},
  year = {2023},
  url = {https://www.youtube.com/watch?v=okvTp0-rBR0}
}
Wegmüller U, Magnard C, Strozzi T, Caduff R and Jones N (2023), "Ground Displacement Mapping with L-band Persistent Scatterer Interferometry", In ESA FRINGE 2023. Leeds, UK, September, 2023. ESA.
BibTeX:
@inproceedings{wegmullerEtAlFRINGE2023b,
  author = {Urs Wegmüller and Christophe Magnard and Tazio Strozzi and Rafael Caduff and Nina Jones},
  title = {Ground Displacement Mapping with L-band Persistent Scatterer Interferometry},
  booktitle = {ESA FRINGE 2023},
  publisher = {ESA},
  year = {2023},
  url = {https://www.youtube.com/watch?v=ZQX_MQ-XCX8}
}
Werner C, Leinss S, Wiesmann A, Caduff R, Frey O, Wegmüller U, Schwank M, Mätzler C and Suess M (2023), "Obtaining Time-Series of Snow Water Equivalent in Alpine Snow by Ground-based Differential Interferometry at 1 to 40 GHz at Davos-Laret", In ESA FRINGE 2023. Leeds, UK, September, 2023. ESA.
BibTeX:
@inproceedings{wernerEtAlFRINGE2023,
  author = {Charles Werner and Silvan Leinss and Andreas Wiesmann and Rafael Caduff and Othmar Frey and Urs Wegmüller and Mike Schwank and Christian Mätzler and Martin Suess},
  title = {Obtaining Time-Series of Snow Water Equivalent in Alpine Snow by Ground-based Differential Interferometry at 1 to 40 GHz at Davos-Laret},
  booktitle = {ESA FRINGE 2023},
  publisher = {ESA},
  year = {2023},
  url = {http://gamma-rs.ch/uploads/media/Fringe_2023_ID485_Werner_Poster.pdf}
}
Xu F, Wang R, Frey O, Huang Y, Mi C, Mao D and Yang J (2023), "Spatial Configuration Design for Multistatic Airborne SAR Based on Multiple Objective Particle Swarm Optimization", IEEE Transactions on Geoscience and Remote Sensing. , pp. 1-17.
Abstract: Multistatic airborne synthetic aperture radar (MuA-SAR) systems can achieve high-resolution imaging in a short time by fusing observation data from multiple radar platforms. However, its imaging quality relies on a rigorous design of the spatial configuration (SC) of each platform, mainly including the relative spatial separation and velocity. The rigorously designed SCs make it difficult to obtain in actual flight and weaken the flexibility advantage brought by the airborne platforms. Therefore, it is meaningful and necessary to explore a new SC design method to obtain relaxed SCs under the condition of ensuring imaging quality. In this paper, to relax the limitations of SC, an optimal design method for MuA-SAR SC is proposed. First, the relationship between the spatial configuration, wavenumber spectrum (WS) distribution, and imaging performance is established, and it visually reveals the configuration limitations. Second, an optimized search space of SC is defined by the peak to sidelobe ratio (PSLR) to relax the space to compromised configurations. Finally, the SC design problem is transformed into a constrained multiple objective optimization problem (CMOP) which is solved by the multiple objective particle swarm optimization (MOPSO) algorithm. The simulation results show that the proposed method can still obtain the optimized SC beyond the strictly restricted configuration space, which expands the SC limitations of the MuA-SAR system.
BibTeX:
@article{xuWangFreyHuangMiMaoYangTGRS2023SpatialConfigurationDesignForMultistaticAirborneSAR,
  author = {Xu, Fanyun and Wang, Rufei and Frey, Othmar and Huang, Yulin and Mi, Chenyang and Mao, Deqing and Yang, Jianyu},
  title = {Spatial Configuration Design for Multistatic Airborne SAR Based on Multiple Objective Particle Swarm Optimization},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2023},
  pages = {1-17},
  doi = {10.1109/TGRS.2023.3326869}
}
Zhou Y, Schwank M, Kurum M and Mialon A (2023), "Modelling Scattering Albedo of Trees from 1 To 37 GHZ and Its Application to Vod Retrieval", In Proc. IEEE Int. Geosci. Remote Sens. Symp.., July, 2023. , pp. 2735-2738.
Abstract: This study focuses on modelling the scattering albedo of a vegetation canopy, which can be used in vegetation opacity depth (VOD) retrieval, over a wide frequency range (1-37 GHz). In this study, boreal tree canopy has been used as an example. A discrete scatter model has been implemented to calculate single scattering albedo and vegetation opacity depth (VOD) of a single-layer canopy consisting of a variety type of scatterers. For a more realistic parameterization, a novel tree structure model has been developed to quantify the vertical structure of a forest. For the first time, we combined the discrete scatter model with the multi-layer 2Stream model to calculate the brightness temperature of the tree canopy based on its vertical structure. This research provides a comprehensive forward modelling tool that can be parameterized with different vegetation types (e.g. tree, crops and grass) and parameters (e.g. height, density, soil condition and vertical water content distribution). The model can be used in retrieval algorithm to find effective scattering albedo and VOD over a wide range of frequencies.
BibTeX:
@inproceedings{zhouEtAl2023,
  author = {Zhou, Yiwen and Schwank, Mike and Kurum, Mehmet and Mialon, Arnaud},
  title = {Modelling Scattering Albedo of Trees from 1 To 37 GHZ and Its Application to Vod Retrieval},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2023},
  pages = {2735-2738},
  doi = {10.1109/IGARSS52108.2023.10281570}
}
Zhu L, Li W, Ciais P, He J, Cescatti A, Santoro M, Tanaka K, Cartus O, Zhao Z, Xu Y, Sun M and Wang J (2023), "Comparable biophysical and biogeochemical feedbacks on warming from tropical moist forest degradation", Nature Geoscience. Vol. 16(3), pp. 244-249. Nature Research.
Abstract: Tropical forests have undergone extensive deforestation and degradation during the past few decades, but the area and the carbon loss due to degradation could be larger than the losses from deforestation. Degraded forests also induce biophysical feedback on climate, as they sustain less cooling from evapotranspiration. Here we estimate the biophysical and biogeochemical temperature changes caused by tropical moist forest degradation using high-resolution remote sensing data from 2010. Degraded forests, including burned, isolated, edge and other degraded forests, account for 24.1% of the total tropical moist forest area. The land surface temperature of degraded tropical moist forests is higher than that of nearby intact forests, leading to a warming effect of 0.022 ± 0.014 °C over the tropics. The cumulative carbon deficit of degraded forests reaches 6.1 ± 2.0 PgC, equivalent to a biogeochemical warming effect of 0.026 ± 0.013 °C. Forest degradation caused by anthropogenic disturbances from 1990 to 2010 induces a daytime warming effect of 0.018 ± 0.008 °C and a carbon deficit of 2.3 ± 0.8 PgC. These values are of the same order of magnitude as those due to deforestation. Our results emphasize the importance of accounting for the combined biophysical and biogeochemical effects in mitigation pledges related to reducing forest degradation and the restoration of tropical forest. © 2023, The Author(s), under exclusive licence to Springer Nature Limited.
BibTeX:
@article{Zhu2023244,
  author = {Zhu, L. and Li, W. and Ciais, P. and He, J. and Cescatti, A. and Santoro, M. and Tanaka, K. and Cartus, O. and Zhao, Z. and Xu, Y. and Sun, M. and Wang, J.},
  title = {Comparable biophysical and biogeochemical feedbacks on warming from tropical moist forest degradation},
  journal = {Nature Geoscience},
  publisher = {Nature Research},
  year = {2023},
  volume = {16},
  number = {3},
  pages = {244-249},
  doi = {10.1038/s41561-023-01137-y}
}
Antropov O, Miettinen J, Hame T, Yrjo R, Seitsonen L, McRoberts R, Santoro M, Cartus O, Duran N, Herold M, Pardini M, Papathanassiou K and Hajnsek I (2022), "Intercomparison of Earth Observation Data and Methods for Forest Mapping in the Context of Forest Carbon Monitoring", In Proc. IEEE Int. Geosci. Remote Sens. Symp.., July, 2022. , pp. 5777-5780.
BibTeX:
@inproceedings{Antropov2022,
  author = {Antropov, O. and Miettinen, J. and Hame, T. and Yrjo, R. and Seitsonen, L. and McRoberts, R.E. and Santoro, M. and Cartus, O. and Duran, N.M. and Herold, M. and Pardini, M. and Papathanassiou, K. and Hajnsek, I.},
  title = {Intercomparison of Earth Observation Data and Methods for Forest Mapping in the Context of Forest Carbon Monitoring},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2022},
  pages = {5777-5780},
  doi = {10.1109/IGARSS46834.2022.9884618}
}
Araza A, de Bruin S, Herold M, Quegan S, Labriere N, Rodriguez-Veiga P, Avitabile V, Santoro M, Mitchard E, Ryan C, Phillips O, Willcock S, Verbeeck H, Carreiras J, Hein L, Schelhaas M-J, Pacheco-Pascagaza A, da Conceicao Bispo P, Laurin G, Vieilledent G, Slik F, Wijaya A, Lewis S, Morel A, Liang J, Sukhdeo H, Schepaschenko D, Cavlovic J, Gilani H and Lucas R (2022), "A comprehensive framework for assessing the accuracy and uncertainty of global above-ground biomass maps", Remote Sensing of Environment. Vol. 272(112917)
BibTeX:
@article{Araza2022,
  author = {Araza, A. and de Bruin, S. and Herold, M. and Quegan, S. and Labriere, N. and Rodriguez-Veiga, P. and Avitabile, V. and Santoro, M. and Mitchard, E.T.A. and Ryan, C.M. and Phillips, O.L. and Willcock, S. and Verbeeck, H. and Carreiras, J. and Hein, L. and Schelhaas, M.-J. and Pacheco-Pascagaza, A.M. and da Conceicao Bispo, P. and Laurin, G.V. and Vieilledent, G. and Slik, F. and Wijaya, A. and Lewis, S.L. and Morel, A. and Liang, J. and Sukhdeo, H. and Schepaschenko, D. and Cavlovic, J. and Gilani, H. and Lucas, R.},
  title = {A comprehensive framework for assessing the accuracy and uncertainty of global above-ground biomass maps},
  journal = {Remote Sensing of Environment},
  year = {2022},
  volume = {272},
  number = {112917},
  doi = {10.1016/j.rse.2022.112917}
}
Bertone A, Barboux C, Bodin X, Bolch T, Brardinoni F, Caduff R, Christiansen H, Darrow M, Delaloye R, Etzelmüller B, Humlum O, Lambiel C, Lilleoren K, Mair V, Pellegrinon G, Rouyet L, Ruiz L and Strozzi T (2022), "Incorporating InSAR kinematics into rock glacier inventories: insights from 11 regions worldwide", Cryosphere. Vol. 16(7), pp. 2769-2792.
BibTeX:
@article{Bertone2022,
  author = {Bertone, A. and Barboux, C. and Bodin, X. and Bolch, T. and Brardinoni, F. and Caduff, R. and Christiansen, H.H. and Darrow, M.M. and Delaloye, R. and Etzelmüller, B. and Humlum, O. and Lambiel, C. and Lilleoren, K.S. and Mair, V. and Pellegrinon, G. and Rouyet, L. and Ruiz, L. and Strozzi, T.},
  title = {Incorporating InSAR kinematics into rock glacier inventories: insights from 11 regions worldwide},
  journal = {Cryosphere},
  year = {2022},
  volume = {16},
  number = {7},
  pages = {2769-2792},
  doi = {10.5194/tc-16-2769-2022}
}
Cartus O, Santoro M, Wegmüller U, Labriere N and Chave J (2022), "Sentinel-1 Coherence for Mapping Above-Ground Biomass in Semiarid Forest Areas", IEEE Geoscience and Remote Sensing Letters. Vol. 19
BibTeX:
@article{Cartus2022,
  author = {Cartus, O. and Santoro, M. and Wegmüller, U. and Labriere, N. and Chave, J.},
  title = {Sentinel-1 Coherence for Mapping Above-Ground Biomass in Semiarid Forest Areas},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  year = {2022},
  volume = {19},
  doi = {10.1109/LGRS.2021.3071949}
}
Cicoira A, Weber S, Biri A, Buchli B, Delaloye R, Da Forno R, Gärtner-Roer I, Gruber S, Gsell T, Hasler A, Lim R, Limpach P, Mayoraz R, Meyer M, Noetzli J, Phillips M, Pointner E, Raetzo H, Scapozza C, Strozzi T, Thiele L, Vieli A, Vonder Mühll D, Wirz V and Beutel J (2022), "In situ observations of the Swiss periglacial environment using GNSS instruments", Earth System Science Data. Vol. 14(11), pp. 5061-5091.
BibTeX:
@article{essd-14-5061-2022,
  author = {Cicoira, A. and Weber, S. and Biri, A. and Buchli, B. and Delaloye, R. and Da Forno, R. and Gärtner-Roer, I. and Gruber, S. and Gsell, T. and Hasler, A. and Lim, R. and Limpach, P. and Mayoraz, R. and Meyer, M. and Noetzli, J. and Phillips, M. and Pointner, E. and Raetzo, H. and Scapozza, C. and Strozzi, T. and Thiele, L. and Vieli, A. and Vonder Mühll, D. and Wirz, V. and Beutel, J.},
  title = {In situ observations of the Swiss periglacial environment using GNSS instruments},
  journal = {Earth System Science Data},
  year = {2022},
  volume = {14},
  number = {11},
  pages = {5061-5091},
  url = {https://essd.copernicus.org/articles/14/5061/2022/},
  doi = {10.5194/essd-14-5061-2022}
}
Coscione R, Hajnsek I, Werner C and Frey O (2022), "Assessing the impact of positioning errors in car-borne repeat-pass SAR interferometry with a controlled rail-based experiment", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 15, pp. 8402-8415. Institute of Electrical and Electronics Engineers (IEEE).
Abstract: Agile synthetic aperture radar (SAR) platforms such as car-borne and UAV-borne SAR systems require combined inertial navigation systems (INS) and global navigation satellite systems (GNSS) to measure the radar sensor trajectories used for focusing and interferometric processing. Measurement inaccuracies from INS/GNSS systems lead to residual phase errors in the SAR products whose minimisation is crucial to derive accurate topographic and deformation information. In this work, we analyse the impact of residual positioning errors on car-borne repeat-pass SAR interferometry at L-band for different INS/GNSS measurement configurations and for the typical car-borne acquisition geometry. The positioning errors are evaluated both during single SAR acquisitions with long integration times and between different acquisitions as a function of the distance of the radar platform from the GNSS reference stations. We show the reduction of interferometric phase errors achievable by additionally using a GNSS receiver mounted in the vicinity of the SAR platform as compared to remote reference stations of the national network of permanent GNSS receivers. Test results obtained in a controlled setup with a rail-based SAR system equipped with a navigation-grade INS/GNSS system show maximum repeat-pass trajectory errors on the order of 1-2 cm using a local GNSS reference station and up to 10-15 cm using the remote reference stations, leading to azimuth and range phase trends in the interferometric products.
BibTeX:
@article{coscioneWernerHajnsekFrey2022ImpactOfPositioningErrorsInCarborneRepeatpassINSAR,
  author = {Coscione, Roberto and Hajnsek, Irena and Werner, Charles and Frey, Othmar},
  title = {Assessing the impact of positioning errors in car-borne repeat-pass SAR interferometry with a controlled rail-based experiment},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers (IEEE)},
  year = {2022},
  volume = {15},
  pages = {8402--8415},
  doi = {10.1109/jstars.2022.3193053}
}
Frey O, Werner C and Caduff R (2022), "Dual-frequency car-borne DInSAR at L-band and Ku-band for mobile mapping of surface displacements", In Proc. of EUSAR 2022 - 14th European Conference on Synthetic Aperture Radar., July, 2022. , pp. 489-492. VDE Verlag GmbH.
Abstract: We present our recent developments and experimental results on car-borne mobile mapping of ground-surface displacementswith our in-house-developed SAR systems. Recently, we have successfully demonstrated car-borne andUAV-borne DInSAR with the Gamma L-band SAR system. Meanwhile we have upgraded our car-borne measurementconfiguration that now permits acquiring simultaneously at L-band and at Ku-band. We show first interferometricresults with short temporal baselines from simultaneous acquisitions at both frequencies and in particular we discussthe complementary aspects of the two frequencies in terms of sensitivity to line-of-sight displacements and temporaldecorrelation in typical measurement scenarios.
BibTeX:
@inproceedings{freyWernerCaduffEUSAR2022DualFrequencyCarborneDInSARatLBandAndKuBandForMobileMappingOfSurfaceDisplacements,
  author = {Frey, Othmar and Werner, Charles and Caduff, Rafael},
  title = {Dual-frequency car-borne DInSAR at L-band and Ku-band for mobile mapping of surface displacements},
  booktitle = {Proc. of EUSAR 2022 - 14th European Conference on Synthetic Aperture Radar},
  publisher = {VDE Verlag GmbH},
  year = {2022},
  pages = {489-492},
  url = {https://www.gamma-rs.ch/uploads/media/freyWernerCaduffEUSAR2022DualFrequencyCarborneDInSARatLBandAndKuBandForMobileMappingOfSurfaceDisplacements.pdf}
}
Frey O, Werner C, Manconi A and Coscione R (2022), "High-resolution mobile mapping of slope stability with car- and UAV-borne InSAR systems", In EGU General Assembly. (EGU22-8587) Copernicus.
Abstract: Terrestrial radar interferometry (TRI) has become an operational tool to measure slope surface displacements [1,2]. The day-and-night and all-weather capability of TRI together with the ability to measure line-of-sight displacements in the range of sub-centimeter to sub-millimeter precision are strong assets that complement other geodetic measurement techniques and devices such as total stations, GNSS, terrestrial laser scanning, and close/mid-range photogrammetric techniques.(Quasi-)stationary TRI systems are bound to relatively high frequencies (X- to Ku-band or even higher) to obtain reasonable spatial resolution in azimuth and yet the azimuth resolution is typically only in the order of tens of meters for range distances beyond a few kilometers. These aspects are limiting factors to obtain surface displacement maps at high spatial resolution for areas of interest at several kilometers distance and also for (slightly) vegetated slopes due to the fast temporal decorrelation at high frequencies. Recently, we have implemented and demonstrated car-borne and UAV-borne repeat-pass interferometry-based mobile mapping of surface displacements with an in-house-developed compact L-band FMCW SAR system which we have deployed 1) on a car and 2) on VTOL UAVs (Scout B1-100 and Scout B-330) by Aeroscout GmbH [3,4]. The SAR imaging and interferometric data processing is performed directly in map coordinates using a time-domain back-projection (TDBP) approach [5,6] which precisely takes into account the 3-D acquisition geometry.We have meanwhile further consolidated our experience with the repeat-pass SAR interferometry data acquisition, SAR imaging, interferometricprocessing, and surface displacement mapping using the car-borne and UAV-borne implementations of our InSAR system based on a number of repeat-pass interferometry campaigns. In our contribution, we present the capabilities of this new InSAR-based mobile mapping system and we discuss the lessons learned from our measurement campaigns.
References:
[1] Caduff, R., Schlunegger, F., Kos, A. & Wiesmann, A. A review of terrestrial radar interferometry for measuring surface change in the geosciences. Earth Surface Processes and Landforms 40, 208-228 (2015).
[2] Monserrat, O., Crosetto, M. & Luzi, G. A review of ground-based SAR interferometry for deformation measurement. ISPRS Journal of Photogrammetry and Remote Sensing 93, 40-48 (2014).
[3] O. Frey, C. L. Werner, and R. Coscione, Car-borne and UAV-borne mobile mapping of surface displacements with a compact repeat-pass interferometric SAR system at L-band, in Proc. IEEE Int. Geosci. Remote Sens. Symp., 2019, pp. 274-277.
[4] O. Frey, C. L. Werner, A. Manconi, and R. Coscione, Measurement of surface displacements with a UAV-borne/car-borne L-band DInSAR system: system performance and use cases, in Proc. IEEE Int. Geosci. Remote Sens. Symp.IEEE, 2021, pp.628-631.
[5] O. Frey, C. Magnard, M. Rüegg, and E. Meier, Focusing of airborne synthetic aperture radar data from highly nonlinear flight tracks, IEEE Trans. Geosci. Remote Sens., vol. 47, no. 6, pp. 1844-1858, June 2009.
[6] O. Frey, C. L. Werner, and U. Wegmuller, GPU-based parallelized time-domain back-projection processing for agile SAR platforms, in Proc. IEEE Int. Geosci. Remote Sens. Symp., July 2014, pp. 1132-113.
BibTeX:
@inproceedings{freyWernerManconiCoscioneEGU2022Abstract,
  author = {Frey, Othmar and Werner, Charles and Manconi, Andrea and Coscione, Roberto},
  title = {High-resolution mobile mapping of slope stability with car- and UAV-borne InSAR systems},
  booktitle = {EGU General Assembly},
  publisher = {Copernicus},
  year = {2022},
  number = {EGU22-8587},
  note = {EGU General Assembly 2022; Conference Location: Vienna, Austria; Conference Date: May 23-27, 2022; Conference lecture held on May 25, 2022.},
  doi = {10.5194/egusphere-egu22-8587}
}
Kellndorfer J, Cartus O, Lavalle M, Magnard C, Milillo P, Oveisgharan S, Osmanoglu B, Rosen P and Wegmüller U (2022), "Global seasonal Sentinel-1 interferometric coherence and backscatter data set", Scientific Data. Vol. 9(1)
BibTeX:
@article{Kellndorfer2022,
  author = {Kellndorfer, J. and Cartus, O. and Lavalle, M. and Magnard, C. and Milillo, P. and Oveisgharan, S. and Osmanoglu, B. and Rosen, P.A. and Wegmüller, U.},
  title = {Global seasonal Sentinel-1 interferometric coherence and backscatter data set},
  journal = {Scientific Data},
  year = {2022},
  volume = {9},
  number = {1},
  doi = {10.1038/s41597-022-01189-6}
}
Kochtitzky W, Copland L, Van Wychen W, Hugonnet R, Hock R, Dowdeswell J, Benham T, Strozzi T, Glazovsky A, Lavrentiev I, Rounce D, Millan R, Cook A, Dalton A, Jiskoot H, Cooley J, Jania J and Navarro F (2022), "The unquantified mass loss of Northern Hemisphere marine-terminating glaciers from 2000-2020", Nature Communications. Vol. 13(1)
BibTeX:
@article{Kochtitzky2022,
  author = {Kochtitzky, W. and Copland, L. and Van Wychen, W. and Hugonnet, R. and Hock, R. and Dowdeswell, J.A. and Benham, T. and Strozzi, T. and Glazovsky, A. and Lavrentiev, I. and Rounce, D.R. and Millan, R. and Cook, A. and Dalton, A. and Jiskoot, H. and Cooley, J. and Jania, J. and Navarro, F.},
  title = {The unquantified mass loss of Northern Hemisphere marine-terminating glaciers from 2000-2020},
  journal = {Nature Communications},
  year = {2022},
  volume = {13},
  number = {1},
  doi = {10.1038/s41467-022-33231-x}
}
Lavalle M, Telli C, Pierdicca N, Khati U, Cartus O and Kellndorfer J (2022), "Global Sentinel-1 InSAR Coherence: Opportunities for Model-Based Estimation of Land Parameters", In Proc. IEEE Int. Geosci. Remote Sens. Symp.., July, 2022. , pp. 1133-1136.
BibTeX:
@inproceedings{Lavalle2022,
  author = {Lavalle, M. and Telli, C. and Pierdicca, N. and Khati, U. and Cartus, O. and Kellndorfer, J.},
  title = {Global Sentinel-1 InSAR Coherence: Opportunities for Model-Based Estimation of Land Parameters},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2022},
  pages = {1133-1136},
  doi = {10.1109/IGARSS46834.2022.9883082}
}
Naderpour R, Schwank M, Houtz D and Matzler C (2022), "L-Band Radiometry of Alpine Seasonal Snow Cover: 4 Years at the Davos-Laret Remote Sensing Field Laboratory", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 15, pp. 8199-8220.
BibTeX:
@article{Naderpour2022a,
  author = {Naderpour, R. and Schwank, M. and Houtz, D. and Matzler, C.},
  title = {L-Band Radiometry of Alpine Seasonal Snow Cover: 4 Years at the Davos-Laret Remote Sensing Field Laboratory},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  year = {2022},
  volume = {15},
  pages = {8199-8220},
  doi = {10.1109/JSTARS.2022.3195614}
}
Naderpour R, Schwank M, Houtz D, Werner C and Mätzler C (2022), "Wideband Backscattering From Alpine Snow Cover: A Full-Season Study", IEEE Transactions on Geoscience and Remote Sensing. Vol. 60, pp. 1-15.
Abstract: This article experimentally investigates relationships between copol backscattering at a wide range of frequencies (L- to Ka-bands) and snow-ground state parameters (SPs) in different evolution phases during the full winter cycle of 2019/2020. Backscattering coefficients from 1 to 40 GHz, in situ snow-ground SPs, and meteorological data are measured at the Davos-Laret Remote Sensing Field Laboratory (Switzerland). Relative strengths of the snow-ground system's three primary scattering elements (air-snow interface, snow volume, and snow-ground interface) on backscattering are assessed. An anticorrelation between reasonably high snow wetness and backscattering coefficient is found, especially at higher microwave frequencies. For small amounts of snow wetness, backscatter coefficients at L- and S-bands are intensified via increasing snow volume and snow surface scattering. Snow-ground SPs influence backscattering according to their characteristic time scales of temporal evolution. Under dry snow conditions and at low and intermediate frequencies, ground permittivity is the major influencer of backscatter at a time scale of roughly two weeks. Snowfall is the major influencer of backscatter at a time scale of a few hours to a few days. The findings of this article are valuable to the development of retrieval algorithms using machine learning while maintaining a grasp on the ongoing physical processes. Another key message is that multifrequency active microwave measurements are critical to maximize the number of retrievable SPs and their estimation accuracy. For example, while Ka-band performs well in the detection of snow cover, L-band measurements are more responsive to changes of snow water equivalent (SWE) under moist or wet snow conditions.
BibTeX:
@article{Naderpour2022,
  author = {Naderpour, Reza and Schwank, Mike and Houtz, Derek and Werner, Charles and Mätzler, Christian},
  title = {Wideband Backscattering From Alpine Snow Cover: A Full-Season Study},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2022},
  volume = {60},
  pages = {1-15},
  doi = {10.1109/TGRS.2021.3112772}
}
Paul F, Piermattei L, Treichler D, Gilbert L, Girod L, Kääb A, Libert L, Nagler T, Strozzi T and Wuite J (2022), "Three different glacier surges at a spot: What satellites observe and what not", Cryosphere. Vol. 16(6), pp. 2505-2526.
BibTeX:
@article{Paul2022,
  author = {Paul, F. and Piermattei, L. and Treichler, D. and Gilbert, L. and Girod, L. and Kääb, A. and Libert, L. and Nagler, T. and Strozzi, T. and Wuite, J.},
  title = {Three different glacier surges at a spot: What satellites observe and what not},
  journal = {Cryosphere},
  year = {2022},
  volume = {16},
  number = {6},
  pages = {2505-2526},
  doi = {10.5194/tc-16-2505-2022}
}
Picard G, Läwe H and Mätzler C (2022), "Brief communication: A continuous formulation of microwave scattering from fresh snow to bubbly ice from first principles", Cryosphere. Vol. 16(9), pp. 3861-3866.
BibTeX:
@article{Picard2022,
  author = {Picard, G. and Läwe, H. and Mätzler, C.},
  title = {Brief communication: A continuous formulation of microwave scattering from fresh snow to bubbly ice from first principles},
  journal = {Cryosphere},
  year = {2022},
  volume = {16},
  number = {9},
  pages = {3861-3866},
  doi = {10.5194/tc-16-3861-2022}
}
Rozendaal D, Requena Suarez D, De Sy V, Avitabile V, Carter S, Adou Yao C, Alvarez-Davila E, Anderson-Teixeira K, Araujo-Murakami A, Arroyo L, Barca B, Baker T, Birigazzi L, Bongers F, Branthomme A, Brienen R, Carreiras J, Cazzolla Gatti R, Cook-Patton S, Decuyper M, Devries B, Espejo A, Feldpausch T, Fox J, G P Gamarra J, Griscom B, Harris N, Härault B, Honorio Coronado E, Jonckheere I, Konan E, Leavitt S, Lewis S, Lindsell J, N'Dja J, N'Guessan A, Marimon B, Mitchard E, Monteagudo A, Morel A, Pekkarinen A, Phillips O, Poorter L, Qie L, Rutishauser E, Ryan C, Santoro M, Silayo D, Sist P, Slik J, Sonkä B, Sullivan M, Vaglio Laurin G, Vilanova E, Wang M, Zahabu E and Herold M (2022), "Aboveground forest biomass varies across continents, ecological zones and successional stages: Refined IPCC default values for tropical and subtropical forests", Environmental Research Letters. Vol. 17(1)
BibTeX:
@article{Rozendaal2022,
  author = {Rozendaal, D.M.A. and Requena Suarez, D. and De Sy, V. and Avitabile, V. and Carter, S. and Adou Yao, C.Y. and Alvarez-Davila, E. and Anderson-Teixeira, K. and Araujo-Murakami, A. and Arroyo, L. and Barca, B. and Baker, T.R. and Birigazzi, L. and Bongers, F. and Branthomme, A. and Brienen, R.J.W. and Carreiras, J.M.B. and Cazzolla Gatti, R. and Cook-Patton, S.C. and Decuyper, M. and Devries, B. and Espejo, A.B. and Feldpausch, T.R. and Fox, J. and G P Gamarra, J. and Griscom, B.W. and Harris, N. and Härault, B. and Honorio Coronado, E.N. and Jonckheere, I. and Konan, E. and Leavitt, S.M. and Lewis, S.L. and Lindsell, J.A. and N'Dja, J.K. and N'Guessan, A.E. and Marimon, B. and Mitchard, E.T.A. and Monteagudo, A. and Morel, A. and Pekkarinen, A. and Phillips, O.L. and Poorter, L. and Qie, L. and Rutishauser, E. and Ryan, C.M. and Santoro, M. and Silayo, D.S. and Sist, P. and Slik, J.W.F. and Sonkä, B. and Sullivan, M.J.P. and Vaglio Laurin, G. and Vilanova, E. and Wang, M.M.H. and Zahabu, E. and Herold, M.},
  title = {Aboveground forest biomass varies across continents, ecological zones and successional stages: Refined IPCC default values for tropical and subtropical forests},
  journal = {Environmental Research Letters},
  year = {2022},
  volume = {17},
  number = {1},
  doi = {10.1088/1748-9326/ac45b3}
}
Sandells M, Löwe H, Picard G, Dumont M, Essery R, Floury N, Kontu A, Lemmetyinen J, Maslanka W, Morin S, Wiesmann A and Mätzler C (2022), "X-Ray Tomography-Based Microstructure Representation in the Snow Microwave Radiative Transfer Model", IEEE Transactions on Geoscience and Remote Sensing. Vol. 60, pp. 1-15.
BibTeX:
@article{Sandells2022,
  author = {Sandells, Melody and Löwe, Henning and Picard, Ghislain and Dumont, Marie and Essery, Richard and Floury, Nicolas and Kontu, Anna and Lemmetyinen, Juha and Maslanka, William and Morin, Samuel and Wiesmann, Andreas and Mätzler, Christian},
  title = {X-Ray Tomography-Based Microstructure Representation in the Snow Microwave Radiative Transfer Model},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2022},
  volume = {60},
  pages = {1-15},
  doi = {10.1109/TGRS.2021.3086412}
}
Santoro M, Cartus O and Fransson J (2022), "Dynamics of the Swedish forest carbon pool between 2010 and 2015 estimated from satellite L-band SAR observations", Remote Sensing of Environment. Vol. 270(112846)
BibTeX:
@article{Santoro2022,
  author = {Santoro, M. and Cartus, O. and Fransson, J.E.S.},
  title = {Dynamics of the Swedish forest carbon pool between 2010 and 2015 estimated from satellite L-band SAR observations},
  journal = {Remote Sensing of Environment},
  year = {2022},
  volume = {270},
  number = {112846},
  doi = {10.1016/j.rse.2021.112846}
}
Santoro M, Cartus O, Wegmüller U, Besnard S, Carvalhais N, Araza A, Herold M, Liang J, Cavlovic J and Engdahl M (2022), "Global estimation of above-ground biomass from spaceborne C-band scatterometer observations aided by LiDAR metrics of vegetation structure", Remote Sensing of Environment. Vol. 279(113114)
BibTeX:
@article{Santoro2022,
  author = {Santoro, M. and Cartus, O. and Wegmüller, U. and Besnard, S. and Carvalhais, N. and Araza, A. and Herold, M. and Liang, J. and Cavlovic, J. and Engdahl, M.E.},
  title = {Global estimation of above-ground biomass from spaceborne C-band scatterometer observations aided by LiDAR metrics of vegetation structure},
  journal = {Remote Sensing of Environment},
  year = {2022},
  volume = {279},
  number = {113114},
  doi = {10.1016/j.rse.2022.113114}
}
Stefko M, Frey O and Hajnsek I (2022), "Snow Characterization at Ku-Band with a Bistatic Polarimetric Ground-Based Radar", In Proc. IEEE Int. Geosci. Remote Sens. Symp.., July, 2022. , pp. 4256-4259.
Abstract: The Ku-band provides opportunities for investigations of snow morphology through radar observations, since it exhibits a relatively high amount of scattering even from snow layers of limited depth, while maintaining low absorption. Due to technological and practical challenges, the bistatic parameter space of Ku-band radar observations of natural media such as snow, has been relatively unexplored. We present radar measurements of snow cover obtained with KAPRI, a bistatic polarimetric Ku-band radar system. In August 2021 and March 2022, we carried out time series observations of the Aletsch glacier in the Swiss Alps, acquiring a fully-polarimetric interferometric time series of both monostatic and simultaneous bistatic observations of the glacier's accumulation zone. This dataset will serve as a test-bed to investigate new snow parameter inversion methods based on bistatic Ku-band radar data. The bistatic polarimetric measurement configuration, as well as preliminary results of the analysis of radar backscatter, are presented.
BibTeX:
@inproceedings{stefkoFreyHajnsekIGARSS2022SnowCharacterizationAtKuBandWithABistaticPolarimetricGroundBasedRadar,
  author = {Stefko, Marcel and Frey, Othmar and Hajnsek, Irena},
  title = {Snow Characterization at Ku-Band with a Bistatic Polarimetric Ground-Based Radar},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2022},
  pages = {4256-4259},
  doi = {10.1109/IGARSS46834.2022.9884442}
}
Stefko M, Frey O, Werner C and Hajnsek I (2022), "Calibration and Operation of a Bistatic Real-Aperture Polarimetric-Interferometric Ku-Band Radar", IEEE Transactions on Geoscience and Remote Sensing. Vol. 60(5106719), pp. 1-19. Institute of Electrical and Electronics Engineers (IEEE).
Abstract: This article presents the bistatic operation mode and the performance analysis of KAPRI, a terrestrial frequency-modulated continuous wave (FMCW) Ku-band polarimetric radar interferometer capable of acquiring bistatic full-polarimetric datasets with high spatial and temporal resolution. In the bistatic configuration, the system is composed of two independently-operating KAPRI devices, one serving as a primary transmitter-receiver, and the other as a secondary receiver. The secondary bistatic dataset is affected by possible offsets between the two devices' reference clocks, as well as distortions arising from geometry. To correct for this, we present a two-chirp bistatic FMCW signal model which accounts for the distortions, and a reference chirp transmission procedure which allows correcting the clock offsets in the deramped signal time domain. The second challenge of operation of a bistatic polarimetric system is polarimetric calibration, since it is not possible to employ purely monostatic targets such as corner reflectors. For this purpose we developed a novel active calibration device VSPARC (Variable-Signature Polarimetric Active Radar Calibrator), designed for monostatic and bistatic calibration of all polarimetric channels. VSPARC and its associated novel polarimetric calibration method were then used to achieve full calibration of both KAPRI devices with polarimetric phase calibration accuracy of 20 deg and 30 dB polarization purity in field conditions. This article thus presents a complete measurement configuration and data processing pipeline necessary for synchronization, coregistration, and polarimetric calibration of bistatic and monostatic datasets acquired by a real-aperture FMCW radar.
BibTeX:
@article{stefkoFreyWernerHajnsekTGRS2022CalibrationAndOperationOfBistaticPolGPRI,
  author = {Stefko, Marcel and Frey, Othmar and Werner, Charles and Hajnsek, Irena},
  title = {Calibration and Operation of a Bistatic Real-Aperture Polarimetric-Interferometric Ku-Band Radar},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers (IEEE)},
  year = {2022},
  volume = {60},
  number = {5106719},
  pages = {1--19},
  doi = {10.1109/TGRS.2021.3121466}
}
Stefko M, Leinss S, Frey O and Hajnsek I (2022), "Coherent backscatter enhancement in bistatic Ku-/X-band radar observations of dry snow", The Cryosphere. Vol. 16(7), pp. 2859-2879. Copernicus GmbH.
Abstract: The coherent backscatter opposition effect (CBOE) enhances the backscatter intensity of electromagnetic waves by up to a factor of two in a very narrow cone around the direct return direction when multiple scattering occurs in a weakly absorbing, disordered medium. So far, this effect has not been investigated in terrestrial snow in the microwave spectrum. It has also received little attention in scattering models. We present the first characterization of the CBOE in dry snow using ground-based and space-borne bistatic radar systems. For a seasonal snow pack in Ku-band (17.2 GHz),we found backscatter enhancement of 50-60% (+1.8-2.0 dB) at zero bistatic angle and a peak half-width-at-half-maximum (HWHM) of 0.25 deg. In X-band (9.65 GHz), we found backscatter enhancement of at least 35% (+1.3 dB) and an estimated HWHM of 0.12 deg in the accumulation areas of glaciers in the Jungfrau-Aletsch region, Switzerland. Sampling of the peak shape at different bistatic angles allows estimating the scattering and absorption mean free paths, Lambda_T and Lambda_A. In the VV polarization, we obtained Lambda_T = 0.4 +/- 0.1 m and Lambda_A = 19 +/- 12 m at Ku-band, and Lambda_T = 2.1 +/- 0.4 m, Lambda_A = 21.8 +/- 2.7 m at X-band. The HH polarization yielded similar results. The observed backscatter enhancement is thus significant enough to require consideration in backscatter models describing monostatic and bistatic radar experiments. Enhanced backscattering beyond the Earth, on the surface of solar system bodies, has been interpreted as being caused by the presence of water ice. In agreement with this interpretation, our results confirm the presence of the CBOE at X- and Ku-band frequencies in terrestrial snow.
BibTeX:
@article{stefkoLeinssFreyHanjsek2022CoherentBackscatterEnhancementInBistaticRadarObservationsOfSnow,
  author = {Marcel Stefko and Silvan Leinss and Othmar Frey and Irena Hajnsek},
  title = {Coherent backscatter enhancement in bistatic Ku-/X-band radar observations of dry snow},
  journal = {The Cryosphere},
  publisher = {Copernicus GmbH},
  year = {2022},
  volume = {16},
  number = {7},
  pages = {2859--2879},
  doi = {10.5194/tc-16-2859-2022}
}
Strozzi T, Caduff R, Jones N, Manconi A and Wegmüller U (2022), "L-Band StripMap-ScanSAR Persistent Scatterer Interferometry in Alpine Environments with ALOS-2 PALSAR-2", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1644-1647.
BibTeX:
@inproceedings{9884743,
  author = {Strozzi, Tazio and Caduff, Rafael and Jones, Nina and Manconi, Andrea and Wegmüller, Urs},
  title = {L-Band StripMap-ScanSAR Persistent Scatterer Interferometry in Alpine Environments with ALOS-2 PALSAR-2},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2022},
  pages = {1644-1647},
  doi = {10.1109/IGARSS46834.2022.9884743}
}
Strozzi T, Wiesmann A, Kääb A, Schellenberger T and Paul F (2022), "Ice Surface Velocity in the Eastern Arctic from Historical Satellite SAR Data", Earth System Science Data Discussions. Vol. 2022, pp. 1-42.
BibTeX:
@article{essd-2022-44,
  author = {Strozzi, T. and Wiesmann, A. and Kääb, A. and Schellenberger, T. and Paul, F.},
  title = {Ice Surface Velocity in the Eastern Arctic from Historical Satellite SAR Data},
  journal = {Earth System Science Data Discussions},
  year = {2022},
  volume = {2022},
  pages = {1-42},
  url = {https://essd.copernicus.org/preprints/essd-2022-44/},
  doi = {10.5194/essd-2022-44}
}
Tao S, Chave J, Frison P-L, Le Toan T, Ciais P, Fang J, Wigneron J-P, Santoro M, Yang H, Li X, Labriere N and Saatchi S (2022), "Increasing and widespread vulnerability of intact tropical rainforests to repeated droughts", Proceedings of the National Academy of Sciences of the United States of America. Vol. 119(37)(e2116626119)
BibTeX:
@article{Tao2022,
  author = {Tao, S. and Chave, J. and Frison, P.-L. and Le Toan, T. and Ciais, P. and Fang, J. and Wigneron, J.-P. and Santoro, M. and Yang, H. and Li, X. and Labriere, N. and Saatchi, S.},
  title = {Increasing and widespread vulnerability of intact tropical rainforests to repeated droughts},
  journal = {Proceedings of the National Academy of Sciences of the United States of America},
  year = {2022},
  volume = {119(37)},
  number = {e2116626119},
  doi = {10.1073/pnas.2116626119}
}
Xu Y, Yu L, Ciais P, Li W, Santoro M, Yang H and Gong P (2022), "Recent expansion of oil palm plantations into carbon-rich forests", Nature Sustainability. Vol. 5(7), pp. 574-577.
BibTeX:
@article{Xu2022,
  author = {Xu, Y. and Yu, L. and Ciais, P. and Li, W. and Santoro, M. and Yang, H. and Gong, P.},
  title = {Recent expansion of oil palm plantations into carbon-rich forests},
  journal = {Nature Sustainability},
  year = {2022},
  volume = {5},
  number = {7},
  pages = {574-577},
  doi = {10.1038/s41893-022-00872-1}
}
Yang H, Ciais P, Wigneron J-P, Chave J, Cartus O, Chen X, Fan L, Green J, Huang Y, Joetzjer E, Kay H, Makowski D, Maignan F, Santoro M, Tao S, Liu L and Yao Y (2022), "Climatic and biotic factors influencing regional declines and recovery of tropical forest biomass from the 2015/16 El Niño", Proceedings of the National Academy of Sciences of the United States of America. Vol. 119(26)
BibTeX:
@article{Yang2022,
  author = {Yang, H. and Ciais, P. and Wigneron, J.-P. and Chave, J. and Cartus, O. and Chen, X. and Fan, L. and Green, J.K. and Huang, Y. and Joetzjer, E. and Kay, H. and Makowski, D. and Maignan, F. and Santoro, M. and Tao, S. and Liu, L. and Yao, Y.},
  title = {Climatic and biotic factors influencing regional declines and recovery of tropical forest biomass from the 2015/16 El Niño},
  journal = {Proceedings of the National Academy of Sciences of the United States of America},
  year = {2022},
  volume = {119},
  number = {26},
  doi = {10.1073/pnas.2101388119}
}
Balenzano A, Mattia F, Satalino G, Lovergine FP, Palmisano D, Peng J, Marzahn P, Wegmüller U, Cartus O, Dąbrowska-Zieliʼnska K, Musial JP, Davidson MW, Pauwels VR, Cosh MH, McNairn H, Johnson JT, Walker JP, Yueh SH, Entekhabi D, Kerr YH and Jackson TJ (2021), "Sentinel-1 soil moisture at 1 km resolution: a validation study", Remote Sensing of Environment., sep, 2021. Vol. 263, pp. 112554. Elsevier BV.
BibTeX:
@article{Balenzano_2021,
  author = {Anna Balenzano and Francesco Mattia and Giuseppe Satalino and Francesco P. Lovergine and Davide Palmisano and Jian Peng and Philip Marzahn and Urs Wegmüller and Oliver Cartus and Katarzyna Dąbrowska-Zieliʼnska and Jan P. Musial and Malcolm W.J. Davidson and Valentijn R.N. Pauwels and Michael H. Cosh and Heather McNairn and Joel T. Johnson and Jeffrey P. Walker and Simon H. Yueh and Dara Entekhabi and Yann H. Kerr and Thomas J. Jackson},
  title = {Sentinel-1 soil moisture at 1 km resolution: a validation study},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier BV},
  year = {2021},
  volume = {263},
  pages = {112554},
  doi = {10.1016/j.rse.2021.112554}
}
Besnard S, Koirala S, Santoro M, Weber U, Nelson J, Gütter J, Herault B, Kassi J, N'Guessan A, Neigh C, Poulter B, Zhang T and Carvalhais N (2021), "Mapping global forest age from forest inventories, biomass and climate data", Earth System Science Data., oct, 2021. Vol. 13(10), pp. 4881-4896. Copernicus GmbH.
BibTeX:
@article{Besnard_2021,
  author = {Simon Besnard and Sujan Koirala and Maurizio Santoro and Ulrich Weber and Jacob Nelson and Jonas Gütter and Bruno Herault and Justin Kassi and Anny N'Guessan and Christopher Neigh and Benjamin Poulter and Tao Zhang and Nuno Carvalhais},
  title = {Mapping global forest age from forest inventories, biomass and climate data},
  journal = {Earth System Science Data},
  publisher = {Copernicus GmbH},
  year = {2021},
  volume = {13},
  number = {10},
  pages = {4881--4896},
  doi = {10.5194/essd-13-4881-2021}
}
Besnard S, Santoro M, Cartus O, Fan N, Linscheid N, Nair R, Weber U, Koirala S and Carvalhais N (2021), "Global sensitivities of forest carbon changes to environmental conditions", Global Change Biology., sep, 2021. Vol. 27(24), pp. 6467-6483. Wiley.
BibTeX:
@article{Besnard_2021,
  author = {Simon Besnard and Maurizio Santoro and Oliver Cartus and Naixin Fan and Nora Linscheid and Richard Nair and Ulrich Weber and Sujan Koirala and Nuno Carvalhais},
  title = {Global sensitivities of forest carbon changes to environmental conditions},
  journal = {Global Change Biology},
  publisher = {Wiley},
  year = {2021},
  volume = {27},
  number = {24},
  pages = {6467--6483},
  doi = {10.1111/gcb.15877}
}
Beutel J, Biri A, Buchli B, Cicoira A, Delaloye R, Forno RD, Gaertner-Roer I, Gruber S, Gsell T, Hasler A, Lim R, Limpach P, Mayoraz R, Meyer M, Noetzli J, Phillips M, Pointner E, Raetzo H, Scapoza C, Strozzi T, Thiele L, Vieli A, Mühll DV, Weber S and Wirz V (2021), "Kinematic observations of the mountain cryosphere using in-situ GNSS instruments", Preprint - Earth System Science Data., jun, 2021. Copernicus GmbH.
BibTeX:
@article{Beutel_2021,
  author = {Jan Beutel and Andreas Biri and Ben Buchli and Alessandro Cicoira and Reynald Delaloye and Reto Da Forno and Isabelle Gaertner-Roer and Stephan Gruber and Tonio Gsell and Andreas Hasler and Roman Lim and Phillipe Limpach and Raphael Mayoraz and Matthias Meyer and Jeannette Noetzli and Marcia Phillips and Eric Pointner and Hugo Raetzo and Cristian Scapoza and Tazio Strozzi and Lothar Thiele and Andreas Vieli and Daniel Vonder Mühll and Samuel Weber and Vanessa Wirz},
  title = {Kinematic observations of the mountain cryosphere using in-situ GNSS instruments},
  journal = {Preprint - Earth System Science Data},
  publisher = {Copernicus GmbH},
  year = {2021},
  doi = {10.5194/essd-2021-176}
}
Caduff R, Strozzi T, Hählen N and Häberle J (2021), "Accelerating Landslide Hazard at Kandersteg, Swiss Alps; combining 28 Years of Satellite InSAR and Single Campaign Terrestrial Radar Data", In Understanding and Reducing Landslide Disaster Risk., dec, 2021. , pp. 267-273. Springer International Publishing.
BibTeX:
@inproceedings{Caduff_2021,
  author = {Rafael Caduff and Tazio Strozzi and Nils Hählen and Jörg Häberle},
  editor = {Vilímek, Vít and Wang, Fawu and Strom, Alexander and Sassa, Kyoji and Bobrowsky, Peter T. and Takara, Kaoru},
  title = {Accelerating Landslide Hazard at Kandersteg, Swiss Alps; combining 28 Years of Satellite InSAR and Single Campaign Terrestrial Radar Data},
  booktitle = {Understanding and Reducing Landslide Disaster Risk},
  publisher = {Springer International Publishing},
  year = {2021},
  pages = {267--273},
  doi = {10.1007/978-3-030-60319-9_29}
}
Dammann DO, Johnson MA, Fedders ER, Mahoney AR, Werner CL, Polashenski CM, Meyer FJ and Hutchings JK (2021), "Ground-Based Radar Interferometry of Sea Ice", Remote Sensing. Vol. 13(1), pp. 57-66.
Abstract: In light of recent Arctic change, there is a need to better understand sea ice dynamic processes at the floe scale to evaluate sea ice stability, deformation, and fracturing. This work investigates the use of the Gamma portable radar interferometer (GPRI) to characterize sea ice displacement and surface topography. We find that the GPRI is best suited to derive lateral surface deformation due to mm-scale horizontal accuracy. We model interferometric phase signatures from sea ice displacement and evaluate possible errors related to noise and antenna motion. We compare the analysis with observations acquired during a drifting ice camp in the Beaufort Sea. We used repeat-scan and stare-mode interferometry to identify two-dimensional shear and to track continuous uni-directional convergence. This paper demonstrates the capacity of the GPRI to derive surface strain on the order of 10−7 and identify different dynamic regions based on sub-mm changes in displacement. The GPRI is thus a promising tool for sea ice applications due to its high accuracy that can potentially resolve pre- and post-fracture deformation relevant to sea ice stability and modeling.
BibTeX:
@article{DammannEtAl2021,
  author = {Dammann, Dyre Oliver and Johnson, Mark A. and Fedders, Emily R. and Mahoney, Andrew R. and Werner, Charles L. and Polashenski, Christopher M. and Meyer, Franz J. and Hutchings, Jennifer K.},
  title = {Ground-Based Radar Interferometry of Sea Ice},
  journal = {Remote Sensing},
  year = {2021},
  volume = {13},
  number = {1},
  pages = {57-66},
  url = {https://www.mdpi.com/2072-4292/13/1/43},
  doi = {10.3390/rs13010043}
}
Deeb E, Lund J, Forster R, LeWinter A, Morriss B, Marshall H-P, Werner C and Frey O (2021), "NASA SnowEx deployment of CarSAR: a mobile L-Band interferometric synthetic aperture radar platform", In AGU Fall Meeting Abstracts., December, 2021. Vol. 2021, pp. C15F-0864.
BibTeX:
@inproceedings{deebElAlAGU2021GammaLBandSAR,
  author = {Deeb, Elias and Lund, Jewell and Forster, Richard and LeWinter, Adam and Morriss, Blaine and Marshall, Hans-Peter and Werner, Charles and Frey, Othmar},
  title = {NASA SnowEx deployment of CarSAR: a mobile L-Band interferometric synthetic aperture radar platform},
  booktitle = {AGU Fall Meeting Abstracts},
  year = {2021},
  volume = {2021},
  pages = {C15F-0864}
}
Fontana P, Preuss G and Mäzler C (2021), "Haarförmiges und bandförmiges Eis", Naturforschende Gesellschaft des Kantons Solothurn. Vol. 44, pp. 11-23.
BibTeX:
@article{Fontana_2021,
  author = {Pietro Fontana and Gisela Preuss and Christian Mäzler},
  title = {Haarförmiges und bandförmiges Eis},
  journal = {Naturforschende Gesellschaft des Kantons Solothurn},
  year = {2021},
  volume = {44},
  pages = {11-23},
  url = {https://www.e-periodica.ch/digbib/vollist?var=true&UID=ngs-004}
}
Frey O and Werner CL (2021), "UAV-borne repeat-pass SAR interferometry and SAR tomography with a compact L-band SAR system", In Proc. Europ. Conf. Synthetic Aperture Radar, EUSAR., March, 2021. , pp. 181-184. VDE.
Abstract: In this contribution, we present SAR image focusing, interferometric, and first tomographic processing results computed from repeat-pass SAR data sets acquired on-board of a vertical-take-off-and-landing (VTOL) unmanned aerial vehicle (UAV): the data was acquired using a novel compact FMCW L-band SAR system in two repeat-pass SAR campaigns flown on 2019-02-13 and 2019-03-28, respectively. In these demonstration campaigns, the Gamma L-band SAR system was deployed and operated on Aeroscout's VTOL UAV Scout B1-100. Repeat-pass interferograms and coherence maps with a temporal baseline of up to 43 days are presented and a tomographic profile obtained from short-term repeat-pass measurements is shown. The results demonstrate the feasibility of UAV-borne repeat-pass SAR interferometry and SAR tomography at L-band
BibTeX:
@inproceedings{freyWernerEUSAR2021UAVborneRepeatPassSARInterferometryAndSARTomography,
  author = {Frey,Othmar and Werner, Charles L.},
  title = {UAV-borne repeat-pass SAR interferometry and SAR tomography with a compact L-band SAR system},
  booktitle = {Proc. Europ. Conf. Synthetic Aperture Radar, EUSAR},
  publisher = {VDE},
  year = {2021},
  pages = {181-184},
  url = {https://www.gamma-rs.ch/uploads/media/freyWernerEUSAR2021UAVborneRepeatPassSARInterferometryAndSARTomography.pdf}
}
Frey O, Werner CL, Manconi A and Coscione R (2021), "Measurement of surface displacements with a UAV-borne/car-borne L-band DInSAR system: system performance and use cases", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 628-631. IEEE.
Abstract: In this paper, we present examples of DInSAR-based measurement of surface displacements using a novel compact L-band SAR system that can be mounted on mobile mapping platforms such as a UAV or a car. The good DInSAR system performance is demonstrated and, particularly, we also show a use case in which a car-borne system setup is employed to map surface displacements of a fast-moving landslide and the surrounding area in Switzerland. Our results show that car-borne and UAV-borne interferometric displacement measurements at L-band are feasible with high quality over various natural terrain. This novel compact DInSAR system for agile platforms complements existing terrestrial, airborne, and space-borne radar interferometry systems in terms of its new combination of (1) radar wavelength (sensitivity to displacement/decorrelation properties), (2) spatial resolution, (3) (near-) terrestrial observation geometry, and (4) mobile mapping capability.
BibTeX:
@inproceedings{freyEtAlIGARSS2021UAVandCarborneDinSARwithGammaLbandSAR,
  author = {Frey, Othmar and Werner, Charles L. and Manconi, Andrea and Coscione, Roberto},
  title = {Measurement of surface displacements with a UAV-borne/car-borne L-band DInSAR system: system performance and use cases},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE},
  year = {2021},
  pages = {628-631},
  url = {https://www.gamma-rs.ch/uploads/media/freyEtAlIGARSS2021UAVandCarborneDinSARwithGammaLbandSAR.pdf},
  doi = {10.1109/IGARSS47720.2021.9553573}
}
Hocke K, Bernet L, Wang W, Matzler C, Hervo M and Haefele A (2021), "Integrated Water Vapor during Rain and Rain-Free Conditions above the Swiss Plateau", Climate., jun, 2021. Vol. 9(7), pp. 105. MDPI AG.
BibTeX:
@article{Hocke_2021,
  author = {Klemens Hocke and Leonie Bernet and Wenyue Wang and Christian Matzler and Maxime Hervo and Alexander Haefele},
  title = {Integrated Water Vapor during Rain and Rain-Free Conditions above the Swiss Plateau},
  journal = {Climate},
  publisher = {MDPI AG},
  year = {2021},
  volume = {9},
  number = {7},
  pages = {105},
  doi = {10.3390/cli9070105}
}
Houtz D, Mätzler C, Naderpour R, Schwank M and Steffen K (2021), "Quantifying Surface Melt and Liquid Water on the Greenland Ice Sheet using L-band Radiometry", Remote Sensing of Environment., apr, 2021. Vol. 256, pp. 112341. Elsevier BV.
BibTeX:
@article{Houtz_2021,
  author = {Derek Houtz and Christian Mätzler and Reza Naderpour and Mike Schwank and Konrad Steffen},
  title = {Quantifying Surface Melt and Liquid Water on the Greenland Ice Sheet using L-band Radiometry},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier BV},
  year = {2021},
  volume = {256},
  pages = {112341},
  doi = {10.1016/j.rse.2021.112341}
}
How P, Messerli A, Mätzler E, Santoro M, Wiesmann A, Caduff R, Langley K, Bojesen MH, Paul F, Kääb A and Carrivick JL (2021), "Greenland-wide inventory of ice marginal lakes using a multi-method approach", Scientific Reports., Feb, 2021. Vol. 11(1), pp. 4481.
Abstract: Ice marginal lakes are a dynamic component of terrestrial meltwater storage at the margin of the Greenland Ice Sheet. Despite their significance to the sea level budget, local flood hazards and bigeochemical fluxes, there is a lack of Greenland-wide research into ice marginal lakes. Here, a detailed multi-sensor inventory of Greenland's ice marginal lakes is presented based on three well-established detection methods to form a unified remote sensing approach. The inventory consists of 3347 ($$backslashpm 8$$%) ice marginal lakes ($$>0.05backslash,backslashtext km ^2$$) detected for the year 2017. The greatest proportion of lakes lie around Greenland's ice caps and mountain glaciers, and the southwest margin of the ice sheet. Through comparison to previous studies, a $$backslashsim 75$$% increase in lake frequency is evident over the west margin of the ice sheet since 1985. This suggests it is becoming increasingly important to include ice marginal lakes in future sea level projections, where these lakes will form a dynamic storage of meltwater that can influence outlet glacier dynamics. Comparison to existing global glacial lake inventories demonstrate that up to 56% of ice marginal lakes could be unaccounted for in global estimates of ice marginal lake change, likely due to the reliance on a single lake detection method.
BibTeX:
@article{How2021,
  author = {How, Penelope and Messerli, Alexandra and Mätzler, Eva and Santoro, Maurizio and Wiesmann, Andreas and Caduff, Rafael and Langley, Kirsty and Bojesen, Mikkel Høegh and Paul, Frank and Kääb, Andreas and Carrivick, Jonathan L.},
  title = {Greenland-wide inventory of ice marginal lakes using a multi-method approach},
  journal = {Scientific Reports},
  year = {2021},
  volume = {11},
  number = {1},
  pages = {4481},
  url = {https://doi.org/10.1038/s41598-021-83509-1},
  doi = {10.1038/s41598-021-83509-1}
}
Huang Y, Ciais P, Santoro M, Makowski D, Chave J, Schepaschenko D, Abramoff RZ, Goll DS, Yang H, Chen Y, Wei W and Piao S (2021), "A global map of root biomass across the world's forests", Earth System Science Data., aug, 2021. Vol. 13(9), pp. 4263-4274. Copernicus GmbH.
BibTeX:
@article{Huang_2021,
  author = {Yuanyuan Huang and Phillipe Ciais and Maurizio Santoro and David Makowski and Jerome Chave and Dmitry Schepaschenko and Rose Z. Abramoff and Daniel S. Goll and Hui Yang and Ye Chen and Wei Wei and Shilong Piao},
  title = {A global map of root biomass across the world's forests},
  journal = {Earth System Science Data},
  publisher = {Copernicus GmbH},
  year = {2021},
  volume = {13},
  number = {9},
  pages = {4263--4274},
  doi = {10.5194/essd-13-4263-2021}
}
Izumi Y, Frey O, Baffelli S, Hajnsek I and Sato M (2021), "Efficient Approach for Atmospheric Phase Screen Mitigation in Time Series of Terrestrial Radar Interferometry Data Applied to Measure Glacier Velocity", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 14, pp. 7734-7750.
Abstract: The accuracy of surface displacements measured by differential radar interferometry is significantly degraded by the atmospheric phase screen (APS). This paper presents a practical and efficient approach for APS mitigation based on the coherent pixels technique (CPT) displacement velocity estimation algorithm. In the proposed approach, all motionless coherent pixels closest to the moving area are defined as seeds surrounding the moving area at the integration step of the CPT. This arrangement consequently minimizes the integration path and the APS effect in the final velocity result. It is designed for terrestrial radar interferometry (TRI) applications. As a continuous operational mode processing framework, a piecewise processing chain is further introduced to derive arbitrary temporal displacement patterns in this work. Three-day datasets measured by Ku-band TRI over a mountainous region in the canton of Valais, Switzerland, were used for validation. Through this validation, a comparative study of five algorithms was carried out. This evaluation showed the efficiency of the proposed approach. The proposed approach does not require phase unwrapping, kriging interpolation, and spatio-temporal covariance inference for APS mitigation, which is appropriate for continuous TRI operation.
BibTeX:
@article{izumiFreyBaffelliHajnsekSatoJSTARS2021APSMitigationInTimeSeriesOfTRIDataGlacierVel,
  author = {Yuta Izumi and Othmar Frey and Simone Baffelli and Irena Hajnsek and Motoyuki Sato},
  title = {Efficient Approach for Atmospheric Phase Screen Mitigation in Time Series of Terrestrial Radar Interferometry Data Applied to Measure Glacier Velocity},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  year = {2021},
  volume = {14},
  pages = {7734-7750},
  doi = {10.1109/JSTARS.2021.3099873}
}
Jones N, Manconi A and Strom A (2021), "Active landslides in the Rogun Catchment, Tajikistan, and their river damming hazard potential", Landslides., aug, 2021. Vol. 18(11), pp. 3599-3613. Springer Science and Business Media LLC.
BibTeX:
@article{Jones_2021,
  author = {Nina Jones and Andrea Manconi and Alexander Strom},
  title = {Active landslides in the Rogun Catchment, Tajikistan, and their river damming hazard potential},
  journal = {Landslides},
  publisher = {Springer Science and Business Media LLC},
  year = {2021},
  volume = {18},
  number = {11},
  pages = {3599--3613},
  doi = {10.1007/s10346-021-01706-5}
}
Kääb A, Strozzi T, Bolch T, Caduff R, Trefall H, Stoffel M and Kokarev A (2021), "Inventory and changes of rock glacier creep speeds in Ile Alatau and Kungöy Ala-Too, northern Tien Shan, since the 1950s", The Cryosphere., feb, 2021. Vol. 15(2), pp. 927-949. Copernicus GmbH.
BibTeX:
@article{K_b_2021,
  author = {Andreas Kääb and Tazio Strozzi and Tobias Bolch and Rafael Caduff and Håkon Trefall and Markus Stoffel and Alexander Kokarev},
  title = {Inventory and changes of rock glacier creep speeds in Ile Alatau and Kungöy Ala-Too, northern Tien Shan, since the 1950s},
  journal = {The Cryosphere},
  publisher = {Copernicus GmbH},
  year = {2021},
  volume = {15},
  number = {2},
  pages = {927--949},
  doi = {10.5194/tc-15-927-2021}
}
Klimeš J, Novotný J, Rapre AC, Balek J, Zahradn\iček P, Strozzi T, Sana H, Frey H, René M, Štěpánek P, Meitner J and Junghardt J (2021), "Paraglacial Rock Slope Stability Under Changing Environmental Conditions, Safuna Lakes, Cordillera Blanca Peru", Frontiers in Earth Science., apr, 2021. Vol. 9 Frontiers Media SA.
BibTeX:
@article{Klime__2021,
  author = {Jan Klimeš and Jan Novotný and Alejo Cochacin Rapre and Jan Balek and Pavel Zahradn\iček and Tazio Strozzi and Hamid Sana and Holger Frey and Miloš René and Petr Štěpánek and Jan Meitner and Johan Junghardt},
  title = {Paraglacial Rock Slope Stability Under Changing Environmental Conditions, Safuna Lakes, Cordillera Blanca Peru},
  journal = {Frontiers in Earth Science},
  publisher = {Frontiers Media SA},
  year = {2021},
  volume = {9},
  doi = {10.3389/feart.2021.607277}
}
Kos A, Amann F, Strozzi T, Osten J, Wellmann F, Jalali M and Dufresne A (2021), "The Surface Velocity Response of a Tropical Glacier to Intra and Inter Annual Forcing, Cordillera Blanca, Peru", Remote Sensing., jul, 2021. Vol. 13(14), pp. 2694. MDPI AG.
BibTeX:
@article{Kos_2021,
  author = {Andrew Kos and Florian Amann and Tazio Strozzi and Julian Osten and Florian Wellmann and Mohammadreza Jalali and Anja Dufresne},
  title = {The Surface Velocity Response of a Tropical Glacier to Intra and Inter Annual Forcing, Cordillera Blanca, Peru},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2021},
  volume = {13},
  number = {14},
  pages = {2694},
  doi = {10.3390/rs13142694}
}
Leinss S, Li S and Frey O (2021), "Measuring Glacier Velocity by Autofocusing Temporally Multilooked SAR Time Series", In Proc. IEEE Int. Geosci. Remote Sens. Symp.., July, 2021. , pp. 5493-5496. IEEE.
Abstract: ABSTRACT
SAR offset tracking, applied on areas with strong temporal decorrelation, requires relatively large image templates for cross-correlation to compensate for incoherent radar speckle. Template edge lengths of 64-12 pixels are common. Furthermore, velocity maps are often incomplete because weakly visible features are obscured by uncorrelated speckle. To improve SAR offset tracking, we propose a new robust method which can significantly enhance both the spatial completeness and the resolution of velocity products by assuming a stationary velocity field. The method minimizes the motion blur of moving features which occurs when SAR backscatter time se- ries are multilooked in time. Our velocity-adaptive temporal multilooking strongly reduces speckle without losing spatial resolution which makes the cross-correlation much more ro- bust even for template sizes as small as
30 x 30 pixels. We demonstrate the method by generating a high resolution velocity map of Great Aletsch Glacier in Switzerland.
BibTeX:
@inproceedings{leinssLiFreyIGARSS2021GlacierVelocityByAutofocusingTemporallyMultilookedSARTimeSeries,
  author = {Leinss, Silvan and Li, Shiyi and Frey, Othmar},
  title = {Measuring Glacier Velocity by Autofocusing Temporally Multilooked SAR Time Series},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE},
  year = {2021},
  pages = {5493-5496},
  doi = {10.1109/IGARSS47720.2021.9554999}
}
Pan J, Durand MT, Courville Z, Jagt BJV, Molotch NP, Margulis SA, Kim EJ, Schneebeli M and Mätzler C (2021), "Evaluation of stereology for snow microstructure measurement and microwave emission modeling: a case study", International Journal of Digital Earth., mar, 2021. Vol. 14(10), pp. 1316-1336. Informa UK Limited.
BibTeX:
@article{Pan_2021,
  author = {Jinmei Pan and M. T. Durand and Z. Courville and B. J. Vander Jagt and N. P. Molotch and S. A. Margulis and E. J. Kim and M. Schneebeli and C. Mätzler},
  title = {Evaluation of stereology for snow microstructure measurement and microwave emission modeling: a case study},
  journal = {International Journal of Digital Earth},
  publisher = {Informa UK Limited},
  year = {2021},
  volume = {14},
  number = {10},
  pages = {1316--1336},
  doi = {10.1080/17538947.2021.1902006}
}
Peng J, Albergel C, Balenzano A, Brocca L, Cartus O, Cosh MH, Crow WT, Dabrowska-Zielinska K, Dadson S, Davidson MW, de Rosnay P, Dorigo W, Gruber A, Hagemann S, Hirschi M, Kerr YH, Lovergine F, Mahecha MD, Marzahn P, Mattia F, Musial JP, Preuschmann S, Reichle RH, Satalino G, Silgram M, van Bodegom PM, Verhoest NE, Wagner W, Walker JP, Wegmüller U and Loew A (2021), "A roadmap for high-resolution satellite soil moisture applications – confronting product characteristics with user requirements", Remote Sensing of Environment., jan, 2021. Vol. 252, pp. 112162. Elsevier BV.
BibTeX:
@article{Peng_2021,
  author = {Jian Peng and Clement Albergel and Anna Balenzano and Luca Brocca and Oliver Cartus and Michael H. Cosh and Wade T. Crow and Katarzyna Dabrowska-Zielinska and Simon Dadson and Malcolm W.J. Davidson and Patricia de Rosnay and Wouter Dorigo and Alexander Gruber and Stefan Hagemann and Martin Hirschi and Yann H. Kerr and Francesco Lovergine and Miguel D. Mahecha and Philip Marzahn and Francesco Mattia and Jan Pawel Musial and Swantje Preuschmann and Rolf H. Reichle and Giuseppe Satalino and Martyn Silgram and Peter M. van Bodegom and Niko E.C. Verhoest and Wolfgang Wagner and Jeffrey P. Walker and Urs Wegmüller and Alexander Loew},
  title = {A roadmap for high-resolution satellite soil moisture applications – confronting product characteristics with user requirements},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier BV},
  year = {2021},
  volume = {252},
  pages = {112162},
  doi = {10.1016/j.rse.2020.112162}
}
Santoro M, Cartus O and Fransson JE (2021), "Integration of allometric equations in the water cloud model towards an improved retrieval of forest stem volume with L-band SAR data in Sweden", Remote Sensing of Environment., feb, 2021. Vol. 253, pp. 112235. Elsevier BV.
BibTeX:
@article{Santoro_2021,
  author = {Maurizio Santoro and Oliver Cartus and Johan E.S. Fransson},
  title = {Integration of allometric equations in the water cloud model towards an improved retrieval of forest stem volume with L-band SAR data in Sweden},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier BV},
  year = {2021},
  volume = {253},
  pages = {112235},
  doi = {10.1016/j.rse.2020.112235}
}
Schepaschenko D, Moltchanova E, Fedorov S, Karminov V, Ontikov P, Santoro M, See L, Kositsyn V, Shvidenko A, Romanovskaya A, Korotkov V, Lesiv M, Bartalev S, Fritz S, Shchepashchenko M and Kraxner F (2021), "Russian forest sequesters substantially more carbon than previously reported", Scientific Reports., jun, 2021. Vol. 11(1) Springer Science and Business Media LLC.
BibTeX:
@article{Schepaschenko_2021,
  author = {Dmitry Schepaschenko and Elena Moltchanova and Stanislav Fedorov and Victor Karminov and Petr Ontikov and Maurizio Santoro and Linda See and Vladimir Kositsyn and Anatoly Shvidenko and Anna Romanovskaya and Vladimir Korotkov and Myroslava Lesiv and Sergey Bartalev and Steffen Fritz and Maria Shchepashchenko and Florian Kraxner},
  title = {Russian forest sequesters substantially more carbon than previously reported},
  journal = {Scientific Reports},
  publisher = {Springer Science and Business Media LLC},
  year = {2021},
  volume = {11},
  number = {1},
  doi = {10.1038/s41598-021-92152-9}
}
Schwank M, Kontu A, Mialon A, Naderpour R, Houtz D, Lemmetyinen J, Rautiainen K, Li Q, Richaume P, Kerr Y and Mätzler C (2021), "Temperature effects on L-band vegetation optical depth of a boreal forest", Remote Sensing of Environment., sep, 2021. Vol. 263, pp. 112542. Elsevier BV.
BibTeX:
@article{Schwank_2021,
  author = {Mike Schwank and Anna Kontu and Arnaud Mialon and Reza Naderpour and Derek Houtz and Juha Lemmetyinen and Kimmo Rautiainen and Qinghuan Li and Philippe Richaume and Yann Kerr and Christian Mätzler},
  title = {Temperature effects on L-band vegetation optical depth of a boreal forest},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier BV},
  year = {2021},
  volume = {263},
  pages = {112542},
  doi = {10.1016/j.rse.2021.112542}
}
Stefko M, Frey O, Werner C and Hajnsek I (2021), "KAPRI: a Bistatic Full-Polarimetric Interferometric Real-Aperture Radar System for Monitoring of Natural Environements", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1950-1953. IEEE.
BibTeX:
@inproceedings{stefkoFreyWernerHajnsekIGARSS2021KAPRIBistaticPolInterferoRealApertureSystem,
  author = {Stefko, Marcel and Frey, Othmar and Werner, Charles and Hajnsek, Irena},
  title = {KAPRI: a Bistatic Full-Polarimetric Interferometric Real-Aperture Radar System for Monitoring of Natural Environements},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE},
  year = {2021},
  pages = {1950-1953},
  doi = {10.1109/IGARSS47720.2021.9553427}
}
Tanase MA, Borlaf-Mena I, Santoro M, Aponte C, Marin G, Apostol B and Badea O (2021), "Growing Stock Volume Retrieval from Single and Multi-Frequency Radar Backscatter", Forests., jul, 2021. Vol. 12(7), pp. 944. MDPI AG.
BibTeX:
@article{Tanase_2021,
  author = {Mihai A. Tanase and Ignacio Borlaf-Mena and Maurizio Santoro and Cristina Aponte and Gheorghe Marin and Bogdan Apostol and Ovidiu Badea},
  title = {Growing Stock Volume Retrieval from Single and Multi-Frequency Radar Backscatter},
  journal = {Forests},
  publisher = {MDPI AG},
  year = {2021},
  volume = {12},
  number = {7},
  pages = {944},
  doi = {10.3390/f12070944}
}
Wang W, Hocke K and Mätzler C (2021), "Physical Retrieval of Rain Rate from Ground-Based Microwave Radiometry", Remote Sensing., jun, 2021. Vol. 13(11), pp. 2217. MDPI AG.
BibTeX:
@article{Wang_2021,
  author = {Wenyue Wang and Klemens Hocke and Christian Mätzler},
  title = {Physical Retrieval of Rain Rate from Ground-Based Microwave Radiometry},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2021},
  volume = {13},
  number = {11},
  pages = {2217},
  doi = {10.3390/rs13112217}
}
Werner C, Frey O, Naderpour R, Wiesmann A, Süss M and Wegmüller U (2021), "Aperture Synthesis and Calibration of the WBSCAT Ground-Based Scatterometer", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1947-1950. IEEE.
BibTeX:
@inproceedings{wernerFreyNaderpourWiesmannSussWegmullerIGARSS2021ApertureSynthesisAndCalibrationOfWBSCAT,
  author = {Werner, Charles and Frey, Othmar and Naderpour, Reza and Wiesmann, Andreas and Süss, Martin and Wegmüller, Urs},
  title = {Aperture Synthesis and Calibration of the WBSCAT Ground-Based Scatterometer},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE},
  year = {2021},
  pages = {1947-1950},
  doi = {10.1109/IGARSS47720.2021.9554592}
}
Zhao Z, Li W, Ciais P, Santoro M, Cartus O, Peng S, Yin Y, Yue C, Yang H, Yu L, Zhu L and Wang J (2021), "Fire enhances forest degradation within forest edge zones in Africa", Nature Geoscience., jul, 2021. Vol. 14(7), pp. 479-483. Springer Science and Business Media LLC.
BibTeX:
@article{Zhao_2021,
  author = {Zhe Zhao and Wei Li and Philippe Ciais and Maurizio Santoro and Oliver Cartus and Shushi Peng and Yi Yin and Chao Yue and Hui Yang and Le Yu and Lei Zhu and Jingmeng Wang},
  title = {Fire enhances forest degradation within forest edge zones in Africa},
  journal = {Nature Geoscience},
  publisher = {Springer Science and Business Media LLC},
  year = {2021},
  volume = {14},
  number = {7},
  pages = {479--483},
  doi = {10.1038/s41561-021-00763-8}
}
Zheng D, Li X, Wen J, Hofste JG, van der Velde R, Wang X, Wang Z, Bai X, Schwank M and Su Z (2021), "Active and Passive Microwave Signatures of Diurnal Soil Freeze-Thaw Transitions on the Tibetan Plateau", IEEE Transactions on Geoscience and Remote Sensing. , pp. 1-14.
Abstract: Active and passive microwave characteristics of diurnal soil freeze-thaw transitions and their relationships are crucial for developing retrieval algorithms of the soil liquid water content ( ?_liq ) and freeze/thaw state, which, however, have been less explored. This study investigates these microwave characteristics and relationships via analysis of ground-based measurements of brightness temperature ( T_B ) and backscattering coefficients (??) in combination with simulations performed with the Tor Vergata discrete radiative transfer model. Both an L-band (1.4 GHz) radiometer ELBARA-III and a wide-band (1-10 GHz) scatterometer are installed in a seasonally frozen Tibetan meadow ecosystem to measure diurnal variations of TB and copolarized ?? at both hh (? _hh ?) and vv (? _vv ?) polarizations. Analysis of measurements collected between December 2017 and March 2018 shows that 1) diurnal cycles are observed in both T _B and ? ? due to the change in surface ?liq caused by diurnal soil freeze-thaw transitions; 2) a negatively linear relationship is found between e and ?? regardless of frequency, polarization combinations, and observation angles; 3) slopes (? ) of linearly fit equations between eH and ? _hh ? decrease with increasing observation angles of ELBARA-III, while the ones between eV and ? _vv ? increase with increasing observation angles; and 4) correlations between e and ?? increase with decreasing microwave frequency of ?? measurements and ELBARA-III observation angles, and magnitudes of diurnal ?? cycles also increase with decreasing microwave frequency. Moreover, the calibrated Tor Vergata model shows capability to reproduce both diurnal e and ?? variations as well as to quantify their relationships at different frequencies and observation angles.
BibTeX:
@article{ZhengEtAl2021,
  author = {Zheng, Donghai and Li, Xin and Wen, Jun and Hofste, Jan G. and van der Velde, Rogier and Wang, Xin and Wang, Zuoliang and Bai, Xiaojing and Schwank, Mike and Su, Zhongbo},
  title = {Active and Passive Microwave Signatures of Diurnal Soil Freeze-Thaw Transitions on the Tibetan Plateau},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2021},
  pages = {1-14},
  doi = {10.1109/TGRS.2021.3092411}
}
Baffelli S, Frey O and Hajnsek I (2020), "Geostatistical Analysis and Mitigation of the Atmospheric Phase Screens in Ku-Band Terrestrial Radar Interferometric Observations of an Alpine Glacier", IEEE Transactions on Geoscience and Remote Sensing., November, 2020. Vol. 58(11), pp. 7533-7556.
Abstract: Terrestrial radar interferometry (TRI) can measure displacements at high temporal resolution, potentially with high accuracy. An application of this method is the observation of the surface flow velocity of steep, fast-flowing aglaciers. For these observations, the main factor limiting the accuracy of TRI observations is the spatial and temporal variabilities in the distribution of atmospheric water vapor content, causing a phase delay [atmospheric phase screen (APS)] whose magnitude is similar to the displacement phase. This contribution presents a geostatistical analysis of the spatial and temporal behaviors of the APS in Ku-Band TRI. The analysis is based on the assumption of a separable spatiotemporal covariance structure, which is tested empirically using variogram analysis. From this analysis, spatial and temporal APS statistics are estimated and used in a two-step procedure combining regression-Kriging with generalized least squares (GLS) inversion to estimate a velocity time-series. The performance of this method is evaluated by cross-validation using phase observations on stable scatterers. This analysis shows a considerable reduction in residual phase variance compared with the standard approach of combining the linear models of APS stratification and interferogram stacking.
BibTeX:
@article{baffelliFreyHajnsekTGRS2020GeostatisticalAtmosphereAnalysisMitigationKuBandGPRIGlacier,
  author = {Baffelli, Simone and Frey, Othmar and Hajnsek, Irena},
  title = {Geostatistical Analysis and Mitigation of the Atmospheric Phase Screens in Ku-Band Terrestrial Radar Interferometric Observations of an Alpine Glacier},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2020},
  volume = {58},
  number = {11},
  pages = {7533-7556},
  doi = {10.1109/TGRS.2020.2976656}
}
Bernet L, Brockmann E, von Clarmann T, Kämpfer N, Mahieu E, Mätzler C, Stober G and Hocke K (2020), "Trends of atmospheric water vapour in Switzerland from ground-based radiometry", FTIR and GNSS data, Atmos. Chem. Phys., 20, 11223?11244.
BibTeX:
@article{Bernet2020,
  author = {Bernet, Leonie and Brockmann, Elmar and von Clarmann, Thomas and Kämpfer, Niklaus and Mahieu, Emmanuel and Mätzler, Christian and Stober, Gunter and Hocke, Klemens},
  title = {Trends of atmospheric water vapour in Switzerland from ground-based radiometry},
  journal = {FTIR and GNSS data, Atmos. Chem. Phys., 20, 11223?11244},
  year = {2020}
}
Besnard S, Koirala S, Santoro M, Bao S, Cartus O, Gans F, Jung M, Trautmann T and Carvalhais N (2020), "Constraining carbon allocation in a terrestrial ecosystem model using long-term forest biomass time series", In EGU General Assembly 2020.. Thesis at: display., March, 2020.
Abstract: Forests cover about 30% of the terrestrial surface of our planet and store a large part of the terrestrial carbon (C), indicating their fundamental role in terrestrial C dynamics. In recent years, significant advances have been made in understanding terrestrial C cycling across scales, albeit uncertainties remain about fundamental processes, such as photosynthesis, allocation, and mortality, which exert dominant controls on vegetation C dynamics. Allocation plays a critical role in forest ecosystem C cycling by partitioning the products of net photosynthesis into leaves, wood, and below-ground components but is still poorly represented mostly given limitations in process understanding as well as in both suitable and commensurate observations.&lt;/p&gt;&lt;p&gt;Here, we explore different approaches in constraining C allocation alongside processes driving assimilation and out fluxes in a terrestrial ecosystem model based on novel forest biomass datasets. More specifically, we use a series of temporally changing above-ground biomass (AGB) data from local (i.e. in-situ forest inventory data) to global (i.e. long-term C-band satellite retrievals from 1992 to 2018) scales, in a multi-constraint approach. We explore the information contained in a novel AGB time series to diagnose the potential of using changes in vegetation C stocks, jointly with C and water fluxes, to constrain and parameterize different C allocation modeling approaches. Both at FLUXNET site level and global scale, we will: i) present these novel AGB datasets, their strengths and limitations, ii) demonstrate the relevance of constraining C allocation with such temporally changing AGB estimates, and iii) provide a comparison of different C allocation approaches (i.e. fixed versus dynamic allocation, and an hybrid modeling approach) and their implications in representing ecosystem dynamics.&lt;/p&gt;
BibTeX:
@conference{Besnard2020,
  author = {Besnard, Simon and Koirala, Sujan and Santoro, Maurizio and Bao, Shanning and Cartus, Oliver and Gans, Fabian and Jung, Martin and Trautmann, Tina and Carvalhais, Nuno},
  title = {Constraining carbon allocation in a terrestrial ecosystem model using long-term forest biomass time series},
  booktitle = {EGU General Assembly 2020},
  school = {display},
  year = {2020},
  url = {https://meetingorganizer.copernicus.org/EGU2020/EGU2020-10523.html},
  doi = {10.5194/egusphere-egu2020-10523}
}
Borlaf-Mena I, Santoro M, Villard L, Badea O and Tanase MA (2020), "Investigating the Impact of Digital Elevation Models on Sentinel-1 Backscatter and Coherence Observations", Remote Sensing., September, 2020. Vol. 12(18), pp. 3016.
Abstract: Spaceborne remote sensing can track ecosystems changes thanks to continuous and systematic coverage at short revisit intervals. Active remote sensing from synthetic aperture radar (SAR) sensors allows day and night imaging as they are not a?ected by cloud cover and solar illumination and can capture unique information about its targets. However, SAR observations are a?ected by the coupled e?ect of viewing geometry and terrain topography. The study aims to assess the impact of global digital elevation models (DEMs) on the normalization of Sentinel-1 backscattered intensity and interferometric coherence. For each DEM, we analyzed the di?erence between orbit tracks, the di?erence with results obtained with a high-resolution local DEM, and the impact on land cover classi?cation. Tests were carried out at two sites located in mountainous regions in Romania and Spain using the SRTM (Shuttle Radar Topography Mission, 30 m), AW3D (ALOS (Advanced Land Observation Satellite) World 3D, 30 m), TanDEM-X (12.5, 30, 90 m), and Spain national ALS (aerial laser scanning) based DEM (5 m resolution). The TanDEM-X DEM was the global DEM most suitable for topographic normalization, since it provided the smallest di?erences between orbital tracks, up to 3.5 dB smaller than with other DEMs for peak landform, and 1.4?1.9 dB for pit and valley landforms.
BibTeX:
@article{BorlafMena2020,
  author = {Borlaf-Mena, Ignacio and Santoro, Maurizio and Villard, Ludovic and Badea, Ovidiu and Tanase, Mihai Andrei},
  title = {Investigating the Impact of Digital Elevation Models on Sentinel-1 Backscatter and Coherence Observations},
  journal = {Remote Sensing},
  year = {2020},
  volume = {12},
  number = {18},
  pages = {3016},
  url = {https://www.mdpi.com/2072-4292/12/18/3016},
  doi = {10.3390/rs12183016}
}
Fan N, Besnard S, Santoro M, Cartus O and Carvalhais N (2020), "Inferring non-steady-state terrestrial vegetation carbon turnover times from multi-decadal space-borne observations on global scale", In EGU General Assembly 2020.. Thesis at: oral., March, 2020.
Abstract: The global biomass is determined by the vegetation turnover times and carbon fixation through photosynthesis. Vegetation turnover time is a central parameter that not only partially determines the terrestrial carbon sink but also the response of terrestrial vegetation to the future changes in climate. However, the change of magnitude, spatial patterns and uncertainties in &amp;#964; as well as the sensitivity of these processes to climate change is not well understood due to lack of observations on global scale. In this study, we explore a new dataset of annual above-ground biomass (AGB) change from 1993 to 2018 from spaceborne scatterometer observations. Using the long-term, spatial-explicit global dynamic dataset, we investigated how &amp;#964; change over almost three decades including the uncertainties. Previous estimations of &amp;#964; under steady-state assumption can now be challenged acknowledging that terrestrial ecosystems are, for the most of cases, not in balance. In this study, we explore this new dataset to derive global maps of &amp;#964; in non-steady-state for different periods of time. We used a non-steady-state carbon model in which the change of AGB is a function of Gross Primary Production (GPP) and &amp;#964; (&amp;#916;AGB = &amp;#945;*GPP-AGB/ &amp;#964;). The parameter &amp;#945; represents the percentage of incorporation of carbon from GPP to biomass. By exploring the AGB change in 5 to 10 years of time step, we were able to infer &amp;#964; and &amp;#945; from the observations of AGB and GPP change by solving the linear equation. We show how &amp;#964; changes after potential disturbances in the early 2000s in comparison to the previous decade. We also show the spatial distributions of &amp;#945; from the change of AGB. By accessing the change in biomass, &amp;#964; and &amp;#945; as well as their associated uncertainties, we provide a comprehensive diagnostic on the vegetation dynamics and the potential response of biomass to disturbance and to climate change.
BibTeX:
@conference{Fan2020a,
  author = {Fan, Naixin and Besnard, Simon and Santoro, Maurizio and Cartus, Oliver and Carvalhais, Nuno},
  title = {Inferring non-steady-state terrestrial vegetation carbon turnover times from multi-decadal space-borne observations on global scale},
  booktitle = {EGU General Assembly 2020},
  school = {oral},
  year = {2020},
  url = {https://meetingorganizer.copernicus.org/EGU2020/EGU2020-17717.html},
  doi = {10.5194/egusphere-egu2020-17717}
}
Fan N, Koirala S, Reichstein M, Thurner M, Avitabile V, Santoro M, Ahrens B, Weber U and Carvalhais N (2020), "Apparent ecosystem carbon turnover time: uncertainties and robust features", Earth Syst. Sci. Data., October, 2020. Vol. 12(4), pp. 2517-2536.
Abstract: Abstract. The turnover time of terrestrial ecosystem carbon is an emergent ecosystem property that
quantifies the strength of land surface on the global carbon cycle?climate feedback. However,
observation- and modeling-based estimates of carbon turnover and its response to climate are
still characterized by large uncertainties. In this study, by assessing the apparent whole
ecosystem carbon turnover times (?) as the ratio between carbon stocks and fluxes, we
provide an update of this ecosystem level diagnostic and its associated uncertainties in high
spatial resolution (0.083?) using multiple, state-of-the-art, observation-based datasets
of soil organic carbon stock (Csoil), vegetation biomass (Cveg)
and gross primary productivity (GPP). Using this new ensemble of data, we estimated the global
median ? to be 43-7+7?yr
(median-difference to percentile 25+difference to percentile
75) when the full soil is considered, in contrast to limiting it to 1?m
depth. Only considering the top 1?m of soil carbon in circumpolar regions (assuming
maximum active layer depth is up to 1?m) yields a global median ? of
37-6+3?yr, which is longer than the previous estimates of 23-4+7?yr
(Carvalhais et al., 2014). We show that the difference is mostly attributed to changes in global
Csoil estimates. Csoil accounts for approximately 84?% of
the total uncertainty in global ? estimates; GPP also contributes significantly
(15?%), whereas Cveg contributes only marginally (less than 1?%) to the
total uncertainty. The high uncertainty in Csoil is reflected in the large range
across state-of-the-art data products, in which full-depth Csoil spans between
3362 and 4792?PgC. The uncertainty is especially high in circumpolar regions with an
uncertainty of 50?% and a low spatial correlation between the different datasets
(0.2textlessrtextless0.5) when compared to other regions (0.6textlessrtextless0.8). These uncertainties cast a shadow
on current global estimates of ? in circumpolar regions, for which further geographical
representativeness and clarification on variations in Csoil with soil depth are
needed. Different GPP estimates contribute significantly to the uncertainties of ? mainly in
semiarid and arid regions, whereas Cveg causes the uncertainties of ? in
the subtropics and tropics. In spite of the large uncertainties, our findings reveal that the
latitudinal gradients of ? are consistent across different datasets and soil depths. The
current results show a strong ensemble agreement on the negative correlation between ? and
temperature along latitude that is stronger in temperate zones (30?60??N) than
in the subtropical and tropical zones (30??S?30??N). Additionally, while the
strength of the ??precipitation correlation was dependent on the Csoil data
source, the latitudinal gradients also agree among different ensemble members. Overall, and
despite the large variation in ?, we identified robust features in the spatial patterns of
? that emerge beyond the differences stemming from the data-driven estimates of
Csoil, Cveg and GPP. These robust patterns, and associated
uncertainties, can be used to infer ??climate relationships and for constraining
contemporaneous behavior of Earth
system models (ESMs), which could contribute to uncertainty reductions in future
projections of the carbon cycle?climate feedback. The dataset of ? is openly available at
https://doi.org/10.17871/bgitau.201911 (Fan et al., 2019).
BibTeX:
@article{Fan2020,
  author = {Fan, Naixin and Koirala, Sujan and Reichstein, Markus and Thurner, Martin and Avitabile, Valerio and Santoro, Maurizio and Ahrens, Bernhard and Weber, Ulrich and Carvalhais, Nuno},
  title = {Apparent ecosystem carbon turnover time: uncertainties and robust features},
  journal = {Earth Syst. Sci. Data},
  year = {2020},
  volume = {12},
  number = {4},
  pages = {2517--2536},
  url = {https://essd.copernicus.org/articles/12/2517/2020/},
  doi = {10.5194/essd-12-2517-2020}
}
Frey O, Werner C, Manconi A and Coscione R (2020), "Measuring surface displacements using a novel UAV/car-borne radar interferometer: including a case study on a fast-moving landslide in Brinzauls", In Swiss Geoscience Meeting 2020: Symposium 20. Remote Sensing of the Spheres. Zurich, Switzerland, November, 2020.
BibTeX:
@inproceedings{freyWernerManconiCoscioneSGM2020UAVandCARSARmobilemappingDisplacements,
  author = {Frey, Othmar and Werner, Charles and Manconi, Andrea and Coscione, Roberto},
  title = {Measuring surface displacements using a novel UAV/car-borne radar interferometer: including a case study on a fast-moving landslide in Brinzauls},
  booktitle = {Swiss Geoscience Meeting 2020: Symposium 20. Remote Sensing of the Spheres},
  year = {2020},
  url = {https://youtu.be/DxAvqFT_03I}
}
Frey O, Werner C, Manconi A and Coscione R (2020), "Mobile Mapping of Surface Displacements Using a Novel Compact UAV-Borne / Car-Borne InSAR System", In American Geophysical Union, Fall Meeting 2020.
Abstract: Flexible mobile mapping of surface displacements with repeat-pass interferometry from moving platforms such as cars and UAVs has been a rather unexplored field.
In this contribution we address this topic comprehensively: we demonstrate InSAR-based measurement of surface displacements with our novel car-borne and UAV-borne L-band SAR system setup at three different test sites in Switzerland.
The reduced temporal decorrelation at L-band is an important advantage and a complementary property as compared to high-frequency (quasi-)stationary systems. While the sensitivity to line-of-sight displacements is lower, the longer wavelength permits to acquire longer interferometric time intervals also in natural terrain and in adverse conditions, in which the decorrelation time at X- or Ku-band (the frequencies of many stationary terrestrial radar interferometers) can be in the order of minutes or less. Terrestrial synthetic aperture radar acquisitions from a car driving on a road or acquisitions from a UAV allow to obtain synthetic aperture lengths of 100m and more which yields high-resolution SAR imagery also at lower frequency such as L-band. At the same time the view geometry can be chosen to offer line-of-sight views to landslides that complement the view geometries available from spaceborne SAR systems. Then, using a time-domain back-projection image focusing approach, it is ensured that even for curvilinear paths (e.g. a car driving along a curved road) high-quality SAR images and interferograms with good spatial resolution are obtained.
Based on these properties we show that such a mobile InSAR system fills a current gap in terms of available InSAR systems for displacement monitoring.
We show the potential and discuss the challenges and the limitations of this novel InSAR-based mobile mapping system.
We do so with the help of three repeat-pass interferometry showcases (see also attached image):
1) car-borne mapping of surface displacements of fast-moving land slide and surrounding area,
2) car-borne mapping of surface displacements of a glacier,
3) UAV-borne mapping of surface displacements of a steep slope with various land covers.
The three test cases show that UAV-borne and car-borne interferometric displacement measurements at L-band are feasible with high quality over various natural terrain.
BibTeX:
@inproceedings{freyWernerManconiCoscioneAGU2020UAVandCARSARmobilemappingDisplacements,
  author = {Frey, Othmar and Werner, Charles and Manconi, Andrea and Coscione, Roberto},
  title = {Mobile Mapping of Surface Displacements Using a Novel Compact UAV-Borne / Car-Borne InSAR System},
  booktitle = {American Geophysical Union, Fall Meeting 2020},
  year = {2020},
  url = {https://agu2020fallmeeting-agu.ipostersessions.com/default.aspx?s=05-89-7D-61-8F-00-52-EE-2A-FC-13-68-68-9B-64-59}
}
Glueer F, Loew S and Manconi A (2020), "Paraglacial history and structure of the Moosfluh Landslide (1850-2016), Switzerland", Geomorphology. Vol. 355 Elsevier B.V..
Abstract: Rock slopes next to the tongue of the Great Aletsch Glacier, Switzerland are characterized by rapid environmental adjustment to non-glacial conditions. This study investigates and describes in detail the historic development of the largest rock slope instability in this area, called Moosfluh Landslide. We study in detail the structure, evolution and stability since the end of the Little Ice Age (LIA) until September 2016 and discuss their relationships with the evolution of the Great Aletsch Glacier since the Lateglacial period. In 2016 around 50 m of glacial ice thickness were left at the Moosfluh Landslide toe, where in 1850 glacial ice was >400 m thick. The changing stability conditions at the interface with the melting valley glacier are studied based on novel balanced cross sections and kinematic model of the Moosfluh Landslide dominated by toppling phenomena in metamorphic rock. The morphology and evolution of this landslide since the LIA are investigated with multi-temporal landslide maps based on aerial digital photogrammetry (ADP) applied to historic images since 1961. Internal deformation at Moosfluh is accommodated by shear slip along uphill-facing foliation and fault planes, and by extensional faulting forming tension cracks and graben-structures at the landslide head. Together with Digital Image Correlation (DIC) and total station monitoring (TPS) the Moosfluh Landslide displacement history was reconstructed, evidencing post-Egesen landslide displacements and an acceleration of movements since the LIA and especially since 2007. The displacement rates increase from few mm per year until the nineties to several meter per day in September 2016. Different kinematic models have been tested and changes in the Moosfluh rock slope stability in response to retreating glacial ice and changing groundwater conditions was explored with limit-equilibrium analysis of the stepped planar block toppling model of Goodman and Bray (1976). For the observed conditions and a toppling joint friction angle of 19° the simulated factor of safety drops non-linearly from the LIA maximum (1.12) to the year 2007 (1.02), when the height of ice above the valley bottom melted down to 100 m. This study illustrates with unprecedented detail the time scales, displacement magnitudes and structural evolutions of a large toppling mode slope instability in a paraglacial setting. The long-term cumulative slope displacements between the Egesen stadial and the LIA are of the same magnitude as the cumulative displacements between the LIA and the year 2016. As large portions of the studied slope underwent multiple retreats and advances of the Great Aletsch Glacier during the Lateglacial and Postglacial period, the observed onset of large slope displacements should be related to incremental damage (slip weakening and weathering) occurring along steeply dipping toppling fractures during the LIA. © 2019
BibTeX:
@article{Glueer2020,
  author = {Glueer, F. and Loew, S. and Manconi, A.},
  title = {Paraglacial history and structure of the Moosfluh Landslide (1850-2016), Switzerland},
  journal = {Geomorphology},
  publisher = {Elsevier B.V.},
  year = {2020},
  volume = {355},
  note = {cited By 2},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85081209981&doi=10.1016%2fj.geomorph.2019.02.021&partnerID=40&md5=a8a9fdc23d4e14f27b6c95a9008389e3},
  doi = {10.1016/j.geomorph.2019.02.021}
}
Houtz D, Naderpour R and Schwank M (2020), "Portable L-Band Radiometer (PoLRa): Design and Characterization", Remote Sensing, vol. 12, no. 17, p. 2780.
BibTeX:
@article{Houtz2020,
  author = {Houtz, D. and Naderpour, R. and Schwank M.},
  title = {Portable L-Band Radiometer (PoLRa): Design and Characterization},
  journal = {Remote Sensing, vol. 12, no. 17, p. 2780},
  year = {2020}
}
Leinss S, Li S, Bernhard P and Frey O (2020), "Temporal Multi-Looking of SAR Image Series for Glacier Velocity Determination and Speckle Reduction", In EGU General Assembly 2020., May, 2020. Vol. EGU2020-3643
Abstract: The velocity of glaciers is commonly derived by offset tracking using pairwise cross correlation or feature matching of either optical or synthetic aperture radar (SAR) images. SAR images, however, are inherently affected by noise-like radar speckle and require therefore much larger images patches for successful tracking compared to the patch size used with optical data. As a consequence, glacier velocity maps based on SAR offset tracking have a relatively low resolution compared to the nominal resolution of SAR sensors. Moreover, tracking may fail because small features on the glacier surface cannot be detected due to radar speckle. Although radar speckle can be reduced by applying spatial low-pass filters (e.g. 5x5 boxcar), the spatial smoothing reduces the image resolution roughly by an order of magnitude which strongly reduces the tracking precision. Furthermore, it blurs out small features on the glacier surface, and therefore tracking can also fail unless clear features like large crevasses are visible.
In order to create high resolution velocity maps from SAR images and to generate speckle-free radar images of glaciers, we present a new method that derives the glacier surface velocity field by correlating temporally averaged sub-stacks of a series of SAR images. The key feature of the method is to warp every pixel in each SAR image according to its temporally increasing offset with respect to a reference date. The offset is determined by the glacier velocity which is obtained by maximizing the cross-correlation between the averages of two sub-stacks. Currently, we need to assume that the surface velocity is constant during the acquisition period of the image series but this assumption can be relaxed to a certain extend.
As the method combines the information of multiple images, radar speckle are highly suppressed by temporal multi-looking, therefore the signal-to-noise ratio of the cross-correlation is significantly improved. We found that the method outperforms the pair-wise cross-correlation method for velocity estimation in terms of both the coverage and the resolution of the velocity field. At the same time, very high resolution radar images are obtained and reveal features that are otherwise hidden in radar speckle.
As the reference date, to which the sub-stacks are averaged, can be arbitrarily chosen a smooth flow animation of the glacier surface can be generated based on a limited number of SAR images. The presented method could build a basis for a new generation of tracking methods as the method is excellently suited to exploit the large number of emerging free and globally available high resolution SAR image time series.
BibTeX:
@inproceedings{leinssEtAlEGU2020Stacking,
  author = {Silvan Leinss and Shiyi Li and Philipp Bernhard and Othmar Frey},
  title = {Temporal Multi-Looking of SAR Image Series for Glacier Velocity Determination and Speckle Reduction},
  booktitle = {EGU General Assembly 2020},
  year = {2020},
  volume = {EGU2020-3643},
  url = {https://meetingorganizer.copernicus.org/EGU2020/EGU2020-3643.html},
  doi = {10.5194/egusphere-egu2020-3643}
}
Li X, Al-Yaari A, Schwank M, Fan L, Frappart F, Swenson J and Wigneron J-P (2020), "Compared performances of SMOS-IC soil moisture and vegetation optical depth retrievals based on Tau-Omega and Two-Stream microwave emission models", Remote Sens. Environ.. Vol. 236 Elsevier Inc..
Abstract: Since 2010, SMOS (Soil Moisture and Ocean Salinity) retrievals of surface soil moisture (SM) and vegetation optical depth (VOD) have been produced through the inversion of the so-called Tau-Omega (TO) vegetation emission model. Tau-Omega is a 0th-order solution of the radiative transfer equations that neglects multiple scattering, conversely to 1st-order solutions as Two-Stream (2S). To date, very little is known about the compared retrieval performances of these emission models. Here, we inter-compared (SM, VOD) retrievals using the SMOS-IC algorithm running with the TO and 2S emission models. Retrieval performances obtained from TO and 2S were found to be relatively similar, except that a larger dry bias and a slightly lower SM unbiased RMSD were obtained with 2S and the VOD values of the two models vary over dense vegetation areas, both in terms of magnitude and seasonal variations. Considering this and the enhanced physical background of 2S that allows its implementation as a unified emission model for different applications, our study reveals the high interest of using Two-Stream in global retrieval algorithms at L-band. © 2019 Elsevier Inc.
BibTeX:
@article{Li2020,
  author = {Li, X. and Al-Yaari, A. and Schwank, M. and Fan, L. and Frappart, F. and Swenson, J. and Wigneron, J.-P.},
  title = {Compared performances of SMOS-IC soil moisture and vegetation optical depth retrievals based on Tau-Omega and Two-Stream microwave emission models},
  journal = {Remote Sens. Environ.},
  publisher = {Elsevier Inc.},
  year = {2020},
  volume = {236},
  note = {cited By 4},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074882885&doi=10.1016%2fj.rse.2019.111502&partnerID=40&md5=7825a9214eb6c1c2b9b110698abef0f4},
  doi = {10.1016/j.rse.2019.111502}
}
Magnard C, Wegmüller U and Werner C (2020), "Persistent Scatterer Interferometry in mountainous areas: advantages of working in map geometry", SARWatch Workshop - Advances in the Science and Applications of SAR Interferometry, Vilamoura, Portugal.
BibTeX:
@article{Magnard2020,
  author = {Magnard, C. and Wegmüller, U. and Werner, C.},
  title = {Persistent Scatterer Interferometry in mountainous areas: advantages of working in map geometry},
  journal = {SARWatch Workshop - Advances in the Science and Applications of SAR Interferometry, Vilamoura, Portugal},
  year = {2020}
}
Manconi A, Caduff R, Strozzi T, Frey O, Werner C and Wegmüller U (2020), "Monitoring displacements of complex landslide with broadband multiplatform radar techniques", Swiss Geoscience Meeting 2020: Symposium 20. Remote Sensing of the Spheres, Zurich, Switzerland.
BibTeX:
@article{Manconi2020,
  author = {Manconi, A. and Caduff, R. and Strozzi, T. and Frey, O. and Werner, C. and Wegmüller, U.},
  title = {Monitoring displacements of complex landslide with broadband multiplatform radar techniques},
  journal = {Swiss Geoscience Meeting 2020: Symposium 20. Remote Sensing of the Spheres, Zurich, Switzerland},
  year = {2020},
  url = {https://youtu.be/EEyA5MI-JpM}
}
Mialon A, Rodriguez-Fernandez NJ, Santoro M, Saatchi S, Mermoz S, Bousquet E and Kerr YH (2020), "Evaluation of the Sensitivity of SMOS L-VOD to Forest Above-Ground Biomass at Global Scale", Remote Sensing., May, 2020. Vol. 12(9), pp. 1450.
Abstract: The present study evaluates the L band Vegetation Optical Depth (L-VOD) derived from the Soil Moisture and Ocean Salinity (SMOS) satellite to monitor Above Ground Biomass (AGB) at a global scale. Although SMOS L-VOD has been shown to be a good proxy for AGB in Africa and Tropics, little is known about this relationship at large scale. In this study, we further examine this relationship at a global scale using the latest AGB maps from Saatchi et al. and GlobBiomass computed using data acquired during the SMOS period. We show that at a global scale the L-VOD from SMOS is well-correlated with the AGB estimates from Saatchi et al. and GlobBiomass with the Pearson?s correlation coefficients (R) of 0.91 and 0.94 respectively. Although AGB estimates in Africa and the Tropics are well-captured by SMOS L-VOD (R textgreater 0.9), the relationship is less straightforward for the dense forests over the northern latitudes (R = 0.32 and 0.69 with Saatchi et al. and GlobBiomass respectively). This paper gives strong evidence in support of the sensitivity of SMOS L-VOD to AGB estimates at a globale scale, providing an interesting alternative and complement to exisiting sensors for monitoring biomass evolution. These findings can further facilitate research on biomass now that SMOS is providing more than 10 years of data.
BibTeX:
@article{Mialon2020,
  author = {Mialon, Arnaud and Rodriguez-Fernandez, Nemesio J. and Santoro, Maurizio and Saatchi, Sassan and Mermoz, Stephane and Bousquet, Emma and Kerr, Yann H.},
  title = {Evaluation of the Sensitivity of SMOS L-VOD to Forest Above-Ground Biomass at Global Scale},
  journal = {Remote Sensing},
  year = {2020},
  volume = {12},
  number = {9},
  pages = {1450},
  url = {https://www.mdpi.com/2072-4292/12/9/1450},
  doi = {10.3390/rs12091450}
}
Montzka C, Cosh M, Bayat B, Bitar AA, Bindlish ABR, Bogena HR, Bolten JD, Cabot F, Caldwell T, Chan S, Colliander A, Crow W, Lannoy NDGD, Dorigo W, Evett SR, Gruber A, Hahn S, Jagdhuber T, Jones S, Kerr Y, Kim S, Koyama C, Kurum M, Lopez-Baeza E, McColl FMKA, Mecklenburg S, Mohanty B, OŃeill P, Or D, Pellarin T, Petropoulos GP, Reichle MPRH, Rodriguez-Fernandez N, Scanlon CRT, Schwartz RC, Spengler D, Suman PSS, van der Schalie R, Wagner W, Wegmüller U, Wigneron J-P, Camacho F and Nickeson J (2020), "Soil Moisture Product Validation Good Practices Protocol Version 1.0.", In Good Practices for Satellite Derived Land Product Validation (p. 123) Land Product Validation Subgroup (WGCV/CEOS).
BibTeX:
@incollection{MontzkaEtAl2020,
  author = {Carsten Montzka and Michael Cosh and Bagher Bayat and Ahmad Al Bitar and Aaron Bergand Rajat Bindlish and Heye Reemt Bogena and John D. Bolten and Francois Cabot and Todd Caldwell and Steven Chan and Andreas Colliander and Wade Crow and Narendra Dasand Gabrielle De Lannoy and Wouter Dorigo and Steven R. Evett and Alexander Gruber and Sebastian Hahn and Thomas Jagdhuber and Scott Jones and Yann Kerr and Seungbum Kim and Christian Koyama and Mehmed Kurum and Ernesto Lopez-Baeza and Francesco Mattiaand Kaighin A. McColl and Susanne Mecklenburg and Binayak Mohanty and Peggy OŃeill and Dani Or and Thierry Pellarin and George P. Petropoulos and Maria Pilesand Rolf H. Reichle and Nemesio Rodriguez-Fernandez and Christoph Rüdigerand Tracy Scanlon and Robert C. Schwartz and Daniel Spengler and Prashant Srivastavaand Swati Suman and Robin van der Schalie and Wolfgang Wagner and Urs Wegmüller and Jean-Pierre Wigneron and Fernando Camacho and Jaime Nickeson},
  editor = {C. Montzka and M. Cosh and J. Nickeson and F. Camacho},
  title = {Soil Moisture Product Validation Good Practices Protocol Version 1.0.},
  booktitle = {Good Practices for Satellite Derived Land Product Validation (p. 123) Land Product Validation Subgroup (WGCV/CEOS)},
  year = {2020},
  doi = {10.5067/doc/ceoswgcv/lpv/sm.001}
}
Naderpour R, Houtz D and Schwank M (2020), "Snow wetness retrieved from close-range L-band radiometry in the western Greenland ablation zone", Journal of Glaciology, pp. 1-12.
BibTeX:
@article{Naderpour2020,
  author = {Naderpour, R. and Houtz, D. and Schwank, M.},
  title = {Snow wetness retrieved from close-range L-band radiometry in the western Greenland ablation zone},
  journal = {Journal of Glaciology, pp. 1-12},
  year = {2020}
}
Naesset E, McRoberts RE, Pekkarinen A, Saatchi S, Santoro M, Trier OD, Zahabu E and Gobakken T (2020), "Use of local and global maps of forest canopy height and aboveground biomass to enhance local estimates of biomass in miombo woodlands in Tanzania", Int. J. Appl. Earth Obs. Geoinf.., July, 2020. Vol. 89, pp. 102109.
Abstract: Field surveys are often a primary source of aboveground biomass (AGB) data, but plot-based estimates of parameters related to AGB are often not sufficiently precise, particularly not in tropical countries. Remotely sensed data may complement field data and thus help to increase the precision of estimates and circumvent some of the problems with missing sample observations in inaccessible areas. Here, we report the results of a study conducted in a 15,867 km� area in the dry miombo woodlands of Tanzania, to quantify the contribution of existing canopy height and biomass maps to improving the precision of canopy height and AGB estimates locally. A local and a global height map and three global biomass maps, and a probability sample of 513 inventory plots were subject to analysis. Model-assisted sampling estimators were used to estimate mean height and AGB across the study area using the original maps and then with the maps calibrated with local inventory plots. Large systematic map errors ? positive or negative ? were found for all the maps, with systematic errors as great as 60?70 %. The maps contributed nothing or even negatively to the precision of mean height and mean AGB estimates. However, after being calibrated locally, the maps contributed substantially to increasing the precision of both mean height and mean AGB estimates, with relative efficiencies (variance of the field-based estimates relative to the variance of the map-assisted estimates) of 1.3?2.7 for the overall estimates. The study, although focused on a relatively small area of dry tropical forests, illustrates the potential strengths and weaknesses of existing global forest height and biomass maps based on remotely sensed data and universal prediction models. Our results suggest that the use of regional or local inventory data for calibration can substantially increase the precision of map-based estimates and their applications in assessing forest carbon stocks for emission reduction programs and policy and financial decisions.
BibTeX:
@article{Naesset2020,
  author = {Naesset, Erik and McRoberts, Ronald E. and Pekkarinen, Anssi and Saatchi, Sassan and Santoro, Maurizio and Trier, Oivind D. and Zahabu, Eliakimu and Gobakken, Terje},
  title = {Use of local and global maps of forest canopy height and aboveground biomass to enhance local estimates of biomass in miombo woodlands in Tanzania},
  journal = {Int. J. Appl. Earth Obs. Geoinf.},
  year = {2020},
  volume = {89},
  pages = {102109},
  url = {https://linkinghub.elsevier.com/retrieve/pii/S0303243419312103},
  doi = {10.1016/j.jag.2020.102109}
}
Prakash N, Manconi A and Loew S (2020), "Mapping landslides on EO data: Performance of deep learning models vs. Traditional machine learning models", Remote Sensing. Vol. 12(3) MDPI AG.
Abstract: Mapping landslides using automated methods is a challenging task, which is still largely done using human efforts. Today, the availability of high-resolution EO data products is increasing exponentially, and one of the targets is to exploit this data source for the rapid generation of landslide inventory. Conventional methods like pixel-based and object-based machine learning strategies have been studied extensively in the last decade. In addition, recent advances in CNN (convolutional neural network), a type of deep-learning method, has been widely successful in extracting information from images and have outperformed other conventional learning methods. In the last few years, there have been only a few attempts to adapt CNN for landslide mapping. In this study, we introduce a modified U-Net model for semantic segmentation of landslides at a regional scale from EO data using ResNet34 blocks for feature extraction. We also compare this with conventional pixel-based and object-based methods. The experiment was done in Douglas County, a study area selected in the south of Portland in Oregon, USA, and landslide inventory extracted from SLIDO (Statewide Landslide Information Database of Oregon) was considered as the ground truth. Landslide mapping is an imbalanced learning problem with very limited availability of training data. Our network was trained on a combination of focal Tversky loss and cross-entropy loss functions using augmented image tiles sampled from a selected training area. The deep-learning method was observed to have a better performance than the conventional methods with an MCC (Matthews correlation coefficient) score of 0.495 and a POD (probability of detection) rate of 0.72. © 2020 by the authors.
BibTeX:
@article{Prakash2020,
  author = {Prakash, N. and Manconi, A. and Loew, S.},
  title = {Mapping landslides on EO data: Performance of deep learning models vs. Traditional machine learning models},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2020},
  volume = {12},
  number = {3},
  note = {cited By 1},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85080933308&doi=10.3390%2frs12030346&partnerID=40&md5=576e7e14cee58b834d8f5987a5ba45a7},
  doi = {10.3390/rs12030346}
}
Santoro M, Cartus O, Carvalhais N, Besnard S and Fan N (2020), "Forest above-ground biomass estimates across three decades from spaceborne scatterometer observations", In EGU General Assembly 2020.. Thesis at: oral., March, 2020.
Abstract: The large uncertainty characterizing the terrestrial carbon (C) cycle is a consequence of the sparse and irregular observations on the ground. In terms of observations, spaceborne remote sensing has been achieving global, repeated coverages of the Earth since the late 1970s, with a continuous increase in terms of density of observations in time and spatial resolution, thus potentially qualifying as data source to fill such gap in knowledge. Above-ground biomass is a baseline for quantifying the terrestrial C pool; however, remote sensing observations do not measure the organic mass of vegetation. Above-ground biomass (AGB) of forests can only be inferred by inverting numerical models relating and combining multiple remote sensing observations. One of the longest time record of observations from space is represented by the backscattered intensity from the European Remote Sensing Wind Scatterometer (ERS WindScat) and the MetOp Advanced Scatterometer (ASCAT), both operating at C-band (wavelength of 6 cm). An almost unbroken time series of backscatter observations at 0.25&amp;#176; spatial resolution exists since 1991 and data continuity is guaranteed in the next decades. In spite of the weak sensitivity of C-band backscatter to AGB, wall-to-wall estimates of AGB have been derived from high-resolution SAR observations by exploiting multiple observations acquired in a relatively short time period&amp;#160; (Santoro et al., Rem. Sens. Env., 2011; Santoro et al., Rem. Sens. Env., 2015). We have now applied this approach to generate a global time series of AGB estimates for each year between 1992 and 2018 from the C-band scatterometer data at 0.25&amp;#176; spatial resolution. The spatial patterns of AGB match known patterns from in situ records and other remote sensing datasets. The uncertainty of our AGB estimates is between 30% and 40% of the estimated value at the pixel level, providing strong confidence in multi-decadal AGB trends. We identify a constant increase of biomass across most boreal and temperate forests of the northern hemisphere. In contrast, we detect severe loss of biomass throughout the wet tropics during the 1990s and the beginning of the 2000 decade in consequence of massive deforestation. This loss in biomass is followed by a steady increase during the 2000s and the beginning of the most recent decade, coming more recently into saturation. Overall, we find that the global AGB density at 0.25&amp;#176; steadily increased by 9% from 71.8 Mg ha&lt;sup&gt;-1&lt;/sup&gt; Pg in the 1990s to 78.1 Mg ha&lt;sup&gt;-1&lt;/sup&gt; in the 2010s. Combining our AGB density estimates with the annual maps of the Climate Change Initiative (CCI) Land Cover dataset, we show that total AGB in forests decreased slightly from 566 Pg in the 1990s to 560 Pg in the 2000s, then increased to 593 Pg in the 2010s, resulting in an almost 5% net increase during the last three decades.
BibTeX:
@conference{Santoro2020a,
  author = {Santoro, Maurizio and Cartus, Oliver and Carvalhais, Nuno and Besnard, Simon and Fan, Naixin},
  title = {Forest above-ground biomass estimates across three decades from spaceborne scatterometer observations},
  booktitle = {EGU General Assembly 2020},
  school = {oral},
  year = {2020},
  url = {https://meetingorganizer.copernicus.org/EGU2020/EGU2020-19673.html},
  doi = {10.5194/egusphere-egu2020-19673}
}
Santoro M, Cartus O, Carvalhais N, Rozendaal D, Avitabilie V, Araza A, de Bruin S, Herold M, Quegan S, Rodriguez Veiga P, Balzter H, Carreiras J, Schepaschenko D, Korets M, Shimada M, Itoh T, Moreno Martinez A, Cavlovic J, Cazzolla Gatti R, da Conceicao Bispo P, Dewnath N, Labriere N, Liang J, Lindsell J, Mitchard ETA, Morel A, Pacheco Pascagaza AM, Ryan CM, Slik F, Vaglio Laurin G, Verbeeck H, Wijaya A and Willcock S (2020), "The global forest above-ground biomass pool for 2010 estimated from high-resolution satellite observations", Earth Syst. Sci. Data Discuss... Thesis at: Biosphere ? Biogeosciences.
Abstract: The terrestrial forest carbon pool is poorly quantified, in particular in regions with low forest inventory capacity. By combining multiple satellite observations of synthetic aperture radar (SAR) backscatter around the year 2010, we generated a global, spatially explicit dataset of above-ground forest biomass (dry mass, AGB) with a spatial resolution of 1?ha. Using an extensive database of 110,897 AGB measurements from field inventory plots, we show that the spatial patterns and magnitude of AGB are well captured in our map with the exception of regional uncertainties in high carbon stock forests with AGB textgreater 250?Mg?ha?1 where the retrieval was effectively based on a single radar observation. With a total global AGB of 522?Pg, our estimate of the terrestrial biomass pool in forests is lower than most estimates published in literature (426?571?Pg). Nonetheless, our dataset increases knowledge on the spatial distribution of AGB compared to the global Forest Resources Assessment (FRA) by the Food and Agriculture Organization (FAO) and highlights the impact of a country?s national inventory capacity on the accuracy of the biomass statistics reported to the FRA. We also reassessed previous remote sensing AGB maps, and identify major biases compared to inventory data, up to 120?% of the inventory value in dry tropical forests, in the sub-tropics and temperate zone. Because of the high level of detail and the overall reliability of the AGB spatial patterns, our global dataset of AGB is likely to have significant impacts on climate, carbon and socio-economic modelling schemes, and provides a crucial baseline in future carbon stock changes estimates. The dataset is available at: https://doi.pangaea.de/10.1594/PANGAEA.894711 (Santoro, 2018).
BibTeX:
@article{Santoro2020,
  author = {Santoro, Maurizio and Cartus, Oliver and Carvalhais, Nuno and Rozendaal, Danae and Avitabilie, Valerio and Araza, Arnan and de Bruin, Sytze and Herold, Martin and Quegan, Shaun and Rodriguez Veiga, Pedro and Balzter, Heiko and Carreiras, Joao and Schepaschenko, Dmitry and Korets, Mikhail and Shimada, Masanobu and Itoh, Takuya and Moreno Martinez, Alvaro and Cavlovic, Jura and Cazzolla Gatti, Roberto and da Conceicao Bispo, Polyanna and Dewnath, Nasheta and Labriere, Nicolas and Liang, Jingjing and Lindsell, Jeremy and Mitchard, Edward T. A. and Morel, Alexandra and Pacheco Pascagaza, Ana Maria and Ryan, Casey M. and Slik, Ferry and Vaglio Laurin, Gaia and Verbeeck, Hans and Wijaya, Arief and Willcock, Simon},
  title = {The global forest above-ground biomass pool for 2010 estimated from high-resolution satellite observations},
  journal = {Earth Syst. Sci. Data Discuss.},
  school = {Biosphere ? Biogeosciences},
  year = {2020},
  url = {https://essd.copernicus.org/preprints/essd-2020-148/},
  doi = {10.5194/essd-2020-148}
}
Santoro M, Cartus O, Carvalhais N, Rozendaal D, Avitabilie V, Araza A, de Bruin S, Herold M, Quegan S, Veiga PR, Balzter H, Carreiras J, Schepaschenko D, Korets M, Shimada M, Itoh T, Mart\inez ÁM, Cavlovic J, Gatti RC, da Conceição Bispo P, Dewnath N, Labrière N, Liang J, Lindsell J, Mitchard ETA, Morel A, Pascagaza AMP, Ryan CM, Slik F, Laurin GV, Verbeeck H, Wijaya A and Willcock S (2020), "The global forest above-ground biomass pool for 2010 estimated from high-resolution satellite observations", jul, 2020. Copernicus GmbH.
BibTeX:
@article{Santoro_2020,
  author = {Maurizio Santoro and Oliver Cartus and Nuno Carvalhais and Dana Rozendaal and Valerio Avitabilie and Arnan Araza and Sytze de Bruin and Martin Herold and Shaun Quegan and Pedro Rodr\iguez Veiga and Heiko Balzter and João Carreiras and Dmitry Schepaschenko and Mikhail Korets and Masanobu Shimada and Takuya Itoh and Álvaro Moreno Mart\inez and Jura Cavlovic and Roberto Cazzolla Gatti and Polyanna da Conceição Bispo and Nasheta Dewnath and Nicolas Labrière and Jingjing Liang and Jeremy Lindsell and Edward T. A. Mitchard and Alexandra Morel and Ana Maria Pacheco Pascagaza and Casey M. Ryan and Ferry Slik and Gaia Vaglio Laurin and Hans Verbeeck and Arief Wijaya and Simon Willcock},
  title = {The global forest above-ground biomass pool for 2010 estimated from high-resolution satellite observations},
  publisher = {Copernicus GmbH},
  year = {2020},
  doi = {10.5194/essd-2020-148}
}
Schwaizer G, Keuris L, Nagler T, Derksen C, Luojus K, Marin C, Metsämäki S, Mudryk L, Naegeli K, Notarnicola C, Salberg A-B, Solberg R, Wiesmann A, Wunderle S, Essery R, Gustafsson D, Krinner G and Trofaier A-M (2020), "Towards a long term global snow climate data record from satellite data generated within the Snow Climate Change Initiative", In EGU General Assembly Conference Abstracts., May, 2020. , pp. 19228.
BibTeX:
@inproceedings{2020EGUGA..2219228S,
  author = {Schwaizer, Gabriele and Keuris, Lars and Nagler, Thomas and Derksen, Chris and Luojus, Kari and Marin, Carlo and Metsämäki, Sari and Mudryk, Lawrence and Naegeli, Kathrin and Notarnicola, Claudia and Salberg, Arnt-Borre and Solberg, Rune and Wiesmann, Andreas and Wunderle, Stefan and Essery, Richard and Gustafsson, David and Krinner, Gerhard and Trofaier, Anna-Maria},
  title = {Towards a long term global snow climate data record from satellite data generated within the Snow Climate Change Initiative},
  booktitle = {EGU General Assembly Conference Abstracts},
  year = {2020},
  pages = {19228}
}
Soto-Navarro C, Ravilious C, Arnell A, De Lamo X, Harfoot M, Hill S, Wearn O, Santoro M, Bouvet A, Mermoz S, Le Toan T, Xia J, Liu S, Yuan W, Spawn S, Gibbs H, Ferrier S, Harwood T, Alkemade R, Schipper A, Schmidt-Traub G, Strassburg B, Miles L, Burgess N and Kapos V (2020), "Mapping co-benefits for carbon storage and biodiversity to inform conservation policy and action", Philosophical Transactions of the Royal Society B: Biological Sciences. Vol. 375(1794) Royal Society Publishing.
Abstract: Integrated high-resolution maps of carbon stocks and biodiversity that identify areas of potential co-benefits for climate change mitigation and biodiversity conservation can help facilitate the implementation of global climate and biodiversity commitments at local levels. However, the multi-dimensional nature of biodiversity presents a major challenge for understanding, mapping and communicating where and how biodiversity benefits coincide with climate benefits. A new integrated approach to biodiversity is therefore needed. Here, we (a) present a new high-resolution map of global above- and belowground carbon stored in biomass and soil, (b) quantify biodiversity values using two complementary indices (BIp and BIr) representing proactive and reactive approaches to conservation, and (c) examine patterns of carbon- biodiversity overlap by identifying 'hotspots' (20% highest values for both aspects). Our indices integrate local diversity and ecosystem intactness, as well as regional ecosystem intactness across the broader area supporting a similar natural assemblage of species to the location of interest. The western Amazon Basin, Central Africa and Southeast Asia capture the last strongholds of highest local biodiversity and ecosystem intactness worldwide, while the last refuges for unique biological communities whose habitats have been greatly reduced are mostly found in the tropical Andes and central Sundaland. There is 38 and 5% overlap in carbon and biodiversity hotspots, for proactive and reactive conservation, respectively. Alarmingly, only around 12 and 21% of these proactive and reactive hotspot areas, respectively, are formally protected. This highlights that a coupled approach is urgently needed to help achieve both climate and biodiversity global targets. This would involve (1) restoring and conserving unprotected, degraded ecosystems, particularly in the Neotropics and Indomalaya, and (2) retaining the remaining strongholds of intactness. © 2019 The Author(s) Published by the Royal Society.
BibTeX:
@article{Soto-Navarro2020,
  author = {Soto-Navarro, C. and Ravilious, C. and Arnell, A. and De Lamo, X. and Harfoot, M. and Hill, S.L.L. and Wearn, O.R. and Santoro, M. and Bouvet, A. and Mermoz, S. and Le Toan, T. and Xia, J. and Liu, S. and Yuan, W. and Spawn, S.A. and Gibbs, H.K. and Ferrier, S. and Harwood, T. and Alkemade, R. and Schipper, A.M. and Schmidt-Traub, G. and Strassburg, B. and Miles, L. and Burgess, N.D. and Kapos, V.},
  title = {Mapping co-benefits for carbon storage and biodiversity to inform conservation policy and action},
  journal = {Philosophical Transactions of the Royal Society B: Biological Sciences},
  publisher = {Royal Society Publishing},
  year = {2020},
  volume = {375},
  number = {1794},
  note = {cited By 2},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85078349717&doi=10.1098%2frstb.2019.0128&partnerID=40&md5=ede27fe9884dcc8e7952514ab6e781be},
  doi = {10.1098/rstb.2019.0128}
}
Strozzi T, Caduff R, Jones N, Barboux C, Delaloye R, Bodin X, Kääb A, Mätzler E and Schrott L (2020), "Monitoring rock glacier kinematics with satellite synthetic aperture radar", Remote Sensing. Vol. 12(3) MDPI AG.
Abstract: Active rock glaciers represent the best visual expression of mountain permafrost that can be mapped and monitored directly using remotely sensed data. Active rock glaciers are bodies that consist of a perennially frozen ice/rock mixture and express a distinct flow-like morphology indicating downslope permafrost creep movement. Annual rates of motion have ranged from a few millimeters to several meters per year, varying within the annual cycle, from year to year, as well as at the decennial time scale. During the last decade, in situ observations in the European Alps have shown that active rock glaciers are responding almost synchronously to inter-annual and decennial changes in ground temperature, suggesting that the relative changes of their kinematics are a general indicator of the evolution of mountain permafrost conditions. Here, we used satellite radar interferometry (InSAR) to monitor the rate of motion of various active rock glaciers in the Swiss Alps, Qeqertarsuaq (Western Greenland), and the semiarid Andes of South America. Velocity time series computed with Sentinel-1 SAR images, regularly acquired since 2014, every six days over Europe and Greenland and every 12 days over the Andes, show annual fluctuations, with higher velocities at the end of the summer. A JERS-1 image pair of 1996 and stacks of very high-resolution SAR images from TerraSAR-X and Cosmo-SkyMed from 2008 to 2017 were analyzed using InSAR and offset tracking over the Western Swiss Alps in order to extend the main observation period of our study. A quantitative assessment of the accuracy of InSAR and offset tracking was performed by comparison with in situ methods. Our results for the three different study regions demonstrate that Sentinel-1 InSAR can complement worldwide in situ measurements of active rock glacier kinematics. © 2020 by the authors.
BibTeX:
@article{Strozzi2020,
  author = {Strozzi, T. and Caduff, R. and Jones, N. and Barboux, C. and Delaloye, R. and Bodin, X. and Kääb, A. and Mätzler, E. and Schrott, L.},
  title = {Monitoring rock glacier kinematics with satellite synthetic aperture radar},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2020},
  volume = {12},
  number = {3},
  note = {cited By 0},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85080895862&doi=10.3390%2frs12030559&partnerID=40&md5=9ab0d7ddff51f0f3b527b52503ea958e},
  doi = {10.3390/rs12030559}
}
Strozzi T, Caduff R, Manconi A, Wegmüller U and Ambrosi C (2020), "Monitoring slow-moving landslides in Switzerland with satellite SARinterferometry", Swiss Bulletin für angewandte Geologie.
BibTeX:
@article{Strozzi2020a,
  author = {Strozzi, T. and Caduff, R. and Manconi, A. and Wegmüller, U. and Ambrosi, C.},
  title = {Monitoring slow-moving landslides in Switzerland with satellite SARinterferometry},
  journal = {Swiss Bulletin für angewandte Geologie},
  year = {2020}
}
Strozzi T, Carreon-Freyre D and Wegmüller U (2020), "Land subsidence andassociated ground fracturing: study cases in central Mexico with ALOS-2 PALSAR-2 ScanSAR Interferometry", Proc. IAHS Tenth InternationalSymposium on Land Subsidence (TISOLS), 382, 179-182.
BibTeX:
@article{Strozzi2020c,
  author = {Strozzi, T. and Carreon-Freyre, D. and Wegmüller, U.},
  title = {Land subsidence andassociated ground fracturing: study cases in central Mexico with ALOS-2 PALSAR-2 ScanSAR Interferometry},
  journal = {Proc. IAHS Tenth InternationalSymposium on Land Subsidence (TISOLS), 382, 179-182},
  year = {2020}
}
Su Z, Wen J, Zeng Y, Zhao H, Lv S, van der Velde R, Zheng D, Wang X, Wang Z, Schwank M, Kerr Y, Yueh S, Colliander A, Qian H, Drusch M and Mecklenburg S (2020), "Multiyear in-situ L-band microwave radiometry of land surface processes on the Tibetan Plateau", Scientific Data, vol. 7, no. 1, p. 317.
BibTeX:
@article{Su2020,
  author = {Su, Z. and Wen, J. and Zeng, Y. and Zhao, H. and Lv, S. and van der Velde, R. and Zheng, D. and Wang, X. and Wang, Z. and Schwank, M. and Kerr, Y. and Yueh, S. and Colliander, A. and Qian, H. and Drusch, M. and Mecklenburg, S.},
  title = {Multiyear in-situ L-band microwave radiometry of land surface processes on the Tibetan Plateau},
  journal = {Scientific Data, vol. 7, no. 1, p. 317},
  year = {2020}
}
Tosi L, Da Lio S, Donnici C, Strozzi T and Teatini P (2020), "Vulnerability of Venice's coastland to relative sea-level rise", Proc. IAHS Tenth International Symposium on Land Subsidence (TISOLS) 382,689-695.
BibTeX:
@article{Tosi2020,
  author = {Tosi, L. and Da Lio, S. and Donnici, C. and Strozzi, T. and Teatini, P.},
  title = {Vulnerability of Venice's coastland to relative sea-level rise},
  journal = {Proc. IAHS Tenth International Symposium on Land Subsidence (TISOLS) 382,689-695},
  year = {2020}
}
Wegmüller U, Caduff R and Strozzi T (2020), "Einsatz von Radarmethoden im Geomonitoring der Schweiz", Tagungsband Geomonitoring 2020, S. 3-15.
BibTeX:
@article{Wegmuller2020,
  author = {Wegmüller, U. and Caduff, R. and Strozzi, T.},
  title = {Einsatz von Radarmethoden im Geomonitoring der Schweiz},
  journal = {Tagungsband Geomonitoring 2020, S. 3-15},
  year = {2020}
}
Wegmüller U, Magnard C, Werner C, Strozzi T, Caduff R and Manconi A (2020), "Methods to avoid being affected by non-zero closure phase in InSAR time series analysis in a multi-reference stack", SARWatch Workshop - Advances in the Science and Applications of SAR Interferometry, Vilamoura, Portugal.
BibTeX:
@article{Wegmuller2020a,
  author = {Wegmüller, Urs and Magnard, Christophe and Werner, Charles and Strozzi, Tazio and Caduff, Rafael and Manconi, Andrea},
  title = {Methods to avoid being affected by non-zero closure phase in InSAR time series analysis in a multi-reference stack},
  journal = {SARWatch Workshop - Advances in the Science and Applications of SAR Interferometry, Vilamoura, Portugal},
  year = {2020}
}
Yang H, Ciais P, Santoro M, Huang Y, Li W, Wang Y, Bastos A, Goll D, Arneth A, Anthoni P, Arora VK, Friedlingstein P, Harverd V, Joetzjer E, Kautz M, Lienert S, Nabel JEMS, O'Sullivan M, Sitch S, Vuichard N, Wiltshire A and Zhu D (2020), "Comparison of forest above-ground biomass from dynamic global vegetation models with spatially explicit remotely sensed observation-based estimates", Global Change Biol.., July, 2020. Vol. 26(7), pp. 3997-4012.
BibTeX:
@article{Yang2020,
  author = {Yang, Hui and Ciais, Philippe and Santoro, Maurizio and Huang, Yuanyuan and Li, Wei and Wang, Yilong and Bastos, Ana and Goll, Daniel and Arneth, Almut and Anthoni, Peter and Arora, Vivek K. and Friedlingstein, Pierre and Harverd, Vanessa and Joetzjer, Emilie and Kautz, Markus and Lienert, Sebastian and Nabel, Julia E. M. S. and O'Sullivan, Michael and Sitch, Stephen and Vuichard, Nicolas and Wiltshire, Andy and Zhu, Dan},
  title = {Comparison of forest above-ground biomass from dynamic global vegetation models with spatially explicit remotely sensed observation-based estimates},
  journal = {Global Change Biol.},
  year = {2020},
  volume = {26},
  number = {7},
  pages = {3997--4012},
  url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.15117},
  doi = {10.1111/gcb.15117}
}
Zheng D, Li X, Zhao T, Wen J, Van Der Velde R, Schwank M, Wang X, Wang Z and Su Z (2020), "Impact of Soil Permittivity and Temperature Profile on L-Band Microwave Emission of Frozen Soil", IEEE Trans. Geosci. Remote Sens.. , pp. 1-14. Institute of Electrical and Electronics Engineers (IEEE).
BibTeX:
@article{Zheng2020,
  author = {Zheng, D. and Li, X. and Zhao, T. and Wen, J. and Van Der Velde, R. and Schwank, M. and Wang, X. and Wang, Z. and Su, Z.},
  title = {Impact of Soil Permittivity and Temperature Profile on L-Band Microwave Emission of Frozen Soil},
  journal = {IEEE Trans. Geosci. Remote Sens.},
  publisher = {Institute of Electrical and Electronics Engineers (IEEE)},
  year = {2020},
  pages = {1--14},
  doi = {10.1109/TGRS.2020.3024971}
}
Baffelli S, Frey O and Hajnsek I (2019), "Polarimetric analysis of natural terrain observed with a ku-band terrestrial radar", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 12(12), pp. 5268-5288. Institute of Electrical and Electronics Engineers.
Abstract: Terrestrial radar interferometers (TRI) are complimentary to spaceborne synthetic aperture radar systems for deformation monitoring in natural terrain: They permit shorter revisit times and greater flexibility in acquisition mode and timing. The additional diversity offered by polarimetric data can also be beneficial for TRI observations because polarized waves are sensitive to the dielectric and geometrical properties of the scatterers. Polarimetric data helps to distinguish different scattering mechanisms in a resolution cell while at the same time estimating terrain displacements. However, the polarimetric scattering signatures of natural surfaces at Ku-Band are not as well characterized as the ones at longer wavelengths, owing to relative rarity of full polarimetric systems operating in Ku-band. This band is often employed in TRI to obtain a fine azimuth resolution with a limited aperture size. This article aims at assessing the potential of polarimetric measurements in Ku-band TRI through an experimental study of polarimetric scattering signatures of natural surfaces using two datasets acquired over a glacier and in an agricultural and urban scene. The main finding of this analysis is that the Cloude-Pottier entropy is high for all land cover types; it is only observed to be less than 0.5 for scatterers with a large radar cross section. Several plausible hypotheses for this observation are formulated and tested, the most likely assumes a combination of depolarizing scattering from natural surfaces and the effect of the large ratio of wavelength to resolution cell size.
BibTeX:
@article{Baffelli20195268,
  author = {Baffelli, S. and Frey, O. and Hajnsek, I.},
  title = {Polarimetric analysis of natural terrain observed with a ku-band terrestrial radar},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2019},
  volume = {12},
  number = {12},
  pages = {5268-5288},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85079352718&doi=10.1109%2fJSTARS.2019.2953206&partnerID=40&md5=5a80f6a1d5c74ee9af3abb50507afcf5},
  doi = {10.1109/JSTARS.2019.2953206}
}
Bartsch A, Leibman M, Strozzi T, Khomutov A, Widhalm B, Babkina E, Mullanurov D, Ermokhina K, Kroisleitner C and Bergstedt H (2019), "Seasonal progression of ground displacement identified with satellite radar interferometry and the impact of unusually warm conditions on permafrost at the Yamal Peninsula in 2016", Remote Sensing. Vol. 11(16) MDPI AG.
Abstract: Ground subsidence monitoring by Synthetic Aperture Radar interferometry (InSAR) over Arctic permafrost areas is largely limited by long revisit intervals, which can lead to signal decorrelation. Recent satellite missions such as COSMO-Skymed (X-band) and Sentinel-1 (C-band) have comparably short time intervals of a few days. We analyze dense records of COSMO-Skymed from 2013 and 2016 and of Sentinel-1 from 2016, 2017, and 2018 for the unfrozen period over central Yamal (Russia). These years were distinct in environmental conditions and 2016 in particular was unusually warm. We evaluate the InSAR-derived displacement with in situ subsidence records, active-layer thickness measurements, borehole temperature records, meteorological data, C-band scatterometer records, and a land-cover classification based on Sentinel-1 and -2 data. Our results indicate that a comparison of seasonal thaw evolution between years is feasible after accounting for the early thaw data gap in InSAR time series (as a result of snow cover) through an assessment with respect to degree-days of thawing. Average rates of subsidence agree between in situ and Sentinel-1 (corrected for viewing geometry), with 3.9mmand 4.3mmper 100 degree-days of thaw at the test site. X-band and C-band records agree well with each other, including seasonal evolution of subsidence. The average displacement is more than twice in magnitude at the active-layer monitoring test site in 2016 compared to the other years. We further demonstrate that InSAR displacement can not only provide information on the magnitude of ground thaw but also on soil properties through analyses of seasonal evolution in extreme years. 2019 by the authors.
BibTeX:
@article{Bartsch2019,
  author = {Bartsch, A. and Leibman, M. and Strozzi, T. and Khomutov, A. and Widhalm, B. and Babkina, E. and Mullanurov, D. and Ermokhina, K. and Kroisleitner, C. and Bergstedt, H.},
  title = {Seasonal progression of ground displacement identified with satellite radar interferometry and the impact of unusually warm conditions on permafrost at the Yamal Peninsula in 2016},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2019},
  volume = {11},
  number = {16},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85071529516&doi=10.3390%2frs11161865&partnerID=40&md5=6c0363c29af2d07e74c2d86782f6032c},
  doi = {10.3390/rs11161865}
}
Bickel V, Lanaras C, Manconi A, Loew S and Mall U (2019), "Automated Detection of Lunar Rockfalls Using a Convolutional Neural Network", IEEE Transactions on Geoscience and Remote Sensing. Vol. 57(6), pp. 3501-3511. Institute of Electrical and Electronics Engineers Inc..
Abstract: This paper implements a novel approach to automatically detect and classify rockfalls in Lunar Reconnaissance Orbiter narrow angle camera (NAC) images using a single-stage dense object detector (RetinaNet). The convolutional neural network has been trained with a data set of 2932 original rockfall images. In order to avoid overfitting, the initial training data set has been augmented during training using random image rotation, scaling, and flipping. Testing images have been labelled by human operators and have been used for RetinaNet performance evaluation. Testing shows that RetinaNet is capable to reach recall values between 0.98 and 0.39, precision values between 1 and 0.25, and average precisions ranging from 0.89 to 0.69, depending on the used confidence threshold and intersection-over-union values. Mean processing time of a single NAC image in RetinaNet is around 10 s using a GeForce GTX 1080 Ti and GeForce Titan Xp, which is in orders of magnitudes faster than a human operator. The processing speed allows to efficiently exploit the currently available NAC data stack with more than 1 million images in a reasonable timeframe. The combination of speed and detection performance can be used to produce lunar rockfall distribution maps on large spatial scales for utilization by the scientific and engineering community.
BibTeX:
@article{Bickel20193501,
  author = {Bickel, V.T. and Lanaras, C. and Manconi, A. and Loew, S. and Mall, U.},
  title = {Automated Detection of Lunar Rockfalls Using a Convolutional Neural Network},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2019},
  volume = {57},
  number = {6},
  pages = {3501-3511},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058993727&doi=10.1109%2fTGRS.2018.2885280&partnerID=40&md5=084e4ce5571a8cede066c26b3dc2d38f},
  doi = {10.1109/TGRS.2018.2885280}
}
Bueechi E, Klimes J, Frey H, Huggel C, Strozzi T and Cochachin A (2019), "Regional-scale landslide susceptibility modelling in the Cordillera Blanca, Peru - a comparison of different approaches", Landslides. Vol. 16(2), pp. 395-407. Springer Verlag.
Abstract: This study applied existing methods of landslide susceptibility modelling of the mountainous area of the Cordillera Blanca (Peru), which is prone to landslides. In heterogeneous regions as in the Cordillera Blanca, the performance of a physically based approach Stability Index Mapping (SINMAP) was compared to empirical statistical models using logistic regression and a landslide density model. All models were applied to three different digital elevation models (DEMs): ASTER GDEM, SRTM (both 30-m spatial resolution), and TanDEM-X (12-m spatial resolution). Obtained results were evaluated using the area under the receiver operating characteristic curve (AUC) approach, once for a landslide inventory which extends over the whole study area and once using an inventory of a smaller area. The physically based approach (AUCs between 0.567 and 0.625) performed worse than the statistical models (AUCs from 0.672 to 0.759) over the large area. Additionally, all models received higher performances within the small area. This coincided with differences of the variability of the DEM-derived characteristics (e.g. slope angle and curvature) from the small to the large evaluation area. Using the smaller evaluation area, all models received higher AUC values (0.743–0.799), and the impact of the DEMs was less visible. The analysis of the susceptibility showed that mainly the same slopes are considered as most or least susceptible by all models, but SINMAP is classifying larger areas as unstable or stable. Overall, this study showed that regional-scale landslide susceptibility modelling can lead to reasonable results even in regions with scarce model input data, but performances of different DEMs and models need to be evaluated carefully. 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
BibTeX:
@article{Bueechi2019395,
  author = {Bueechi, E. and Klimes, J. and Frey, H. and Huggel, C. and Strozzi, T. and Cochachin, A.},
  title = {Regional-scale landslide susceptibility modelling in the Cordillera Blanca, Peru - a comparison of different approaches},
  journal = {Landslides},
  publisher = {Springer Verlag},
  year = {2019},
  volume = {16},
  number = {2},
  pages = {395-407},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055695245&doi=10.1007%2fs10346-018-1090-1&partnerID=40&md5=130082890be85257fe6feebdfd6ff99b},
  doi = {10.1007/s10346-018-1090-1}
}
Cartus O and Santoro M (2019), "Exploring combinations of multi-temporal and multi-frequency radar backscatter observations to estimate above-ground biomass of tropical forest", Remote Sensing of Environment. Vol. 232 Elsevier Inc..
Abstract: Approaches exploiting the complementary information on forest above-ground biomass (AGB) contained in multi-temporal and multi-frequency radar backscatter have hardly been explored in the tropics. Having available a multi-seasonal stack of air- and spaceborne X-, C-, L-, and P-band imagery for forest sites in Lope and Mondah, Gabon, we analyzed the sensitivity of backscatter at different frequencies to AGB under varying environmental imaging conditions, and the performance of an AGB retrieval when combining multi-temporal and multi-frequency backscatter observations. For the tropical forest sites in Gabon, which differ significantly with respect to forest composition and climatic conditions, we find that i) P-band allows for estimating AGB with the highest accuracy, ii) multi-temporal L-band backscatter may achieve accuracies close to what can be achieved with few P-band observations, iii) the use of multi-temporal observations is beneficial/crucial at all frequencies, in particular when the imaging conditions are persistently moist and the sensitivity of individual images to AGB reduced, and iv) combining P- and L-band backscatter allows for improving the AGB retrieval primarily when few P-band observations are complemented by a larger number of L-band observations. While the results of this study reemphasize that P-band is the most suitable frequency for mapping AGB in the tropics, they also advise consideration of the growing archives of spaceborne backscatter observations acquired at higher frequencies when mapping AGB in the tropics. 2019 Elsevier Inc.
BibTeX:
@article{Cartus2019a,
  author = {Cartus, O. and Santoro, M.},
  title = {Exploring combinations of multi-temporal and multi-frequency radar backscatter observations to estimate above-ground biomass of tropical forest},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2019},
  volume = {232},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85069974980&doi=10.1016%2fj.rse.2019.111313&partnerID=40&md5=d0055171bde32f798eeb3b83ba796ab9},
  doi = {10.1016/j.rse.2019.111313}
}
Cartus O, Santoro M, Wegmüller U and Rommen B (2019), "Benchmarking the retrieval of biomass in boreal forests using P-band SAR backscatter with multi-temporal C- and L-band observations", Remote Sensing. Vol. 11(14) MDPI AG.
Abstract: The planned launch of a spaceborne P-band radar mission and the availability of C- and L-band data from several spaceborne missions suggest investigating the complementarity of C-, L-, and P-band backscatter with respect to the retrieval of forest above-ground biomass. Existing studies on the retrieval of biomass with multi-frequency backscatter relied on single observations of the backscatter and were thus not able to demonstrate the potential of multi-temporal C- and L-band data that are now available from spaceborne missions. Based on spaceborne C- and L-band and airborne P-band images acquired over a forest site in southern Sweden, we investigated whether Cand L-band backscatter may complement retrievals of above-ground biomass from P-band. To this end, a retrieval framework was adopted that utilizes a semi-empirical model for C- and L-bands and an empirical parametric model for P-band. Estimates of above-ground biomass were validated with the aid of 20 m-diameter plots and a LiDAR-derived biomass map with 100 m × 100 m pixel size. The highest retrieval accuracy when not combining frequencies was obtained for P-band with a relative root mean square error (RMSE) of 30% at the hectare scale. The retrieval with multi-temporal L- and C-bands produced errors of the order of 40% and 50%, respectively. The P-band retrieval could be improved for 4% when using P-, L-, and C-bands jointly. The combination of C- and L-bands allowed for retrieval accuracies close to those achieved with P-band. A crucial requirement for achieving an error of 30% with C- and L-bands was the use of multi-temporal observations, which was highlighted by the fact that the retrieval with the best individual L-band image was associated with an error of 61%. The results of this study reconfirmed that P-band is the most suited frequency for the retrieval of above-ground biomass of boreal forests based on backscatter, but also highlight the potential of multi-temporal C- and L-band imagery for mapping above-ground biomass, for instance in areas where the planned ESA BIOMASS P-band mission will not be allowed to acquire data. 2019 by the authors.
BibTeX:
@article{Cartus2019b,
  author = {Cartus, O. and Santoro, M. and Wegmüller, U. and Rommen, B.},
  title = {Benchmarking the retrieval of biomass in boreal forests using P-band SAR backscatter with multi-temporal C- and L-band observations},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2019},
  volume = {11},
  number = {14},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85071575637&doi=10.3390%2frs11141695&partnerID=40&md5=8610d5a6340abbe0b1cfedb98f2698cc},
  doi = {10.3390/rs11141695}
}
Coscione R, Hajnsek I and Frey O (2019), "Trajectory Uncertainty in Repeat-Pass SAR Interferometry: A Case Study", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 338-341. Institute of Electrical and Electronics Engineers Inc..
Abstract: In the context of differential synthetic aperture radar interferometry (DInSAR), precise trajectory estimation of the SAR platform is necessary to minimize residual phase errors induced by inaccurate knowledge of the 3D acquisition geometry.Inertial navigation systems (INS) and global navigation satellite system (GNSS) are usually employed to track the position of the platform. However, their unavoidable inaccuracies lead to motion estimation errors that negatively affect the quality of the processed radar data.To assess the positioning performance in a repeat-pass scenario, we used a navigation-grade INS/GNSS system to preciselytrack the position and the attitude of a platform moving along a rail and carrying a SAR sensor. We analyse the performance of the positioning solution for different scenarios relevant to repeat-pass DInSAR. since the position of the platform is nearly perfectly repeated at every pass (zero interferometric baseline), the precision of the estimated position can be assessed and the interferometric performance evaluated. 2019 IEEE.
BibTeX:
@conference{Coscione2019338,
  author = {Coscione, R. and Hajnsek, I. and Frey, O.},
  title = {Trajectory Uncertainty in Repeat-Pass SAR Interferometry: A Case Study},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2019},
  pages = {338-341},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077693695&doi=10.1109%2fIGARSS.2019.8898809&partnerID=40&md5=bd5321b8343f8933b70d8041ba546edd},
  doi = {10.1109/IGARSS.2019.8898809}
}
Dini B, Daout S, Manconi A and Loew S (2019), "Classification of slope processes based on multitemporal DInSAR analyses in the Himalaya of NW Bhutan", Remote Sensing of Environment. Vol. 233 Elsevier Inc..
Abstract: Slope deformation in mountainous terrain can be driven by different processes, the nature of which is either gravitational and irreversible or seasonal and reversible, the latter induced by permafrost variations or by hydromechanical or thermomechanical effects. The importance of identifying such deformations is not only related to the hazard they can pose, but also to the understanding of changes that permafrost or local hydrological conditions undergo. Here, we carry out a multi-temporal InSAR analysis over a mountainous area 8000 km2 large, straddling north-western Bhutan and southern Tibet. We propose a methodology to separate locally deforming areas from the effects of long-wavelength signals through the analysis of the spatio-temporal behaviour of 4-years long time series of surface displacements. We present the mapping of hundreds of small-scale features that appear to be actively deforming, as well as several examples of reversible deformation rarely detected at this scale in such a challenging and vast region. The analysis of the multi-annual trend of ground deformation shows a relatively small number of irreversible gravitational movements clearly related to rock slides which attests a low level of recent activity of large rock slope instabilities in the region. In the southernmost, lower elevation parts of the study area, we quantify reversible surface displacements with amplitudes ranging between 5 and 17 mm, and showing maximum displacements towards the satellite in summer months, thus compatible with hydro-mechanical effects related to groundwater table variations. In addition, the ground movement induced by the active layer's response to thawing and freezing over the gentler slopes and high-elevation permafrost regions of Bhutan and southern Tibet is on average around 10 mm, with maxima up to 28 mm. The localised displacements appear to be largely associated to braided stream plains, glacier outwash plains or low angle, fine sediment covered slopes. 2019 Elsevier Inc.
BibTeX:
@article{Dini2019,
  author = {Dini, B. and Daout, S. and Manconi, A. and Loew, S.},
  title = {Classification of slope processes based on multitemporal DInSAR analyses in the Himalaya of NW Bhutan},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2019},
  volume = {233},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85071919212&doi=10.1016%2fj.rse.2019.111408&partnerID=40&md5=4ee4298b425040fb70ba0dacc43f8e13},
  doi = {10.1016/j.rse.2019.111408}
}
Dini B, Manconi A and Loew S (2019), "Investigation of slope instabilities in NW Bhutan as derived from systematic DInSAR analyses", Engineering Geology. Vol. 259 Elsevier B.V..
Abstract: In this work we present a methodology based on remote sensing data to map and classify unstable slopes in high alpine areas and apply this methodology to the Himalaya of northwestern Bhutan. We leverage on radar images acquired by the ESA Envisat and the JAXA ALOS-1 satellites between 2007 and 2011. Synthetic aperture radar differential interferometry (DInSAR) is used to identify and quantify recent ground surface displacements associated with potentially unstable slopes. Optical satellite images and a high-resolution digital surface model is used for the geomorphological classification of individual landforms and deposits associated with displacements. The analysis of the geomorphological characteristics reveals that displacements are associated with: rock slides, mountain slope deformation and rock slope deformation (77.5%), soil creep (4%), soil slides (1.9%) and rock glaciers (12.3%); 4.3% of the detected displacements remain of unknown origin. The method applied here for the assessment of activity likelihood uses a very large number of interferograms obtained with images acquired by different satellites. The method, which is new and replicable, takes advantage of the combination of different acquisition geometries and then combines indices of vegetation cover, layover, velocity estimate and temporal sampling associated with each detected active area to assign a weight. The analysis shows that a cluster of unstable slopes exists in the northwest, potentially related to the presence of an important regional lineament and the distribution of permafrost. Comparatively little ongoing activity is detected in the south, but field validation documents substantial landslide activity in the recent geological past. The dataset here generated, containing 700 potentially unstable areas with an associated activity likelihood, is a novel dataset that makes an essential basis of future analysis to investigate rock slope instability distribution and predisposing factors. Moreover, this dataset represents a new important step towards future landslide hazard assessment in the Himalaya of Bhutan. 2019
BibTeX:
@article{Dini2019b,
  author = {Dini, B. and Manconi, A. and Loew, S.},
  title = {Investigation of slope instabilities in NW Bhutan as derived from systematic DInSAR analyses},
  journal = {Engineering Geology},
  publisher = {Elsevier B.V.},
  year = {2019},
  volume = {259},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067296350&doi=10.1016%2fj.enggeo.2019.04.008&partnerID=40&md5=a7506c435cd89e3eb2f427802ef824cb},
  doi = {10.1016/j.enggeo.2019.04.008}
}
Frey O, Werner C and Coscione R (2019), "Car-borne and UAV-borne mobile mapping of surface displacements with a compact repeat-pass interferometric SAR system at L-band", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 274-277. Institute of Electrical and Electronics Engineers.
Abstract: In this paper, we present first results of car-borne and UAV-borne mobile mapping of potential surface displacements with a compact repeat-pass interferometric FMCW SAR system at L-band: (1) glacier-flow-induced displacements were measured at Stein glacier in the Swiss alps in car-borne mode along a slightly curved road section; (2) a valley slope was observed repeatedly using the vertical-take-off-and-landing (VTOL) UAV Scout B1-100 flown by Aeroscout. The SAR raw data were focused directly to an image grid in map coordinates, involving a digital elevation model and accurate GNSS/INS navigation data, by using a time-domain back-projection (TDBP) approach. These geocoded complex SAR images then allow to directly form differential interferograms in map coordinates. The feasibility of repeat-pass interferometry using our novel FMCW L-band SAR on mobile platforms such as a car or a UAV is successfully demonstrated with several data examples.
BibTeX:
@conference{Frey2019274,
  author = {Frey, O. and Werner, C.L. and Coscione, R.},
  title = {Car-borne and UAV-borne mobile mapping of surface displacements with a compact repeat-pass interferometric SAR system at L-band},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2019},
  pages = {274-277},
  url = {https://www.gamma-rs.ch/uploads/media/freyWernerCoscioneIGARSS2019CARandUAVborneDInSARLBand.pdf},
  doi = {10.1109/IGARSS.2019.8897827}
}
Glueer F, Loew S, Manconi A and Aaron J (2019), "From Toppling to Sliding: Progressive Evolution of the Moosfluh Landslide, Switzerland", Journal of Geophysical Research: Earth Surface. Vol. 124(12), pp. 2899-2919. Blackwell Publishing Ltd.
Abstract: This paper presents a detailed analysis of a dramatic rock slope acceleration that occurred in fall 2016 at the Moosfluh Landslide, located at the glacier tongue of the Great Aletsch Glacier (Switzerland). The acceleration that occurred in 2016 was unanticipated and exposed the valley bottom and an adjacent damned lake to high risk. This acceleration occurred in an active deep-seated gravitational slope deformation (DSGSD) controlled primarily by deep block-flexural toppling. In 2013, a highly accurate displacement monitoring system was developed and installed in the surroundings of the Great Aletsch Glacier, including a time-lapse camera, GNSS, and robotic total stations. This monitoring system provided unique data during the 2016 slope acceleration which are used in this study to assess failure mechanisms, landslide volumes, and subsurface displacement geometry. Based on a novel displacement vector analysis, we find that three retrogressive secondary rockslides developed during the first six weeks of the slope acceleration, with rupture surface depths of 30 to 40 m, and estimated volumes between 1 and 4 Mm3. These rockslides display complex deformation features, including head and lateral scarps, which developed during the slope acceleration. The kinematics of these secondary rockslides changed through time, from primarily toppling to combined toppling and sliding. Our results provide a uniquely detailed understanding of the spatial and temporal evolution of deformation features and movement kinematics that occur when several sectors of a slowly moving DSGSD transitions into rapid rockslides. 2019. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Glueer20192899,
  author = {Glueer, F. and Loew, S. and Manconi, A. and Aaron, J.},
  title = {From Toppling to Sliding: Progressive Evolution of the Moosfluh Landslide, Switzerland},
  journal = {Journal of Geophysical Research: Earth Surface},
  publisher = {Blackwell Publishing Ltd},
  year = {2019},
  volume = {124},
  number = {12},
  pages = {2899-2919},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076403241&doi=10.1029%2f2019JF005019&partnerID=40&md5=8fa8e89fdd5671bfbff5496469cc4e56},
  doi = {10.1029/2019JF005019}
}
Hocke K, Bernet L, Hagen J, Murk A, Renker M and Matzler C (2019), "Diurnal cycle of short-term fluctuations of integrated water vapour above Switzerland", Atmospheric Chemistry and Physics. Vol. 19(19), pp. 12083-12090. Copernicus GmbH.
Abstract: The TROpospheric WAter RAdiometer (TROWARA) continuously measures integrated water vapour (IWV) with a time resolution of 6 s at Bern in Switzerland. During summer, we often see that IWV has temporal fluctuations during daytime, while the nighttime data are without fluctuations. The data analysis is focused on the year 2010, where TROWARA has a good data quality without data gaps. We derive the spectrum of the IWV fluctuations in the period range from about 1 to 100 min. The FFT spectrum with a window size of 3 months leads to a serious underestimation of the spectral amplitudes of the fluctuations. Thus, we apply a band pass filtering method to derive the amplitudes as a function of period Tp. The amplitudes are proportional to Tp0:5. Another method is the calculation of the moving standard deviation with time window lengths from about 1 to 100 min. Here, we get similar results to those with the band pass filtering method. At all periods, the IWV fluctuations are strongest during summer, while they are smallest during winter. We derive the diurnal variation of the short-term IWV fluctuations by applying a moving standard deviation with a window length of 10 min. The daily cycle is strongest during the summer season, with standard deviations up to 0.22 mm at about 14:00 CET. The diurnal cycle disappears during wintertime. A similar seasonal behaviour is observed in the diurnal cycle of latent heat flux as provided by the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2 reanalysis) at Bern. Further, the 3 d averages of the latent heat flux and the magnitude of the short-term IWV variability show a strong correlation at Bern in 2010 (r D 0:82 with a 95 % confidence interval from 0.75 to 0.87). Thus, we suggest that the diurnal cycle of short-term IWV fluctuations at Bern is mainly caused by large convective heating during daytime in summer. 2019 Author(s).
BibTeX:
@article{Hocke201912083,
  author = {Hocke, K. and Bernet, L. and Hagen, J. and Murk, A. and Renker, M. and Matzler, C.},
  title = {Diurnal cycle of short-term fluctuations of integrated water vapour above Switzerland},
  journal = {Atmospheric Chemistry and Physics},
  publisher = {Copernicus GmbH},
  year = {2019},
  volume = {19},
  number = {19},
  pages = {12083-12090},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073054689&doi=10.5194%2facp-19-12083-2019&partnerID=40&md5=c5c02eb2b07d337d40f83b2a8c16179a},
  doi = {10.5194/acp-19-12083-2019}
}
Houtz D, Naderpour R, Schwank M and Steffen K (2019), "Snow wetness and density retrieved from L-band satellite radiometer observations over a site in the West Greenland ablation zone", Remote Sensing of Environment. Vol. 235 Elsevier Inc..
Abstract: We demonstrate a novel method to retrieve snow liquid water content and density over a site in the ablation zone of the Western Greenland Ice Sheet from L-band radiometer data measured by the Soil Moisture and Ocean Salinity (SMOS) satellite. Previous demonstrations using ground-based close-range radiometry separately retrieved snow density and snow wetness over frozen and thawed ground. We apply similar techniques over the ice sheet to simultaneously retrieve snow density and wetness at the location of “Swiss Camp” from June 2010 through August 2018 at nearly daily temporal resolution. Achieved results are compared to in-situ air temperature data and to a well-known 19 GHz and 37 GHz passive-microwave melt characterization technique known as the cross-polarized gradient ratio (XPGR). The L-band based snow wetness retrievals often detect the onset of seasonal melt earlier than the XPGR algorithm without the need for empirically tuned thresholds. We also demonstrate the performance of the SMOS based snow wetness retrievals based on error statistics compared with an air temperature melt proxy. By applying temporal averaging to the SMOS based snow density retrievals, we achieve reasonable agreement with in-situ observations from May 2014 and May 2018. The demonstrated retrieval algorithm shows potential as a future SMOS data product for ice-covered regions of the cryosphere. 2019 Elsevier Inc.
BibTeX:
@article{Houtz2019,
  author = {Houtz, D. and Naderpour, R. and Schwank, M. and Steffen, K.},
  title = {Snow wetness and density retrieved from L-band satellite radiometer observations over a site in the West Greenland ablation zone},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2019},
  volume = {235},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074707041&doi=10.1016%2fj.rse.2019.111361&partnerID=40&md5=3ab84441cc88ba218c0b98ac8252600e},
  doi = {10.1016/j.rse.2019.111361}
}
Manconi A, Ziegler M, Blochliger T and Wolter A (2019), "Technical note: optimization of unmanned aerial vehicles flight planning in steep terrains", International Journal of Remote Sensing. Taylor and Francis Ltd..
Abstract: We present an approach to manage Unmanned Aerial Vehicle (UAV) photogrammetric data acquisition in areas with steep slopes, i.e., typical conditions of high mountain environments prone to slope instabilities and potentially to catastrophic failures. Starting from the Mission Planner from Ardupilot, an open access and widely used UAV flight planning software, we have developed a set of Matlab™ routines to take into account available topographic relief of the area under investigation. We validated our approach in the Swiss Alps, in a steep slope area where very high-resolution digital models and orthophotos are necessary to analyze fracture surface geometries in detail and to better understand the exfoliation fracture processes. Our results provide a best-practice solution to generate very high-resolution photogrammetric products and can be applied in different UAV mapping tasks and/or monitoring scenarios. 2019, 2019 Informa UK Limited, trading as Taylor & Francis Group.
BibTeX:
@article{Manconi2019,
  author = {Manconi, A. and Ziegler, M. and Blochliger, T. and Wolter, A.},
  title = {Technical note: optimization of unmanned aerial vehicles flight planning in steep terrains},
  journal = {International Journal of Remote Sensing},
  publisher = {Taylor and Francis Ltd.},
  year = {2019},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85061013274&doi=10.1080%2f01431161.2019.1573334&partnerID=40&md5=a7b556f53b31e7bd3c2b3ba7107568ba},
  doi = {10.1080/01431161.2019.1573334}
}
Mendez Dominguez E, Magnard C, Meier E, Small D, Schaepman M and Henke D (2019), "A Back-Projection Tomographic Framework for VHR SAR Image Change Detection", IEEE Transactions on Geoscience and Remote Sensing. Vol. 57(7), pp. 4470-4484. Institute of Electrical and Electronics Engineers Inc..
Abstract: Information on 3-D structure expands the scope of change detection applications, for example, in urban studies, human activity, and forest monitoring. Current change detection methods do not fully consider the specifics of SAR data or the properties of the corresponding image focusing techniques. We propose a three-stage method complementing the properties of 2-D and 3-D very high-resolution (VHR) synthetic aperture radar imagery to improve the performance of 2-D only approaches. The method takes advantage of back-projection tomography to ease translation of the 2-D location of the targets into their corresponding 3-D location and vice versa. Detection of changes caused by objects with a small vertical extent is based on the corresponding backscatter difference, while changes caused by objects with a large vertical extent are detected with both backscatter and height difference information combined in a conditional random field. Using multitemporal images, the kappa coefficient improved by a factor of two in comparison with traditional schemes.
BibTeX:
@article{MendezDominguez20194470,
  author = {Mendez Dominguez, E. and Magnard, C. and Meier, E. and Small, D. and Schaepman, M.E. and Henke, D.},
  title = {A Back-Projection Tomographic Framework for VHR SAR Image Change Detection},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2019},
  volume = {57},
  number = {7},
  pages = {4470-4484},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85068206460&doi=10.1109%2fTGRS.2019.2891308&partnerID=40&md5=3657140738958ac21e994898c1ddb346},
  doi = {10.1109/TGRS.2019.2891308}
}
Mondini A, Santangelo M, Rocchetti M, Rossetto E, Manconi A and Monserrat O (2019), "Sentinel-1 SAR amplitude imagery for rapid landslide detection", Remote Sensing. Vol. 11(7) MDPI AG.
Abstract: Despite landslides impact the society worldwide every day, landslide information isinhomogeneous and lacking. When landslides occur in remote areas or where the availability ofoptical images is rare due to cloud persistence, they might remain unknown, or unnoticed for longtime, preventing studies and hampering civil protection operations. The unprecedented availabilityof SAR C-band images provided by the Sentinel-1 constellation offers the opportunity to proposenew solutions to detect landslides events. In this work, we perform a systematic assessment ofSentinel-1 SAR C-band images acquired before and after known events. We present the resultsof a pilot study on 32 worldwide cases of rapid landslides entailing different types, sizes, slopeexpositions, as well as pre-existing land cover, triggering factors and climatic regimes. Results showthat in about eighty-four percent of the cases, changes caused by landslides on SAR amplitudesare unambiguous, whereas only in about thirteen percent of the cases there is no evidence. On theother hand, the signal does not allow for a systematic use to produce inventories because only in8 cases, a delineation of the landslide borders (i.e., mapping) can be manually attempted. In a fewcases, cascade multi-hazard (e.g., floods caused by landslides) and evidences of extreme triggeringfactors (e.g., strong earthquakes or very rapid snow melting) were detected. The method promises toincrease the availability of information on landslides at different spatial and temporal scales withbenefits for event magnitude assessment during weather-related emergencies, model tuning, andlandslide forecast model validation, in particular when accurate mapping is not required. 2019 by the authors.
BibTeX:
@article{Mondini2019,
  author = {Mondini, A.C. and Santangelo, M. and Rocchetti, M. and Rossetto, E. and Manconi, A. and Monserrat, O.},
  title = {Sentinel-1 SAR amplitude imagery for rapid landslide detection},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2019},
  volume = {11},
  number = {7},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064014108&doi=10.3390%2frs11070760&partnerID=40&md5=92e95fa29e376ea72bb2c4f5da30d7fe},
  doi = {10.3390/rs11070760}
}
Palmisano D, Satalino G, Balenzano A, Bovenga F, Mattia F, Rinaldi M, Ruggieri S, Skriver H, Davidson M, Cartus O and Wegmüller U (2019), "Sensitivity of Sentinel-1 Interferometric Coherence to Crop Structure and Soil Moisture", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 6219-6222. Institute of Electrical and Electronics Engineers Inc..
Abstract: This paper investigates the sensitivity of Sentinel-1 (S-1) interferometric coherence to crop structure and near surface soil moisture (SSM) content. The study analyzes a data set collected in 2017 over the Apulian Tavoliere agricultural site (Southern Italy). The data set includes: i) in situ data over more than 600 agricultural fields monitored during the 2017 winter and spring growing seasons; ii) time-series of S-1 IW VV and VH backscatter and interferometric coherence; iii) time series of S-1 SSM maps. The temporal behavior of S-1 coherence and VH backscatter has been assessed over the monitored agricultural fields. Initial results indicate a stronger sensitivity of S-1 coherence than VH backscatter to crop geometric structure. In addition, an analysis at site scale, conducted before and after an important rain event, indicates a change of SSM from 0.18 to 0.30 m3/m3 along with a change of S-1 coherence from 0.61 to 0.53.
BibTeX:
@conference{Palmisano20196219,
  author = {Palmisano, D. and Satalino, G. and Balenzano, A. and Bovenga, F. and Mattia, F. and Rinaldi, M. and Ruggieri, S. and Skriver, H. and Davidson, M.W.J. and Cartus, O. and Wegmüller, U.},
  title = {Sensitivity of Sentinel-1 Interferometric Coherence to Crop Structure and Soil Moisture},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2019},
  pages = {6219-6222},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077674004&doi=10.1109%2fIGARSS.2019.8899164&partnerID=40&md5=5b4a90f4cbeca7e6235fcb68a43eb2b7},
  doi = {10.1109/IGARSS.2019.8899164}
}
Rodriguez-Veiga P, Quegan S, Carreiras J, Persson H, Fransson J, Hoscilo A, Ziotkowski D, Sterenczak K, Lohberger S, Stangel M, Berninger A, Siegert F, Avitabile V, Herold M, Mermoz S, Bouvet A, Le Toan T, Carvalhais N, Santoro M, Cartus O, Rauste Y, Mathieu R, Asner G, Thiel C, Pathe C, Schmullius C, Seifert F, Tansey K and Balzter H (2019), "Forest biomass retrieval approaches from earth observation in different biomes", International Journal of Applied Earth Observation and Geoinformation. Vol. 77, pp. 53-68. Elsevier B.V..
Abstract: The amount and spatial distribution of forest aboveground biomass (AGB) were estimated using a range of regionally developed methods using Earth Observation data for Poland, Sweden and regions in Indonesia (Kalimantan), Mexico (Central Mexico and Yucatan peninsula), and South Africa (Eastern provinces) for the year 2010. These regions are representative of numerous forest biomes and biomass levels globally, from South African woodlands and savannas to the humid tropical forest of Kalimantan. AGB retrieval in each region relied on different sources of reference data, including forest inventory plot data and airborne LiDAR observations, and used a range of retrieval algorithms. This is the widest inter-comparison of regional-to-national AGB maps to date in terms of area, forest types, input datasets, and retrieval methods. The accuracy assessment of all regional maps using independent field data or LiDAR AGB maps resulted in an overall root mean square error (RMSE) ranging from 10 t ha −1 to 55 t ha −1 (37% to 67% relative RMSE), and an overall bias ranging from −1 t ha −1 to +5 t ha −1 at pixel level. The regional maps showed better agreement with field data than previously developed and widely used pan-tropical or northern hemisphere datasets. The comparison of accuracy assessments showed commonalities in error structures despite the variety of methods, input data, and forest biomes. All regional retrievals resulted in overestimation (up to 63 t ha −1 ) in the lower AGB classes, and underestimation (up to 85 t ha −1 ) in the higher AGB classes. Parametric model-based algorithms present advantages due to their low demand on in situ data compared to non-parametric algorithms, but there is a need for datasets and retrieval methods that can overcome the biases at both ends of the AGB range. The outcomes of this study should be considered when developing algorithms to estimate forest biomass at continental to global scale level. 2019 The Authors
BibTeX:
@article{RodriguezVeiga201953,
  author = {Rodriguez-Veiga, P. and Quegan, S. and Carreiras, J. and Persson, H.J. and Fransson, J.E.S. and Hoscilo, A. and Ziotkowski, D. and Sterenczak, K. and Lohberger, S. and Stangel, M. and Berninger, A. and Siegert, F. and Avitabile, V. and Herold, M. and Mermoz, S. and Bouvet, A. and Le Toan, T. and Carvalhais, N. and Santoro, M. and Cartus, O. and Rauste, Y. and Mathieu, R. and Asner, G.P. and Thiel, C. and Pathe, C. and Schmullius, C. and Seifert, F.M. and Tansey, K. and Balzter, H.},
  title = {Forest biomass retrieval approaches from earth observation in different biomes},
  journal = {International Journal of Applied Earth Observation and Geoinformation},
  publisher = {Elsevier B.V.},
  year = {2019},
  volume = {77},
  pages = {53-68},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062857698&doi=10.1016%2fj.jag.2018.12.008&partnerID=40&md5=b1b9f49718f14e2b61617f4c6892a6ae},
  doi = {10.1016/j.jag.2018.12.008}
}
Santoro M, Cartus O, Fransson J and Wegmüller U (2019), "Complementarity of X-, C-, and L-band SAR backscatter observations to retrieve forest stem volume in boreal forest", Remote Sensing. Vol. 11(13) MDPI AG.
Abstract: The simultaneous availability of observations from space by remote sensing platforms operating atmultiple frequencies in themicrowave domain suggests investigating their complementarity in thematic mapping and retrieval of biophysical parameters. In particular, there is an interest to understand whether the wealth of short wavelength Synthetic Aperture Radar (SAR) backscatter observations at X-, C-, and L-band from currently operating spaceborne missions can improve the retrieval of forest stem volume, i.e., above-ground biomass, in the boreal zone with respect to a single frequency band. To this scope, repeated observations from TerraSAR-X, Sentinel-1 and ALOS-2 PALSAR-2 from the test sites of Remningstorp and Krycklan, Sweden, have been analyzed and used to estimate stem volume with a retrieval framework based on theWater Cloud Model. Individual estimates of stem volume were then combined linearly to form single-frequency and multi-frequency estimates. The retrieval was assessed at large 0.5 ha forest inventory plots (Remningstorp) and small 0.03 ha forest inventory plots (Krycklan). The relationship between SAR backscatter and stem volume differed depending on forest structure and environmental conditions, in particular at X- and C-band. The highest retrieval accuracy was obtained at both test sites at L-band. The combination of stem volume estimates from data acquired at two or three frequencies achieved an accuracy that was superior to values obtained at a single frequency. When combining estimates from X-, C-, and L-band data, the relative RMSE for the 0.5 ha inventory plots at Remningstorp was 31.3%. For the 0.03 ha inventory plots at Krycklan, the relative RMSE was above 50%. In a retrieval scenario involving short wavelength SAR backscatter data, these results suggest combining multiple frequencies to ensure the highest possible retrieval accuracy achievable. Retrievals should be undertaken to target spatial scales well above the size of a pixel. 2019 by the authors.
BibTeX:
@article{Santoro2019,
  author = {Santoro, M. and Cartus, O. and Fransson, J.E.S. and Wegmüller, U.},
  title = {Complementarity of X-, C-, and L-band SAR backscatter observations to retrieve forest stem volume in boreal forest},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2019},
  volume = {11},
  number = {13},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85068529553&doi=10.3390%2frs11131563&partnerID=40&md5=0d6b9d2ea6c9cf9c99729e98c3ad4952},
  doi = {10.3390/rs11131563}
}
Scapozza C, Ambrosi C, Cannata M and Strozzi T (2019), "Glacial lake outburst flood hazard assessment by satellite Earth observation in the Himalayas (Chomolhari area, Bhutan)", Geographica Helvetica. Vol. 74(1), pp. 125-139. Copernicus GmbH.
Abstract: A case study of glacial lakes outburst flood (GLOF) hazard assessment by satellite Earth observation (EO) and numerical modelling is presented for the supraglacial and ice-contact lakes on Thangothang Chhu glacier, Chomolhari area (Bhutan). Detailed geomorphological mapping, including landslide and rock glacier inventories, as well as surface displacement determination using an interferometric SAR (InSAR) satellite, allowed a GLOF hazard assessment for lake Wa-007 to be performed. Outburst scenario modelling was achieved by combining both empirical and numerical modelling approaches, revealing that only a flood wave can have an impact on the two human settlements located downslope of Wa-007 lake. The worst-case scenario, modelled thanks to r.damflood, allowed the wave-front arrival time, the maximum water depth and the arrival time of maximum water height for the two human settlements to be quantified. A long-term monitoring strategy based entirely on EO data, with an update cycle of 5 years, is proposed to assess the future evolution of the area. Author(s) 2019.
BibTeX:
@article{Scapozza2019125,
  author = {Scapozza, C. and Ambrosi, C. and Cannata, M. and Strozzi, T.},
  title = {Glacial lake outburst flood hazard assessment by satellite Earth observation in the Himalayas (Chomolhari area, Bhutan)},
  journal = {Geographica Helvetica},
  publisher = {Copernicus GmbH},
  year = {2019},
  volume = {74},
  number = {1},
  pages = {125-139},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063632674&doi=10.5194%2fgh-74-125-2019&partnerID=40&md5=409841239be1c9df17c28b4ee1052ed9},
  doi = {10.5194/gh-74-125-2019}
}
Schwank M, Li X, Kerr Y, Naderpour R, Matzler C and Wigneron J-P (2019), "tau-Omega- and Two-Stream Emission Models applied to Close-Range and SMOS Measurements", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 6158-6161. Institute of Electrical and Electronics Engineers Inc..
Abstract: An Emission Models (EM) adequate for a retrieval algorithm requires being simple while still capturing the responses of brightness temperatures T textBp, theta to the retrieval parameters. The objective of this study is to explore the benefits of the multiple-scattering Two-Stream (2S) EM over the "Tau-Omega" (TO) EM to retrieve soil Water Content WC and vegetation optical depth τ from L-band T textBp, theta . For sparse and low-scattering vegetation T textB, EMp, theta simulated with EM = TO and EM = 2S converge, which is not the case for dense and strongly scattering vegetation. WCRC and τRC are retrieved with Retrieval Configurations RC = TO, 2S from T textBp, theta measured: i) from a tower within a deciduous forest, and ii) by the "Soil Moisture and Ocean Salinity" (SMOS) mission. Using 2S EM instead of TO EM resulted in marginally lower WCRC retrievals while τRC retrievals are reduced more considerably. With respect to in-situ WCin-situ, retrievals WC2S derived from tower-based T textBp, theta performed better than forest soil water-content WCTO retrieved via the inversion of the "reference" TO EM. Likewise, SMOS based WC2S retrievals revealed better agreement with ECMWF WC simulations than WCTO achieved with the "reference" RC = TO. In short, our study provides clear evidence that it is meaningful to replace TO EM used for current SMOS and SMAP land retrieval with 2S EM.Further advantages of the 2S EM over the TO EM are outlined in this study.
BibTeX:
@conference{Schwank20196158,
  author = {Schwank, M. and Li, X. and Kerr, Y. and Naderpour, R. and Matzler, C. and Wigneron, J.-P.},
  title = {tau-Omega- and Two-Stream Emission Models applied to Close-Range and SMOS Measurements},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2019},
  pages = {6158-6161},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074882946&doi=10.1109%2fIGARSS.2019.8898225&partnerID=40&md5=dc8078f0b6d421bb25f3c135280e4afe},
  doi = {10.1109/IGARSS.2019.8898225}
}
Siddique M, Strozzi T, Hajnsek I and Frey O (2019), "A Case Study on the Correction of Atmospheric Phases for SAR Tomography in Mountainous Regions", IEEE Transactions on Geoscience and Remote Sensing. Vol. 57(1), pp. 416-431. Institute of Electrical and Electronics Engineers Inc..
Abstract: Synthetic aperture radar (SAR) tomography with repeat-pass acquisitions generally requires a priori phase calibration of the interferometric data stack by compensating for the atmosphere-induced phase delay variations. These variations act as a disturbance in tomographic focusing. In mountainous regions, the mitigation of these disturbances is particularly challenging due to strong spatial variations of the local atmospheric conditions and propagation paths through the troposphere. In this paper, we assess a data-driven approach to estimate these phase variations under a regression-kriging framework. The vertical stratification of the troposphere is modeled functionally, while the impact of the spatial turbulence is considered in a stochastic sense. The methodology entails an initial persistent scatterer interferometry (PSI) analysis. The atmospheric phases isolated for the persistent scatterers (PS) within the PSI processing are considered as samples of the 3-D distribution of the phase delay variations over the scene. These atmospheric phases are regressed against the spatial coordinates in map geometry at PS locations. In turn, kriging predictions are obtained at each location along the elevation profile, where tomographic focusing is intended. A key point of this approach is that the requisite atmospheric corrections are incorporated within the tomographic focusing model. A case study has been performed on a data stack comprising 32 COSMO-SkyMed stripmap images acquired over the Matter Valley in the Swiss Alps, in the summers of 2008-2013. The results show locally improved deformation sampling with tomographic methods compared to the initial PSI solution, primarily due to the improved phase calibration. In general, this paper underscores the indispensability of height-dependent correction of atmospheric phases for SAR tomography.
BibTeX:
@article{Siddique2019416,
  author = {Siddique, M.A. and Strozzi, T. and Hajnsek, I. and Frey, O.},
  title = {A Case Study on the Correction of Atmospheric Phases for SAR Tomography in Mountainous Regions},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2019},
  volume = {57},
  number = {1},
  pages = {416-431},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85052649884&doi=10.1109%2fTGRS.2018.2855101&partnerID=40&md5=570852f8fd5c26432f03b270289ab67f},
  doi = {10.1109/TGRS.2018.2855101}
}
Siddique M, Wilgan K, Strozzi T, Geiger A, Hajnsek I and Frey O (2019), "A Comparison of Tropospheric Path Delays Estimated in PSI Processing Against Delays Derived from a GNSS Network in the Swiss Alps", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 342-345. Institute of Electrical and Electronics Engineers Inc..
Abstract: This paper reports the first results of a comparative study of tropospheric delays retrieved by means of PSI processing of an interferometric stack of SAR images against those derived independently from a permanent GNSS network. The stack comprises 33 Cosmo-SkyMed stripmap images acquired in the summers between 2008-13 over the Matter Valley in the Swiss Alps. The long-term objective of the study is to explore whether GNSS-derived delays from existing networks (i.e., not deployed specifically for a test site) in Swiss Alpine regions can aid in tropospheric phase corrections in SAR data, or rather the phase corrections derived within the PSI processing being at a higher spatial resolution might be appropriate to build upon the GNSS products by improving their resolution.
BibTeX:
@conference{Siddique2019342,
  author = {Siddique, M.A. and Wilgan, K. and Strozzi, T. and Geiger, A. and Hajnsek, I. and Frey, O.},
  title = {A Comparison of Tropospheric Path Delays Estimated in PSI Processing Against Delays Derived from a GNSS Network in the Swiss Alps},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2019},
  pages = {342-345},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077680515&doi=10.1109%2fIGARSS.2019.8899799&partnerID=40&md5=e83f560a210de55db0f4920774cfed6c},
  doi = {10.1109/IGARSS.2019.8899799}
}
Wiesmann A, Caduff R, Werner C, Frey O, Schneebeli M, Lowe H, Jaggi M, Schwank M, Naderpour R and Fehr T (2019), "ESA SnowLab Project: 4 Years of Wide Band Scatterometer Measurements of Seasonal Snow", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 5745-5748. Institute of Electrical and Electronics Engineers Inc..
Abstract: The aim of the ESA SnowLab project is to provide a comprehensive multi-frequency, multi-polarisation, multi-temporal dataset of active microwave measurements over snow-covered grounds to investigate the relationship between effective snow- and ground parameters and the resultant signals detected by microwave radar. An important part for the development of microwave models is the microstructural characterisation. This characterisation can only be done by repeated measurements by SnowMicroPen and more completely, but also much more expensive, by X-ray micro-tomography. Within this project we complemented the microwave measurements of Alpine snow in Switzerland with extensive effective snow- and ground parameters and meteorological data. Microwave backscatter measurements were conducted using the 9 - 18 GHz ESA SnowScat instrument and since December 2018 the recently built ESA WBScat instrument. WBScat allows to extend the spectral coverage to 1 - 40 GHz.
BibTeX:
@conference{Wiesmann20195745,
  author = {Wiesmann, A. and Caduff, R. and Werner, C. and Frey, O. and Schneebeli, M. and Lowe, H. and Jaggi, M. and Schwank, M. and Naderpour, R. and Fehr, T.},
  title = {ESA SnowLab Project: 4 Years of Wide Band Scatterometer Measurements of Seasonal Snow},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2019},
  pages = {5745-5748},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077691980&doi=10.1109%2fIGARSS.2019.8898961&partnerID=40&md5=8bd7f90b83c18a1c0ad6e29f0165a302},
  doi = {10.1109/IGARSS.2019.8898961}
}
Wilgan K, Siddique M, Strozzi T, Geiger A and Frey O (2019), "Comparison of tropospheric path delay estimates from GNSS and space-borne SAR interferometry in alpine conditions", Remote Sensing. Vol. 11(15) MDPI AG.
Abstract: We compare tropospheric delays from Global Navigation Satellite Systems (GNSS) and Synthetic Aperture Radar (SAR) Interferometry (InSAR) in a challenging mountainous environment in the Swiss Alps, where strong spatial variations of the local tropospheric conditions are often observed. Tropospheric delays are usually considered to be an error for both GNSS and InSAR, and are typically removed. However, recently these delays are also recognized as a signal of interest, for example for assimilation into numerical weather models or climate studies. The GNSS and InSAR are techniques of complementary nature, as one has sparse spatial but high temporal resolution, and the other very dense spatial coverage but repeat pass of only a few days. This raises expectations for a combination of these techniques. For this purpose, a comprehensive comparison between the techniques must be first performed. Due to the relative nature of InSAR estimates, we compare the difference slant tropospheric delays (dSTD) retrieved from GNSS with the dSTDs estimated using Persistent Scatterer Interferometry (PSI) of 32 COSMO-SkyMed SAR images taken in a snow-free period from June to October between 2008 and 2013. The GNSS estimates calculated at permanent geodetic stations are interpolated to the locations of persistent scatterers using an in-house developed least-squares collocation software COMEDIE. The Pearson's correlation coefficient between InSAR and GNSS estimates averaged over all acquisitions is equal to 0.64 and larger than 0.8 for approximately half of the layers. Better agreement is obtained mainly for days with high variability of the troposphere (relative to the tropospheric conditions at the time of the reference acquisition), expressed as standard deviations of the GNSS-based dSTDs. On the other hand, the most common feature for the days with poor agreement is represented by very stable, almost constant GNSS estimates. In addition, there is a weak correlation between the agreement and the water vapor values in the area, as well as with the number of stations in the closest vicinity of the study area. Adding low-cost L-1 only GPS stations located within the area of the study increases the biases for most of the dates, but the standard deviations between InSAR and GNSS decrease for the limited area with low-cost stations. 2019 by the authors.
BibTeX:
@article{Wilgan2019,
  author = {Wilgan, K. and Siddique, M.A. and Strozzi, T. and Geiger, A. and Frey, O.},
  title = {Comparison of tropospheric path delay estimates from GNSS and space-borne SAR interferometry in alpine conditions},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2019},
  volume = {11},
  number = {15},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070463337&doi=10.3390%2frs11151789&partnerID=40&md5=db4909ae89cd746b6462fdf77de009d2},
  doi = {10.3390/rs11151789}
}
Zheng D, Li X, Wang X, Wang Z, Wen J, van der Velde R, Schwank M and Su Z (2019), "Sampling depth of L-band radiometer measurements of soil moisture and freeze-thaw dynamics on the Tibetan Plateau", Remote Sensing of Environment. Vol. 226, pp. 16-25. Elsevier Inc..
Abstract: Knowing the exact sampling depth of microwave radiometry is essential for quantifying the performance and appreciation of the applicability of satellite soil moisture products. We investigate in this study the sampling depth (δ SM ) of the L-band microwave emission under frozen and thawed soil conditions on the Tibetan Plateau. Two years of diurnal brightness temperature (T B p ) measurements at a time interval of 30 min are collected by the ELBARA-III radiometer deployed at a Tibetan meadow site. Vertical profiles of soil temperature and volumetric liquid water content (θ liq ) are measured simultaneously at soil depths up to 1 m below the surface. The impact of the θ liq measured at different depths on the microwave emission simulations is assessed using the τ-ω emission model, whereby the permittivity of frozen and thawed soil is estimated by the four-phase dielectric mixing model. It is found that: 1) the sampling depth for the effective temperature depends on the magnitude of θ liq , and is estimated to be, on average, about 50 and 15 cm for the cold dry and wet warm period, respectively, because of the seasonality in θ liq ; 2) the δ SM is determined at 2.5 cm for both frozen and thawed soil conditions during both cold and warm periods, which is shallower than the commonly used θ liq measurement depth (i.e. 5 cm) adopted for the in-situ monitoring networks across the globe; 3) the T B p simulations performed with the θ liq measurements taken at the estimated δ SM of 2.5 cm result in lower unbiased root mean squared errors, about 14% (3.16 K) and 22% (3.36 K) for the horizontal and vertical polarizations respectively, in comparison to the simulations with the θ liq measurements taken from 5 cm soil depth; and 4) the θ liq retrieved with the single channel algorithm from the ELBARA-III measured vertically polarized T B p are in better agreement with the θ liq measured at 2.5 cm than the one measured at 5 cm. These findings are crucial for developing strategies for the calibration/validation as well as the application of satellite based soil moisture products relying on the L-band radiometry. 2019 Elsevier Inc.
BibTeX:
@article{Zheng201916,
  author = {Zheng, D. and Li, X. and Wang, X. and Wang, Z. and Wen, J. and van der Velde, R. and Schwank, M. and Su, Z.},
  title = {Sampling depth of L-band radiometer measurements of soil moisture and freeze-thaw dynamics on the Tibetan Plateau},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2019},
  volume = {226},
  pages = {16-25},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063607073&doi=10.1016%2fj.rse.2019.03.029&partnerID=40&md5=99af5b33a448880ee3bca830b799c408},
  doi = {10.1016/j.rse.2019.03.029}
}
Ambrosi C, Strozzi T, Scapozza C and Wegmüller U (2018), "Landslide hazard assessment in the Himalayas (Nepal and Bhutan) based on Earth-Observation data", Engineering Geology. Vol. 237, pp. 217-228. Elsevier B.V..
Abstract: The Himalayan range is a high-risk area where landslides can destroy villages, access roads, and other important infrastructures and cause numerous injuries and deaths each year. Hazard assessment is one of the most important actions in the disaster risk management strategy with a direct impact on land use and land planning. Because of a lack of diffuse field data and mapping, landslide hazard maps are however not available for vast regions of the Himalayas. Earth-Observation (EO) data can support the preparation of landslide hazard maps through the compilation of landslide inventory maps at regional scale by means of satellite photo-interpretation and the assessment of the state of activity of mapped phenomena based on surface displacement rates quantified from satellite SAR interferometry. We compiled landslide inventory maps and landslide hazard maps for two areas in Nepal and Bhutan. For the Lukla region in Nepal, our analysis indicates that 10.5% of the total area of 725 km2 is affected by landslides and 57% of the mapped landslides are classified as active. For the Chomolhari area in Bhutan, 6% of the total area of 620 km2 is affected by landslides and 55% of them are classified as active. For both regions rockslides represent the most mapped phenomena. Landslide hazard assessment over large regions based on EO products represents an important aspect for disaster risk reduction not only in the whole Himalayan region but also in other mountain areas worldwide in absence of detailed landslide inventory maps. 2018 Elsevier B.V.
BibTeX:
@article{Ambrosi2018217,
  author = {Ambrosi, C. and Strozzi, T. and Scapozza, C. and Wegmüller, U.},
  title = {Landslide hazard assessment in the Himalayas (Nepal and Bhutan) based on Earth-Observation data},
  journal = {Engineering Geology},
  publisher = {Elsevier B.V.},
  year = {2018},
  volume = {237},
  pages = {217-228},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85043375715&doi=10.1016%2fj.enggeo.2018.02.020&partnerID=40&md5=c6a98e3aebeebd09077e436ff7f352c7},
  doi = {10.1016/j.enggeo.2018.02.020}
}
Antonova S, Sudhaus H, Strozzi T, Zwieback S, Kaab A, Heim B, Langer M, Bornemann N and Boike J (2018), "Thaw subsidence of a yedoma landscape in Northern Siberia, measured in situ and estimated from TerraSAR-X Interferometry", Remote Sensing. Vol. 10(4) MDPI AG.
Abstract: In permafrost areas, seasonal freeze-thaw cycles result in upward and downward movements of the ground. For some permafrost areas, long-term downward movements were reported during the last decade. We measured seasonal and multi-year ground movements in a yedoma region of the Lena River Delta, Siberia, in 2013-2017, using reference rods installed deep in the permafrost. The seasonal subsidence was 1.7 ± 1.5 cm in the cold summer of 2013 and 4.8 ± 2 cm in the warm summer of 2014. Furthermore, we measured a pronounced multi-year net subsidence of 9.3 ± 5.7 cm from spring 2013 to the end of summer 2017. Importantly, we observed a high spatial variability of subsidence of up to 6 cm across a sub-meter horizontal scale. In summer 2013, we accompanied our field measurements with Differential Synthetic Aperture Radar Interferometry (DInSAR) on repeat-pass TerraSAR-X (TSX) data from the summer of 2013 to detect summer thaw subsidence over the same study area. Interferometry was strongly affected by a fast phase coherence loss, atmospheric artifacts, and possibly the choice of reference point. A cumulative ground movement map, built from a continuous interferogram stack, did not reveal a subsidence on the upland but showed a distinct subsidence of up to 2 cm in most of the thermokarst basins. There, the spatial pattern of DInSAR-measured subsidence corresponded well with relative surface wetness identified with the near infra-red band of a high-resolution optical image. Our study suggests that (i) although X-band SAR has serious limitations for ground movement monitoring in permafrost landscapes, it can provide valuable information for specific environments like thermokarst basins, and (ii) due to the high sub-pixel spatial variability of ground movements, a validation scheme needs to be developed and implemented for future DInSAR studies in permafrost environments. 2018 by the authors.
BibTeX:
@article{Antonova2018,
  author = {Antonova, S. and Sudhaus, H. and Strozzi, T. and Zwieback, S. and Kaab, A. and Heim, B. and Langer, M. and Bornemann, N. and Boike, J.},
  title = {Thaw subsidence of a yedoma landscape in Northern Siberia, measured in situ and estimated from TerraSAR-X Interferometry},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {4},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045981435&doi=10.3390%2frs10040494&partnerID=40&md5=763d32f1c3b4a6d0ea01436392e9ee19},
  doi = {10.3390/rs10040494}
}
Baffelli S, Frey O and Hajnsek I (2018), "Geostatistical analysis and mitigation of atmosphere induced phase in terrestrial radar interferometric observations of an alpine glacier", In Proc. European Conf. Synthetic Aperture Radar. Vol. 2018-June, pp. 626-631. Institute of Electrical and Electronics Engineers Inc..
Abstract: Terrestrial Radar Interferometry is used to map surface displacement velocites with high temporal resolution, irrespective of sunlight and cloud cover. The main factor limiting estimation accuracy are variations in the atmospheric refractive index, observed as atmospheric phase screens (APS). A statistical model for APS assuming a separable spatio-temporal covariance structure is described. It facilitates the extrapolation of the APS from observations at persistent scatterers (PS) using regression-Kriging, which is followed by a timeseries inversion to estimate the surface velocity. A statistical analysis of the APS is performed using a Ku-Band radar timeseries of Bisgletscher, a glacier in the Southwestern Swiss Alps. The results show that, while some non-stationarity in the covariance structure is observed at large timescales, the covariance models obtained assuming separability perform well in APS mitigation using regression-Kriging. VDE VERLAG GMBH  Berlin  Offenbach.
BibTeX:
@conference{Baffelli2018626,
  author = {Baffelli, S. and Frey, O. and Hajnsek, I.},
  title = {Geostatistical analysis and mitigation of atmosphere induced phase in terrestrial radar interferometric observations of an alpine glacier},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-June},
  pages = {626-631},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050470984&partnerID=40&md5=b37be343722601d990414b037f4fe628}
}
Baffelli S, Frey O and Hajnsek I (2018), "Geostatistical analysis and mitigation of atmospheric phase screens in Ku-band terrestrial radar interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2018-July, pp. 6504-6507. Institute of Electrical and Electronics Engineers Inc..
Abstract: A geostatistical analysis of the atmospheric phase screen (APS) affecting Ku-Band terrestrial radar interferometric (TRI) observations of a fast-flowing alpine glacier is made assuming a separable spatio-temporal covariance structure. Such a structure facilitates the mitigation of APS: the atmospheric phase affecting individual interferograms can be extrapolated form a set of persistent scatterers (PS) using regression-Kriging. After removing this estimate the residual APS is only correlated in time; its effect on surface displacement estimation is mitigated with a generalized least squares (GLS) inversion employing an estimate of the temporal covariance of the APS. The applicability of a separable covariance structure and the performance of the APS correction method are assessed on a TRI timeseries of Bisgletscher, a glacier in the southwestern Swiss Alps. 2018 IEEE
BibTeX:
@conference{Baffelli20186504,
  author = {Baffelli, S. and Frey, O. and Hajnsek, I.},
  title = {Geostatistical analysis and mitigation of atmospheric phase screens in Ku-band terrestrial radar interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-July},
  pages = {6504-6507},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063126277&doi=10.1109%2fIGARSS.2018.8517479&partnerID=40&md5=b9a16841fd01f94a78dc79f7ae59b11b},
  doi = {10.1109/IGARSS.2018.8517479}
}
Baffelli S, Frey O, Werner C and Hajnsek I (2018), "Polarimetric calibration of the ku-band advanced polarimetric radar interferometer", IEEE Transactions on Geoscience and Remote Sensing. Vol. 56(4), pp. 2295-2311. Institute of Electrical and Electronics Engineers Inc..
Abstract: Differential interferometry using ground-based radar systems permits to monitor displacements in natural terrain with high flexibility in location, time of acquisition, and revisit time. In combination with polarimetric imaging, discrimination of different scattering mechanisms present in a resolution cell can be obtained simultaneously with the estimation of surface displacement. In this paper, we present the preprocessing steps and the calibration procedure required to produce high-quality calibrated polarimetric single-look complex imagery with KAPRI, a new portable Ku-band polarimetric radar interferometer. The processing of KAPRI data into single look complex images is addressed, including the correction of beam squint and of azimuthal phase variations. A polarimetric calibration model adapted to the acquisition mode is presented and used to produce calibrated polarimetric covariance matrix data. The methods are validated by means of a scene containing five trihedral corner reflectors. Data preprocessing is assessed by analyzing the oversampled response of a corner reflector, and the polarimetric calibration quality is verified by computing polarimetric signatures and residual calibration parameters.
BibTeX:
@article{Baffelli20182295,
  author = {Baffelli, S. and Frey, O. and Werner, C. and Hajnsek, I.},
  title = {Polarimetric calibration of the ku-band advanced polarimetric radar interferometer},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {56},
  number = {4},
  pages = {2295-2311},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85039768815&doi=10.1109%2fTGRS.2017.2778049&partnerID=40&md5=6751425ed59d75041166ea7aeb997f4f},
  doi = {10.1109/TGRS.2017.2778049}
}
Balenzano A, Satalino G, Lovergine F, Mattia F, Cartus O, Davidson M, Al-Khaldi M and Johnson J (2018), "Cross-comparison of three SAR soil moisture retrieval algorithms using synthetic and experimental data", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2018-July, pp. 6123-6126. Institute of Electrical and Electronics Engineers Inc..
Abstract: The objective of this study is to cross-compare three algorithms for retrieving surface soil moisture (SSM) from ESA's Sentinel-1 (S-1) data. The context is provided by the large scientific and application interest in SSM products at high resolution and regional/continental scale that can be retrieved from S-1 data alone or in combination with other missions such as NASA/SMAP and ESA/SMOS. Of the three investigated algorithms, one inverts a scattering model exploiting a Bayesian approach, whereas the other two are change detection approaches. The cross-comparison is carried out by using both simulated and experimental data. Strengths and weaknesses of the three algorithms are identified and discussed. 2018 IEEE
BibTeX:
@conference{Balenzano20186123,
  author = {Balenzano, A. and Satalino, G. and Lovergine, F. and Mattia, F. and Cartus, O. and Davidson, M. and Al-Khaldi, M. and Johnson, J.},
  title = {Cross-comparison of three SAR soil moisture retrieval algorithms using synthetic and experimental data},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-July},
  pages = {6123-6126},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063139800&doi=10.1109%2fIGARSS.2018.8517759&partnerID=40&md5=7dbdda81d48da320e6f67ad0b6164089},
  doi = {10.1109/IGARSS.2018.8517759}
}
Bickel V, Manconi A and Amann F (2018), "Quantitative assessment of digital image correlation methods to detect and monitor surface displacements of large slope instabilities", Remote Sensing. Vol. 10(6) MDPI AG.
Abstract: We evaluate the capability of three different digital image correlation (DIC) algorithms to measure long-term surface displacement caused by a large slope instability in the Swiss Alps. DIC was applied to high-resolution optical imagery taken by airborne sensors, and the accuracy of the displacements assessed against global navigation satellite system measurements. A dynamic radiometric correction of the input images prior to DIC application was shown to enhance both the correlation success and accuracy. Moreover, a newly developed spatial filter considering the displacement direction and magnitude proved to be an effective tool to enhance DIC performance and accuracy. Our results show that all algorithms are capable of quantifying slope instability displacements, with average errors ranging from 8 to 12% of the observed maximum displacement, depending on the DIC processing parameters, and the pre- and postprocessing of the in- and output. Among the tested approaches, the results based on a fast Fourier transform correlation approach provide a considerably better spatial coverage of the displacement field of the slope instability. The findings of this study are relevant for slope instability detection and monitoring via DIC, especially in the context of an ever-increasing availability of high-resolution air- and spaceborne imagery. 2018 by the authors.
BibTeX:
@article{Bickel2018,
  author = {Bickel, V.T. and Manconi, A. and Amann, F.},
  title = {Quantitative assessment of digital image correlation methods to detect and monitor surface displacements of large slope instabilities},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {6},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048984521&doi=10.3390%2frs10060865&partnerID=40&md5=2ebcb7c63822a1d7a134b979b68f9ba0},
  doi = {10.3390/rs10060865}
}
Boncori J, Andersen M, Dall J, Kusk A, Kamstra M, Andersen S, Bechor N, Bevan S, Bignami C, Gourmelen N, Joughin I, Jung H-S, Luckman A, Mouginot J, Neelmeijer J, Rignot E, Scharrer K, Nagler T, Scheuchl B and Strozzi T (2018), "Intercomparison and validation of SAR-based ice velocity measurement techniques within the Greenland Ice Sheet CCI project", Remote Sensing. Vol. 10(6) MDPI AG.
Abstract: Ice velocity is one of the products associated with the Ice Sheets Essential Climate Variable. This paper describes the intercomparison and validation of ice-velocity measurements carried out by several international research groups within the European Space Agency Greenland Ice Sheet Climate Change Initiative project, based on space-borne Synthetic Aperture Radar (SAR) data. The goal of this activity was to survey the best SAR-based measurement and error characterization approaches currently in practice. To this end, four experiments were carried out, related to different processing techniques and scenarios, namely differential SAR interferometry, multi aperture SAR interferometry and offset-tracking of incoherent as well as of partially-coherent data. For each task, participants were provided with common datasets covering areas located on the Greenland ice-sheet margin and asked to provide mean velocity maps, quality characterization and a description of processing algorithms and parameters. The results were then intercompared and validated against GPS data, revealing in several cases significant differences in terms of coverage and accuracy. The algorithmic steps and parameters influencing the coverage, accuracy and spatial resolution of the measurements are discussed in detail for each technique, as well as the consistency between quality parameters and validation results. This allows several recommendations to be formulated, in particular concerning procedures which can reduce the impact of analyst decisions, and which are often found to be the cause of sub-optimal algorithm performance. 2018 by the authors.
BibTeX:
@article{Boncori2018,
  author = {Boncori, J.P.M. and Andersen, M.L. and Dall, J. and Kusk, A. and Kamstra, M. and Andersen, S.B. and Bechor, N. and Bevan, S. and Bignami, C. and Gourmelen, N. and Joughin, I. and Jung, H.-S. and Luckman, A. and Mouginot, J. and Neelmeijer, J. and Rignot, E. and Scharrer, K. and Nagler, T. and Scheuchl, B. and Strozzi, T.},
  title = {Intercomparison and validation of SAR-based ice velocity measurement techniques within the Greenland Ice Sheet CCI project},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {6},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048953457&doi=10.3390%2frs10060929&partnerID=40&md5=f08a7168334b41a3c4400863b5163cc1},
  doi = {10.3390/rs10060929}
}
Cartus O, Siqueira P and Kellndorfer J (2018), "An error model for mapping forest cover and forest cover change using L-band SAR", IEEE Geoscience and Remote Sensing Letters. Vol. 15(1), pp. 107-111. Institute of Electrical and Electronics Engineers Inc..
Abstract: We present an error model for forest cover mapping and change detection with L-band synthetic aperture radar (SAR), which considers measurement noise, forest height, number of images available, and imaging conditions. When applied to a multiseasonal set of Advanced Land Observing Satellite Phased-Array type L-band SAR images acquired over a forest site in southern Sweden, the error model, which is founded on a semiempirical model, suggests that a bitemporal set of crosspolarized L-band backscatter observations is sufficient to detect a forest cover loss of 50% at hectare scale for mature forests. The error probability increases when using co-polarization images, images acquired under adverse imaging conditions, or when detecting forest cover change in a forest of low height. The availability of multitemporal L-band observations is expected to improve forest cover retrieval and change detection, albeit highly correlated forest cover retrieval errors between images acquired within narrow time intervals (e.g., months) pose a limit on the improvements that can be achieved.
BibTeX:
@article{Cartus2018107,
  author = {Cartus, O. and Siqueira, P. and Kellndorfer, J.},
  title = {An error model for mapping forest cover and forest cover change using L-band SAR},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {15},
  number = {1},
  pages = {107-111},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85038823609&doi=10.1109%2fLGRS.2017.2775659&partnerID=40&md5=f55dc1ec0e52d0ea4f27150d39c42649},
  doi = {10.1109/LGRS.2017.2775659}
}
Coscione R, Hajnsek I and Frey O (2018), "An experimental car-borne SAR system: Measurement setup and positioning error analysis", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2018-July, pp. 6364-6367. Institute of Electrical and Electronics Engineers Inc..
Abstract: Repeat-pass differential SAR interferometry (DInSAR) using spaceborne SAR data or stationary terrestrial radar data is an established technique to measure surface displacements. However, repeat-pass DInSAR from agile platforms (airborne/car-borne) is challenging due to residual motion errors. This is particularly true for high-frequency radar where motion errors of few millimeters represent a non-negligible fraction of the wavelength. In this paper, an experimental car-borne SAR system is presented. Such a system is complementary to the existing solutions (namely spaceborne, airborne, and terrestrial systems) in terms of geometry of acquisition, and flexibility in the selection of temporal baselines and location of the acquisitions. To meet the need of consistent and precise trajectory information, proper postprocessing procedure must be applied to the raw positioning data collected from the inertial navigation system (INS) and the global positioning system (GNSS). A viable procedure is here presented and first results discussed.
BibTeX:
@conference{Coscione20186364,
  author = {Coscione, R. and Hajnsek, I. and Frey, O.},
  title = {An experimental car-borne SAR system: Measurement setup and positioning error analysis},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-July},
  pages = {6364-6367},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064274232&doi=10.1109%2fIGARSS.2018.8519408&partnerID=40&md5=ef1ff23b08eee2224650c498e3d86bbf},
  doi = {10.1109/IGARSS.2018.8519408}
}
Da Lio C, Teatini P, Strozzi T and Tosi L (2018), "Understanding land subsidence in salt marshes of the Venice Lagoon from SAR Interferometry and ground-based investigations", Remote Sensing of Environment. Vol. 205, pp. 56-70. Elsevier Inc..
Abstract: The existence of salt marshes and tidal morphologies is strictly connected to their elevation with respect to the mean sea level. Quantifying land subsidence of these high-valued transitional environments is therefore crucial to investigate their long-term possible survival, also in view of the expected climate changes. However, monitoring with a certain accuracy their movements has been challenging until now due to the peculiar features of these morphological forms: they are difficult to access, made of largely unconsolidated deposits, without anthropogenic structures, relatively far from anthropogenic facilities, and become submerged by the sea water twice a day. For these reasons, they have never be linked to traditional levelling and GPS networks, and also standard Interferometric SAR applications returned very poor results in terms of spatial and temporal coverage. An advanced Persistent Scatterer Interferometry (PSI) technique on a 5-year long stack of X-bandwidth SAR acquisitions of the Venice Lagoon is here presented. The regularity of the acquisitions, the short satellite revisiting time (11 days), the high image resolution (  3 × 3 m), and the strategies used in the PSI application have allowed us to detect thousands of measurable persistent targets (PTs) in the Venice Lagoon salt marshes. The measured displacements range from small uplifts to subsidence rates of more than 20 mm/yr. The analyses of the observed displacements point out that land subsidence is much larger on man-made than natural salt marshes, with a significant negative correlation with the marsh age. In addition, land subsidence with the presence of halophytic vegetation species is generally smaller than on unvegetated marshes. Finally, at a few selected sites, the integration of the PSI outcome with local ground-based measurements, such as multi-depth benchmarks, feldspar marker horizons and surface elevation tables, has allowed quantifying the displacement variability versus depth and therefore developing a first conceptual model of the salt marsh consolidation and accretion processes. 2017 Elsevier Inc.
BibTeX:
@article{DaLio201856,
  author = {Da Lio, C. and Teatini, P. and Strozzi, T. and Tosi, L.},
  title = {Understanding land subsidence in salt marshes of the Venice Lagoon from SAR Interferometry and ground-based investigations},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2018},
  volume = {205},
  pages = {56-70},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85034809299&doi=10.1016%2fj.rse.2017.11.016&partnerID=40&md5=4371863f1b54d1ad2d2bb8fd3a640c6e},
  doi = {10.1016/j.rse.2017.11.016}
}
Frey O, Werner C, Caduff R and Wiesmann A (2018), "Tomographic profiling with SnowScat within the ESA SnowLab campaign: Time series of snow profiles over three snow seasons", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2018-July, pp. 6512-6515. Institute of Electrical and Electronics Engineers Inc..
Abstract: As part of the ESA SnowLab campaign the SnowScat device, a terrestrial stepped-frequency continuous-wave (SFCW) scatterometer which supports fully-polarimetric measurements within a frequency band from 9.2 to 17.8 GHz, was operated in tomographic profiling mode. In this tomographic profiling mode the SnowScat device is subsequently displaced in elevation direction to obtain a high-resolution not only in range direction but also along elevation. This leads to two-dimensional vertical profiles of a snowpack, which means that radar backscatter, co-polar phase difference, interferometric phase and coherence can be distinguished also along the vertical dimension of the snowpack. In this paper, we provide a summary and a few examples of a time series of tomographic measurements of snow obtained within the ESA SnowLab campaign at two different locations in the Swiss Alps during three snow seasons. 2018 IEEE
BibTeX:
@conference{Frey20186512,
  author = {Frey, O. and Werner, C.L. and Caduff, R. and Wiesmann, A.},
  title = {Tomographic profiling with SnowScat within the ESA SnowLab campaign: Time series of snow profiles over three snow seasons},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-July},
  pages = {6512-6515},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063131128&doi=10.1109%2fIGARSS.2018.8517692&partnerID=40&md5=7545c974d34eafeaca6b498d4a336df7},
  doi = {10.1109/IGARSS.2018.8517692}
}
Frey O, Werner C, Hajnsek I and Coscione R (2018), "A car-borne SAR system for interferometric measurements: Development status and system enhancements", In Proc. IEEE Int. Geosci. Remote Sens. Symp.., July, 2018. , pp. 6508-6511. Institute of Electrical and Electronics Engineers.
Abstract: Terrestrial radar systems are used operationally for area-wide measurement and monitoring of surface displacements on steep slopes, as prevalent in mountainous areas or also in open pit mines. One limitation of these terrestrial systems is the decreasing cross-range resolution with increasing distance of observation due to the limited antenna size of the real aperture radar or the limited synthetic aperture of the quasi-stationary SAR systems. Recently, we have conducted a first experiment using a car-borne SAR system at Ku-band, demonstrating the time-domain back-projection (TDBP) focusing capability for the FMCW case and single-pass interferometric capability of our experimental Ku-band car-borne SAR system. The cross-range spatial resolution provided by such a car-based SAR system is potentially independent from the distance of observation, given that an adequate sensor trajectory can be built. In this paper, we give (1) an overview of the updated system hardware (radar setup and high-precision combined INS/GNSS positioning and attitude determination), and (2) present SAR imagery obtained with the updated prototype Ku-band car-borne SAR system. 2018 IEEE
BibTeX:
@conference{Frey20186508,
  author = {Frey, O. and Werner, C.L. and Hajnsek, I. and Coscione, R.},
  title = {A car-borne SAR system for interferometric measurements: Development status and system enhancements},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2018},
  pages = {6508-6511},
  url = {https://www.gamma-rs.ch/uploads/media/freyWernerHajnsekCoscioneIGARSS2018CarborneSARforInSARDevelopmentAndEnhancements.pdf},
  doi = {10.1109/IGARSS.2018.8518840}
}
Grigoli F, Cesca S, Rinaldi A, Manconi A, Lopez-Comino J, Clinton J, Westaway R, Cauzzi C, Dahm T and Wiemer S (2018), "The November 2017 Mw5.5 Pohang earthquake: A possible case of induced seismicity in South Korea", Science. Vol. 360(6392), pp. 1003-1006. American Association for the Advancement of Science.
Abstract: The moment magnitude (Mw) 5.5 earthquake that struck South Korea in November 2017 was one of the largest and most damaging events in that country over the past century. Its proximity to an enhanced geothermal system site, where high-pressure hydraulic injection had been performed during the previous 2 years, raises the possibility that this earthquake was anthropogenic. We have combined seismological and geodetic analyses to characterize the mainshock and its largest aftershocks, constrain the geometry of this seismic sequence, and shed light on its causal factors. According to our analysis, it seems plausible that the occurrence of this earthquake was influenced by the aforementioned industrial activities. Finally, we found that the earthquake transferred static stress to larger nearby faults, potentially increasing the seismic hazard in the area. 2017 The Authors.
BibTeX:
@article{Grigoli20181003,
  author = {Grigoli, F. and Cesca, S. and Rinaldi, A.P. and Manconi, A. and Lopez-Comino, J.A. and Clinton, J.F. and Westaway, R. and Cauzzi, C. and Dahm, T. and Wiemer, S.},
  title = {The November 2017 Mw5.5 Pohang earthquake: A possible case of induced seismicity in South Korea},
  journal = {Science},
  publisher = {American Association for the Advancement of Science},
  year = {2018},
  volume = {360},
  number = {6392},
  pages = {1003-1006},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046696950&doi=10.1126%2fscience.aat2010&partnerID=40&md5=5104f2d315278c2872f550b3c3adbe14},
  doi = {10.1126/science.aat2010}
}
Lemmetyinen J, Derksen C, Rott H, Macelloni G, King J, Schneebeli M, Wiesmann A, Leppanen L, Kontu A and Pulliainen J (2018), "Retrieval of effective correlation length and snow water equivalent from radar and passive microwave measurements", Remote Sensing. Vol. 10(2) MDPI AG.
Abstract: Current methods for retrieving SWE (snow water equivalent) from space rely on passive microwave sensors. Observations are limited by poor spatial resolution, ambiguities related to separation of snow microstructural properties from the total snow mass, and signal saturation when snow is deep (  > 80 cm). The use of SAR (Synthetic Aperture Radar) at suitable frequencies has been suggested as a potential observation method to overcome the coarse resolution of passive microwave sensors. Nevertheless, suitable sensors operating from space are, up to now, unavailable. Active microwave retrievals suffer, however, from the same difficulties as the passive case in separating impacts of scattering efficiency from those of snow mass. In this study, we explore the potential of applying active (radar) and passive (radiometer) microwave observations in tandem, by using a dataset of co-incident tower-based active and passive microwave observations and detailed in situ data from a test site in Northern Finland. The dataset spans four winter seasons with daily coverage. In order to quantify the temporal variability of snow microstructure, we derive an effective correlation length for the snowpack (treated as a single layer), which matches the simulated microwave response of a semi-empirical radiative transfer model to observations. This effective parameter is derived from radiometer and radar observations at different frequencies and frequency combinations (10.2, 13.3 and 16.7 GHz for radar; 10.65, 18.7 and 37 GHz for radiometer). Under dry snow conditions, correlations are found between the effective correlation length retrieved from active and passive measurements. Consequently, the derived effective correlation length from passive microwave observations is applied to parameterize the retrieval of SWE using radar, improving retrieval skill compared to a case with no prior knowledge of snow-scattering efficiency. The same concept can be applied to future radar satellite mission concepts focused on retrieving SWE, exploiting existing methods for retrieval of snow microstructural parameters, as employed within the ESA (European Space Agency) GlobSnow SWE product. Using radar alone, a seasonally optimized value of effective correlation length to parameterize retrievals of SWE was sufficient to provide an accuracy of < 25 mm (unbiased) Root-Mean Square Error using certain frequency combinations. A temporally dynamic value, derived from e.g., physical snow models, is necessary to further improve retrieval skill, in particular for snow regimes with larger temporal variability in snow microstructure and a more pronounced layered structure. 2018 by the authors.
BibTeX:
@article{Lemmetyinen2018,
  author = {Lemmetyinen, J. and Derksen, C. and Rott, H. and Macelloni, G. and King, J. and Schneebeli, M. and Wiesmann, A. and Leppanen, L. and Kontu, A. and Pulliainen, J.},
  title = {Retrieval of effective correlation length and snow water equivalent from radar and passive microwave measurements},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {2},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042531312&doi=10.3390%2frs10020170&partnerID=40&md5=5b09d59e61d25e8d9f8462fee48520ef},
  doi = {10.3390/rs10020170}
}
Magnard C, Wegmüller U, Werner C, Bonvin F and Meier E (2018), "Planning tool for SAR missions", In Proc. European Conf. Synthetic Aperture Radar. Vol. 2018-June, pp. 1052-1057. Institute of Electrical and Electronics Engineers Inc..
Abstract: A methodology was developed to assist in the planning of SAR acquisitions, supported by a user-friendly software. Using sensor parameters, the position and topography of the region of interest, and a proposed flight path, this planning tool simulates backscatter images, maps of scattering characteristics and image quality parameters such as the local incidence angle and the noise equivalent sigmaO. It produces flight and ground profiles and lists of key parameters. These outputs inform about expected SAR image characteristics and can be employed for optimization of the planning. Using this tool, a non-specialist can perform a robust planning of SAR acquisitions. VDE VERLAG GMBH • Berlin • Offenbach.
BibTeX:
@conference{Magnard20181052,
  author = {Magnard, C. and Wegmüller, U. and Werner, C. and Bonvin, F. and Meier, E.},
  title = {Planning tool for SAR missions},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-June},
  pages = {1052-1057},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050505782&partnerID=40&md5=cc483818aff21c4d87e3e28fc76776aa}
}
Manconi A, Coviello V, Galletti M and Seifert R (2018), "Short communication: Monitoring rockfalls with the Raspberry Shake", Earth Surface Dynamics. Vol. 6(4), pp. 1219-1227. Copernicus GmbH.
Abstract: We evaluate the performance of the low-cost seismic sensor Raspberry Shake to identify and monitor rockfall activity in alpine environments. The test area is a slope adjacent to the Great Aletsch Glacier in the Swiss Alps, i.e. the Moosfluh deep-seated instability, which has recently undergone a critical acceleration phase. A local seismic network composed of three Raspberry Shake was deployed starting from May 2017 in order to record rockfall activity and its relation with the progressive rock-slope degradation potentially leading to a large rock-slope failure. Here we present a first assessment of the seismic data acquired from our network after a monitoring period of 1 year. We show that our network performed well during the whole duration of the experiment, including the winter period in severe alpine conditions, and that the seismic data acquired allowed us to clearly discriminate between rockfalls and other events. This work also provides general information on the potential use of such low-cost sensors in environmental seismology. 2018 Author(s).
BibTeX:
@article{Manconi20181219,
  author = {Manconi, A. and Coviello, V. and Galletti, M. and Seifert, R.},
  title = {Short communication: Monitoring rockfalls with the Raspberry Shake},
  journal = {Earth Surface Dynamics},
  publisher = {Copernicus GmbH},
  year = {2018},
  volume = {6},
  number = {4},
  pages = {1219-1227},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058557157&doi=10.5194%2fesurf-6-1219-2018&partnerID=40&md5=434f613d5d9202ff085be2ee61b196ba},
  doi = {10.5194/esurf-6-1219-2018}
}
Manconi A, Kourkouli P, Caduff R, Strozzi T and Loew S (2018), "Monitoring surface deformation over a failing rock slope with the ESA sentinels: Insights from Moosfluh instability, Swiss Alps", Remote Sensing. Vol. 10(5) MDPI AG.
Abstract: We leverage on optical and radar remote sensing data acquired from the European Space Agency (ESA) Sentinels to monitor the surface deformation evolution on a large and very active instability located in the Swiss Alps, i.e., the Moosfluh rock slope. In the late summer 2016, a sudden acceleration was reported at this location, with surface velocity rates passing from maximum values of 0.2 cm/day to 80 cm/day. A dense pattern of uphill-facing scarps and tension cracks formed within the instability and rock fall activity started to become very pronounced. This evolution of the rock mass may suggest that the most active portion of the slope could fail catastrophically. Here we discuss advantages and limitations of the use of spaceborne methods for hazard analyses and early warning by using the ESA Sentinels, and show that in critical scenarios they are often not sufficient to reliably interpret the evolution of surface deformation. The insights obtained from this case study are relevant for similar scenarios in the Alps and elsewhere. 2018 by the authors.
BibTeX:
@article{Manconi2018,
  author = {Manconi, A. and Kourkouli, P. and Caduff, R. and Strozzi, T. and Loew, S.},
  title = {Monitoring surface deformation over a failing rock slope with the ESA sentinels: Insights from Moosfluh instability, Swiss Alps},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {5},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047514503&doi=10.3390%2frs10050672&partnerID=40&md5=b2da4c0ea1504183ba7cbbd97c4e529a},
  doi = {10.3390/rs10050672}
}
Mattia F, Balenzano A, Satalino G, Lovergine F, Peng J, Wegmüller U, Cartus O, Davidson M, Kim S, Johnson J, Walker J, Wu X, Pauwels V, McNairn H, Caldwell T, Cosh M and Jackson T (2018), "Sentinel-1 and Sentinel-2 for soil moisture retrieval at field scale", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2018-July, pp. 6143-6146. Institute of Electrical and Electronics Engineers Inc..
Abstract: Soil moisture content is an essential climate variable that is operationally delivered at low resolution (e.g. 36-9 ) by earth observation missions, such as ESA/SMOS, NASA/SMAP and EUMETSAT/ASCAT. However numerous land applications would benefit from the availability of soil moisture maps at higher resolution. For this reason, there is a large research effort to develop soil moisture products at higher resolution using, for instance, data acquired by the new ESA's Sentinel missions. The objective of this study is twofold. First, it presents the validation status of a pre-operational soil moisture product derived from Sentinel-1 at 1 resolution. Second, it assesses the possibility of integrating Sentinel-2 data and additional ancillary information, such as parcel borders and high resolution soil texture maps, in order to obtain soil moisture maps at “field scale” resolution, i.e.  0.1 . Case studies concerning agricultural sites located in Europe are presented. 2018 IEEE
BibTeX:
@conference{Mattia20186143,
  author = {Mattia, F. and Balenzano, A. and Satalino, G. and Lovergine, F. and Peng, J. and Wegmüller, U. and Cartus, O. and Davidson, M.W.J. and Kim, S. and Johnson, J. and Walker, J. and Wu, X. and Pauwels, V.R.N. and McNairn, H. and Caldwell, T. and Cosh, M. and Jackson, T.},
  title = {Sentinel-1 and Sentinel-2 for soil moisture retrieval at field scale},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-July},
  pages = {6143-6146},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063160566&doi=10.1109%2fIGARSS.2018.8518170&partnerID=40&md5=2aa1be526dccb673af6069f7d0e8810e},
  doi = {10.1109/IGARSS.2018.8518170}
}
Molg N, Bolch T, Rastner P, Strozzi T and Paul F (2018), "A consistent glacier inventory for Karakoram and Pamir derived from Landsat data: Distribution of debris cover and mapping challenges", Earth System Science Data. Vol. 10(4), pp. 1807-1827. Copernicus GmbH.
Abstract: Knowledge about the coverage and characteristics of glaciers in High Mountain Asia (HMA) is still incomplete and heterogeneous. However, several applications, such as modelling of past or future glacier development, run-off, or glacier volume, rely on the existence and accessibility of complete datasets. In particular, precise outlines of glacier extent are required to spatially constrain glacier-specific calculations such as length, area, and volume changes or flow velocities. As a contribution to the Randolph Glacier Inventory (RGI) and the Global Land Ice Measurements from Space (GLIMS) glacier database, we have produced a homogeneous inventory of the Pamir and the Karakoram mountain ranges using 28 Landsat TM and ETM+ scenes acquired around the year 2000. We applied a standardized method of automated digital glacier mapping and manual correction using coherence images from the Advanced Land Observing Satellite 1 (ALOS-1) Phased Array type L-band Synthetic Aperture Radar 1 (PALSAR-1) as an additional source of information; we then (i) separated the glacier complexes into individual glaciers using drainage divides derived by watershed analysis from the ASTER global digital elevation model version 2 (GDEM2) and (ii) separately delineated all debris-covered areas. Assessment of uncertainties was performed for debris-covered and clean-ice glacier parts using the buffer method and independent multiple digitizing of three glaciers representing key challenges such as shadows and debris cover. Indeed, along with seasonal snow at high elevations, shadow and debris cover represent the largest uncertainties in our final dataset. In total, we mapped more than 27 800 glaciers > 0.02 km2 covering an area of 35 520±1948 km2 and an elevation range from 2260 to 8600 m. Regional median glacier elevations vary from 4150 m (Pamir Alai) to almost 5400 m (Karakoram), which is largely due to differences in temperature and precipitation. Supraglacial debris covers an area of 3587±662 km2, i.e. 10 % of the total glacierized area. Larger glaciers have a higher share in debris-covered area (up to > 20 %), making it an important factor to be considered in subsequent applications (https://doi.org/10.1594/PANGAEA.894707). Author(s) 2018.
BibTeX:
@article{Molg20181807,
  author = {Molg, N. and Bolch, T. and Rastner, P. and Strozzi, T. and Paul, F.},
  title = {A consistent glacier inventory for Karakoram and Pamir derived from Landsat data: Distribution of debris cover and mapping challenges},
  journal = {Earth System Science Data},
  publisher = {Copernicus GmbH},
  year = {2018},
  volume = {10},
  number = {4},
  pages = {1807-1827},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054693653&doi=10.5194%2fessd-10-1807-2018&partnerID=40&md5=1f2fac41d05ce3abf3eb07d14a7070a2},
  doi = {10.5194/essd-10-1807-2018}
}
Naderpour R and Schwank M (2018), "Snow wetness retrieved from L-band radiometry", Remote Sensing. Vol. 10(3) MDPI AG.
Abstract: The present study demonstrates the successful use of the high sensitivity of L-band brightness temperatures to snow liquid water in the retrieval of snow liquid water from multi-angular L-band brightness temperatures. The emission model employed was developed from parts of the "microwave emission model of layered snowpacks" (MEMLS), coupled with components adopted from the "L-band microwave emission of the biosphere" (L-MEB) model. Two types of snow liquid water retrievals were performed based on L-band brightness temperatures measured over (i) areas with a metal reflector placed on the ground ("reflector area"-TB, R), and (ii) natural snow-covered ground ("natural area"-TB, N). The reliable representation of temporal variations of snow liquid water is demonstrated for both types of the aforementioned quasi-simultaneous retrievals. This is verified by the fact that both types of snow liquid water retrievals indicate a dry snowpack throughout the "cold winter period" with frozen ground and air temperatures well below freezing, and synchronously respond to snowpack moisture variations during the "early spring period". The robust and reliable performance of snow liquid water retrieved from TB, R, together with their level of detail, suggest the use of these retrievals as "references" to assess the meaningfulness of the snow liquid water retrievals based on TB, N. It is noteworthy that the latter retrievals are achieved in a two-step retrieval procedure using exclusively L-band brightness temperatures, without the need for in-situ measurements, such as ground permittivity εG and snow mass-density ρS. The latter two are estimated in the first retrieval-step employing the well-established two-parameter (ρS, εG) retrieval scheme designed for dry snow conditions and explored in the companion paper that is included in this special issue in terms of its sensitivity with respect to disturbative melting effects. The two-step retrieval approach proposed and investigated here, opens up the possibility of using airborne or spaceborne L-band radiometry to estimate (ρS,εG) and additionally snow liquid water as a new passive L-band data product. 2018 by the authors.
BibTeX:
@article{Naderpour2018,
  author = {Naderpour, R. and Schwank, M.},
  title = {Snow wetness retrieved from L-band radiometry},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {3},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042526532&doi=10.3390%2frs10030359&partnerID=40&md5=c13e5cf6596f34fa1d0216592fd6df44},
  doi = {10.3390/rs10030359}
}
Naderpour R and Schwank M (2018), "Snow wetness retrieved from L-band radiometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2018-July, pp. 1466-1469. Institute of Electrical and Electronics Engineers Inc..
Abstract: The present study demonstrates the successful use of L-band brightness temperatures to retrieve snow liquid water from multi-angular measurements . The emission model employed was developed from parts of the “microwave emission model of layered snowpacks” (MEMLS) coupled with components adopted from the “L-band microwave emission of the biosphere” (L-MEB) model. Two types of snow liquid water retrievals were performed based on measured over i) areas with a metal reflector placed on the ground (“reflector area”- ), and ii) natural snow-covered ground (“natural area”- ). The reliable representation of temporal variations of snow liquid water is demonstrated for both types of retrievals. This is verified by the fact that both types of - retrievals indicate a dry snowpack throughout the “cold winter period” with frozen ground and air temperatures well below freezing, and synchronously respond to snowpack moisture variations during the “early spring period”. Snow liquid water retrievals based on are achieved in a two-step retrieval procedure using exclusively L-band brightness temperatures, without the need for in-situ measurements such as ground permittivity and snow mass-density . The latter two are estimated in the first retrieval-step employing the well-established two-parameter , retrieval scheme. The proposed and investigated two-step retrieval approach opens up the possibility of using airborne or spaceborne L-band radiometry to estimate. 2018 IEEE
BibTeX:
@conference{Naderpour20181466,
  author = {Naderpour, R. and Schwank, M.},
  title = {Snow wetness retrieved from L-band radiometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-July},
  pages = {1466-1469},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064157491&doi=10.1109%2fIGARSS.2018.8518614&partnerID=40&md5=b728fc8fcd5ace5c59d56ac3f054b084},
  doi = {10.1109/IGARSS.2018.8518614}
}
Roy A, Leduc-Leballeur M, Picard G, Royer A, Toose P, Derksen C, Lemmetyinen J, Berg A, Rowlandson T and Schwank M (2018), "Modelling the L-band Snow-covered surface emission in a winter Canadian prairie environment", Remote Sensing. Vol. 10(9) MDPI AG.
Abstract: Detailed angular ground-based L-band brightness temperature (TB) measurements over snow covered frozen soil in a prairie environment were used to parameterize and evaluate an electromagnetic model, the Wave Approach for LOw-frequency MIcrowave emission in Snow (WALOMIS), for seasonal snow. WALOMIS, initially developed for Antarctic applications, was extended with a soil interface model. A Gaussian noise on snow layer thickness was implemented to account for natural variability and thus improve the TB simulations compared to observations. The model performance was compared with two radiative transfer models, the Dense Media Radiative Transfer-Multi Layer incoherent model (DMRT-ML) and a version of the Microwave Emission Model for Layered Snowpacks (MEMLS) adapted specifically for use at L-band in the original one-layer configuration (LS-MEMLS-1L). Angular radiometer measurements (30°, 40°, 50°, and 60°) were acquired at six snow pits. The root-mean-square error (RMSE) between simulated and measured TB at vertical and horizontal polarizations were similar for the three models, with overall RMSE between 7.2 and 10.5 K. However, WALOMIS and DMRT-ML were able to better reproduce the observed TB at higher incidence angles (50° and 60°) and at horizontal polarization. The similar results obtained betweenWALOMIS and DMRT-ML suggests that the interference phenomena are weak in the case of shallow seasonal snow despite the presence of visible layers with thicknesses smaller than the wavelength, and the radiative transfer model can thus be used to compute L-band brightness temperature. 2018 by the authors.
BibTeX:
@article{Roy2018,
  author = {Roy, A. and Leduc-Leballeur, M. and Picard, G. and Royer, A. and Toose, P. and Derksen, C. and Lemmetyinen, J. and Berg, A. and Rowlandson, T. and Schwank, M.},
  title = {Modelling the L-band Snow-covered surface emission in a winter Canadian prairie environment},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {9},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053599745&doi=10.3390%2frs10091451&partnerID=40&md5=3d568e815c2518c0b8b041c81f09b160},
  doi = {10.3390/rs10091451}
}
Santoro M and Cartus O (2018), "Research pathways of forest above-ground biomass estimation based on SAR backscatter and interferometric SAR observations", Remote Sensing. Vol. 10(4) MDPI AG.
Abstract: Estimation of forest biomass with synthetic aperture radar (SAR) and interferometric SAR (InSAR) observables has been surveyed in 186 peer-reviewed papers to identify major research pathways in terms of data used and retrieval models. Research evaluated primarily (i) L-band observations of SAR backscatter; and, (ii) single-image or multi-polarized retrieval schemes. The use of multi-temporal or multi-frequency data improved the biomass estimates when compared to single-image retrieval. Low frequency SAR backscatter contributed the most to the biomass estimates. Single-pass InSAR height was reported to be a more reliable predictor of biomass, overcoming the loss of sensitivity of SAR backscatter and coherence in high biomass forest. A variety of empirical and semi-empirical regression models relating biomass to the SAR observables were proposed. Semi-empirical models were mostly used for large-scale mapping because of the simple formulation and the robustness of the model parameters estimates to forest structure and environmental conditions. Non-parametric models were appraised for their capability to ingest multiple observations and perform accurate retrievals having a large number of training samples available. Some studies argued that estimating compartment biomass (in stems, branches, foliage) with different types of SAR observations would lead to an improved estimate of total biomass. Although promising, scientific evidence for such an assumption is still weak. The increased availability of free and open SAR observations from currently orbiting and forthcoming spaceborne SAR missions will foster studies on forest biomass retrieval. Approaches attempting to maximize the information content on biomass of individual data streams shall be pursued. 2018 by the authors.
BibTeX:
@article{Santoro2018,
  author = {Santoro, M. and Cartus, O.},
  title = {Research pathways of forest above-ground biomass estimation based on SAR backscatter and interferometric SAR observations},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {4},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045999782&doi=10.3390%2frs10040608&partnerID=40&md5=fcef84234f3e46ef9b97bb153cc4d802},
  doi = {10.3390/rs10040608}
}
Santoro M, Wegmüller U and Askne J (2018), "Forest stem volume estimation using C-band interferometric SAR coherence data of the ERS-1 mission 3-days repeat-interval phase", Remote Sensing of Environment. Vol. 216, pp. 684-696. Elsevier Inc..
Abstract: Interferometric synthetic aperture radar (InSAR) coherence datasets from the 3-days phase of the European Remote Sensing Satellite (ERS-1) mission during the winter months of 1992 have been analyzed to assess the capability to retrieve forest stem volume in boreal forests. For three test sites in Sweden and Finland, coherence decreased for increasing repeat-pass interval from 3- to 12-days due to increasing temporal decorrelation. Overall strong decorrelation was observed for images acquired under unfrozen conditions or thawing conditions. Coherence was best preserved under stable frozen conditions and, in addition, short perpendicular component of the interferometric baseline (i.e., <300 m). Stem volume was estimated with the Interferometric Water Cloud Model (IWCM) and multi-temporal combination of single-image estimates. For the test site of Tuusula, Finland, data from eight 3-days image pairs yielded a relative RMSE of 28.2% for stem volumes ranging between 3 and 482 m3/ha. For the 6-days repeat-pass interval, the relative RMSE was only slightly worse (32.4%). For longer repeat-pass intervals, the relative RMSE was above 50%. This study suggests that C-band short-term coherence has potential to support retrieval of forest biomass but the prospects of Sentinel-1 coherence to estimate biomass appear to be limited to the 6-days coherence in areas characterized by stable frozen, or likewise stable dry, conditions. 2018 Elsevier Inc.
BibTeX:
@article{Santoro2018684,
  author = {Santoro, M. and Wegmüller, U. and Askne, J.},
  title = {Forest stem volume estimation using C-band interferometric SAR coherence data of the ERS-1 mission 3-days repeat-interval phase},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2018},
  volume = {216},
  pages = {684-696},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050944421&doi=10.1016%2fj.rse.2018.07.032&partnerID=40&md5=a329952686b15530f77fc9526957c4c0},
  doi = {10.1016/j.rse.2018.07.032}
}
Schwank M and Naderpour R (2018), "Snow density and ground permittivity retrieved from L-band radiometry: Melting effects", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2018-July, pp. 1245-1248. Institute of Electrical and Electronics Engineers Inc..
Abstract: Ground permittivity and snow density retrievals are performed using the tower-based experimental L-band radiometry data from the winter 2016/2017 campaign at the Davos-Laret Remote Sensing Field Laboratory. The performance of multi-angle two-parameter retrieval algorithms to estimate snow density and ground permittivity PRM = (?SRM, eGRM) is assessed using in-situ measured eG and ?S. Additionally, a synthetic retrieval sensitivity analysis is conducted which studies impacts of “melting effects” on retrievals (?SRM, eGRM) in the form of snow liquid water. Experimental and synthetic analyses show that snow liquid water noticeably disturbs the retrievals and result in increased correlation R2(?SRM, eGRM) between them. The strength of this correlation is used as a quality-indicator flag to filter out highly correlated retrieval pairs. It is demonstrated that this filtering significantly improves the accuracy of both ground permittivity and snow density retrievals compared to corresponding reference in-situ data. Our analysis shows that retrievals P "V"= (?S"V" , eG "V") using vertical polarization only (RM = “V”) are predominantly least prone to snow liquid water. The presented experimental results indicate that retrievals match in-situ observations best for the “snow-free period” and the “cold winter period” when snow liquid water is at minimum. 2018 IEEE
BibTeX:
@conference{Schwank20181245,
  author = {Schwank, M. and Naderpour, R.},
  title = {Snow density and ground permittivity retrieved from L-band radiometry: Melting effects},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-July},
  pages = {1245-1248},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063125521&doi=10.1109%2fIGARSS.2018.8517581&partnerID=40&md5=e8a333e472b09d6b761e5b2bd2eb5e46},
  doi = {10.1109/IGARSS.2018.8517581}
}
Schwank M and Naderpour R (2018), "Snow density and ground permittivity retrieved from L-band radiometry: Melting effects", Remote Sensing. Vol. 10(2) MDPI AG.
Abstract: Ground permittivity and snow density retrievals for the "snow-free period", "cold winter period", and "early spring period" are performed using the experimental L-band radiometry data from the winter 2016/2017 campaign at the Davos-Laret Remote Sensing Field Laboratory. The performance of the single-angle and multi-angle two-parameter retrieval algorithms employed during each of the aforementioned three periods is assessed using in-situ measured ground permittivity and snow density. Additionally, a synthetic sensitivity analysis is conducted that studies melting effects on the retrievals in the form of two types of "geophysical noise" (snow liquid water and footprint-dependent ground permittivity). Experimental and synthetic analyses show that both types of investigated "geophysical noise" noticeably disturb the retrievals and result in an increased correlation between them. The strength of this correlation is successfully used as a quality-indicator flag for the purpose of filtering out highly correlated ground permittivity and snow density retrievals. It is demonstrated that this filtering significantly improves the accuracy of both ground permittivity and snow density retrievals compared to corresponding reference in-situ data. Experimental and synthetic retrievals are performed in retrieval modes RM = "H", "V", and "HV", where brightness temperatures from polarizations p = H, p = V, or both p = H and V are used, respectively, in the retrieval procedure. Our analysis shows that retrievals for RM = "V" are predominantly least prone to the investigated "geophysical noise". The presented experimental results indicate that retrievals match in-situ observations best for the "snow-free period" and the "cold winter period" when "geophysical noise" is at minimum. 2018 by the authors.
BibTeX:
@article{Schwank2018c,
  author = {Schwank, M. and Naderpour, R.},
  title = {Snow density and ground permittivity retrieved from L-band radiometry: Melting effects},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {2},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042548031&doi=10.3390%2frs10020354&partnerID=40&md5=3f983b1467000c85ab28719c5622297a},
  doi = {10.3390/rs10020354}
}
Schwank M, Naderpour R and Matzler C (2018), "Tau-Omega - and Two-Stream emission models used for passive L-Band retrievals: Application to close-range measurements over a forest", Remote Sensing. Vol. 10(12) MDPI AG.
Abstract: Microwave Emission Models (EM) are used in retrieval algorithms to estimate geophysical state parameters such as soil Water Content (WC) and vegetation optical depth (τ), from brightness temperatures T B p,θ measured at nadir angles θ at Horizontal and Vertical polarizations p = (H,V). An EM adequate for implementation in a retrieval algorithm must capture the responses of T B p,θ to the retrieval parameters, and the EM parameters must be experimentally accessible and representative of the measurement footprint. The objective of this study is to explore the benefits of the multiple-scattering Two-Stream (2S) EM over the "Tau-Omega" (TO) EM considered as the "reference" to retrieve WC and τ from L-band T B p,θ . For sparse and low-scattering vegetation T B,EM p,θ simulated with EM = (TO, 2S) converge. This is not the case for dense and strongly scattering vegetation. Two-Parameter (2P) retrievals 2P RC = (WC RC , τ RC ) are computed from elevation scans T B p,θj = T B TO p,θj , synthesized with TO EM and from T B p,θj measured from a tower within a deciduous forest. Retrieval Configurations (RC) employ either EM = TO or EM = 2S and assume fixed scattering albedos. WC RC achieved with the 2S RC is marginally lower ( 1 m 3 m -3 ) than if achieved with the "reference" TO RC, while τRC is reduced considerably when using 2S EM instead of TO EM. Our study outlines a number of advantages of the 2S EM over the TO EM currently implemented in the operational SMOS and SMAP retrieval algorithms. 2018 by the authors.
BibTeX:
@article{Schwank2018a,
  author = {Schwank, M. and Naderpour, R. and Matzler, C.},
  title = {Tau-Omega - and Two-Stream emission models used for passive L-Band retrievals: Application to close-range measurements over a forest},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {12},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85057073180&doi=10.3390%2frs10121868&partnerID=40&md5=f232f9c088c32b690dbab8274b1aff78},
  doi = {10.3390/rs10121868}
}
Siddique M, Strozzi T, Hajnsek I and Frey O (2018), "A case study on the correction of atmosphere-induced phase disturbances for SAR tomography in mountainous areas", In Proc. European Conf. Synthetic Aperture Radar. Vol. 2018-June, pp. 1412-1416. Institute of Electrical and Electronics Engineers Inc..
Abstract: The estimation of the atmosphere-induced phase delay variations is often more involved in mountainous areas due to strong spatial variations of the local atmospheric conditions and propagation paths through the troposphere. Height-dependent phase delay variation owing to vertical stratification of the atmosphere within the same range-azimuth resolution cell cannot be ignored. We propose a regression kriging-based data-driven method whereby phase corrections are applied for differential tomographic focusing at each 3D point of interest along the elevation axis. Experiments are performed on an interferometric stack comprising 32 Cosmo-SkyMed stripmap images acquired between 2008-2013 over the Matter Valley in the Swiss Alps. VDE VERLAG GMBH  Berlin  Offenbach.
BibTeX:
@conference{Siddique20181412,
  author = {Siddique, M.A. and Strozzi, T. and Hajnsek, I. and Frey, O.},
  title = {A case study on the correction of atmosphere-induced phase disturbances for SAR tomography in mountainous areas},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-June},
  pages = {1412-1416},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050480326&partnerID=40&md5=7db583599ee5407243c22a4dc2d1d530}
}
Siddique M, Strozzi T, Hajnsek I and Frey O (2018), "SAR tomography for spatio-temporal inversion of coherent scatterers in villages of alpine regions", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2018-July, pp. 6099-6102. Institute of Electrical and Electronics Engineers Inc..
Abstract: Differential synthetic aperture radar (SAR) tomography allows separation of multiple coherent scatterers interfering in the same range-azimuth resolution cell as well as the estimation of the deformation parameters of each scatterer. In this way, the spatio-temporal tomographic inversion serves as a means to resolve the layover and simultaneously improve deformation sampling. Compared to metropolitan regions with several man-made structures, the prevalence of coherent scatterers in the villages of alpine regions is generally low, while at the same time layovers are widespread due to the ruggedness of the terrain. Moreover, the drastic height variations in the imaged scene necessitate height-dependent compensation of the atmospheric phase delay variations within the tomographic inversion. This paper addresses these concerns while performing experiments on an interferometric stack comprising 33 Cosmo-SkyMed strimap images acquired in the summers between 2008-13 over Matter Valley in the Swiss Alps. The results show improved deformation sampling along the layover-affected mountainside.
BibTeX:
@conference{Siddique20186099,
  author = {Siddique, M.A. and Strozzi, T. and Hajnsek, I. and Frey, O.},
  title = {SAR tomography for spatio-temporal inversion of coherent scatterers in villages of alpine regions},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-July},
  pages = {6099-6102},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063144918&doi=10.1109%2fIGARSS.2018.8518296&partnerID=40&md5=b5d471786810f929686579ba84aaadc2},
  doi = {10.1109/IGARSS.2018.8518296}
}
Siddique M, Wegmüller U, Hajnsek I and Frey O (2018), "SAR tomography as an add-On to PSI: Detection of coherent scatterers in the presence of phase instabilities", Remote Sensing. Vol. 10(7) MDPI AG.
Abstract: The estimation of deformation parameters using persistent scatterer interferometry (PSI) is limited to single dominant coherent scatterers. As such, it rejects layovers wherein multiple scatterers are interfering in the same range-azimuth resolution cell. Differential synthetic aperture radar (SAR) tomography can improve deformation sampling as it has the ability to resolve layovers by separating the interfering scatterers. In this way, both PSI and tomography inevitably require a means to detect coherent scatterers, i.e., to perform hypothesis testing to decide whether a given candidate scatterer is coherent. This paper reports the application of a detection strategy in the context of "tomography as an add-on to PSI". As the performance of a detector is typically linked to the statistical description of the underlying mathematical model, we investigate how the statistics of the phase instabilities in the PSI analysis are carried forward to the subsequent tomographic analysis. While phase instabilities in PSI are generally modeled as an additive noise term in the interferometric phase model, their impact in SAR tomography manifests as a multiplicative disturbance. The detection strategy proposed in this paper allows extending the same quality considerations as used in the prior PSI processing (in terms of the dispersion of the residual phase) to the subsequent tomographic analysis. In particular, the hypothesis testing for the detection of coherent scatterers is implemented such that the expected probability of false alarm is consistent between PSI and tomography. The investigation is supported with empirical analyses on an interferometric data stack comprising 50 TerraSAR-X acquisitions in stripmap mode, over the city of Barcelona, Spain, from 2007-2012. 2018 by the authors.
BibTeX:
@article{Siddique2018,
  author = {Siddique, M.A. and Wegmüller, U. and Hajnsek, I. and Frey, O.},
  title = {SAR tomography as an add-On to PSI: Detection of coherent scatterers in the presence of phase instabilities},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {7},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050493688&doi=10.3390%2frs10071014&partnerID=40&md5=ae2dd4d2a33491a409c4e9a1806e0203},
  doi = {10.3390/rs10071014}
}
Smolander T, Lemmetyinen J, Rautiainen K, Schwank M and Pulliainen J (2018), "Soil permittivity and soil frost retrievals using a synergistic method for active and passive microwave instruments", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2018-July, pp. 7782-7784. Institute of Electrical and Electronics Engineers Inc..
Abstract: A synergistic method for obtaining soil permittivity and soil frost was developed. The method incorporates a semiempirical backscattering model for forested land. Soil permittivity is retrieved from active microwave observations using least squares inversion method. Bayesian assimilation scheme can be applied to combine the active retrieval with a permittivity estimate from a passive instrument. Soil frost can be determined from permittivity estimates using a threshold method. The synergistic method was tested on boreal forest site in Northern Finland using ASAR for active and SMOS for passive observations. Satellite retrievals were compared to in situ soil permittivity, temperature and frost measurements. The results show that high resolution SAR data (e.g., ASAR, Sentinel) can be used to downscale coarse resolution SMOS estimates and that synergistic method reduces variability and biases of the ASAR retrieval. 2018 IEEE
BibTeX:
@conference{Smolander20187782,
  author = {Smolander, T. and Lemmetyinen, J. and Rautiainen, K. and Schwank, M. and Pulliainen, J.},
  title = {Soil permittivity and soil frost retrievals using a synergistic method for active and passive microwave instruments},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {2018-July},
  pages = {7782-7784},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063128002&doi=10.1109%2fIGARSS.2018.8517284&partnerID=40&md5=086282facf56d31394a6143402c0c9ad},
  doi = {10.1109/IGARSS.2018.8517284}
}
Strozzi T, Antonova S, Gunther F, Matzler E, Vieira G, Wegmüller U, Westermann S and Bartsch A (2018), "Sentinel-1 SAR interferometry for surface deformation monitoring in low-land permafrost areas", Remote Sensing. Vol. 10(9) MDPI AG.
Abstract: Low-land permafrost areas are subject to intense freeze-thaw cycles and characterized by remarkable surface displacement. We used Sentinel-1 SAR interferometry (InSAR) in order to analyse the summer surface displacement over four spots in the Arctic and Antarctica since 2015. Choosing floodplain or outcrop areas as the reference for the InSAR relative deformation measurements, we found maximum subsidence of about 3 to 10 cm during the thawing season with generally high spatial variability. Sentinel-1 time-series of interferograms with 6-12 day time intervals highlight that subsidence is often occurring rather quickly within roughly one month in early summer. Intercomparison of summer subsidence from Sentinel-1 in 2017 with TerraSAR-X in 2013 over part of the Lena River Delta (Russia) shows a high spatial agreement between both SAR systems. A comparison with in-situ measurements for the summer of 2014 over the Lena River Delta indicates a pronounced downward movement of several centimetres in both cases but does not reveal a spatial correspondence between InSAR and local in-situ measurements. For the reconstruction of longer time-series of deformation, yearly Sentinel-1 interferograms from the end of the summer were considered. However, in order to infer an effective subsidence of the surface through melting of excess ice layers over multi-annual scales with Sentinel-1, a longer observation time period is necessary. 2018 by the authors.
BibTeX:
@article{Strozzi2018,
  author = {Strozzi, T. and Antonova, S. and Gunther, F. and Matzler, E. and Vieira, G. and Wegmüller, U. and Westermann, S. and Bartsch, A.},
  title = {Sentinel-1 SAR interferometry for surface deformation monitoring in low-land permafrost areas},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {9},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053610234&doi=10.3390%2frs10091360&partnerID=40&md5=c917688c8f189ddf1bb79e4028229b2a},
  doi = {10.3390/rs10091360}
}
Strozzi T, KlimeÅ¡ J, Frey H, Caduff R, Huggel C, Wegmüller U and Rapre A (2018), "Satellite SAR interferometry for the improved assessment of the state of activity of landslides: A case study from the Cordilleras of Peru", Remote Sensing of Environment. Vol. 217, pp. 111-125. Elsevier Inc..
Abstract: In Peru landslides have been causing damages and casualties annually due to the high mountain relief and distinct seasonal precipitation distribution. Satellite Synthetic Aperture Radar (SAR) interferometry represents one possibility for mapping surface deformation at fine spatial resolution over large areas in order to characterize aspects of terrain motion and potentially hazardous processes. We present land surface motion maps derived from satellite SAR interferometry (InSAR) for a part of the Santa River Basin between the Cordilleras Blanca and Negra around the city of Carhuaz in Peru. Using both Persistent Scatterer Interferometry (PSI) and differential SAR Interferograms (DInSAR) from ALOS-1 PALSAR-1, ENVISAT ASAR, ALOS-2 PALSAR-2 and Sentinel-1 we mapped 42 landslides extending over 17,190,141 m2 within three classes of activity (i.e. 0–2 cm/a, 2–10 cm/a and >10 cm/a). A geomorphological inventory of landslides was prepared from optical satellite imagery and field experience and compared to the InSAR-based slope-instability inventory. The two approaches provide slightly different information about landslide spatial and temporal activity patterns, but altogether they can be combined for the assessment of the state of activity of landslides and possibly the development of hazard maps, which are not systematically available in this region. We conclude that ALOS PALSAR (1 and 2) and Sentinel-1 data have a high potential to derive high-quality surface deformation information of landslides in many mountainous regions worldwide due to their global and frequent acquisition strategies. 2018
BibTeX:
@article{Strozzi2018111,
  author = {Strozzi, T. and KlimeÅ¡, J. and Frey, H. and Caduff, R. and Huggel, C. and Wegmüller, U. and Rapre, A.C.},
  title = {Satellite SAR interferometry for the improved assessment of the state of activity of landslides: A case study from the Cordilleras of Peru},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2018},
  volume = {217},
  pages = {111-125},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85051411956&doi=10.1016%2fj.rse.2018.08.014&partnerID=40&md5=ed7b88e6ed042e6af798778cd56ab5f5},
  doi = {10.1016/j.rse.2018.08.014}
}
Tosi L, Da Lio C, Teatini P and Strozzi T (2018), "Land subsidence in coastal environments: Knowledge advance in the Venice coastland by TerraSAR-X PSI", Remote Sensing. Vol. 10(8) MDPI AG.
Abstract: The use of satellite SAR interferometric methods has significantly improved the monitoring of ground movements over the last decades, thus opening new possibilities for a more accurate interpretation of land subsidence and its driving mechanisms. TerraSAR-X has been extensively used to study land subsidence in the Venice Lagoon, Italy, with the aim of quantifying the natural and anthropogenic causes. In this paper, we review and update the main results achieved by three research projects supported by DLR AOs (German Aerospace Center Announcement of Opportunity) and conducted to test the capability of TerraSAR-X PSI (Persistent Scatterer Interferometry) to detect ground movements in the complex physiographic setting of the Venice transitional coastal environment. The investigations have been focused on the historical center of Venice, the lagoon inlets where the MoSE is under construction, salt marshes, and newly built-up areas in the littoral. PSI on stacks of stripmap TerraSAR-X images covering short- to long-time periods (i.e., the years 2008-2009, 2008-2011 and 2008-2013) has proven particularly effective to measure land subsidence in the Venice coastland. The very high spatial resolution (3 m) and the short repeat time interval (11 days) of the TerraSAR-X acquisitions make it possible to investigate ground movements with a detail unavailable in the past. The interferometric products, properly calibrated, allowed for a millimetric vertical accuracy of the land movements at both the regional and local scales, even for short-term analyses, i.e., spanning one year only. The new picture of the land movement resulted from processing TerraSAR-X images has significantly contributed to update the knowledge on the subsidence process at the Venice coast. 2018 by the authors.
BibTeX:
@article{Tosi2018,
  author = {Tosi, L. and Da Lio, C. and Teatini, P. and Strozzi, T.},
  title = {Land subsidence in coastal environments: Knowledge advance in the Venice coastland by TerraSAR-X PSI},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2018},
  volume = {10},
  number = {8},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85051656903&doi=10.3390%2frs10081191&partnerID=40&md5=3e47f55707851ad9a7f6854b2f23670e},
  doi = {10.3390/rs10081191}
}
Wegmüller U, Werner C, Frey O, Magnard C and Strozzi T (2018), "Reformulating the split-spectrum method to facilitate the estimation and compensation of the ionospheric phase in SAR interferograms", Procedia Computer Science. Vol. 138, pp. 318-325. Elsevier B.V..
Abstract: Spatial and temporal variation of the free electron concentration in the ionosphere affects SAR interferograms, in particular at low radar frequencies. The split-spectrum method permits separating the ionospheric and the non-dispersive phase terms using spectral sub-band images. In this work a reformulation of the split-spectrum method facilitates the necessary processing steps. Reformulating the split-spectrum method permits determining the ionospheric phase component based on a split-spectrum double-difference interferogram and the full-bandwidth differential interferogram. In this way differing a pair of unwrapped phase images, each one scaled by a large factor, can be avoided, making the method more robust. The applicability of the proposed method is demonstrated with examples including cases with very strong ionospheric effects. 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.
BibTeX:
@article{Wegmuller2018318,
  author = {Wegmüller, U. and Werner, C. and Frey, O. and Magnard, C. and Strozzi, T.},
  title = {Reformulating the split-spectrum method to facilitate the estimation and compensation of the ionospheric phase in SAR interferograms},
  journal = {Procedia Computer Science},
  publisher = {Elsevier B.V.},
  year = {2018},
  volume = {138},
  pages = {318-325},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85061975908&doi=10.1016%2fj.procs.2018.10.045&partnerID=40&md5=d0cbc9cb7116a40996e2a6bc00df0d1e},
  doi = {10.1016/j.procs.2018.10.045}
}
Zhang B, Ding X, Werner C, Tan K, Zhang B, Jiang M, Zhao J and Xu Y (2018), "Dynamic displacement monitoring of long-span bridges with a microwave radar interferometer", ISPRS Journal of Photogrammetry and Remote Sensing. Vol. 138, pp. 252-264. Elsevier B.V..
Abstract: Structural health monitoring of long-span bridges is a critical process in ensuring the operational safety of the structures. In this paper, we present experimental results of monitoring the displacements of two long-span bridges in Hong Kong Ting Kau Bridge (TKB) and Tsing Ma Bridge (TMB) with a terrestrial microwave radar interferometer named the GAMMA Portable Radar Interferometer (GPRI). A technique for fusing the measurements from two receiving antennas of the radar instrument is proposed. In addition, a two-step phase unwrapping approach is also tested. The results reveal the bridge dynamic responses under different loading conditions, including winds, vehicle traffic, and passing trains. The results also show that the terrestrial microwave radar interferometer can be used to monitor the dynamics of long-span bridges with unprecedented spatial and temporal resolutions. 2018
BibTeX:
@article{Zhang2018252,
  author = {Zhang, B. and Ding, X. and Werner, C. and Tan, K. and Zhang, B. and Jiang, M. and Zhao, J. and Xu, Y.},
  title = {Dynamic displacement monitoring of long-span bridges with a microwave radar interferometer},
  journal = {ISPRS Journal of Photogrammetry and Remote Sensing},
  publisher = {Elsevier B.V.},
  year = {2018},
  volume = {138},
  pages = {252-264},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042874489&doi=10.1016%2fj.isprsjprs.2018.02.020&partnerID=40&md5=88b9677635cc9fc606fc594128414c3b},
  doi = {10.1016/j.isprsjprs.2018.02.020}
}
Zheng D, Van Der Velde R, Wen J, Wang X, Ferrazzoli P, Schwank M, Colliander A, Bindlish R and Su Z (2018), "Assessment of the SMAP Soil Emission Model and Soil Moisture Retrieval Algorithms for a Tibetan Desert Ecosystem", IEEE Transactions on Geoscience and Remote Sensing. Vol. 56(7), pp. 3786-3799. Institute of Electrical and Electronics Engineers Inc..
Abstract: The Soil Moisture Active Passive (SMAP) satellite mission launched in January 2015 provides worldwide soil moisture (SM) monitoring based on L-band brightness temperature (TBp) measurements at horizontal (TBH) and vertical (TBV) polarizations. This paper presents a performance assessment of SMAP soil emission model and SM retrieval algorithms for a Tibetan desert ecosystem. It is found that the SMAP emission model largely underestimates the SMAP measured TBH (≈ 15 K), and the TBV is underestimated during dry-down episodes. A cold bias is noted for the SMAP effective temperature due to underestimation of soil temperature, leading to the TB p underestimation (>5 K). The remaining TB H underestimation is found to be related to the surface roughness parameterization that underestimates its effect on modulating the T B p measurements. Further, the topography and uncertainty of soil information are found to have minor impacts on the TB p simulations. The SMAP baseline SM products produced by single-channel algorithm (SCA) using the TBV measurements capture the measured SM dynamics well, while an underestimation is noted for the dry-down periods because of TB V underestimation. The products based on the SCA with TBH measurements underestimate the SM due to underestimation of TB H, and the dual-channel algorithm overestimates the SM. After implementing a new surface roughness parameterization and improving the soil temperature and texture information, the deficiencies noted above in TBp simulation and SM retrieval are greatly resolved. This indicates that the SMAP SM retrievals can be enhanced by improving both surface roughness and adopted soil temperature and texture information for Tibetan desert ecosystem.
BibTeX:
@article{Zheng20183786,
  author = {Zheng, D. and Van Der Velde, R. and Wen, J. and Wang, X. and Ferrazzoli, P. and Schwank, M. and Colliander, A. and Bindlish, R. and Su, Z.},
  title = {Assessment of the SMAP Soil Emission Model and Soil Moisture Retrieval Algorithms for a Tibetan Desert Ecosystem},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2018},
  volume = {56},
  number = {7},
  pages = {3786-3799},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044378015&doi=10.1109%2fTGRS.2018.2811318&partnerID=40&md5=9d216eab367bc60bb1b05b7dbf44c6f1},
  doi = {10.1109/TGRS.2018.2811318}
}
Zheng D, Wang X, van der Velde R, Ferrazzoli P, Wen J, Wang Z, Schwank M, Colliander A, Bindlish R and Su Z (2018), "Impact of surface roughness, vegetation opacity and soil permittivity on L-band microwave emission and soil moisture retrieval in the third pole environment", Remote Sensing of Environment. Vol. 209, pp. 633-647. Elsevier Inc..
Abstract: The brightness temperature (TBp) observed by the Soil Moisture Active Passive (SMAP) satellite mission is significantly affected by the soil permittivity (εs), surface roughness and vegetation opacity (τp). This study assesses the impact of these factors on simulating the SMAP horizontally (p = H) and vertically (p = V) polarized TBp measurements and retrieving the liquid soil water content (θliq) for both frozen and thawed soils in the typical Tibetan desert and meadow ecosystems. For this investigation, the zero-order approximation of the radiative transfer equations, i.e., τ-ω emission model, is configured with surface roughness and τp parameterizations adopted by current SMAP soil moisture retrieval algorithms, and the εs is computed with the four-phase dielectric mixing model that is applicable for both frozen and thawed soils. For the Tibetan desert site, the τ-ω emission model with above configurations underestimates year-round the SMAP TBH measurements (bias > 20 K), while TBV are underestimated during the cold season. Implementation of a new surface roughness parameterization reduces the TBH underestimation, and the improved TBp simulations lead to better θliq retrievals produced by the single channel algorithm (SCA) using the TBV as well as TBH measurements. The remaining TBH and TBV underestimations are removed by further adopting a new εs parameterization. For the Tibetan meadow site, the τ-ω emission model overestimates both TBH and TBV during the warm season and underestimates TBH during the cold season when the vegetation is sparse. Implementation of the new surface roughness parameterization reduces the TBH underestimation, and further the TBp overestimation is mitigated by adopting a new τp parameterization derived from a discrete radiative transfer model previously developed and tested for the same site. The in-situ measured θliq dynamics are better captured by corresponding retrievals for both frozen and thawed soils with implementation of the new surface roughness and τp parameterizations, which reduces the unbiased RMSEs by more than 40%. The parameterizations developed in this study are useful to provide consistent and reasonable TBp simulations and θliq retrievals over the Tibetan Plateau for both frozen and thawed soils based on both SMAP TBH and TBV measurements. 2018 Elsevier Inc.
BibTeX:
@article{Zheng2018633,
  author = {Zheng, D. and Wang, X. and van der Velde, R. and Ferrazzoli, P. and Wen, J. and Wang, Z. and Schwank, M. and Colliander, A. and Bindlish, R. and Su, Z.},
  title = {Impact of surface roughness, vegetation opacity and soil permittivity on L-band microwave emission and soil moisture retrieval in the third pole environment},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2018},
  volume = {209},
  pages = {633-647},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85043391931&doi=10.1016%2fj.rse.2018.03.011&partnerID=40&md5=ceeb8f9298b8b76eb36572c4789b56e5},
  doi = {10.1016/j.rse.2018.03.011}
}
Agarwal V, Bolch T, Syed T, Pieczonka T, Strozzi T and Nagaich R (2017), "Area and mass changes of Siachen Glacier (East Karakoram)", Journal of Glaciology. Vol. 63(237), pp. 148-163. Cambridge University Press.
Abstract: Here, we present a comprehensive assessment of Siachen Glacier (East Karakoram), in terms of its area and elevation change, velocity variations and mass budget, utilizing different satellite datasets including Landsat, Hexagon, Cartosat-I, Shuttle Radar Topography Mission, Envisat Advanced Synthetic Aperture Radar and Japanese Advanced Land Observing Satellite Phased Array-type L-band SAR. The total areal extent of Siachen Glacier did not change significantly between 1980 and 2014; however the exposed-ice area decreased during that period. The terminus of the glacier has experienced substantial downwasting (on average 30 m) over the period of 1999-2007, followed by a retreat of the transition between exposed and debris-covered ice by a distance of 1.3 km during the short span 2007-14. The spatial patterns of the elevation difference and velocity are heterogeneous over the large areal extent of Siachen Glacier. The average velocity of the entire glacier, as computed between 11 December 2008 and 26 January 2009, was 12.3 ± 0.4 cm d-1, while those estimated separately for the accumulation and ablation regions were 9.7 ± 0.4 cm d-1 and 20.4 ± 0.4 cm d-1, respectively. The mass budget of Siachen Glacier is estimated to be -0.03 ± 0.21 m w.e. a-1 for the period of 1999-2007. The Author(s) 2016.
BibTeX:
@article{Agarwal2017148,
  author = {Agarwal, V. and Bolch, T. and Syed, T.H. and Pieczonka, T. and Strozzi, T. and Nagaich, R.},
  title = {Area and mass changes of Siachen Glacier (East Karakoram)},
  journal = {Journal of Glaciology},
  publisher = {Cambridge University Press},
  year = {2017},
  volume = {63},
  number = {237},
  pages = {148-163},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85009971505&doi=10.1017%2fjog.2016.127&partnerID=40&md5=dc940a44b267aa596a237d8b776c0c44},
  doi = {10.1017/jog.2016.127}
}
Cartus O, Santoro M, Wegmüller U and Rommen B (2017), "Estimating total aboveground, stem and branch biomass using multi-frequency SAR", In 2017 9th International Workshop on the Analysis of Multitemporal Remote Sensing Images, MultiTemp 2017. Institute of Electrical and Electronics Engineers Inc..
Abstract: We have investigated the retrieval of total aboveground, stem and branch biomass using multi-temporal SAR data acquired at C-, L-, and P-band by Radarsat-2, ERS-2, ALOS PALSAR, and SETHI for a forest site in Sweden. A semi-empirical model was used to model C- and L-band backscatter as function of total aboveground, stem and branch biomass; a linear regression model was used for P-band. Calibrated with the aid of inventory plots, the models were used to estimate total aboveground, stem, and branch biomass for each individual scene in the multi-temporal and multi-frequency stack of observations. Individual estimates were then combined using weights reflecting each scenes' sensitivity to the biomass component in question. At the plot scale, the retrieval errors were 37, 40, and 33 % for total aboveground, stem, and branch biomass in terms of the relative RMSE; the error further reduced to 33, 38, and 27 % when calibrating models per species. We find that i) the retrieval of total aboveground, stem and branch biomass benefits from the availability of multi-temporal/-frequency data as the lowest retrieval errors with the best single image (P-band) were about 6 to 8 % higher, ii) there is no benefit in estimating total aboveground biomass via independent estimates of stem and branch biomass, iii) consideration of species specific differences associated with different allocations of biomass to stems and branches allows for improving the retrieval.
BibTeX:
@conference{Cartus2017,
  author = {Cartus, O. and Santoro, M. and Wegmüller, U. and Rommen, B.},
  title = {Estimating total aboveground, stem and branch biomass using multi-frequency SAR},
  booktitle = {2017 9th International Workshop on the Analysis of Multitemporal Remote Sensing Images, MultiTemp 2017},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2017},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85032378778&doi=10.1109%2fMulti-Temp.2017.8035231&partnerID=40&md5=93a79c696d4669b6779fd0729e744ae5},
  doi = {10.1109/Multi-Temp.2017.8035231}
}
Frey O, Werner C, Caduff R and Wiesmann A (2017), "Inversion of SNOW structure parameters from time series of tomographic measurements with SnowScat", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2017-July, pp. 2472-2475. Institute of Electrical and Electronics Engineers Inc..
Abstract: SnowScat is a terrestrial stepped-frequency continuous-wave (SFCW) scatterometer which supports fully-polarimetric measurements within a frequency band from 9.2 to 17.8 GHz. Recently, the hardware has been upgraded by adding a tomographic profiling mode. This tomographic approach allows to retrieve high-resolution information about a snowpack via observables, such as radar backscatter, co-polar phase difference, interferometric phase and coherence. Since the tomographic imaging itself is also affected by the refraction occurring at the air-snow interface and within the snowpack the two problems, 1) the production of well-focused and correctly located tomographic profiles, and 2) the retrieval of snow structure parameters are inherently linked. In this contribution, a tomographic inversion scheme to retrieve the refractive index of snow through an autofocus approach is presented. The current autofocus-based retrieval relies on using an aluminium sphere of a test target deployed in the scene. The refractive indices and accompanying snow density measurements obtained at four dates during a cold period in January during the ESA SnowLab 2016/2017 campaign are compared to an empirical model by Matzler and Wiesmann that describes the relation between snow density and the real part of the relative permittivity for dry snow.
BibTeX:
@conference{Frey20172472,
  author = {Frey, O. and Werner, C.L. and Caduff, R. and Wiesmann, A.},
  title = {Inversion of SNOW structure parameters from time series of tomographic measurements with SnowScat},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2017},
  volume = {2017-July},
  pages = {2472-2475},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041826573&doi=10.1109%2fIGARSS.2017.8127494&partnerID=40&md5=74f614ab9a0a4079a8b1a7a39a672fed},
  doi = {10.1109/IGARSS.2017.8127494}
}
Giordan D, Manconi A, Remondino F and Nex F (2017), "Use of unmanned aerial vehicles in monitoring application and management of natural hazards", Geomatics, Natural Hazards and Risk. Vol. 8(1), pp. 1-4. Taylor and Francis Ltd..
Abstract: The recent development of unmanned aerial vehicles (UAVs) has been increasing the number of technical solutions that can be used to monitor and map the effects of natural hazards. UAVs are generally cheaper and more versatile than traditional remote-sensing techniques, and they can be therefore considered as a good alternative for the acquisition of imagery and other physical parameters before, during and after a natural hazard event. This is an important added value especially for investigations over small areas (few km2). In the special issue ‘The use of Unmanned Aerial Vehicles in monitoring application and management of natural hazards’, we collected a number of case studies, aiming at providing a range of applications of monitoring and management of natural hazards assessed through the use of UAVs. 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
BibTeX:
@article{Giordan20171,
  author = {Giordan, D. and Manconi, A. and Remondino, F. and Nex, F.},
  title = {Use of unmanned aerial vehicles in monitoring application and management of natural hazards},
  journal = {Geomatics, Natural Hazards and Risk},
  publisher = {Taylor and Francis Ltd.},
  year = {2017},
  volume = {8},
  number = {1},
  pages = {1-4},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018381426&doi=10.1080%2f19475705.2017.1315619&partnerID=40&md5=ed9265dc7af78cd3c2af58136730d999},
  doi = {10.1080/19475705.2017.1315619}
}
Hocke K, Navas-Guzmán F, Moreira L, Bernet L and Matzler C (2017), "Diurnal cycle in atmospheric water over Switzerland", Remote Sensing. Vol. 9(9) MDPI AG.
Abstract: Abstract: The TROpospheric WAter RAdiometer (TROWARA) is a ground-based microwave radiometer with an additional infrared channel observing atmospheric water parameters in Bern, Switzerland. TROWARA measures with nearly all-weather capability during day- and nighttime with a high temporal resolution (about 10 s). Using the almost complete data set from 2004 to 2016, we derive and discuss the diurnal cycles in cloud fraction (CF), integrated liquid water (ILW) and integrated water vapour (IWV) for different seasons and the annual mean. The amplitude of the mean diurnal cycle in IWV is 0.41 kg/m2. The sub-daily minimum of IWV is at 10:00 LT while the maximum of IWV occurs at 19:00 LT. The relative amplitudes of the diurnal cycle in ILW are up to 25% in October, November and January, which is possibly related to a breaking up of the cloud layer at 10:00 LT. The minimum of ILW occurs at 12:00 LT, which is due to cloud solar absorption. In case of cloud fraction of liquid water clouds, maximal values of +10% are reached at 07:00 LT and then a decrease starts towards the minimum of -10%, which is reached at 16:00 LT in autumn. This breakup of cloud layers in the late morning and early afternoon hours seems to be typical for the weather in Bern in autumn. Finally, the diurnal cycle in rain fraction is analysed, which shows an increase of a few percent in the late afternoon hours during summer. 2017 by the authors.
BibTeX:
@article{Hocke2017,
  author = {Hocke, K. and Navas-Guzmán, F. and Moreira, L. and Bernet, L. and Matzler, C.},
  title = {Diurnal cycle in atmospheric water over Switzerland},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2017},
  volume = {9},
  number = {9},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029385311&doi=10.3390%2frs9090909&partnerID=40&md5=ede2969f2612c6dab013a3152fd703e0},
  doi = {10.3390/rs9090909}
}
Hocke K, Navas-Guzmán F, Moreira L, Bernet L and Matzler C (2017), "Oscillations in atmospheric water above Switzerland", Atmospheric Chemistry and Physics. Vol. 17(19), pp. 12121-12131. Copernicus GmbH.
Abstract: Cloud fraction (CF), integrated liquid water (ILW) and integrated water vapour (IWV) were continuously measured from 2004 to 2016 by the TROpospheric WAter RAdiometer (TROWARA) in Bern, Switzerland. There are indications for interannual variations of CF and ILW. A spectral analysis shows that IWV is dominated by an annual oscillation, leading to an IWV maximum of 24kg m-2 in July to August and a minimum of 8kg m-2 in February. The seasonal behaviour of CF and ILW is composed by both the annual and the semiannual oscillation. However, the annual oscillation of CF has a maximum in December while the annual oscillation of ILW has a maximum in July. The semiannual oscillations of CF and ILW are strong from 2010 to 2014. The normalized power spectra of ILW and CF show statistically significant spectral components with periods of 76, 85, 97 and 150 days. We find a similarity between the power spectra of ILW and CF with those of zonal wind at 830hPa (1.5km) above Bern. Particularly, the occurrence of higher harmonics in the CF and ILW spectra is possibly forced by the behaviour of the lower-tropospheric wind. The mean amplitude spectra of CF, ILW and IWV show increased short-term variability on timescales less than 40 days from spring to fall. We find a weekly cycle of CF and ILW from June to September with increased values on Saturday, Sunday and Monday. 2017 Author(s).
BibTeX:
@article{Hocke201712121,
  author = {Hocke, K. and Navas-Guzmán, F. and Moreira, L. and Bernet, L. and Matzler, C.},
  title = {Oscillations in atmospheric water above Switzerland},
  journal = {Atmospheric Chemistry and Physics},
  publisher = {Copernicus GmbH},
  year = {2017},
  volume = {17},
  number = {19},
  pages = {12121-12131},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85031316815&doi=10.5194%2facp-17-12121-2017&partnerID=40&md5=7f6c0ee771a9f1b6cecb46e8a7fcfafa},
  doi = {10.5194/acp-17-12121-2017}
}
Kerr Y, Mahmoodi A, Mialon A, Al Biltar A, Rodríguez-Fernández N, Richaume P, Cabot F, Wigneron J, Waldteufel P, Ferrazzoli P, Schwank M and Delwart S (2017), "Soil moisture retrieval algorithms: The SMOS case", Comprehensive Remote Sensing. Vol. 1-9, pp. 156-190. Elsevier.
Abstract: After the successful acquisition by a coarse L-band radiometer on board Skylab in the early seventies, the potential of L-band radiometry was made clear in spite of a strict limitation linked to minimum antenna dimensions required for appropriate spatial resolution. More than 20 years later new antenna concepts emerged to mitigate this physical constraint. The first to emerge, in 1997, and to become a reality, was the Soil Moisture and Ocean Salinity (SMOS) mission (Kerr, 1997, Kerr, 1998). It is European Space Agency’s (ESA’s) second Earth Explorer Opportunity mission (Kerr et al., 2001), launched in November 2009. It is a joint program between ESA, CNES (Centre National d’Etudes Spatiales), and CDTI (Centro para el Desarrollo Tecnologico Industrial). SMOS carries a single payload, an L-band 2D interferometric radiometer in the 1400-1427 MHz protected band. This wavelength penetrates well through the atmosphere, and hence, the instrument probes the Earth surface emissivity from space. Surface emissivity can be related to the moisture content in the first few centimeters of soil, and after some surface roughness and temperature corrections, to the sea surface salinity over ocean. Soil moisture retrieval from SMOS observations with a required accuracy of 0.04 m3/m3 is challenging and involves many steps. The retrieval algorithms are developed and implemented in the ground segment, which processes level 1 and level 2 data. Level 1 consists mainly of directional brightness temperatures, while level 2 consists of geophysical products in swath mode, i.e., for successive imaging snapshots acquired by the sensor during a half orbit from pole to pole. Level 3 consists in composites of brightness temperatures, or geophysical products over time and space, i.e., global maps over given temporal periods from 1 day to 1 month. In this context, a group of institutes prepared the soil moisture and ocean salinity Algorithm Theoretical Basis Documents (ATBD), used to in operational soil moisture and sea salinity retrieval algorithms (Kerr et al., 2010a). The principle of the level 2 soil moisture retrieval algorithm is based on an iterative approach, which aims at minimizing a cost function. The main component of the cost function is given by the sum of the squared weighted differences between measured and modeled brightness temperature (TB) at horizontal and vertical polarizations, for a variety of incidence angles. The algorithm finds the best set of parameters, e.g., soil moisture (SM) and vegetation characteristics, which drive the TB model and minimizes the cost function. From this algorithm, a more sophisticated one was developed to take into account multiorbit retrievals (i.e., level 3). Subsequently, after several years of data acquisition and algorithm improvements, a neural network approach was developed so as to be able to infer soil moisture fields in near-real time. In parallel, several simplified algorithms were tested, the goal being to achieve a seamless transition with other sensors, along with other studies targeted on specific targets such as dense forests, organic rich soils, or frozen and snow-covered grounds. Finally, it may be noted that most of these approaches deliver not only the surface soil moisture but also other quantities of interest such as vegetation optical depth, surface roughness, and surface dielectric constant. The goal of this article is to give an overview of these different approaches and corresponding results and adequate references for those wishing to go further. Sea surface salinity is not covered in this article, while the focus is SMOS data. 2018 Elsevier Inc. All rights reserved.
BibTeX:
@book{Kerr2017156,
  author = {Kerr, Y.H. and Mahmoodi, A. and Mialon, A. and Al Biltar, A. and Rodríguez-Fernández, N. and Richaume, P. and Cabot, F. and Wigneron, J.P. and Waldteufel, P. and Ferrazzoli, P. and Schwank, M. and Delwart, S.},
  title = {Soil moisture retrieval algorithms: The SMOS case},
  journal = {Comprehensive Remote Sensing},
  publisher = {Elsevier},
  year = {2017},
  volume = {1-9},
  pages = {156-190},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85068151872&doi=10.1016%2fB978-0-12-409548-9.10355-0&partnerID=40&md5=8c67df4f9d61ebc2650b0dd95610d904},
  doi = {10.1016/B978-0-12-409548-9.10355-0}
}
Lamarche C, Santoro M, Bontemps S, d'Andrimont R, Radoux J, Giustarini L, Brockmann C, Wevers J, Defourny P and Arino O (2017), "Compilation and validation of sar and optical data products for a complete and global map of inland/ocean water tailored to the climate modeling community", Remote Sensing. Vol. 9(1) MDPI AG.
Abstract: Accurate maps of surface water extent are of paramount importance for water management, satellite data processing and climate modeling. Several maps of water bodies based on remote sensing data have been released during the last decade. Nonetheless, none has a truly (90°N/90°S) global coverage while being thoroughly validated. This paper describes a global, spatially-complete (void-free) and accurate mask of inland/ocean water for the 2000-2012 period, built in the framework of the European Space Agency (ESA) Climate Change Initiative (CCI). This map results from the synergistic combination of multiple individual SAR and optical water body and auxiliary datasets. A key aspect of this work is the original and rigorous stratified random sampling designed for the quality assessment of binary classifications where one class is marginally distributed. Input and consolidated products were assessed qualitatively and quantitatively against a reference validation database of 2110 samples spread throughout the globe. Using all samples, overall accuracy was always very high among all products, between 98% and 100%. The CCI global map of open water bodies provided the best water class representation (F-score of 89%) compared to its constitutive inputs. When focusing on the challenging areas for water bodies' mapping, such as shorelines, lakes and river banks, all products yielded substantially lower accuracy figures with overall accuracies ranging between 74% and 89%. The inland water area of the CCI global map of open water bodies was estimated to be 3.17 million km2 ± 0.24 million km2. The dataset is freely available through the ESA CCI Land Cover viewer. 2017 by the authors; licensee MDPI, Basel, Switzerland.
BibTeX:
@article{Lamarche2017,
  author = {Lamarche, C. and Santoro, M. and Bontemps, S. and d'Andrimont, R. and Radoux, J. and Giustarini, L. and Brockmann, C. and Wevers, J. and Defourny, P. and Arino, O.},
  title = {Compilation and validation of sar and optical data products for a complete and global map of inland/ocean water tailored to the climate modeling community},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2017},
  volume = {9},
  number = {1},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85010644464&doi=10.3390%2frs9010036&partnerID=40&md5=20448e3b47010ee7d4b319054adecb08},
  doi = {10.3390/rs9010036}
}
Lemmetyinen J, Rautiainen K, Luojus K, Rott H, Nagler T, Parrella G, Hajnsek I, Derksen C, Macelloni G, Brogioni M, Wiesmann A, Matzler C and Kern M (2017), "Future mission concepts for measuring snow mass", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2017-July, pp. 1370-1371. Institute of Electrical and Electronics Engineers Inc..
Abstract: There is a long-stranding need of reliable space-borne observations on snow mass. Current satellite sensors and data products are largely unable to meet requirements presented in particular by numerical prediction and watershed management. Consequently, several concept studies have been initiated to address these specific needs, outlining possibilities for future space sensors focusing on retrieval of snow mass and other characteristics of the terrestrial cryosphere. The results of these of-going mission concept studies are presented and discussed. Several possible sensor options are presented, which would address diverse needs on either hemispheric or regional scales.
BibTeX:
@conference{Lemmetyinen20171370,
  author = {Lemmetyinen, J. and Rautiainen, K. and Luojus, K. and Rott, H. and Nagler, T. and Parrella, G. and Hajnsek, I. and Derksen, C. and Macelloni, G. and Brogioni, M. and Wiesmann, A. and Matzler, C. and Kern, M.},
  title = {Future mission concepts for measuring snow mass},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2017},
  volume = {2017-July},
  pages = {1370-1371},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041849585&doi=10.1109%2fIGARSS.2017.8127217&partnerID=40&md5=ea03cd7990d402018a4a05e502fac525},
  doi = {10.1109/IGARSS.2017.8127217}
}
Li W, Ciais P, Peng S, Yue C, Wang Y, Thurner M, Saatchi S, Arneth A, Avitabile V, Carvalhais N, Harper A, Kato E, Koven C, Liu Y, Nabel J, Pan Y, Pongratz J, Poulter B, Pugh T, Santoro M, Sitch S, Stocker B, Viovy N, Wiltshire A, Yousefpour R and Zaehle S (2017), "Land-use and land-cover change carbon emissions between 1901 and 2012 constrained by biomass observations", Biogeosciences. Vol. 14(22), pp. 5053-5067. Copernicus GmbH.
Abstract: The use of dynamic global vegetation models (DGVMs) to estimate CO2 emissions from land-use and land-cover change (LULCC) offers a new window to account for spatial and temporal details of emissions and for ecosystem processes affected by LULCC. One drawback of LULCC emissions from DGVMs, however, is lack of observation constraint. Here, we propose a new method of using satellite- and inventory-based biomass observations to constrain historical cumulative LULCC emissions (ELUCc) from an ensemble of nine DGVMs based on emerging relationships between simulated vegetation biomass and ELUCc. This method is applicable on the global and regional scale. The original DGVM estimates of ELUCc range from 94 to 273PgC during 1901-2012. After constraining by current biomass observations, we derive a best estimate of 155±50PgC (1σ Gaussian error). The constrained LULCC emissions are higher than prior DGVM values in tropical regions but significantly lower in North America. Our emergent constraint approach independently verifies the median model estimate by biomass observations, giving support to the use of this estimate in carbon budget assessments. The uncertainty in the constrained ELUCc is still relatively large because of the uncertainty in the biomass observations, and thus reduced uncertainty in addition to increased accuracy in biomass observations in the future will help improve the constraint. This constraint method can also be applied to evaluate the impact of land-based mitigation activities.
BibTeX:
@article{Li20175053,
  author = {Li, W. and Ciais, P. and Peng, S. and Yue, C. and Wang, Y. and Thurner, M. and Saatchi, S.S. and Arneth, A. and Avitabile, V. and Carvalhais, N. and Harper, A.B. and Kato, E. and Koven, C. and Liu, Y.Y. and Nabel, J.E.M.S. and Pan, Y. and Pongratz, J. and Poulter, B. and Pugh, T.A.M. and Santoro, M. and Sitch, S. and Stocker, B.D. and Viovy, N. and Wiltshire, A. and Yousefpour, R. and Zaehle, S.},
  title = {Land-use and land-cover change carbon emissions between 1901 and 2012 constrained by biomass observations},
  journal = {Biogeosciences},
  publisher = {Copernicus GmbH},
  year = {2017},
  volume = {14},
  number = {22},
  pages = {5053-5067},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85034055468&doi=10.5194%2fbg-14-5053-2017&partnerID=40&md5=2c1570087902ded73088c5f7a451a467},
  doi = {10.5194/bg-14-5053-2017}
}
da Lio C, Strozzi T, Teatini P and Tosi L (2017), "Computing the relative land subsidence at Venice, Italy, over the last fifty years", In Proceedings - 22nd International Congress on Modelling and Simulation, MODSIM 2017. , pp. 999-1005. Modelling and Simulation Society of Australia and New Zealand Inc. (MSSANZ).
Abstract: Land subsidence causes various damages to the infrastructures and cultural heritage in many cities worldwide. Urban flooding is one of the main consequences of land subsidence in coastal cities, where it is exacerbated by sea-level rise accompanying global climate change, but also in inland metropolitan areas such as Mexico City, where subsidence zones are increasingly flooded following intense rainstorms. The subsidence of Venice, one of the most beautiful and famous cities in the world, is well known not for the magnitude of subsidence but because subsidence has seriously compromised the heritage and the safety of the city in relation to its small elevation above the sea. The storm that flooded the historical center of Venice on November 4, 1966 dramatically revealed its fragility with respect to land subsidence and sea-level rise, or the Relative Land Subsidence (RLS), i.e. land movement with respect to sea-level changes. That event signaled the beginning of a systematic monitoring of the loss in elevation of the ground surface of Venice with respect to the mean level of the Northern Adriatic (NA) Sea. Tide gauge measurements, available from the beginning of the last century, have been supplied historically by levelling and more recently by Synthetic Aperture Radar (SAR)-based Interferometry. On the occasion of the 50th anniversary of the 1966 flood event, we quantify the RLS experienced by the city over these last five decades with a detail never achieved before. The computation of the loss of elevation has been obtained by processing and superposing the results of levelling surveys carried out in 1961, 1969, 1973, and 1993, together with the results of Interferometric processing of SAR images acquired from satellites: 1993 to 2002 by ERS-1/2, 2003 and 2010 by ENVISAT, 2008 to 2013 by TerraSAR-X, and 2012 to 2016 by COSMO-SkyMED. The records from the tide gauge in Trieste, which is a city on the coast of the NA Sea close to the Alps and known to be stable, are used to evaluate the sea-level rise over the targeted time interval. The mean land velocity (v) for each analyzed period has been obtained by interpolating the original measurements using the Kriging method on a same regular 50-m grid covering the entire city. Then, cumulative land subsidence (LStot)) from 1966 to 2016 has been simulated in a GIS environment by summing the partial land subsidence over the various periods covered by the levelling and SAR surveys. The results point out that in the Venice historical center between 1966 and 2016: • Land subsidence rate has been more variable in space but less variable over time than the changes of the NA mean sea level; • average subsidence has amounted to 0.8 mm/yr and the average NA msl rise to 1.9 mm/yr; • minimum and maximum cumulative subsidence has totalled 8 mm and 93 mm, respectively; and • maximum loss of elevation with respect to the NA msl (i.e. RLS) has been 190 mm. RLS has produced a tangible effect on the Venice historical center revealed by the continuous increase in frequency of the flooding events, locally called "acqua alta". In the next years, any further loss of elevation with respect to the mean sea level, even a few mm, will threaten the city’s survival with severe social and environmental impacts. Considering the present average land subsidence of Venice and sea level rise of the NA (i.e. both about 1.2 mm/yr), an additional loss of elevation of about 190 mm will likely occur by 2100. Actually, according to conservative and pessimistic IPCC scenarios, the sea-level accompanying global climate change is expected to rise from 32 to 56 cm. Therefore, the outcomes from this study should be properly taken in account for the planning of effective interventions for the mitigation of climate changes to maintain the historical center of this unique city. 2017 Proceedings - 22nd International Congress on Modelling and Simulation, MODSIM 2017. All rights reserved.
BibTeX:
@conference{daLio2017999,
  author = {da Lio, C. and Strozzi, T. and Teatini, P. and Tosi, L.},
  title = {Computing the relative land subsidence at Venice, Italy, over the last fifty years},
  booktitle = {Proceedings - 22nd International Congress on Modelling and Simulation, MODSIM 2017},
  publisher = {Modelling and Simulation Society of Australia and New Zealand Inc. (MSSANZ)},
  year = {2017},
  pages = {999-1005},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85080943446&partnerID=40&md5=710592c4d6969a107b13e9051aaedb56}
}
Manconi A, Glueer F and Loew S (2017), "Spatial and temporal evolution of rock fall activity on a failing slope", In ISRM Progressive Rock Failure Conference, PRF 2017. Vol. 2017-June International Society for Rock Mechanics.
Abstract: The main goal of this study is to describe the spatial and temporal evolution of rock fall phenomena triggered by rapid slope deformation. To this end, we combine low cost seismic sensors and image processing to study a large instability adjacent to the Great Aletsch glacier in the Swiss Alps, i.e. the Moosfluh slope, which is undergoing an acceleration phase since the late summer 2016. With this analysis, we aim at a better understanding of the relationship between the kinematic behavior of rock slope instabilities and progressive rock mass damage, which may lead to catastrophic failure. 2017 Brno University of Technology. All Rights Reserved.
BibTeX:
@conference{Manconi2017,
  author = {Manconi, A. and Glueer, F. and Loew, S.},
  title = {Spatial and temporal evolution of rock fall activity on a failing slope},
  booktitle = {ISRM Progressive Rock Failure Conference, PRF 2017},
  publisher = {International Society for Rock Mechanics},
  year = {2017},
  volume = {2017-June},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048554487&partnerID=40&md5=4ae95567574e4051703e91f3d11a4ad8}
}
Mattia F, Balenzano A, Satalino G, Lovergine F, Loew A, Peng J, Wegmüller U, Santoro M, Cartus O, Dabrowska-Zielinska K, Musial J, Davidson M, Yueh S, Kim S, Das N, Colliander A, Johnson J, Ouellette J, Walker J, Wu X, McNairn H, Merzouki A, Powers J, Caldwell T, Entekhabi D, Cosh M and Jackson T (2017), "Sentinel-1 high resolution soil moisture", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2017-July, pp. 5533-5536. Institute of Electrical and Electronics Engineers Inc..
Abstract: The systematic retrieval of near surface soil moisture (SSM) fields at high resolution (e.g., 0.1-1.0 km) is a challenging task that requires the exploitation of new retrieval algorithms and SAR data with advanced observational capabilities (in terms of spatial/temporal resolution, radiometric accuracy, very large swath, long-term continuity and rapid data dissemination). The launch of the Sentinel-1 (S-1) constellation provides these capabilities and calls for the development and validation of pre-operational SSM products at high resolution. The objective of this paper is to present and initially assess a SSM retrieval algorithm developed in view of S-1 data exploitation. The activity is supported by a large scientific community engaged in fostering a more effective interaction between researchers working in the field of high and low resolution SSM retrieval.
BibTeX:
@conference{Mattia20175533,
  author = {Mattia, F. and Balenzano, A. and Satalino, G. and Lovergine, F. and Loew, A. and Peng, J. and Wegmüller, U. and Santoro, M. and Cartus, O. and Dabrowska-Zielinska, K. and Musial, J. and Davidson, M.W.J. and Yueh, S. and Kim, S. and Das, N. and Colliander, A. and Johnson, J. and Ouellette, J. and Walker, J. and Wu, X. and McNairn, H. and Merzouki, A. and Powers, J. and Caldwell, T. and Entekhabi, D. and Cosh, M. and Jackson, T.},
  title = {Sentinel-1 high resolution soil moisture},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2017},
  volume = {2017-July},
  pages = {5533-5536},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041865566&doi=10.1109%2fIGARSS.2017.8128257&partnerID=40&md5=5c7b7cca90a917b2f9c631fd64b76aba},
  doi = {10.1109/IGARSS.2017.8128257}
}
Mendez Dominguez E, Magnard C, Frioud M, Small D and Meier E (2017), "Adaptive Pulse Compression for Range Focusing in SAR Imagery", IEEE Transactions on Geoscience and Remote Sensing. Vol. 55(4), pp. 2262-2275. Institute of Electrical and Electronics Engineers Inc..
Abstract: Synthetic aperture radar (SAR) images are focused via range and azimuth compression. Typically, a matched filter is used for range compression. However, its inherent operation introduces target masking due to sidelobes, reducing the recognition and interpretability of the underlying targets. To optimize the focusing quality, adaptive pulse compression (APC) can be applied. In this paper, APC is assessed for range processing in SAR image focusing. The performance of the method is evaluated with airborne SAR imagery and compared with those of traditional schemes. We show that by applying APC under single-channel interferometric and stepped frequency scenarios, the quality of the SAR images, the corresponding phase maps, and interferometric coherence images can be significantly improved, and that APC provides both better amplitude and phase estimates of the range profiles. APC is shown to preserve the characteristics of the azimuth signals and can be applied without restricting the azimuth compression scheme.
BibTeX:
@article{MendezDominguez20172262,
  author = {Mendez Dominguez, E. and Magnard, C. and Frioud, M. and Small, D. and Meier, E.},
  title = {Adaptive Pulse Compression for Range Focusing in SAR Imagery},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2017},
  volume = {55},
  number = {4},
  pages = {2262-2275},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85009840453&doi=10.1109%2fTGRS.2016.2641041&partnerID=40&md5=59378c56c2924c5d1d45db2d8a4deb6f},
  doi = {10.1109/TGRS.2016.2641041}
}
Moro M, Saroli M, Stramondo S, Bignami C, Albano M, Falcucci E, Gori S, Doglioni C, Polcari M, Tallini M, Macerola L, Novali F, Costantini M, Malvarosa F and Wegmüller U (2017), "New insights into earthquake precursors from InSAR", Scientific Reports. Vol. 7(1) Nature Publishing Group.
Abstract: We measured ground displacements before and after the 2009 L'Aquila earthquake using multi-temporal InSAR techniques to identify seismic precursor signals. We estimated the ground deformation and its temporal evolution by exploiting a large dataset of SAR imagery that spans seventy-two months before and sixteen months after the mainshock. These satellite data show that up to 15 mm of subsidence occurred beginning three years before the mainshock. This deformation occurred within two Quaternary basins that are located close to the epicentral area and are filled with sediments hosting multi-layer aquifers. After the earthquake, the same basins experienced up to 12 mm of uplift over approximately nine months. Before the earthquake, the rocks at depth dilated, and fractures opened. Consequently, fluids migrated into the dilated volume, thereby lowering the groundwater table in the carbonate hydrostructures and in the hydrologically connected multi-layer aquifers within the basins. This process caused the elastic consolidation of the fine-grained sediments within the basins, resulting in the detected subsidence. After the earthquake, the fractures closed, and the deep fluids were squeezed out. The pre-seismic ground displacements were then recovered because the groundwater table rose and natural recharge of the shallow multi-layer aquifers occurred, which caused the observed uplift. 2017 The Author(s).
BibTeX:
@article{Moro2017,
  author = {Moro, M. and Saroli, M. and Stramondo, S. and Bignami, C. and Albano, M. and Falcucci, E. and Gori, S. and Doglioni, C. and Polcari, M. and Tallini, M. and Macerola, L. and Novali, F. and Costantini, M. and Malvarosa, F. and Wegmüller, U.},
  title = {New insights into earthquake precursors from InSAR},
  journal = {Scientific Reports},
  publisher = {Nature Publishing Group},
  year = {2017},
  volume = {7},
  number = {1},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029649721&doi=10.1038%2fs41598-017-12058-3&partnerID=40&md5=07801712c8bc2db4f975e46fb523b2f9},
  doi = {10.1038/s41598-017-12058-3}
}
Naderpour R, Schwank M and Matzler C (2017), "Davos-laret remote sensing field laboratory: 2016/2017 Winter season L-band measurements data-processing and analysis", Remote Sensing. Vol. 9(11) MDPI AG.
Abstract: The L-band radiometry data and in-situ ground and snow measurements performed during the 2016/2017 winter campaign at the Davos-Laret remote sensing field laboratory are presented and discussed. An improved version of the procedure for the computation of L-band brightness temperatures from ELBARA radiometer raw data is introduced. This procedure includes a thorough explanation of the calibration and filtering including a refined radio frequency interference (RFI) mitigation approach. This new mitigation approach not only performs better than conventional "normality" tests (kurtosis and skewness) but also allows for the quantification of measurement uncertainty introduced by non-thermal noise contributions. The brightness temperatures of natural snow covered areas and areas with a reflector beneath the snow are simulated for varying amounts of snow liquid water content distributed across the snow profile. Both measured and simulated brightness temperatures emanating from natural snow covered areas and areas with a reflector beneath the snow reveal noticeable sensitivity with respect to snow liquid water. This indicates the possibility of estimating snow liquid water using L-band radiometry. It is also shown that distinct daily increases in brightness temperatures measured over the areas with the reflector placed on the ground indicate the onset of the snow melting season, also known as "early-spring snow". 2017 by the authors.
BibTeX:
@article{Naderpour2017,
  author = {Naderpour, R. and Schwank, M. and Matzler, C.},
  title = {Davos-laret remote sensing field laboratory: 2016/2017 Winter season L-band measurements data-processing and analysis},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2017},
  volume = {9},
  number = {11},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85034768764&doi=10.3390%2frs9111185&partnerID=40&md5=e4eb313a2662e85461cc3d4776f0a19d},
  doi = {10.3390/rs9111185}
}
Naderpour R, Schwank M, Matzler C, Lemmetyinen J and Steffen K (2017), "Snow Density and Ground Permittivity Retrieved From L-Band Radiometry: A Retrieval Sensitivity Analysis", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 10(7), pp. 3148-3161. Institute of Electrical and Electronics Engineers.
Abstract: Aboveground dry snow influences the L-band ground-snow system emissivity as the result of impedance matching and refraction effects. Against this background, a retrieval scheme was proposed to estimate dry-snow density and ground permittivity from passive L-band measurements. In this study, the sensitivity of the recently proposed retrieval scheme with respect to surface roughness and snowpack density profile heterogeneities is investigated using synthetic brightness temperatures TBp. While the original retrieval algorithm proposed to use TBp(θ) at observation angles θ and both polarizations p = "H" and p = "V", the present analysis involves three polarization retrieval modes: "HV", "H", and "V" to identify the most robust one. The analyses based on synthetic TBp(θ) suggest the use of exclusively vertical polarization ("V" retrieval mode) in case of low "instrumental noise" of σTB < 0.5 K, as it yields most accurate results in the presence of heterogeneities in profiles and imperfect parametrization of ground surface roughness. The applied retrieval scheme still yields accurate results even in the presence of "instrumental noise" (σTB ≥ 0.5 K) in retrieval mode "HV". Furthermore, it is shown that ground-permittivity retrievals are less affected than snow density retrievals by ground roughness variations or heterogeneities in snow density profiles. Altogether, our sensitivity investigations indicate the robustness of the retrieval scheme applied thereto with respect to snow density profile heterogeneities, which is expedient for its use with spaceborne radiometry data from, for example, "Soil Moisture and Ocean Salinity" or "Soil Moisture Active Passive" satellites.
BibTeX:
@article{Naderpour20173148,
  author = {Naderpour, R. and Schwank, M. and Matzler, C. and Lemmetyinen, J. and Steffen, K.},
  title = {Snow Density and Ground Permittivity Retrieved From L-Band Radiometry: A Retrieval Sensitivity Analysis},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2017},
  volume = {10},
  number = {7},
  pages = {3148-3161},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85015677887&doi=10.1109%2fJSTARS.2017.2669336&partnerID=40&md5=630bf52b38a258722e0919224d4db133},
  doi = {10.1109/JSTARS.2017.2669336}
}
Paul F, Bolch T, Briggs K, Kaab A, McMillan M, McNabb R, Nagler T, Nuth C, Rastner P, Strozzi T and Wuite J (2017), "Error sources and guidelines for quality assessment of glacier area, elevation change, and velocity products derived from satellite data in the Glaciers_cci project", Remote Sensing of Environment. Vol. 203, pp. 256-275. Elsevier Inc..
Abstract: Satellite data provide a large range of information on glacier dynamics and changes. Results are often reported, provided and used without consideration of measurement accuracy (difference to a true value) and precision (variability of independent assessments). Whereas accuracy might be difficult to determine due to the limited availability of appropriate reference data and the complimentary nature of satellite measurements, precision can be obtained from a large range of measures with a variable effort for determination. This study provides a systematic overview on the factors influencing accuracy and precision of glacier area, elevation change (from altimetry and DEM differencing), and velocity products derived from satellite data, along with measures for calculating them. A tiered list of recommendations is provided (sorted for effort from Level 0 to 3) as a guide for analysts to apply what is possible given the datasets used and available to them. The more simple measures to describe product quality (Levels 0 and 1) can often easily be applied and should thus always be reported. Medium efforts (Level 2) require additional work but provide a more realistic assessment of product precision. Real accuracy assessment (Level 3) requires independent and coincidently acquired reference data with high accuracy. However, these are rarely available and their transformation into an unbiased source of information is challenging. This overview is based on the experiences and lessons learned in the ESA project Glaciers_cci rather than a review of the literature. 2017
BibTeX:
@article{Paul2017256,
  author = {Paul, F. and Bolch, T. and Briggs, K. and Kaab, A. and McMillan, M. and McNabb, R. and Nagler, T. and Nuth, C. and Rastner, P. and Strozzi, T. and Wuite, J.},
  title = {Error sources and guidelines for quality assessment of glacier area, elevation change, and velocity products derived from satellite data in the Glaciers_cci project},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2017},
  volume = {203},
  pages = {256-275},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029384858&doi=10.1016%2fj.rse.2017.08.038&partnerID=40&md5=f75d1041f062c917c43775f3f453914e},
  doi = {10.1016/j.rse.2017.08.038}
}
Paul F, Strozzi T, Schellenberger T and Kaab A (2017), "The 2015 surge of hispar glacier in the karakoram", Remote Sensing. Vol. 9(9) MDPI AG.
Abstract: The Karakoram mountain range iswell known for its numerous surge-type glaciers of which several have recently surged or are still doing so. Analysis of multi-temporal satellite images and digital elevation models have revealed impressive details about the related changes (e.g., in glacier length, surface elevation and flow velocities) and considerably expanded the database of known surge-type glaciers. One glacier that has so far only been reported as impacted by surging tributaries, rather than surging itself, is the 50 km long main trunk of Hispar Glacier in the Hunza catchment. We here present the evolution of flow velocities and surface features from its 2015/16 surge as revealed from a dense time series of SAR and optical images along with an analysis of historic satellite images. We observed maximum flow velocities of up to 14 m d-1 (5 km a-1) in spring 2015, sudden drops in summer velocities, a second increase in winter 2015/16 and a total advance of the surge front of about 6 km. During a few months the surge front velocity was much higher (about 90 m d-1) than the maximum flow velocity. We assume that one of its northern tributary glaciers, Yutmaru, initiated the surge at the end of summer 2014 and that the variability in flow velocities was driven by changes in the basal hydrologic regime (Alaska-type surge). We further provide evidence that Hispar Glacier has surged before (around 1960) over a distance of about 10 km so that it can also be regarded as a surge-type glacier. 2017 by the authors. Licensee MDPI, Basel, Switzerland.
BibTeX:
@article{Paul2017,
  author = {Paul, F. and Strozzi, T. and Schellenberger, T. and Kaab, A.},
  title = {The 2015 surge of hispar glacier in the karakoram},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2017},
  volume = {9},
  number = {9},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029385560&doi=10.3390%2frs9090888&partnerID=40&md5=bc462034b0f58067c622c6bdc432dbf5},
  doi = {10.3390/rs9090888}
}
Rastner P, Strozzi T and Paul F (2017), "Fusion of multi-source satellite data and DEMs to create a new glacier inventory for Novaya Zemlya", Remote Sensing. Vol. 9(11) MDPI AG.
Abstract: Monitoring glacier changes in remote Arctic regions are strongly facilitated by satellite data. This is especially true for the Russian Arctic where recently increased optical and SAR satellite imagery (Landsat 8 OLI, Sentinel 1/2) and digital elevation models (TanDEM-X, ArcticDEM) are becoming available. These datasets offer new possibilities to create high-quality glacier inventories. Here, we present a new glacier inventory derived from a fusion of multi-source satellite data for Novaya Zemlya in the Russian Arctic. We mainly used Landsat 8 OLI data to automatically map glaciers with the band ratio method. Missing debris-covered glacier parts and misclassified lakes were manually corrected. Whereas perennial snow fields were a major obstacle in glacier identification, seasonal snow was identified and removed using Landsat 5 TM scenes from the year 1998. Drainage basins were derived semi-automatically using the ArcticDEM (gap-filled by the ASTER GDEM V2) and manually corrected using fringes from ALOS PALSAR. The new glacier inventory gives a glacierized area of 22,379 ± 246.2 km2 with 1474 glacier entities > 0.05 km2. The region is dominated by large glaciers, as 909 glaciers < 0.5 km2 (62% by number) cover only 156 ± 1.7 km2 or 0.7% of the area, whereas 49 glaciers > 100 km2 (3.3% by number) cover 18,724 ± 205.9 km2 or 84%. In total, 41 glaciers are marine terminating covering an area of 16,063.7 ± 118.8 km2. The mean elevation is 596 m for all glaciers in the study region (528 m in the northern part, 641 in the southern part). South-east (north-west) facing glaciers cover > 35% (20%) of the area. For the smaller glaciers in the southern part we calculated an area loss of 3.4% (-52.5 ± 3.1 km2) from 2001 to 2016. 2017 by the authors.
BibTeX:
@article{Rastner2017,
  author = {Rastner, P. and Strozzi, T. and Paul, F.},
  title = {Fusion of multi-source satellite data and DEMs to create a new glacier inventory for Novaya Zemlya},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2017},
  volume = {9},
  number = {11},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029382655&doi=10.3390%2frs9111122&partnerID=40&md5=272fd6c85ee25f166655ecdebcb63191},
  doi = {10.3390/rs9111122}
}
Siddique M, Hajnsek I and Frey O (2017), "A case study on the use of differential SAR tomography for measuring deformation in layover areas in rugged alpine terrain", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2017-July, pp. 5850-5853. Institute of Electrical and Electronics Engineers Inc..
Abstract: Differential SAR tomography is a means to resolve layover of temporally coherent scatterers while simultaneously estimating their elevation and average deformation. In alpine regions, drastic height variations result in frequent layovers which are rejected during typical persistent scatterer interferometric (PSI) analyses. In this paper, we explore the potential of tomographic techniques to improve deformation sampling in an alpine region of interest relative to a PSI-based deformation assessment. The mitigation of the atmospheric phase contributions, as required for both tomography and PSI, is often more involved in alpine regions due to strong spatial variations of the local atmospheric conditions and propagation paths through the troposphere. We assume a linear multivariate dependence of atmospheric phase on the spatial location and height of the scatterers, estimate it using universal/regression kriging and subsequently incorporate it within the tomographic focusing. Experiments are performed on an interferometric stack comprising of 32 Cosmo-SkyMed strimap images acquired in the summers of 2008-2013 over Mattervalley in the Swiss Alps.
BibTeX:
@conference{Siddique20175850,
  author = {Siddique, M.A. and Hajnsek, I. and Frey, O.},
  title = {A case study on the use of differential SAR tomography for measuring deformation in layover areas in rugged alpine terrain},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2017},
  volume = {2017-July},
  pages = {5850-5853},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041819260&doi=10.1109%2fIGARSS.2017.8128339&partnerID=40&md5=0dac0f3cc4ac54157eb2bff17de5e2d1},
  doi = {10.1109/IGARSS.2017.8128339}
}
Strozzi T, Caduff R, Wegmüller U, Raetzo H and Hauser M (2017), "Widespread surface subsidence measured with satellite SAR interferometry in the Swiss alpine range associated with the construction of the Gotthard Base Tunnel", Remote Sensing of Environment. Vol. 190, pp. 1-12. Elsevier Inc..
Abstract: Drilling deep tunnels in alpine rocks might induce surface settlements of a few centimetres because of groundwater drainage and associated pore pressure reduction. Settlements of this order of magnitude are sufficient to pose a potential threat to the integrity of any large concrete structure such as arch dams located above the tunnel and an accurate survey of surface deformation before, during and after construction is of high importance. We present the spatial and temporal evolution of surface subsidence measured with satellite SAR interferometry associated with the construction of the 57 km long Gotthard Base Tunnel in Switzerland. Significant deformations of 1 to 12 mm/year were detected between 2003 and 2010 with ENVISAT ASAR data above the tunnel on villages and sparsely vegetated alpine slopes where no displacement was recorded between 1992 and 2000 with ERS-1/2 SAR data. Our results, available also for sectors where there is no information from any other surveying technique, are important not only to assess the hazard posed on any large concrete structure but also for the development and calibration of numerical models - to be employed to simulate the expected surface deformation before and during the construction works - and to study the effect of groundwater drainage on the dynamic of large deep-seated landslides. 2016 Elsevier Inc.
BibTeX:
@article{Strozzi20171,
  author = {Strozzi, T. and Caduff, R. and Wegmüller, U. and Raetzo, H. and Hauser, M.},
  title = {Widespread surface subsidence measured with satellite SAR interferometry in the Swiss alpine range associated with the construction of the Gotthard Base Tunnel},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2017},
  volume = {190},
  pages = {1-12},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85006395750&doi=10.1016%2fj.rse.2016.12.007&partnerID=40&md5=c3309a88e0a4986ccff433b13e7aed5f},
  doi = {10.1016/j.rse.2016.12.007}
}
Strozzi T, Kaab A and Schellenberger T (2017), "Frontal destabilization of Stonebreen, Edgeoya, Svalbard", Cryosphere. Vol. 11(1), pp. 553-566. Copernicus GmbH.
Abstract: In consideration of the strong atmospheric warming that has been observed since the 1990s in polar regions there is a need to quantify mass loss of Arctic ice caps and glaciers and their contribution to sea level rise. In polar regions a large part of glacier ablation is through calving of tidewater glaciers driven by ice velocities and their variations. The Svalbard region is characterized by glaciers with rapid dynamic fluctuations of different types, including irreversible adjustments of calving fronts to a changing mass balance and reversible, surge-type activities. For large areas, however, we do not have much past and current information on glacier dynamic fluctuations. Recently, through frequent monitoring based on repeat optical and synthetic aperture radar (SAR) satellite data, a number of zones of velocity increases have been observed at formerly slow-flowing calving fronts on Svalbard. Here we present the dynamic evolution of the southern lobe of Stonebreen on Edgeøya. We observe a slowly steady retreat of the glacier front from 1971 until 2011, followed by a strong increase in ice surface velocity along with a decrease of volume and frontal extension since 2012. The considerable losses in ice thickness could have made the tide-water calving glacier, which is grounded below sea level some 6 km inland from the 2014 front, more sensitive to surface meltwater reaching its bed and/or warm ocean water increasing frontal ablation with subsequent strong multi-annual ice-flow acceleration. 2017 Author(s).
BibTeX:
@article{Strozzi2017553,
  author = {Strozzi, T. and Kaab, A. and Schellenberger, T.},
  title = {Frontal destabilization of Stonebreen, Edgeoya, Svalbard},
  journal = {Cryosphere},
  publisher = {Copernicus GmbH},
  year = {2017},
  volume = {11},
  number = {1},
  pages = {553-566},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013200625&doi=10.5194%2ftc-11-553-2017&partnerID=40&md5=3c4a835a7bf5cb56db8705076aa93b44},
  doi = {10.5194/tc-11-553-2017}
}
Strozzi T, Paul F, Wiesmann A, Schellenberger T and Kaab A (2017), "Circum-arctic changes in the flow of glaciers and ice caps from satellite SAR data between the 1990s and 2017", Remote Sensing. Vol. 9(9) MDPI AG.
Abstract: We computed circum-Arctic surface velocity maps of glaciers and ice caps over the Canadian Arctic, Svalbard and the Russian Arctic for at least two times between the 1990s and 2017 using satellite SAR data. Our analyses are mainly performed with offset-tracking of ALOS-1 PALSAR-1 (2007-2011) and Sentinel-1 (2015-2017) data. In certain cases JERS-1 SAR (1994-1998), TerraSAR-X (2008-2012), Radarsat-2 (2009-2016) and ALOS-2 PALSAR-2 (2015-2016) data were used to fill-in spatial or temporal gaps. Validation of the latest Sentinel-1 results was accomplished by means of SAR data at higher spatial resolution (Radarsat-2Wide Ultra Fine) and ground-based measurements. In general, we observe a deceleration of flow velocities for the major tidewater glaciers in the Canadian Arctic and an increase in frontal velocity along with a retreat of frontal positions over Svalbard and the Russian Arctic. However, all regions have strong accelerations for selected glaciers. The latter developments can be well traced based on the very high temporal sampling of Sentinel-1 acquisitions since 2015, revealing new insights in glacier dynamics. For example, surges on Spitsbergen (e.g., Negribreen, Nathorsbreen, Penckbreen and Strongbreen) have a different characteristic and timing than those over Eastern Austfonna and Edgeoya (e.g., Basin 3, Basin 2 and Stonebreen). Events similar to those ongoing on Eastern Austofonna were also observed over the Vavilov Ice Cap on Severnaya Zemlya and possibly Simony Glacier on Franz-Josef Land. Collectively, there seems to be a recently increasing number of glaciers with frontal destabilization over Eastern Svalbard and the Russian Arctic compared to the 1990s. 2017 by the authors. Licensee MDPI, Basel, Switzerland.
BibTeX:
@article{Strozzi2017,
  author = {Strozzi, T. and Paul, F. and Wiesmann, A. and Schellenberger, T. and Kaab, A.},
  title = {Circum-arctic changes in the flow of glaciers and ice caps from satellite SAR data between the 1990s and 2017},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2017},
  volume = {9},
  number = {9},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029366896&doi=10.3390%2frs9090947&partnerID=40&md5=2c9846a253dff7f157287a39eae70b21},
  doi = {10.3390/rs9090947}
}
Werner C, Baker B, Cassotto R, Magnard C, Wegmüller U and Fahnestock M (2017), "Measurement of fault creep using multi-aspect terrestrial radar interferometry at Coyote Dam", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2017-July, pp. 949-952. Institute of Electrical and Electronics Engineers Inc..
Abstract: The Calaveras fault passes directly through Coyote Dam located near Gilroy, California. The earthen structure of the dam was constructed to withstand the expected deformation due to fault creep at a rate of 10 to 15 mm/year. As part of a possible dam retrofit, the Santa Clara Valley Water District initiated a series of measurements using a Ku-Band terrestrial interferometer to accurately localize the fault trace through the dam. Measurements over the period 12-May 2016 to 18-Nov-2016 were acquired from 4 different positions situated around the down-stream face. Time series of measurements from each position were obtained after performing corrections for variable tropospheric phase delay. These measurements were combined using least-squares estimation to generate three-dimensional maps delineating both stable and rapidly deforming regions.
BibTeX:
@conference{Werner2017949,
  author = {Werner, C. and Baker, B. and Cassotto, R. and Magnard, C. and Wegmüller, U. and Fahnestock, M.},
  title = {Measurement of fault creep using multi-aspect terrestrial radar interferometry at Coyote Dam},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2017},
  volume = {2017-July},
  pages = {949-952},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041807935&doi=10.1109%2fIGARSS.2017.8127110&partnerID=40&md5=1ef364bb08405d170f725399a446bd43},
  doi = {10.1109/IGARSS.2017.8127110}
}
Wigneron J-P, Jackson T, O'Neill P, De Lannoy G, de Rosnay P, Walker J, Ferrazzoli P, Mironov V, Bircher S, Grant J, Kurum M, Schwank M, Munoz-Sabater J, Das N, Royer A, Al-Yaari A, Al Bitar A, Fernandez-Moran R, Lawrence H, Mialon A, Parrens M, Richaume P, Delwart S and Kerr Y (2017), "Modelling the passive microwave signature from land surfaces: A review of recent results and application to the L-band SMOS & SMAP soil moisture retrieval algorithms", Remote Sensing of Environment. Vol. 192, pp. 238-262. Elsevier Inc..
Abstract: Two passive microwave missions are currently operating at L-band to monitor surface soil moisture (SM) over continental surfaces. The SMOS sensor, based on an innovative interferometric technology enabling multi-angular signatures of surfaces to be measured, was launched in November 2009. The SMAP sensor, based on a large mesh reflector 6 m in diameter providing a conically scanning antenna beam with a surface incidence angle of 40°, was launched in January of 2015. Over the last decade, an intense scientific activity has focused on the development of the SM retrieval algorithms for the two missions. This activity has relied on many field (mainly tower-based) and airborne experimental campaigns, and since 2010–2011, on the SMOS and Aquarius space-borne L-band observations. It has relied too on the use of numerical, physical and semi-empirical models to simulate the microwave brightness temperature of natural scenes for a variety of scenarios in terms of system configurations (polarization, incidence angle) and soil, vegetation and climate conditions. Key components of the inversion models have been evaluated and new parameterizations of the effects of the surface temperature, soil roughness, soil permittivity, and vegetation extinction and scattering have been developed. Among others, global maps of select radiative transfer parameters have been estimated very recently. Based on this intense activity, improvements of the SMOS and SMAP SM inversion algorithms have been proposed. Some of them have already been implemented, whereas others are currently being investigated. In this paper, we present a review of the significant progress which has been made over the last decade in this field of research with a focus on L-band, and a discussion on possible applications to the SMOS and SMAP soil moisture retrieval approaches. 2017 Elsevier Inc.
BibTeX:
@article{Wigneron2017238,
  author = {Wigneron, J.-P. and Jackson, T.J. and O'Neill, P. and De Lannoy, G. and de Rosnay, P. and Walker, J.P. and Ferrazzoli, P. and Mironov, V. and Bircher, S. and Grant, J.P. and Kurum, M. and Schwank, M. and Munoz-Sabater, J. and Das, N. and Royer, A. and Al-Yaari, A. and Al Bitar, A. and Fernandez-Moran, R. and Lawrence, H. and Mialon, A. and Parrens, M. and Richaume, P. and Delwart, S. and Kerr, Y.},
  title = {Modelling the passive microwave signature from land surfaces: A review of recent results and application to the L-band SMOS & SMAP soil moisture retrieval algorithms},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2017},
  volume = {192},
  pages = {238-262},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014435143&doi=10.1016%2fj.rse.2017.01.024&partnerID=40&md5=862bf5216223b766912339d6f77db424},
  doi = {10.1016/j.rse.2017.01.024}
}
Zheng D, Wang X, Van Der Velde R, Zeng Y, Wen J, Wang Z, Schwank M, Ferrazzoli P and Su Z (2017), "L-band microwave emission of soil freeze-thaw process in the third pole environment", IEEE Transactions on Geoscience and Remote Sensing. Vol. 55(9), pp. 5324-5338. Institute of Electrical and Electronics Engineers Inc..
Abstract: Soil freeze-thaw transition monitoring is essential for quantifying climate change and hydrologic dynamics over cold regions, for instance, the Third Pole. We investigate the L-band (1.4 GHz) microwave emission characteristics of soil freeze-thaw cycle via analysis of tower-based brightness temperature (T-B) measurements in combination with simulations performed by a model of soil microwave emission considering vertical variations of permittivity and temperature. Vegetation effects are modeled using Tor Vergata discrete emission model. The ELBARA-III radiometer is installed in a seasonally frozen Tibetan grassland site to measure diurnal cycles of L-band T-B every 30 min, and supporting micrometeorological as well as volumetric soil moisture (θ) and temperature profile measurements are also conducted. Soil freezing/thawing phases are clearly distinguished by using T-B measurements at two polarizations, and further analyses show that: 1) the four-phase dielectric mixing model is appropriate for estimating permittivity of frozen soil; 2) the soil effective temperature is well comparable with the temperature at 25 cm depth when soil liquid water is freezing, while it is closer to the one measured at 5 cm when soil ice is thawing; and 3) the impact on T-B caused by diurnal changes of ground permittivity is dominating the impact of changing ground temperature. Moreover, the simulations performed with the integrated Tor Vergata emission model and Noah land surface model indicate that the T-B signatures of diurnal soil freeze-thaw cycle is more sensitive to the liquid water content of the soil surface layer than the in situ measurements taken at 5 cm depth.
BibTeX:
@article{Zheng20175324,
  author = {Zheng, D. and Wang, X. and Van Der Velde, R. and Zeng, Y. and Wen, J. and Wang, Z. and Schwank, M. and Ferrazzoli, P. and Su, Z.},
  title = {L-band microwave emission of soil freeze-thaw process in the third pole environment},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2017},
  volume = {55},
  number = {9},
  pages = {5324-5338},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020422898&doi=10.1109%2fTGRS.2017.2705248&partnerID=40&md5=e01ddc01e38a4314b7294baf56980ade},
  doi = {10.1109/TGRS.2017.2705248}
}
Baffelli S, Frey O, Werner C and Hajnsek I (2016), "System characterization and polarimetric calibration of theku-band advanced polarimetric interferometer", In Proc. European Conf. Synthetic Aperture Radar.
Abstract: This paper addresses the system characterization and the polarimetric calibration of the Ku-Band Advanced Polarimetric Interferometer (KAPRI). KAPRI is an FMCW ground-based real aperture radar system that uses slotted waveguide antennas. The rotation of the antennas introduces undesired phase ramps in azimuth. We present a geometrical model to account for this phase, and propose a method to correct it. Experimental data with a set of trihedral corner reflectors (TCR) in the scene was acquired with the system. A linear phase variation of 30 degrees was observed over the TCR which was geometrically modeled and successfully corrected. VDE VERLAG GMBH · Berlin · Offenbach.
BibTeX:
@conference{Baffelli2016,
  author = {Baffelli, S. and Frey, O. and Werner, C. and Hajnsek, I.},
  title = {System characterization and polarimetric calibration of theku-band advanced polarimetric interferometer},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  year = {2016},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85001043425&partnerID=40&md5=53410bcfa53436e51b7797e9059b133d}
}
Bartsch A, Grosse G, Kaab A, Westermann S, Strozzi T, Wiesmann A, Duguay C, Seifert F, Obu J and Goler R (2016), "GlobPermafrost - How space-based earth observation supports understanding of permafrost", In European Space Agency, (Special Publication) ESA SP. Vol. SP-740 European Space Agency.
Abstract: The GlobPermafrost project develops, validates and implements Earth Observation (EO) products to support research communities and international organisations in their work on better understanding permafrost characteristics and dynamics. To facilitate usability of these products by the target audience, user requirements with respect to the planned products have been requested and collected through an online community survey as well as by interview. This paper provides an overview on the planned thematic EO products as well as results of the user requirement survey.
BibTeX:
@conference{Bartsch2016,
  author = {Bartsch, A. and Grosse, G. and Kaab, A. and Westermann, S. and Strozzi, T. and Wiesmann, A. and Duguay, C. and Seifert, F.M. and Obu, J. and Goler, R.},
  editor = {Ouwehand L.},
  title = {GlobPermafrost - How space-based earth observation supports understanding of permafrost},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  publisher = {European Space Agency},
  year = {2016},
  volume = {SP-740},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988451789&partnerID=40&md5=fa6e598fa0ef5ccb81f7e6d7adfaf8e8}
}
Cartus O and Santoro M (2016), "Multi-scale mapping of forest growing stock volume using Envisat ASAR, Alos Palsar, Landsat, and icesat glas", In European Space Agency, (Special Publication) ESA SP. Vol. SP-740 European Space Agency.
Abstract: Multi-scale approaches for mapping aboveground biomass globally are evaluated that exploit the multitemporal archive of low-resolution (1 km) ENVISAT ASAR C-band observations and ca. 30 m resolution ALOS PALSAR L-band and Landsat mosaics. The BIOMASAR algorithm, which was initially developed for ENVISAT ASAR C-band data and boreal forest [1], is deployed to map growing stock volume, a proxy for aboveground biomass, globally at 1 km resolution. We explore different options for improving ASAR based maps using high resolution data. Two approaches are pursued: 1) the BIOMASAR algorithm adopted for Lband, 2) a simple re-scaling of ASAR derived estimates of growing stock volume from 1 km pixel posting to 30 m using PALSAR and Landsat data [2]. The initial results for different forest ecosystems suggest that both approaches allow for improved estimates, albeit with the expected limitations in high biomass forests.
BibTeX:
@conference{Cartus2016,
  author = {Cartus, O. and Santoro, M.},
  editor = {Ouwehand L.},
  title = {Multi-scale mapping of forest growing stock volume using Envisat ASAR, Alos Palsar, Landsat, and icesat glas},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  publisher = {European Space Agency},
  year = {2016},
  volume = {SP-740},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988529657&partnerID=40&md5=810c108c038fc16ee38bac3f0da67203}
}
Casu F and Manconi A (2016), "Four-dimensional surface evolution of active rifting from spaceborne SAR data", Geosphere. Vol. 12(3), pp. 697-705. Geological Society of America.
Abstract: We present a case study for detecting the four-dimensional (4-D) displacement of rift zones affected by large-magnitude deformation, by using spaceborne synthetic aperture radar (SAR) data. Our method relies on the combination of displacement time series generated from pixel offset estimates on the amplitude information of multitemporal SAR images acquired from different orbit passes and with different looking geometries. We successfully applied the technique on advanced SAR (ASAR) Envisat data acquired from ascending and descending orbits over the Afar rift zone (Ethiopia) during the 2006-2010 time span. Our results demonstrate the effectiveness of the proposed technique to retrieve the full 4-D (i.e., north, east, up, and time) displacement field associated with active rifting affected by very large-magnitude deformation. 2016 The Authors.
BibTeX:
@article{Casu2016697,
  author = {Casu, F. and Manconi, A.},
  title = {Four-dimensional surface evolution of active rifting from spaceborne SAR data},
  journal = {Geosphere},
  publisher = {Geological Society of America},
  year = {2016},
  volume = {12},
  number = {3},
  pages = {697-705},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84980377996&doi=10.1130%2fGES01225.1&partnerID=40&md5=a649acb163efff18890c702170313534},
  doi = {10.1130/GES01225.1}
}
Cignetti M, Manconi A, Manunta M, Giordan D, De Luca C, Allasia P and Ardizzone F (2016), "Taking advantage of the ESA G-POD service to study ground deformation processes in high mountain areas: A Valle d'Aosta case study, Northern Italy", Remote Sensing. Vol. 8(10) MDPI AG.
Abstract: This paper presents a methodology taking advantage of the GPOD-SBAS service to study the surface deformation information over high mountain regions. Indeed, the application of the advanced DInSAR over the arduous regions represents a demanding task. We implemented an iterative selection procedure of the most suitable SAR images, aimed to preserve the largest number of SAR scenes, and the fine-tuning of several advanced configuration parameters. This method is aimed at minimizing the temporal decorrelation effects, principally due to snow cover, and maximizing the number of coherent targets and their spatial distribution. The methodology is applied to the Valle d'Aosta (VDA) region, Northern Italy, an alpine area characterized by high altitudes, complex morphology, and susceptibility to different mass wasting phenomena. The approach using GPOD-SBAS allows for the obtainment of mean deformation velocity maps and displacement time series relative to the time period from 1992 to 2000, relative to ESR-1/2, and from 2002 to 2010 for ASAR-Envisat. Our results demonstrate how the DInSAR application can obtain reliable information of ground displacement over time in these regions, and may represent a suitable instrument for natural hazards assessment. 2016 by the authors.
BibTeX:
@article{Cignetti2016,
  author = {Cignetti, M. and Manconi, A. and Manunta, M. and Giordan, D. and De Luca, C. and Allasia, P. and Ardizzone, F.},
  title = {Taking advantage of the ESA G-POD service to study ground deformation processes in high mountain areas: A Valle d'Aosta case study, Northern Italy},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2016},
  volume = {8},
  number = {10},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84992521865&doi=10.3390%2frs8100852&partnerID=40&md5=f6400d8dd3d288d460848661930e5407},
  doi = {10.3390/rs8100852}
}
De Santis F, Coviello V, Manconi A, Picozzi M and Godio A (2016), "Characterization of mass movements in the Italian Alps using regional seismic networks", In Landslides and Engineered Slopes. Experience, Theory and Practice. Vol. 2, pp. 771-780. Taylor and Francis Inc..
Abstract: In order to evaluate the exploitation of broad-band seismic networks for landslide characterization, we selected a number of well known mass movements occurred in the Italian Alps, characterized by volumes ranging between 25.000 and 34.000.000 cubic meters and different failure dynamics. We analyzed the related seismic signals recorded by seismic stations located, on average, 50 km away from the sources, focusing the study on the 1-30 Hz frequency band. The time frequency domain analysis of data allowed identifying some common signal characteristics, including emergent onsets on all channels, slowly decaying tails and a triangular spectrogram shape. Moreover, the time series of seismic record allowed identifying the different sub-events in which it is possible to divide a landslide, giving a first qualitative characterization of these phenomena from seismic records. In this work, the selected events are described and the associated seismograms are presented and analyzed together with a first discussion of their spectral characteristics. 2016 Associazione Geotecnica Italiana, Rome, Italy.
BibTeX:
@conference{DeSantis2016771,
  author = {De Santis, F. and Coviello, V. and Manconi, A. and Picozzi, M. and Godio, A.},
  title = {Characterization of mass movements in the Italian Alps using regional seismic networks},
  booktitle = {Landslides and Engineered Slopes. Experience, Theory and Practice},
  publisher = {Taylor and Francis Inc.},
  year = {2016},
  volume = {2},
  pages = {771-780},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84984813542&partnerID=40&md5=86337d495084bb0e2e109856387bc874}
}
Devanthery N, Luzi G, Stramondo S, Bignami C, Pierdicca N, Wegmüller U, Romaniello V, Anniballe R, Piscini A, Albano M, Moro M and Crosetto M (2016), "The validation activities of the aphorism EC 7FP project, aimed at post seismic damage mapping, through a combined use of EOS and ground data", In European Space Agency, (Special Publication) ESA SP. Vol. SP-740 European Space Agency.
Abstract: The estimate of damage after an earthquake using spaceborne remote sensing data is one of the main application of the change detection methodologies widely discussed in literature. APhoRISM-Advanced PRocedures for volcanIc and Seismic Monitoring is a collaborative European Commission project (FP7-SPACE-2013-1) addressing the development of innovative methods, using space and ground sensors to support the management and mitigation of the seismic and the volcanic risk. In this paper a novel approach aimed at damage assessment based on the use of a priori information derived by different sources in a preparedness phase is described and a preliminary validation is shown.
BibTeX:
@conference{Devanthery2016,
  author = {Devanthery, N. and Luzi, G. and Stramondo, S. and Bignami, C. and Pierdicca, N. and Wegmüller, U. and Romaniello, V. and Anniballe, R. and Piscini, A. and Albano, M. and Moro, M. and Crosetto, M.},
  editor = {Ouwehand L.},
  title = {The validation activities of the aphorism EC 7FP project, aimed at post seismic damage mapping, through a combined use of EOS and ground data},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  publisher = {European Space Agency},
  year = {2016},
  volume = {SP-740},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988520878&partnerID=40&md5=c0586156017fcc26f2d894202b719939}
}
Fransson J, Santoro M, Wallerman J, Persson H, Monteith A, Eriksson L, Nilsson M, Olsson H, Soja M and Ulander L (2016), "Estimation of forest stem volume using ALOS-2 PALSAR-2 satellite images", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2016-November, pp. 5327-5330. Institute of Electrical and Electronics Engineers Inc..
Abstract: A first evaluation of ALOS-2 PALSAR-2 data for forest stem volume estimation has been performed at a coniferous dominated test site in southern Sweden. Both the Fine Beam Dual (FBD) polarization and the Quad-polarimetric mode were investigated. Forest plots with stem volume reaching up to a maximum of about 620 m3 ha-1 (corresponding to 370 tons ha-1) were analyzed by relating backscatter intensity to field data using an exponential model derived from the Water Cloud Model. The estimation accuracy of stem volume at plot level (0.5 ha) was calculated in terms of Root Mean Square Error (RMSE). For the best case investigated an RMSE of 39.8% was obtained using one of the FBD HV-polarized images. The corresponding RMSE for the FBD HH-polarized images was 43.9%. In the Quad-polarimetric mode the lowest RMSE at HV- and HH-polarization was found to be 43.1% and 66.1%, respectively. 2016 IEEE.
BibTeX:
@conference{Fransson20165327,
  author = {Fransson, J.E.S. and Santoro, M. and Wallerman, J. and Persson, H.J. and Monteith, A.R. and Eriksson, L.E.B. and Nilsson, M. and Olsson, H. and Soja, M.J. and Ulander, L.M.H.},
  title = {Estimation of forest stem volume using ALOS-2 PALSAR-2 satellite images},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2016},
  volume = {2016-November},
  pages = {5327-5330},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85007492106&doi=10.1109%2fIGARSS.2016.7730388&partnerID=40&md5=5709da3779005e3bdf1c54c33f354c72},
  doi = {10.1109/IGARSS.2016.7730388}
}
Frey O, Werner C, Caduff R and Wiesmann A (2016), "A time series of tomographic profiles of a snow pack measured with SnowScat at X-/Ku-band", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2016-November, pp. 17-20. Institute of Electrical and Electronics Engineers Inc..
Abstract: The SnowScat device is a ground-based stepped-frequency continuous-wave (SFCW) scatterometer supporting fully-polarimetric measurements within a frequency band from 9.2 to 17.8 GHz. It was originally designed to support the investigation and validation of Snow Water Equivalent (SWE) retrieval algorithms in the context of the development of the deselected COld REgions Hydrology High-resolution Observatory (CoReH20) candidate Earth Explorer 7 mission. Recently, the SnowScat hardware has been enhanced to also provide a tomographic profiling mode which allows to obtain high-resolution 2-D vertical profiles that may provide further insight into the electromagnetic interaction within layered snow packs. In winter 2014/2015, a first test campaign was carried out yielding a successful proof of concept of the enhanced hardware, tomographic measurement, and basic processing concept. In Nov/Dec 2015, the SnowScat device was then installed as a part of the SnowLab experiment at a test site on 1700m altitude close to the Grimsel pass in Switzerland. A comprehensive time series of tomographic profiles of a snow pack was acquired until end of March, 2016. In this paper, we present and discuss first results of this new time series of tomographic profiles including 2-D vertical profiles of backscatter, phase difference between the co-polar channels, and interferometric phase difference.
BibTeX:
@conference{Frey201617,
  author = {Frey, O. and Werner, C.L. and Caduff, R. and Wiesmann, A.},
  title = {A time series of tomographic profiles of a snow pack measured with SnowScat at X-/Ku-band},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2016},
  volume = {2016-November},
  pages = {17-20},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85007480304&doi=10.1109%2fIGARSS.2016.7728995&partnerID=40&md5=169f3e23954390946faf4c117e1a3e3d},
  doi = {10.1109/IGARSS.2016.7728995}
}
Frey O, Werner CL, Caduff R and Wiesmann A (2016), "A time series of SAR tomographic profiles of a snowpack", In Proc. European Conf. Synthetic Aperture Radar.
Abstract: Recently, the SnowScat hardware 'a tower-mounted fully-polarimetric scatterometer at X-/Ku-band' has been enhanced to also provide a tomographic profiling mode which allows to obtain high-resolution 2-D vertical profiles that may provide further insights into the electromagnetic interaction within layered snowpacks. In winter 2014/2015, a first test campaign was carried out yielding a successful proof of concept of the hardware, tomographic measurement, and basic processing concept. As a follow-up, in Nov/Dec 2015, the SnowScat device was installed at a test site on 1700m altitude close to the Grimsel pass in Switzerland. Since then it has been acquiring a time series of tomographic profiles of a snow pack. In this paper, we present and discuss first results of this new time series. VDE VERLAG GMBH · Berlin · Offenbach.
BibTeX:
@conference{Frey2016,
  author = {Frey, O. and Werner, C. L. and Caduff, R. and Wiesmann, A.},
  title = {A time series of SAR tomographic profiles of a snowpack},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  year = {2016},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85000961950&partnerID=40&md5=c5e1403b4f593fd9c7f119d73eeebc80}
}
Hocke K, Guzmán F, Cossu F and Matzler C (2016), "Cloud fraction of liquid water clouds above Switzerland over the last 12 years", Climate. Vol. 4(4) MDPI AG.
Abstract: Cloud fraction (CF) plays a crucial role in the Earth's radiative energy budget and thus in the climate. Reliable long-term measurements of CF are rare. The ground-based TROpospheric WAter RAdiometer (TROWARA) at Bern, Switzerland continuously measures integrated liquid water and infrared brightness temperature with a time resolution of 6-11 s since 2004. The view direction of TROWARA is constant (zenith angle 50°), and all radiometer channels see the same volume of the atmosphere. TROWARA is sensitive to liquid water clouds while the microwave signal of ice clouds is negligible. By means of the measurement data we derived CF of thin liquid water clouds (1); thick supercooled liquid water clouds (2); thick warm liquid water clouds (3) and all liquid water clouds (4). The article presents the time series and seasonal climatologies of these four classes of CF. CF of thick supercooled liquid water clouds is larger than 15% from November to March. A significant negative trend of -0.29% ± 0.10%/yr is found for CF of thin liquid water clouds. No trends are found for the other classes (2, 3, 4) since their strong natural variability impedes a significant trend. However, CF of warm liquid water clouds increased by about +0.51% ± 0.27%/yr from 2004 to 2015. Finally, we performed a Mann-Kendall analysis of seasonal trends which gave several significant trends in the classes 1, 2 and 3. 2016 by the authors.
BibTeX:
@article{Hocke2016,
  author = {Hocke, K. and Guzmán, F.N. and Cossu, F. and Matzler, C.},
  title = {Cloud fraction of liquid water clouds above Switzerland over the last 12 years},
  journal = {Climate},
  publisher = {MDPI AG},
  year = {2016},
  volume = {4},
  number = {4},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029378784&doi=10.3390%2fcli4040048&partnerID=40&md5=67025ab023bba3e02a25d33361b3e2e2},
  doi = {10.3390/cli4040048}
}
Klimes J, Novotny J, Novotná I, de Urries B, Vilímek V, Emmer A, Strozzi T, Kusák M, Rapre A, Hartvich F and Frey H (2016), "Landslides in moraines as triggers of glacial lake outburst floods: example from Palcacocha Lake (Cordillera Blanca, Peru)", Landslides. Vol. 13(6), pp. 1461-1477. Springer Verlag.
Abstract: Studies focusing on moraine deposits which slide into glacial lakes are scarce, even though they can trigger impact waves responsible for generating glacial lake outburst floods. We focused on landslides in lateral moraines as possible triggers. Detailed geomorphological, geophysical, and satellite radar interferometric investigations of the Palcacocha Lake moraine (Cordillera Blanca, Peru) together with laboratory tests on samples from the site provided data for slope stability calculations using GeoSlope software and hydrodynamic impact wave modeling using the Iber code. We identified landslides that could affect Palcacocha Lake and calculated their stability (factor of safety) under specified conditions, including variable water saturation and earthquake effects. Calculations showed that the moraine slopes are close to the threshold value (Fs = 1) for stability and are especially sensitive to water saturation. The height of impact waves triggered by a landslide in 2003 and the potential wave heights from newly identified, possibly active landslides were calculated, based on landslide volume estimates, detailed lake bathymetry, and basin topography. Results show that potential future landslide-triggered waves could have similar properties to the 2003 impact wave. Evidence gathered in this study suggests that glacial lake outburst floods triggered by landslides from moraines, however, would be probably smaller than floods resulting from other types of slope processes (e.g., ice/rock avalanches) if dam breach is not taken into account. This assumption has to be critically evaluated against site-specific conditions at a given lake and any possible environmental factors, such as climate change or earthquake that may mobilize larger volumes of moraine material. 2016, Springer-Verlag Berlin Heidelberg.
BibTeX:
@article{Klimes20161461,
  author = {Klimes, J. and Novotny, J. and Novotná, I. and de Urries, B.J. and Vilímek, V. and Emmer, A. and Strozzi, T. and Kusák, M. and Rapre, A.C. and Hartvich, F. and Frey, H.},
  title = {Landslides in moraines as triggers of glacial lake outburst floods: example from Palcacocha Lake (Cordillera Blanca, Peru)},
  journal = {Landslides},
  publisher = {Springer Verlag},
  year = {2016},
  volume = {13},
  number = {6},
  pages = {1461-1477},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84978906348&doi=10.1007%2fs10346-016-0724-4&partnerID=40&md5=fc0c4fe1213a2e27cbf17eed905bda22},
  doi = {10.1007/s10346-016-0724-4}
}
Kos A, Amann F, Strozzi T, Delaloye R, von Ruette J and Springman S (2016), "Contemporary glacier retreat triggers a rapid landslide response, Great Aletsch Glacier, Switzerland", Geophysical Research Letters. Vol. 43(24), pp. 12,466-12,474. Blackwell Publishing Ltd.
Abstract: The destabilization and catastrophic failure of landslides triggered by retreating glaciers is an expected outcome of global climate change and poses a significant threat to inhabitants of glaciated mountain valleys around the globe. Of particular importance are the formation of landslide-dammed lakes, outburst floods, and related sediment entrainment. Based on field observations and remote sensing of a deep-seated landslide, located at the present-day terminus of the Great Aletsch Glacier, we show that the spatiotemporal response of the landslide to glacier retreat is rapid, occurring within a decade. Our observations uniquely capture the critical period of increase in slope deformations, onset of failure, and show that measured displacements at the crown and toe regions of the landslide demonstrate a feedback mechanism between glacier ice reduction and response of the entire landslide body. These observations shed new light on the geomorphological processes of landslide response in paraglacial environments, which were previously understood to occur over significantly longer time periods. 2016. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Kos201612,
  author = {Kos, A. and Amann, F. and Strozzi, T. and Delaloye, R. and von Ruette, J. and Springman, S.},
  title = {Contemporary glacier retreat triggers a rapid landslide response, Great Aletsch Glacier, Switzerland},
  journal = {Geophysical Research Letters},
  publisher = {Blackwell Publishing Ltd},
  year = {2016},
  volume = {43},
  number = {24},
  pages = {12,466-12,474},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85008474065&doi=10.1002%2f2016GL071708&partnerID=40&md5=34354a42c9b724adb8dc10abf0fec2e2},
  doi = {10.1002/2016GL071708}
}
Lamarche C, Santoro M, Bontemps S, D'Andrimont R, Giustarini L, Brockmann C, Militzer J, Defourny P and Arino O (2016), "A global map of open water bodies and coastlines at 150 M based on synergies between SAR and optical datasets", In European Space Agency, (Special Publication) ESA SP. Vol. SP-740 European Space Agency.
Abstract: In the framework of the European Space Agency Climate Change Initiative, a global map of open water bodies and coastlines at 150 m resolution was derived using synthetic aperture radar and optical datasets including observations from the 2000-2012 period. This map and constitutive inputs were assessed qualitatively and quantitatively against a global reference validation database of 2110 samples, intentionally biased towards areas prone to errors in characterizing water bodies. It yielded more informative quality assessment figures in terms of the relative improvement between products and types of errors. The overall accuracy of the Climate Change Initiative global map of open water bodies at 150 m was found equal to 99% with a F-score of 89% for class water, significantly superior to its constitutive input water bodies datasets. The dataset is openly available at: http://maps.elie.ucl.ac.be/CCI/viewer since 2016.
BibTeX:
@conference{Lamarche2016,
  author = {Lamarche, C. and Santoro, M. and Bontemps, S. and D'Andrimont, R. and Giustarini, L. and Brockmann, C. and Militzer, J. and Defourny, P. and Arino, O.},
  editor = {Ouwehand L.},
  title = {A global map of open water bodies and coastlines at 150 M based on synergies between SAR and optical datasets},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  publisher = {European Space Agency},
  year = {2016},
  volume = {SP-740},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988517298&partnerID=40&md5=aff6d0866f2944547a0c1991c81d59da}
}
Leinss S, Lowe H, Proksch M, Lemmetyinen J, Wiesmann A and Hajnsek I (2016), "Anisotropy of seasonal snow measured by polarimetric phase differences in radar time series", Cryosphere. Vol. 10(4), pp. 1771-1797. Copernicus GmbH.
Abstract: The snow microstructure, i.e., the spatial distribution of ice and pores, generally shows an anisotropy which is driven by gravity and temperature gradients and commonly determined from stereology or computer tomography. This structural anisotropy induces anisotropic mechanical, thermal, and dielectric properties. We present a method based on radio-wave birefringence to determine the depth-averaged, dielectric anisotropy of seasonal snow with radar instruments from space, air, or ground. For known snow depth and density, the birefringence allows determination of the dielectric anisotropy by measuring the copolar phase difference (CPD) between linearly polarized microwaves propagating obliquely through the snowpack. The dielectric and structural anisotropy are linked by Maxwell- Garnett-type mixing formulas. The anisotropy evolution of a natural snowpack in Northern Finland was observed over four winters (2009-2013) with the ground-based radar instrument "SnowScat". The radar measurements indicate horizontal structures for fresh snow and vertical structures in old snow which is confirmed by computer tomographic in situ measurements. The temporal evolution of the CPD agreed in ground-based data compared to space-borne measurements from the satellite TerraSAR-X. The presented dataset provides a valuable basis for the development of new snow metamorphism models which include the anisotropy of the snow microstructure. Author(s) 2016.
BibTeX:
@article{Leinss20161771,
  author = {Leinss, S. and Lowe, H. and Proksch, M. and Lemmetyinen, J. and Wiesmann, A. and Hajnsek, I.},
  title = {Anisotropy of seasonal snow measured by polarimetric phase differences in radar time series},
  journal = {Cryosphere},
  publisher = {Copernicus GmbH},
  year = {2016},
  volume = {10},
  number = {4},
  pages = {1771-1797},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84983449810&doi=10.5194%2ftc-10-1771-2016&partnerID=40&md5=bd4e980a1f8e1feade6647ec0473a98f},
  doi = {10.5194/tc-10-1771-2016}
}
Lemmetyinen J, Kontu A, Pulliainen J, Vehvilainen J, Rautiainen K, Wiesmann A, Matzler C, Werner C, Rott H, Nagler T, Schneebeli M, Proksch M, Schuttemeyer D, Kern M and Davidson M (2016), "Nordic Snow Radar Experiment", Geoscientific Instrumentation, Methods and Data Systems. Vol. 5(2), pp. 403-415. Copernicus GmbH.
Abstract: The objective of the Nordic Snow Radar Experiment (NoSREx) campaign was to provide a continuous time series of active and passive microwave observations of snow cover at a representative location of the Arctic boreal forest area, covering a whole winter season. The activity was a part of Phase A studies for the ESA Earth Explorer 7 candidate mission CoReH2O (Cold Regions Hydrology High-resolution Observatory).

The NoSREx campaign, conducted at the Finnish Meteorological Institute Arctic Research Centre (FMI-ARC) in Sodankyla, Finland, hosted a frequency scanning scatterometer operating at frequencies from X-to Ku-band. The radar observations were complemented by a microwave dual-polarization radiometer system operating from X-to W-bands. In situ measurements consisted of manual snow pit measurements at the main test site as well as extensive automated measurements on snow, ground and meteorological parameters.

This study provides a summary of the obtained data, detailing measurement protocols for each microwave instrument and in situ reference data. A first analysis of the microwave signatures against snow parameters is given, also comparing observed radar backscattering and microwave emission to predictions of an active/passive forward model.

All data, including the raw data observations, are available for research purposes through the European Space Agency and the Finnish Meteorological Institute. A consolidated dataset of observations, comprising the key microwave and in situ observations, is provided through the ESA campaign data portal to enable easy access to the data. 2016 Author(s).
BibTeX:
@article{Lemmetyinen2016403,
  author = {Lemmetyinen, J. and Kontu, A. and Pulliainen, J. and Vehvilainen, J. and Rautiainen, K. and Wiesmann, A. and Matzler, C. and Werner, C. and Rott, H. and Nagler, T. and Schneebeli, M. and Proksch, M. and Schuttemeyer, D. and Kern, M. and Davidson, M.W.J.},
  title = {Nordic Snow Radar Experiment},
  journal = {Geoscientific Instrumentation, Methods and Data Systems},
  publisher = {Copernicus GmbH},
  year = {2016},
  volume = {5},
  number = {2},
  pages = {403-415},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84987608682&doi=10.5194%2fgi-5-403-2016&partnerID=40&md5=3b91c6f1f3bedba1173e1448339be130},
  doi = {10.5194/gi-5-403-2016}
}
Lemmetyinen J, Schwank M, Derksen C, Roy A, Colliander A, Rautiainen K and Pulliainen J (2016), "Retrieval of snow parameters from L-band observations - Application for SMOS and SMAP", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2016-November, pp. 7067-7070. Institute of Electrical and Electronics Engineers Inc..
Abstract: Recent theoretical and experimental studies have indicated the feasibility of passive microwave L-band observations for observing dry snow cover characteristics, namely snow density in the lower approx.. 10 cm of the snowpack. The sensitivity of L-band emission to snow density is based on the dual influence of refraction and impedance matching on observed brightness temperature with changing effective snow permittivity. The permittivity of pure, dry snow, on the other hand, depends largely on snow density. In this study, we expand the theoretical and experimental results of retrieving dry snow density to passive L-band satellite observations. Such retrievals could be appealing in the context of improving satellite based retrievals of e.g. Snow Water Equivalent (SWE) using other sensors. Retrievals are applied to both multi-angular observations from the ESA SMOS mission, and observations of the NASA SMAP radiometer on a single angle of observation. While in theory the multi-angular approach is preferable, improved RFI mitigation in SMAP provides more spatially and temporally more stable retrievals. The applied dual-parameter retrieval scheme produces also an estimate of ground permittivity; experimental data showed dry snow cover to have a clear influence on ground permittivity retrievals, implicating that even dry snow cover is non-negligible also in retrievals of soil moisture from L-band observations. 2016 IEEE.
BibTeX:
@conference{Lemmetyinen20167067,
  author = {Lemmetyinen, J. and Schwank, M. and Derksen, C. and Roy, A. and Colliander, A. and Rautiainen, K. and Pulliainen, J.},
  title = {Retrieval of snow parameters from L-band observations - Application for SMOS and SMAP},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2016},
  volume = {2016-November},
  pages = {7067-7070},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85007463527&doi=10.1109%2fIGARSS.2016.7730843&partnerID=40&md5=b8232472bdd88fa6a46ab862d654fa65},
  doi = {10.1109/IGARSS.2016.7730843}
}
Lemmetyinen J, Schwank M, Rautiainen K, Kontu A, Parkkinen T, Matzler C, Wiesmann A, Wegmüller U, Derksen C, Toose P, Roy A and Pulliainen J (2016), "Snow density and ground permittivity retrieved from L-band radiometry: Application to experimental data", Remote Sensing of Environment. Vol. 180, pp. 377-391. Elsevier Inc..
Abstract: The potential of retrieving the bottom layer snow density and soil permittivity under dry snow cover conditions from L-band passive microwave observations was analyzed using multi-angular brightness temperatures measured at horizontal and vertical polarization over two test sites in northern Finland. The near-continuous time series of L-band brightness temperatures covers a total of six winter seasons, over both dry mineral soil in a forest clearing, and organic soil over a wetland site. Detailed measurements of snow and soil conditions are available from both sites. Complementing a previous theoretical study, we show that dry snow cover influences the observed L-band brightness temperatures as a result of both impedance matching and changes in the refraction angle at the snow-soil interface. Exploiting these effects, we demonstrate the retrieval of the bottom layer snow density and the influence of dry snow cover on simultaneously retrieved soil permittivity - a consideration which is currently not accounted for in Soil Moisture and Ocean Salinity (SMOS) retrievals of soil permittivity in the presence of dry snow. Depending on season, the mean bias error between retrieved and in situ snow density measured in the lower snow layers was between -6 kg m-3 and 15 kg m-3 for the forest clearing site, and between 37 kg m-3 and 90 kg m-3 for the wetland site, demonstrating the feasibility of the retrieval approach at the plot scale. In winter conditions, the ground permittivity retrieved without considering the impact of dry snow on L-band emission was, on average, 35% lower for both test sites, which indicates possible errors in current SMOS ground permittivity retrievals under dry snow conditions. The application of SMOS data to simultaneously retrieve dry snow density and ground permittivity is a complex task due to heterogeneous land cover and snow/soil conditions within SMOS pixels (≈45 km resolution). An approach that considers land cover variations and the spatial variability of snow cover is required to fully determine the feasibility of the methodology to aid e.g. improving estimates snow water equivalent from other sensors, and to take into account effects of dry snow in SMOS-based retrievals of ground permittivities. The results should also be applicable to other L-band sensors in space, such as the recently launched NASA Soil Moisture Active Passive (SMAP) mission. 2016 Elsevier Inc.
BibTeX:
@article{Lemmetyinen2016377,
  author = {Lemmetyinen, J. and Schwank, M. and Rautiainen, K. and Kontu, A. and Parkkinen, T. and Matzler, C. and Wiesmann, A. and Wegmüller, U. and Derksen, C. and Toose, P. and Roy, A. and Pulliainen, J.},
  title = {Snow density and ground permittivity retrieved from L-band radiometry: Application to experimental data},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2016},
  volume = {180},
  pages = {377-391},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957640848&doi=10.1016%2fj.rse.2016.02.002&partnerID=40&md5=8734b18ef54aaabcf49e946b38a664f9},
  doi = {10.1016/j.rse.2016.02.002}
}
Lin C-C, Rommen B, Floury N, Schuttemeyer D, Davidson M, Kern M, Kontu A, Lemmetyinen J, Pulliainen J, Wiesmann A, Werner C, Matzler C, Schneebeli M, Proksch M and Nagler T (2016), "Active Microwave Scattering Signature of Snowpack - Continuous Multiyear SnowScat Observation Experiments", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 9(8), pp. 3849-3869. Institute of Electrical and Electronics Engineers.
Abstract: European Space Agency's SnowScat instrument is a real aperture scatterometer which was developed by Gamma Remote Sensing AG. It operates in a continuous-wave mode, covers a frequency range of 9.15-17.9 GHz in a user-defined frequency-step and has a full polarimetric capability. The measurement campaigns were started first in February 2009 at Weissfluhjoch, in Davos, Switzerland, as an initial test of the instrument over a deep alpine snowpack. Physical characterizations of the snowpack and meteorological measurements were carried out, which formed a detailed in situ dataset. SnowScat was then moved to Sodankyla in Finland in early November 2009, a site of the Finnish Meteorological Institute in Lapland. In addition to the in situ snowpack characterizations and meteorological observations, continuous passive microwave observations were also performed. During the 2012-2013 winter period, a vertical time-domain snow profiling experiment was carried out in addition for resolving the scattering contributions from the snow layers of different physical properties. This paper summarizes the results of the SnowScat observations and initial comparisons against the in situ meteorological and snowpack data. The Sodankyla campaign data evidenced the high variability of the radar backscatter behavior of snowpack from year to year, which indicates its strong dependency on changing snow microstructure. Indeed, the snow microstructure is continuously driven by snow metamorphism, which are further affected by meteorological conditions and their interannual variability. The backscattering property of snowpack in the range X- to Ku-band for all polarizations appeared to be dominated by its microstructural morphology and underlying ground conditions, and to a lesser extent by the snow depth, or its snow-water-equivalent. 2016 IEEE.
BibTeX:
@article{Lin20163849,
  author = {Lin, C.-C. and Rommen, B. and Floury, N. and Schuttemeyer, D. and Davidson, M.W.J. and Kern, M. and Kontu, A. and Lemmetyinen, J. and Pulliainen, J. and Wiesmann, A. and Werner, C.L. and Matzler, C. and Schneebeli, M. and Proksch, M. and Nagler, T.},
  title = {Active Microwave Scattering Signature of Snowpack - Continuous Multiyear SnowScat Observation Experiments},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2016},
  volume = {9},
  number = {8},
  pages = {3849-3869},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84971516920&doi=10.1109%2fJSTARS.2016.2560168&partnerID=40&md5=136501a759db78ffef951c17a3f32059},
  doi = {10.1109/JSTARS.2016.2560168}
}
Magnard C, Frioud M, Small D, Brehm T and Meier E (2016), "Analysis of a Maximum Likelihood Phase Estimation Method for Airborne Multibaseline SAR Interferometry", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 9(3), pp. 1072-1085. Institute of Electrical and Electronics Engineers.
Abstract: It has been shown using simulated data that phase estimation of cross-track multibaseline synthetic aperture radar (SAR) interferometric data was most efficiently achieved through a maximum likelihood (ML) method. In this paper, we apply and assess the ML approach on real data, acquired with an experimental Ka-band multibaseline system. Compared to simulated data, dealing with real data implies that several calibration steps be carried out to ensure that the data fit the model. A processing chain was, therefore, designed, including steps responsible for compensating for imperfections observed in the data, such as beam elevation angle dependent phase errors or phase errors caused by imperfect motion compensation. The performance of the ML phase estimation was evaluated by comparing it to results based on a coarse-to-fine (C2F) algorithm, where information from the shorter baselines was used only to unwrap the phase from the longest available baseline. For this purpose, flat areas with high coherence and homogeneous texture were selected in the acquired data. The results show that with only four looks, the noise level was marginally better with the C2F approach and contained fewer outliers. However, with more looks, the ML method consistently delivered better results: noise variance with the C2F approach was slightly but steadily larger than the variance obtained with ML method. 2015 IEEE.
BibTeX:
@article{Magnard20161072,
  author = {Magnard, C. and Frioud, M. and Small, D. and Brehm, T. and Meier, E.},
  title = {Analysis of a Maximum Likelihood Phase Estimation Method for Airborne Multibaseline SAR Interferometry},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2016},
  volume = {9},
  number = {3},
  pages = {1072-1085},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945398017&doi=10.1109%2fJSTARS.2015.2487685&partnerID=40&md5=b23300a980e6af7335ed16ab81681702},
  doi = {10.1109/JSTARS.2015.2487685}
}
Magnard C, Morsdorf F, Small D, Stilla U, Schaepman M and Meier E (2016), "Single tree identification using airborne multibaseline SAR interferometry data", Remote Sensing of Environment. Vol. 186, pp. 567-580. Elsevier Inc..
Abstract: Remote sensing data allow large scale observation of forested ecosystems. Forest assessment benefits from information about individual trees. Multibaseline SAR interferometry (InSAR) is able to generate dense point clouds of forest canopies, similar to airborne laser scanning (ALS). This type of point cloud was generated using data from the Ka-band MEMPHIS system, acquired over a mainly coniferous forest near Vordemwald in the Swiss Midlands. This point cloud was segmented using an advanced clustering technique to detect individual trees and derive their positions, heights, and crown diameters. To evaluate the InSAR point cloud properties and limitations, it was compared to products derived from ALS and stereo-photogrammetry. All point clouds showed similar geolocation accuracies with 0.2–0.3 m relative shifts. Both InSAR and photogrammetry techniques yielded points predominantly located in the upper levels of the forest vegetation, while ALS provided points from the top of the canopy down to the understory and forest floor. The canopy height models agreed very well with each other, with R2 values between 0.84 and 0.89. The detected trees and their estimated physical and structural parameters were validated by comparing them to reference forestry data. A detection rate of  Â 90% was achieved for larger trees, corresponding to half of the reference trees. The smaller trees were detected with a success rate of  Â 50%. The tree height was slightly underestimated, with a R2 value of 0.63. The estimated crown diameter agreed on an average sense, however with a relatively low R2 value of 0.19. Very high success rates (> 90%) were obtained when matching the trees detected from the InSAR-data with those detected from the ALS- and photogrammetry-data. There, InSAR tree heights were in the mean 1–1.5 m lower, with high R2 values ranging between 0.8 and 0.9. Our results demonstrate the use of millimeter wave SAR interferometry data as an alternative to ALS- and photogrammetry-based data for forest monitoring. 2016 Elsevier Inc.
BibTeX:
@article{Magnard2016567,
  author = {Magnard, C. and Morsdorf, F. and Small, D. and Stilla, U. and Schaepman, M.E. and Meier, E.},
  title = {Single tree identification using airborne multibaseline SAR interferometry data},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2016},
  volume = {186},
  pages = {567-580},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988944502&doi=10.1016%2fj.rse.2016.09.018&partnerID=40&md5=368f18f810ec94277a4f3f06cf5fc958},
  doi = {10.1016/j.rse.2016.09.018}
}
Manconi A and Giordan D (2016), "Landslide failure forecast in near-real-time", Geomatics, Natural Hazards and Risk. Vol. 7(2), pp. 639-648. Taylor and Francis Ltd..
Abstract: We present a new method to achieve failure forecast of landslide phenomena by considering near-real-time monitoring data. Starting from the inverse velocity theory, we jointly analyse landslide surface displacements on different time windows, and apply straightforward statistical methods to obtain confidence intervals on the forecasted time of failure. Our results can be relevant to support the management of early warning systems during landslide emergency conditions, also when the predefined displacement and/or velocity thresholds are exceeded. In addition, our statistical approach for the definition of confidence interval and forecast reliability can be applied also to different failure forecast methods. We applied for the first time the herein presented approach in near-real-time during the emergency scenario relevant to the reactivation of the La Saxe rockslide, a large mass wasting menacing the population of Courmayeur, northern Italy, and the important European route E25. Our results show how the application of simplified but robust forecast models can be a convenient method to manage and support early warning systems during critical situations. 2014 Taylor & Francis.
BibTeX:
@article{Manconi2016639,
  author = {Manconi, A. and Giordan, D.},
  title = {Landslide failure forecast in near-real-time},
  journal = {Geomatics, Natural Hazards and Risk},
  publisher = {Taylor and Francis Ltd.},
  year = {2016},
  volume = {7},
  number = {2},
  pages = {639-648},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84955655481&doi=10.1080%2f19475705.2014.942388&partnerID=40&md5=b22721088e1c33711042e5d2481cf137},
  doi = {10.1080/19475705.2014.942388}
}
Manconi A, Picozzi M, Coviello V, De Santis F and Elia L (2016), "Real-time detection, location, and characterization of rockslides using broadband regional seismic networks", Geophysical Research Letters. Vol. 43(13), pp. 6960-6967. Blackwell Publishing Ltd.
Abstract: We propose a new real-time approach to detect, locate, and estimate the volume of rockslides by analyzing waveforms acquired from broadband regional seismic networks. The identification of signals generated by rockslides from other sources, such as natural and/or induced earthquakes, is accomplished by exploiting the ratio between local magnitudes (ML) and duration magnitudes (MD). We found that signals associated with rockslides have ML/MD < 0.8, while for earthquakes ML/MD ≅ 1. In addition, we derived an empirical relationship between MD and rockslide volumes, obtaining a preliminary characterization of rockslide volume within seconds after their occurrence. The key points of this study are presented by testing the hypothesis on a recent rockslide event that occurred in northern Italy. We discuss also the potential evolution of the methodology for early warning and/or rapid response purposes. 2016. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Manconi20166960,
  author = {Manconi, A. and Picozzi, M. and Coviello, V. and De Santis, F. and Elia, L.},
  title = {Real-time detection, location, and characterization of rockslides using broadband regional seismic networks},
  journal = {Geophysical Research Letters},
  publisher = {Blackwell Publishing Ltd},
  year = {2016},
  volume = {43},
  number = {13},
  pages = {6960-6967},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84978138197&doi=10.1002%2f2016GL069572&partnerID=40&md5=01b54144828c709a001ccd05f35d9a50},
  doi = {10.1002/2016GL069572}
}
Pellarin T, Mialon A, Biron R, Coulaud C, Gibon F, Kerr Y, Lafaysse M, Mercier B, Morin S, Redor I, Schwank M and Volksch I (2016), "Three years of L-band brightness temperature measurements in a mountainous area: Topography, vegetation and snowmelt issues", Remote Sensing of Environment. Vol. 180, pp. 85-98. Elsevier Inc..
Abstract: L-band passive measurements (1.4 GHz) over continental areas are known to be related to surface soil moisture. Two satellite missions were recently launched to measure land surface emissions at this frequency band (SMOS-Soil Moisture and Ocean Salinity in 2009 and SMAP-Soil Moisture Active/Passive in 2015). In order to improve soil moisture retrievals from satellite data, ground-based radiometer systems operating at the same frequency were deployed over specified areas to investigate the L-band emission of various land covers under various climatological conditions. In this study, three years of L-band passive measurements from a radiometer installed on top of a steep mountain in the French Alps were analyzed and compared to L-band passive simulations. The innovative radiometer location led to large footprints due to the distance between the radiometer and the area under study. This experiment also produced microwave measurements affected by various potential difficulties typically encountered in SMOS/SMAP satellite missions: topography, heterogeneous footprints, dry/wet snow events, dew and vegetation litter. Based on in situ and modeling data, this paper investigates the potential of a radiative transfer model (L-band Microwave Emission of the Biosphere, L-MEB) to simulate L-band measurements and analyzes the differences with ELBARA observations. First, it was found that the topography generated a mixing of the horizontal and vertical polarizations. In addition, a large positive bias was found on ELBARA measurements (31 K and 12 K in horizontal and vertical polarizations respectively). Investigations showed that the sky reflection measured by the radiometer was partially substituted by land reflection coming from the surrounding topography. Second, the low-vegetation emission was investigated and highlighted the inability of the MODIS NDVI product to correctly represent the vegetation dynamics. Finally, dry snow conditions were found to have non-negligible impact at L-band and a particular signature was found during snow melting periods, with potential applications at the SMOS/SMAP spatial scales (  40 km). 2016 Elsevier Inc.
BibTeX:
@article{Pellarin201685,
  author = {Pellarin, T. and Mialon, A. and Biron, R. and Coulaud, C. and Gibon, F. and Kerr, Y. and Lafaysse, M. and Mercier, B. and Morin, S. and Redor, I. and Schwank, M. and Volksch, I.},
  title = {Three years of L-band brightness temperature measurements in a mountainous area: Topography, vegetation and snowmelt issues},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2016},
  volume = {180},
  pages = {85-98},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977746299&doi=10.1016%2fj.rse.2016.02.047&partnerID=40&md5=3aad93ffaccfe6e38b3ba9c6ffefacb1},
  doi = {10.1016/j.rse.2016.02.047}
}
Peres T, Silva J, Ruivo C, Silva P, Palomo J, Colomina I, Peña O, Hill C, Guerriero L, Carvalhais N, Erickson A and Cartus O (2016), "COREGAL: Exploring galileo E5 reflected signals for biomass applications", In 29th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS 2016. Vol. 2, pp. 881-891. Institute of Navigation.
Abstract: This paper presents a high-level view of the Combined Positioning-Reflectometry Galileo Code Receiver for Forest Management (COREGAL) System architecture, focusing on the development of a GNSS-P+R (Positioning and Reflectometry) receiver. The COREGAL GNSS-P+R receiver will be the main sensor platform for positioning and biomass estimation. Biomass estimation uses GNSS reflectometry (GNSS-R) signals propagated through tree canopies. The goal of this work was to develop a GNSS receiver capable of simultaneous high-accuracy positioning and raw reflected signal acquisition. The first prototype of the receiver is currently under testing. This paper also presents the results for the first COREGAL field campaign. The purpose of this test campaign was to receive GNSS signals reflected over vegetation, generating GNSS-R raw data using Galileo E5 signals.
BibTeX:
@conference{Peres2016881,
  author = {Peres, T. and Silva, J. and Ruivo, C. and Silva, P.F. and Palomo, J.M. and Colomina, I. and Peña, O. and Hill, C. and Guerriero, L. and Carvalhais, N. and Erickson, A. and Cartus, O.},
  title = {COREGAL: Exploring galileo E5 reflected signals for biomass applications},
  booktitle = {29th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS 2016},
  publisher = {Institute of Navigation},
  year = {2016},
  volume = {2},
  pages = {881-891},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85017298599&partnerID=40&md5=a3d17aace7027011f0e446c37ab2a2ba}
}
Rautiainen K, Parkkinen T, Lemmetyinen J, Schwank M, Wiesmann A, Ikonen J, Derksen C, Davydov S, Davydova A, Boike J, Langer M, Drusch M and Pulliainen J (2016), "SMOS prototype algorithm for detecting autumn soil freezing", Remote Sensing of Environment. Vol. 180, pp. 346-360. Elsevier Inc..
Abstract: A prototype algorithm for hemispheric scale detection of autumn soil freezing using space-borne L-band passive microwave observations is presented. The methodology is based on earlier empirical and theoretical studies of L-band emission properties of freezing and thawing soils. We expand a method originally developed for soil freeze-thaw (F/T) state detection from L-band tower based observations to satellite scale, applying observations from the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission. The developed algorithm is based on first establishing spatially variable thresholds for L-band brightness temperatures representing frozen and thawed states of soil, and comparing these to current values of different indicators of soil freezing, calculated based on observed brightness temperature at different polarizations and incidence angles. An exponential relation between the freezing indicators and the depth of soil frost is developed based on a large amount of manual soil frost tube observations across Finland. An additional processing filter based on observed physical temperature and snow cover information is used to flag obvious F/T detection errors. The estimated soil F/T-states provided in this study are limited to the autumn freezing period, as melting snow in spring effectively prevents acquisition of information from the soil surface using microwaves for large areas in Northern latitudes. The F/T estimate is produced as daily information and provided in the equal-area scalable Earth (EASE) grid. Soil F/T-state is categorized into three discrete levels: 'frozen', 'partially frozen', and 'thawed', and accompanied with a quality data matrix estimating the data reliability for each freezing season separately. Comparisons to in situ data were conducted at 10 different locations in Finland, Northern America and Siberia. These comparison results indicate that the onset of autumn soil freezing can be estimated from SMOS observations to within 1 to 14 days, depending on the freezing indicator applied and the in situ data used in comparison. Although the initial results are encouraging, more comprehensive assessment of SMOS based soil F/T estimates still requires further comparison to other reference sites, particularly to sites with measurements available for all locally representative land cover types, as well as other satellite-based soil freezing products. 2016 The Authors.
BibTeX:
@article{Rautiainen2016346,
  author = {Rautiainen, K. and Parkkinen, T. and Lemmetyinen, J. and Schwank, M. and Wiesmann, A. and Ikonen, J. and Derksen, C. and Davydov, S. and Davydova, A. and Boike, J. and Langer, M. and Drusch, M. and Pulliainen, J.},
  title = {SMOS prototype algorithm for detecting autumn soil freezing},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2016},
  volume = {180},
  pages = {346-360},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957894849&doi=10.1016%2fj.rse.2016.01.012&partnerID=40&md5=cc22b602a6e0c98268768cb499152e2d},
  doi = {10.1016/j.rse.2016.01.012}
}
Robson B, Holbling D, Nuth C, Strozzi T and Dahl S (2016), "Decadal scale changes in Glacier area in the Hohe Tauern national park (Austria) determined by object-based image analysis", Remote Sensing. Vol. 8(1) MDPI AG.
Abstract: In this paper, we semi-automatically classify clean and debris-covered ice for 145 glaciers within Hohe Tauern National Park in the Austrian Alps for the years 1985, 2003, and 2013. We also map the end-summer transient snowline (TSL), which approximates the annual Equilibrium Line Altitude (ELA). By comparing our results with the Austrian Glacier Inventories from 1969 and 1998, we calculate a mean reduction in glacier area of 33% between 1969 and 2013. The total ice area reduced at a mean rate of 1.4 km2 per year. This TSL rose by 92 m between 1985 and 2013 to an altitude of 3005 m. Despite some limitations, such as some seasonal snow being present at higher elevations, as well as uncertainties related to the range of years that the LiDAR DEM was collected, our results show that the glaciers within Hohe Tauern National Park conform to the heavy shrinkage experienced in other areas of the European Alps. Moreover, we believe that Object-Based Image Analysis (OBIA) is a promising methodology for future glacier mapping. 2016 by the authors; licensee MDPI, Basel, Switzerland.
BibTeX:
@article{Robson2016,
  author = {Robson, B.A. and Holbling, D. and Nuth, C. and Strozzi, T. and Dahl, S.O.},
  title = {Decadal scale changes in Glacier area in the Hohe Tauern national park (Austria) determined by object-based image analysis},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2016},
  volume = {8},
  number = {1},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957888494&doi=10.3390%2frs8010067&partnerID=40&md5=c391c3f023955b84a9d5c6e4cc245040},
  doi = {10.3390/rs8010067}
}
Siddique M, Wegmüller U, Hajnsek I and Frey O (2016), "SAR tomography as an add-on to PSI for improved deformation sampling in urban areas: A quality assessment", In Proc. European Conf. Synthetic Aperture Radar.
Abstract: Persistent scatterer interferometry (PSI) typically rejects layovers. Therefore, layover-Affected urban areas may suffer from inadequate deformation sampling. SAR tomography, when used as an add-on to PSI, reveals additional deformation samples by resolving layovers. In this paper we quantify the relative gain in deformation sampling, while taking into account the quality of the additional (double) scatterers in terms of root-mean-square (RMS) phase deviation. We experiment on an interferometric stack of 50 TerraSAR-X stripmap images acquired over the city of Barcelona. The results show a tradeoff between the gain and the quality of the detected scatterers. For the observed urban area, we obtain a gain of 9.8% while the RMS phase deviation for 99% of the detected double scatterers is less than 1.1 radians. VDE VERLAG GMBH · Berlin · Offenbach.
BibTeX:
@conference{Siddique2016,
  author = {Siddique, M.A. and Wegmüller, U. and Hajnsek, I. and Frey, O.},
  title = {SAR tomography as an add-on to PSI for improved deformation sampling in urban areas: A quality assessment},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  year = {2016},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85000962118&partnerID=40&md5=f3f9b1c7477c96a68cf7ecd78abf9697}
}
Siddique M, Wegmüller U, Hajnsek I and Frey O (2016), "SAR tomography as an add-on to PSI: Gain in deformation sampling vis-a-vis quality of the detected scatterers", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2016-November, pp. 1452-1455. Institute of Electrical and Electronics Engineers Inc..
Abstract: SAR tomography can be used as an add-on to persistent scatterer interferometry (PSI) to increase deformation sampling in urban areas by resolving the frequently occurring layovers that are by definition rejected in the PSI processing. This paper, while focusing on the case of a typical high-rise building in layover, quantitatively assesses the potential gain in deformation sampling achieved by the added use of an advanced SAR tomographic technique relative to a PSI approach. At the same time, the quantity of the detected scatterers is weighed against their quality, as assessed on the basis of root-mean-square (RMS) phase deviation between the measurements and the model fit. The quality of the scatterers is also compared with the quality of the persistent scatterers as identified with a PSI approach. The experiments are performed on an interferometric stack of 50 TerraSAR-X stripmap mode images.
BibTeX:
@conference{Siddique20161452,
  author = {Siddique, M.A. and Wegmüller, U. and Hajnsek, I. and Frey, O.},
  title = {SAR tomography as an add-on to PSI: Gain in deformation sampling vis-a-vis quality of the detected scatterers},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2016},
  volume = {2016-November},
  pages = {1452-1455},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85007415465&doi=10.1109%2fIGARSS.2016.7729371&partnerID=40&md5=b3880819e0aff4979bb6837a4ea98747},
  doi = {10.1109/IGARSS.2016.7729371}
}
Siddique M, Wegmüller U, Hajnsek I and Frey O (2016), "Single-Look SAR Tomography as an Add-On to PSI for Improved Deformation Analysis in Urban Areas", IEEE Transactions on Geoscience and Remote Sensing. Vol. 54(10), pp. 6119-6137. Institute of Electrical and Electronics Engineers Inc..
Abstract: Persistent scatterer interferometry (PSI) is in operational use for spaceborne synthetic aperture radar (SAR)-based deformation analysis. A limitation inherently associated with PSI is that, by definition, a persistent scatterer (PS) is a single dominant scatterer. Therefore, pixels containing signal contributions from multiple scatterers, as in the case of a layover, are typically rejected in the PSI processing, which in turn limits deformation retrieval. SAR tomography has the ability to resolve layovers. This paper investigates the added value that can be achieved by operationally combining SAR tomography with a PSI approach toward the objective of improving deformation sampling in layover-affected urban areas. Different tomographic phase models are implemented and compared as regards their suitability in resolving layovers. Single-look beamforming-based tomographic inversion and a generalized likelihood ratio test (GLRT)-based detection strategy are used to detect single and double scatterers. The quantity of the detected scatterers is weighed against their quality as defined in terms of the phase deviation between the single-look complex (SLC) measurements and the tomographic model fit. The gain in deformation sampling that can be derived with tomography relative to a PSI-based analysis is quantitatively assessed, and alongside the quality of the scatterers obtained with tomography is compared with the quality of the PSs identified with a PSI approach. The experiments are performed on an interferometric stack of 50 TerraSAR-X stripmap images. The results obtained show that, although there is a tradeoff between the quantity and the quality of the detected scatterers, the tested SAR tomography approach leads to an improvement in deformation sampling in layover-affected areas. 2016 IEEE.
BibTeX:
@article{Siddique20166119,
  author = {Siddique, M.A. and Wegmüller, U. and Hajnsek, I. and Frey, O.},
  title = {Single-Look SAR Tomography as an Add-On to PSI for Improved Deformation Analysis in Urban Areas},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2016},
  volume = {54},
  number = {10},
  pages = {6119-6137},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84978971071&doi=10.1109%2fTGRS.2016.2581261&partnerID=40&md5=ace29b8c6dbea23df0ecec89c7786d07},
  doi = {10.1109/TGRS.2016.2581261}
}
Thurner M, Beer C, Carvalhais N, Forkel M, Santoro M, Tum M and Schmullius C (2016), "Large-scale variation in boreal and temperate forest carbon turnover rate related to climate", Geophysical Research Letters. Vol. 43(9), pp. 4576-4585. Blackwell Publishing Ltd.
Abstract: Vegetation carbon turnover processes in forest ecosystems and their dominant drivers are far from being understood at a broader scale. Many of these turnover processes act on long timescales and include a lateral dimension and thus can hardly be investigated by plot-level studies alone. Making use of remote sensing-based products of net primary production (NPP) and biomass, here we show that spatial gradients of carbon turnover rate (k) in Northern Hemisphere boreal and temperate forests are explained by different climate-related processes depending on the ecosystem. k is related to frost damage effects and the trade-off between growth and frost adaptation in boreal forests, while drought stress and climate effects on insects and pathogens can explain an elevated k in temperate forests. By identifying relevant processes underlying broadscale patterns in k, we provide the basis for a detailed exploration of these mechanisms in field studies, and ultimately the improvement of their representations in global vegetation models (GVMs). 2016. The Authors.
BibTeX:
@article{Thurner20164576,
  author = {Thurner, M. and Beer, C. and Carvalhais, N. and Forkel, M. and Santoro, M. and Tum, M. and Schmullius, C.},
  title = {Large-scale variation in boreal and temperate forest carbon turnover rate related to climate},
  journal = {Geophysical Research Letters},
  publisher = {Blackwell Publishing Ltd},
  year = {2016},
  volume = {43},
  number = {9},
  pages = {4576-4585},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84969916819&doi=10.1002%2f2016GL068794&partnerID=40&md5=c6a82e3dd2c9e5b7fb2e56fdf2237827},
  doi = {10.1002/2016GL068794}
}
Tosi L, Da Lio C, Strozzi T and Teatini P (2016), "Combining L- and X-Band SAR interferometry to assess ground displacements in heterogeneous coastal environments: The Po River Delta and Venice Lagoon, Italy", Remote Sensing. Vol. 8(4) MDPI AG.
Abstract: From leveling to SAR-based interferometry, the monitoring of land subsidence in coastal transitional environments significantly improved. However, the simultaneous assessment of the ground movements in these peculiar environments is still challenging. This is due to the presence of relatively small built-up zones and infrastructures, e.g., coastal infrastructures, bridges, and river embankments, within large natural or rural lands, e.g., river deltas, lagoons, and farmland. In this paper we present a multi-band SAR methodology to integrate COSMO-SkyMed and ALOS-PALSAR images. The method consists of a proper combination of the very high-resolution X-band Persistent Scatterer Interferometry (PSI), which achieves high-density and precise measurements on single structures and constructed areas, with L-band Short-Baseline SAR Interferometry (SBAS), properly implemented to raise its effectiveness in retrieving information in vegetated and wet zones. The combined methodology is applied on the Po River Delta and Venice coastland, Northern Italy, using 16 ALOS-PALSAR and 31 COSMO-SkyMed images covering the period between 2007 and 2011. After a proper calibration of the single PSI and SBAS solution using available GPS records, the datasets have been combined at both the regional and local scales. The measured displacements range from  0 mm/yr down to -35 mm/yr. The results reveal the variable pattern of the subsidence characterizing the more natural and rural environments without losing the accuracy in quantifying the sinking of urban areas and infrastructures. Moreover, they allow improving the interpretation of the natural and anthropogenic processes responsible for the ongoing subsidence. 2016 by the authors.
BibTeX:
@article{Tosi2016b,
  author = {Tosi, L. and Da Lio, C. and Strozzi, T. and Teatini, P.},
  title = {Combining L- and X-Band SAR interferometry to assess ground displacements in heterogeneous coastal environments: The Po River Delta and Venice Lagoon, Italy},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2016},
  volume = {8},
  number = {4},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84971656721&doi=10.3390%2frs8040308&partnerID=40&md5=c88f7a7c11d231dd82b2f6ee250b62c2},
  doi = {10.3390/rs8040308}
}
Tosi L, Da Lio C, Strozzi T and Teatini P (2016), "Cosmo-SkyMed vs RADARSAT-2 for monitoring natural and anthropogenic components of the land movements in Venice", In European Space Agency, (Special Publication) ESA SP. Vol. SP-740 European Space Agency.
Abstract: We present the result of a test aimed at evaluating the capability of RADARSAT-2 and COSMO-SkyMed to map the natural subsidence and ground movements induced by anthropogenic activities in the historical center of Venice. Firstly, ground movements have been retrieved at quite long- and short-term by the Persistent Scattered Interferometry (PSI) on 2008-2015 RADARSAT-2 and 2013-2015 COSMO-SkyMed image stacks, respectively. Secondly, PSI has been calibrated at regional scale using the records of permanent GPS stations. Thirdly, considering that over the last two decades "in the historical center of Venice" natural land movements are primarily ascribed to longterm processes, and those induced by human activities act at short-term, we have properly resampled 83-month RADARSAT-2 C-band and 27-month COSMOSkyMed X-band interferometric products by a common grid and processed the outcome to estimate the two components of the displacements. Results show that the average natural subsidence is generally in the range of 0.9 - 1.1 mm/yr and the anthropogenic ground movements are up to 2 mm/yr.
BibTeX:
@conference{Tosi2016a,
  author = {Tosi, L. and Da Lio, C. and Strozzi, T. and Teatini, P.},
  editor = {Ouwehand L.},
  title = {Cosmo-SkyMed vs RADARSAT-2 for monitoring natural and anthropogenic components of the land movements in Venice},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  publisher = {European Space Agency},
  year = {2016},
  volume = {SP-740},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988529674&partnerID=40&md5=ca12f6624590c251311ad39284b4fd4f}
}
Wadge G, Costa A, Pascal K, Werner C and Webb T (2016), "The Variability of Refractivity in the Atmospheric Boundary Layer of a Tropical Island Volcano Measured by Ground-Based Interferometric Radar", Boundary-Layer Meteorology. Vol. 161(2), pp. 309-333. Springer Netherlands.
Abstract: For 24 h we measured continuously the variability of atmospheric refractivity over a volcano on the tropical island of Montserrat using a ground-based radar interferometer. We observed variations in phase that we interpret as due to changing water vapour on the propagation path between the radar and the volcano and we present them here in the context of the behaviour of the atmospheric boundary layer over the island. The water vapour behaviour was forced by diurnal processes, the passage of a synoptic-scale system and the presence of a plume of volcanic gas. The interferometer collected images of amplitude and phase every minute. From pairs of phase images, interferograms were calculated and analyzed every minute and averaged hourly, together with contemporaneous measurements of zenith delays estimated from a network of 14 GPS receivers. The standard deviation of phase at two sites on the volcano surface spanned a range of about 1–5 radians, the lowest values occurring at night on the lower slopes and the highest values during the day on the upper slopes. This was also reflected in spatial patterns of variability. Two-dimensional profiles of radar-measured delays were modelled using an atmosphere with water vapour content decreasing upwards and water vapour variability increasing upwards. Estimates of the effect of changing water vapour flux from the volcanic plume indicate that it should contribute only a few percent to this atmospheric variability. A diurnal cycle within the lower boundary layer producing a turbulence-dominated mixed layer during the day and stable layers at night is consistent with the observed refractivity. 2016, The Author(s).
BibTeX:
@article{Wadge2016309,
  author = {Wadge, G. and Costa, A. and Pascal, K. and Werner, C. and Webb, T.},
  title = {The Variability of Refractivity in the Atmospheric Boundary Layer of a Tropical Island Volcano Measured by Ground-Based Interferometric Radar},
  journal = {Boundary-Layer Meteorology},
  publisher = {Springer Netherlands},
  year = {2016},
  volume = {161},
  number = {2},
  pages = {309-333},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975295232&doi=10.1007%2fs10546-016-0168-3&partnerID=40&md5=eca8644bfa4097cfd2104b90e44a7be6},
  doi = {10.1007/s10546-016-0168-3}
}
Wegmüller U, Santoro M and Werner C (2016), "Time-series analysis of Sentinel-1 interferometric wide swath data: Techniques and challenges", In European Space Agency, (Special Publication) ESA SP. Vol. SP-740 European Space Agency.
Abstract: Narrow directional scattering over agricultural fields can have severe implications for the confidence with which we assimilate satellite SAR data. So far directional scattering was investigated at like-polarization. Now, with ALOS PALSAR-2 and Sentinel-1 cross-polarized backscatter data are becoming much more widely available, and so directional scattering effects at cross-polarization should also be investigated, characterized and modeled. Split-beam techniques applied to dual-polarization PALSAR-2 clearly reveal that strong narrow directional scattering over agricultural fields is also present at cross-polarization - and this not only for fields with cultivation directions perpendicular to the line of sight, but also for fields with different cultivation directions. In our contribution we confirm the presence of strong directional scattering over some agricultural fields at L-band cross-polarization. Furthermore, we present a methodology that permits to at least partly mitigate the directional scattering effects.
BibTeX:
@conference{Wegmuller2016,
  author = {Wegmüller, U. and Santoro, M. and Werner, C.},
  editor = {Ouwehand L.},
  title = {Time-series analysis of Sentinel-1 interferometric wide swath data: Techniques and challenges},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  publisher = {European Space Agency},
  year = {2016},
  volume = {SP-740},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988472332&partnerID=40&md5=7fcb1b4324e6e18eaaf6e6f140a65cb4}
}
Wegmüller U, Werner C, Strozzi T, Wiesmann A, Frey O and Santoro M (2016), "Sentinel-1 Support in the GAMMA Software", Procedia Computer Science. Vol. 100, pp. 1305-1312. Elsevier B.V..
Abstract: First results using the new Sentinel-1 SAR look very promising but the special interferometric wide-swath data acquired in the TOPS mode makes InSAR processing more challenging than for normal stripmap mode data. The steep azimuth spectra ramp in each burst results in very stringent co-registration requirements. Combining the data of the individual bursts and sub-swaths into consistent mosaics requires careful "book-keeping" in the handling of the data and meta data and the large file sizes and high data throughputs require also a good performance. Considering these challenges good support from software is getting increasingly important. In this contribution we describe the Sentinel-1 support in the GAMMA Software, a high-level software package used by researchers, service providers and operational users in their SAR, InSAR, PSI and offset tracking work. 2016 The Authors.
BibTeX:
@article{Wegmuller20161305,
  author = {Wegmüller, U. and Werner, C. and Strozzi, T. and Wiesmann, A. and Frey, O. and Santoro, M.},
  editor = {Martinho R., Rijo R., Cruz-Cunha M.M., Bjorn-Andersen N., Quintela Varajao J.E.},
  title = {Sentinel-1 Support in the GAMMA Software},
  journal = {Procedia Computer Science},
  publisher = {Elsevier B.V.},
  year = {2016},
  volume = {100},
  pages = {1305-1312},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85006945250&doi=10.1016%2fj.procs.2016.09.246&partnerID=40&md5=6d1da67b1279d4426adced034b3bb23d},
  doi = {10.1016/j.procs.2016.09.246}
}
Wegmüller U, Werner C, Wiesmann A, Strozzi T, Kourkouli P and Frey O (2016), "Time-series analysis of Sentinel-1 interferometric wide swath data: Techniques and challenges", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2016-November, pp. 3898-3901. Institute of Electrical and Electronics Engineers Inc..
Abstract: Sentinel-1 IWS interferometric time-series analysis (SBAS and PSI) is discussed and results over Mexico City, a mega-city subject to very substantial ground deformation, are presented. In the early steps the processing needs to be adapted to the organization of the data in sub-swaths and burst, and for the SLC co-registration an extremely accurate co-registration is required for interferometry, because of the strong along-track Doppler centroid variation. Furthermore, a deramping of the co-registered SLC for an along-track phase ramp present in each burst is applied. After that interferometric time-series techniques (SBAS, PSI) can be applied in the same way as for stripmap mode data.
BibTeX:
@conference{Wegmuller20163898,
  author = {Wegmüller, U. and Werner, C. and Wiesmann, A. and Strozzi, T. and Kourkouli, P. and Frey, O.},
  title = {Time-series analysis of Sentinel-1 interferometric wide swath data: Techniques and challenges},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2016},
  volume = {2016-November},
  pages = {3898-3901},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85007440007&doi=10.1109%2fIGARSS.2016.7730012&partnerID=40&md5=5f6d0f3fc2df514e7690f53c106ce56c},
  doi = {10.1109/IGARSS.2016.7730012}
}
Werner C, Lowry B, Wegmüller U, Pugh N, Schrock G and Zhou W (2016), "Deformation time-series derived from terrestrial radar observations using persistent scatterer interferometry in Seattle, Washington", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2016-November, pp. 6835-6838. Institute of Electrical and Electronics Engineers Inc..
Abstract: The GPRI2 Ground-Based Real-Aperture radar was deployed in Seattle over a 6-week period during March and April 2015 to measure sub-millimeter scale subsidence related to construction of the Alaskan Way Viaduct and Seawall Replacement Program (AWVSRP). The radar was located on the mid-level roof of the Smith Tower overlooking Pioneer Square at an altitude of about 75 meters above street level. Radar images at 2 hour intervals were processed to obtain Line-of-Sight (LOS) deformation maps. Point target analysis was used to identify stable targets and to mitigate variations in propagation path length due to atmospheric changes. Geolocation and rectification of the more than 100,000 monitored points was carried out using a LiDAR DEM. 2016 IEEE.
BibTeX:
@conference{Werner20166835,
  author = {Werner, C. and Lowry, B. and Wegmüller, U. and Pugh, N. and Schrock, G. and Zhou, W.},
  title = {Deformation time-series derived from terrestrial radar observations using persistent scatterer interferometry in Seattle, Washington},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2016},
  volume = {2016-November},
  pages = {6835-6838},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85007448331&doi=10.1109%2fIGARSS.2016.7730784&partnerID=40&md5=65eca0330d5c29e361f59d3378a105b7},
  doi = {10.1109/IGARSS.2016.7730784}
}
Askne J and Santoro M (2015), "On the estimation of boreal forest biomass from TanDEM-X data without training samples", IEEE Geoscience and Remote Sensing Letters. Vol. 12(4), pp. 771-775. Institute of Electrical and Electronics Engineers Inc..
Abstract: Boreal forests play an important part in the climate system, and estimates of the biomass are important also from an economic point of view. In this letter, forest aboveground biomass is estimated from bistatic TanDEM-X data, a Lidar digital elevation model (DEM), and the interferometric water cloud model, without using training samples to calibrate the model. The forest was characterized by allometric relations for area fill (vegetation fraction) and height versus stem volume, and stem volume versus biomass. Biomass was estimated for 202 forest stands at least 1 ha large at the forest test site of Remningstorp, Sweden, from 18 bistatic TanDEM-X acquisitions with a relative root-mean-square error (RMSE) of 16%-32%. TanDEM-X acquisitions with a height of ambiguity around 80 m resulted in the best results. A multitemporal combination resulted in a relative RMSE of 17%. This result is comparable with the retrieval error obtained in a previous study when training the model using a set of known forest stands. 2004-2012 IEEE.
BibTeX:
@article{Askne2015771,
  author = {Askne, J.I.H. and Santoro, M.},
  title = {On the estimation of boreal forest biomass from TanDEM-X data without training samples},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  volume = {12},
  number = {4},
  pages = {771-775},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84910038278&doi=10.1109%2fLGRS.2014.2361393&partnerID=40&md5=e125da9c0cc54fb5c65b479d66242d61},
  doi = {10.1109/LGRS.2014.2361393}
}
Barboux C, Strozzi T, Delaloye R, Wegmüller U and Collet C (2015), "Mapping slope movements in Alpine environments using TerraSAR-X interferometric methods", ISPRS Journal of Photogrammetry and Remote Sensing. Vol. 109, pp. 178-192. Elsevier B.V..
Abstract: Mapping slope movements in Alpine environments is an increasingly important task in the context of climate change and natural hazard management. We propose the detection, mapping and inventorying of slope movements using different interferometric methods based on TerraSAR-X satellite images. Differential SAR interferograms (DInSAR), Persistent Scatterer Interferometry (PSI), Short-Baseline Interferometry (SBAS) and a semi-automated texture image analysis are presented and compared in order to determine their contribution for the automatic detection and mapping of slope movements of various velocity rates encountered in Alpine environments. Investigations are conducted in a study region of about 6 km × 6 km located in the Western Swiss Alps using a unique large data set of 140 DInSAR scenes computed from 51 summer TerraSAR-X (TSX) acquisitions from 2008 to 2012. We found that PSI is able to precisely detect only points moving with velocities below 3.5 cm/yr in the LOS, with a root mean squared error of about 0.58 cm/yr compared to DGPS records. SBAS employed with 11 days summer interferograms increases the range of detectable movements to rates up to 35 cm/yr in the LOS with a root mean squared error of 6.36. cm/yr, but inaccurate measurements due to phase unwrapping are already possible for velocity rates larger than 20 cm/year. With the semi-automated texture image analysis the rough estimation of the velocity rates over an outlined moving zone is accurate for rates of "cm/day", "dm/month" and "cm/month", but due to the decorrelation of yearly TSX interferograms this method fails for the observation of slow movements in the "cm/yr" range. 2015 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS).
BibTeX:
@article{Barboux2015178,
  author = {Barboux, C. and Strozzi, T. and Delaloye, R. and Wegmüller, U. and Collet, C.},
  title = {Mapping slope movements in Alpine environments using TerraSAR-X interferometric methods},
  journal = {ISPRS Journal of Photogrammetry and Remote Sensing},
  publisher = {Elsevier B.V.},
  year = {2015},
  volume = {109},
  pages = {178-192},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84943803045&doi=10.1016%2fj.isprsjprs.2015.09.010&partnerID=40&md5=94317cf9932ae7553f4de3d6d2a72a6c},
  doi = {10.1016/j.isprsjprs.2015.09.010}
}
Beck I, Ludwig R, Bernier M, Strozzi T and Boike J (2015), "Vertical movements of frost mounds in subarctic permafrost regions analyzed using geodetic survey and satellite interferometry", Earth Surface Dynamics. Vol. 3(3), pp. 409-421. Copernicus GmbH.
Abstract: Permafrost-affected soils cover about 40-45 % of Canada. The environment in such areas, especially those located within the discontinuous permafrost zone, has been impacted more than any other by recorded climatic changes. A number of changes, such as surface subsidence and the degradation of frost mounds due to permafrost thawing, have already been observed at many locations. We surveyed three frost mounds (lithalsas) in the subarctic, close to Umiujaq in northern Quebec, using high-precision differential global positioning system (d-GPS) technology during field visits in 2009, 2010 and 2011, thus obtaining detailed information on their responses to the freezing and thawing that occur during the course of the annual temperature cycle. Seasonal pulsations were detected in the frost mounds, and these responses were shown to vary with their state of degradation and the land cover. The most degraded lithalsa showed a maximum amplitude of vertical movement (either up or down) between winter (freezing) and summer (thawing) of 0.19 ± 0.09 m over the study period, while for the least degraded lithalsa this figure was far greater (1.24 ± 0.47 m). Records from areas with little or no vegetation showed far less average vertical movement over the study period (0.17 ± 0.03 m) than those with prostrate shrubs (0.56 ± 0.02 m), suggesting an influence from the land cover. A differential interferometric synthetic aperture radar (D-InSAR) analysis was also completed over the lithalsas using selected TerraSAR-X images acquired from April to October 2009 and from March to October 2010, with a repeat cycle of 11 days. Interferograms with baselines shorter than 200 m were computed revealing a generally very low interferometric coherence, restricting the quantification of vertical movements of the lithalsas. Vertical surface movements of the order of a few centimeters were recorded in the vicinity of Umiujaq. 2014 Author(s).
BibTeX:
@article{Beck2015409,
  author = {Beck, I. and Ludwig, R. and Bernier, M. and Strozzi, T. and Boike, J.},
  title = {Vertical movements of frost mounds in subarctic permafrost regions analyzed using geodetic survey and satellite interferometry},
  journal = {Earth Surface Dynamics},
  publisher = {Copernicus GmbH},
  year = {2015},
  volume = {3},
  number = {3},
  pages = {409-421},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941358363&doi=10.5194%2fesurf-3-409-2015&partnerID=40&md5=269642d02b500ed3b5472185064835af},
  doi = {10.5194/esurf-3-409-2015}
}
Bontemps S, Boettcher M, Brockmann C, Kirches G, Lamarche C, Radoux J, Santoro M, Van Bogaert E, Wegmüller U, Herold M, Achard F, Ramoino F, Arino O and Defourny P (2015), "Multi-year global land cover mapping at 300 M and characterization for climate modelling: Achievements of the land cover component of the ESA climate change initiative", In International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives. Vol. 40,7W3, pp. 323-328. International Society for Photogrammetry and Remote Sensing.
Abstract: Essential Climate Variables were listed by the Global Climate Observing System as critical information to further understand the climate system and support climate modelling. The European Space Agency launched its Climate Change Initiative in order to provide an adequate response to the set of requirements for long-term satellite-based products for climate. Within this program, the CCI Land Cover project aims at revisiting all algorithms required for the generation of global land cover products that are stable and consistent over time, while also reflecting the land surface seasonality. To this end, the land cover concept is revisited to deliver a set of three consistent global land cover products corresponding to the 1998-2002, 2003-2007 and 2008-2012 periods, along with climatological 7-day time series representing the average seasonal dynamics of the land surface over the 1998-2012 period. The full Envisat MERIS archive (2003-2012) is used as main Earth Observation dataset to derive the 300-m global land cover maps, complemented with SPOT-Vegetation time series between 1998 and 2012. Finally, a 300-m global map of open permanent water bodies is derived from the 2005-2010 archive of the Envisat Advanced SAR imagery mainly acquired in the 150m Wide Swath Mode.
BibTeX:
@conference{Bontemps2015323,
  author = {Bontemps, S. and Boettcher, M. and Brockmann, C. and Kirches, G. and Lamarche, C. and Radoux, J. and Santoro, M. and Van Bogaert, E. and Wegmüller, U. and Herold, M. and Achard, F. and Ramoino, F. and Arino, O. and Defourny, P.},
  editor = {Schreier G., Skrovseth P.E., Staudenrausch H.},
  title = {Multi-year global land cover mapping at 300 M and characterization for climate modelling: Achievements of the land cover component of the ESA climate change initiative},
  booktitle = {International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives},
  publisher = {International Society for Photogrammetry and Remote Sensing},
  year = {2015},
  volume = {40,7W3},
  pages = {323-328},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930409672&doi=10.5194%2fisprsarchives-XL-7-W3-323-2015&partnerID=40&md5=88bf9713f0b1df36b8355223bedd9dff},
  doi = {10.5194/isprsarchives-XL-7-W3-323-2015}
}
Caduff R, Schlunegger F, Kos A and Wiesmann A (2015), "A review of terrestrial radar interferometry for measuring surface change in the geosciences", Earth Surface Processes and Landforms. Vol. 40(2), pp. 208-228. John Wiley and Sons Ltd.
Abstract: This paper presents a review of the current state of the art in the use of terrestrial radar interferometry for the detection of surface changes related to mass movement. Different hardware-types and acquisition concepts are described, which use either real or synthetic aperture for radar image formation. We present approaches for data processing procedures, paying special attention to the separation of high resolution displacement information from atmospheric phase variations. Recent case studies are used to illustrate applications in terrestrial radar interferometry for change detection. Applications range from detection and quantification of very slow moving (millimeters to centimeters per year) displacements in rock walls from repeat monitoring, to rapid processes resulting in fast displacements ( 50m/yr) acquired during single measurement campaigns with durations of only a few hours. Fast and episodic acting processes such as rockfall and snow avalanches can be assessed qualitatively in the spatial domain by mapping decorrelation caused by those processes. A concluding guide to best practice outlines the necessary preconditions that have to be fulfilled for successful application of the technique, as well as in areas characterized by rapid decorrelation. Empirical data from a Ku-band sensor show the range of temporal decorrelation of different surfaces after more than two years for rock-surfaces and after a few seconds to minutes in vegetated areas during windy conditions. The examples show that the displacement field can be measured for landslides in dense grassland, ice surfaces on flowing glaciers and snowpack creep. 2014 John Wiley & Sons, Ltd.
BibTeX:
@article{Caduff2015208,
  author = {Caduff, R. and Schlunegger, F. and Kos, A. and Wiesmann, A.},
  title = {A review of terrestrial radar interferometry for measuring surface change in the geosciences},
  journal = {Earth Surface Processes and Landforms},
  publisher = {John Wiley and Sons Ltd},
  year = {2015},
  volume = {40},
  number = {2},
  pages = {208-228},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921486170&doi=10.1002%2fesp.3656&partnerID=40&md5=4b5dc407a2097098a4958d7feb1b174d},
  doi = {10.1002/esp.3656}
}
Caduff R, Wiesmann A, Buhler Y and Pielmeier C (2015), "Continuous monitoring of snowpack displacement at high spatial and temporal resolution with terrestrial radar interferometry", Geophysical Research Letters. Vol. 42(3), pp. 813-820. Blackwell Publishing Ltd.
Abstract: Terrestrial radar interferometry is used in geotechnical applications for monitoring hazardous Earth or rock movements. In this study, we use it to continuously monitor snowpack displacements. As test site, the Dorfberg slope at Davos, Switzerland, was measured continuously during March 2014. The line of sight displacement was retrieved at a spatial resolution of millimeter to centimeter and a temporal resolution of up to 1min independent of visibility. The results reveal several temperature-driven diurnal acceleration and deceleration cycles. The initiation of a small full-depth glide avalanche was observed after 50cm total differential displacement. The maximum measured displacement of another differential glide area reached 43cm/h without resulting in a full-depth avalanche even after a total measured differential displacement of 4.5m. In regard of the difficulty to predict full-depth glide avalanches on the regional scale, the presented method has big potential for operational snow glide monitoring on critical slopes. 2015 The Authors.
BibTeX:
@article{Caduff2015813,
  author = {Caduff, R. and Wiesmann, A. and Buhler, Y. and Pielmeier, C.},
  title = {Continuous monitoring of snowpack displacement at high spatial and temporal resolution with terrestrial radar interferometry},
  journal = {Geophysical Research Letters},
  publisher = {Blackwell Publishing Ltd},
  year = {2015},
  volume = {42},
  number = {3},
  pages = {813-820},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84925161852&doi=10.1002%2f2014GL062442&partnerID=40&md5=26950fea50190b5888ad5d1202f208ab},
  doi = {10.1002/2014GL062442}
}
Casu F, Manconi A, Elefante S and Zinno I (2015), "Surface displacement time series retrieved by fully exploiting space-borne SAR data", Engineering Geology for Society and Territory - Volume 2: Landslide Processes. , pp. 417-420. Springer International Publishing.
Abstract: We present two applications of a novel approach to analyze surface deformation in areas experiencing large and/or rapid surface displacements. We show how the joint consideration of the phase and amplitude information of a space-borne Synthetic Aperture Radar (SAR) dataset can be used to better describe the near-field and the far-field characteristics of the surface deformation. This methodology has potential applications in the analysis of surface deformation phenomena relevant to natural hazards and/or anthropic activities. The consideration of this approach on SAR data acquired by high resolution and short revisit time satellites opens new scenarios in the use of SAR data to monitor the Earth’s crust. . Springer International Publishing Switzerland 2015.
BibTeX:
@book{Casu2015417,
  author = {Casu, F. and Manconi, A. and Elefante, S. and Zinno, I.},
  title = {Surface displacement time series retrieved by fully exploiting space-borne SAR data},
  journal = {Engineering Geology for Society and Territory - Volume 2: Landslide Processes},
  publisher = {Springer International Publishing},
  year = {2015},
  pages = {417-420},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84944539859&doi=10.1007%2f978-3-319-09057-3_66&partnerID=40&md5=6c463e1ffa3abbc8a68686ad77d17b6b},
  doi = {10.1007/978-3-319-09057-3_66}
}
Cossu F, Hocke K, Martynov A, Martius O and Matzler C (2015), "Atmospheric water parameters measured by a ground-based microwave radiometer and compared with the WRF model", Atmospheric Science Letters. Vol. 16(4), pp. 465-472. John Wiley and Sons Ltd.
Abstract: The microwave radiometer TROWARA measures integrated water vapour (IWV) and integrated cloud liquid water (ILW) at Bern since 1994 with a time resolution of 7s. In this study, we compare TROWARA measurements with a simulation of summer 2012 in Switzerland performed with the Weather Research and Forecasting (WRF) model. It is found that the WRF model agrees very well with TROWARA's IWV variations with a mean bias of only 0.7mm. The ILW distribution of the WRF model, although similar in shape to TROWARA's distribution, overestimates the fraction of clear sky periods (83% compared to 60%). 2015 Royal Meteorological Society.
BibTeX:
@article{Cossu2015465,
  author = {Cossu, F. and Hocke, K. and Martynov, A. and Martius, O. and Matzler, C.},
  title = {Atmospheric water parameters measured by a ground-based microwave radiometer and compared with the WRF model},
  journal = {Atmospheric Science Letters},
  publisher = {John Wiley and Sons Ltd},
  year = {2015},
  volume = {16},
  number = {4},
  pages = {465-472},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84944441077&doi=10.1002%2fasl.583&partnerID=40&md5=4e10398846ad8b734b0454974e84ceea},
  doi = {10.1002/asl.583}
}
Cossu F, Hocke K and Matzler C (2015), "A 10-year cloud fraction climatology of liquid water clouds over Bern observed by a ground-based microwave radiometer", Remote Sensing. Vol. 7(6), pp. 7768-7784. MDPI AG.
Abstract: Cloud fraction (CF) is known as the dominant modulator of Earth's radiative fluxes. Ground-based CF observations are useful to characterize the cloudiness of a specific site and are valuable for comparison with satellite observations and numerical models. We present for the first time CF statistics (relative to liquid clouds only) for Bern, Switzerland, derived from the observations of a ground-based microwave radiometer. CF is derived with a new method involving the analysis of the integrated liquid water distribution measured by the radiometer. The 10-year analyzed period (2004-2013) allowed us to compute a CF climatology for Bern, showing a maximum CF of 60.9% in winter and a minimum CF of 42.0% in summer. The CF monthly anomalies are identified with respect to the climatological mean values, and they are confirmed through MeteoSwiss yearly climatological bulletins. The CF monthly mean variations are similar to the observations taken at another Swiss location, Payerne, suggesting a large-scale correlation between different sites on the Swiss Plateau. A CF diurnal cycle is also computed, and large intraseasonal variations are found. The overall mean CF diurnal cycle, however, shows a typical sinusoidal cycle, with higher values in the morning and lower values in the afternoon. 2015 by the authors.
BibTeX:
@article{Cossu20157768,
  author = {Cossu, F. and Hocke, K. and Matzler, C.},
  title = {A 10-year cloud fraction climatology of liquid water clouds over Bern observed by a ground-based microwave radiometer},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2015},
  volume = {7},
  number = {6},
  pages = {7768-7784},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84933544292&doi=10.3390%2frs70607768&partnerID=40&md5=642cd3efd8f43b09baa0a6243912527b},
  doi = {10.3390/rs70607768}
}
Facello A, Giordan D and Manconi A (2015), "Analysis of snow cover in landslide prone areas: The example of Tena Valley, Central Pyrenees, Spain", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2015-November, pp. 766-769. Institute of Electrical and Electronics Engineers Inc..
Abstract: In this work, we analyze the characteristics of snow cover using two space borne products (Level 1C and Level 2A) provided by the SPOT4 Take 5 Initiative. The principal aim of this initiative is to evaluate the benefits of Sentinel 2 acquisition mode before its launch. We processed SPOT4 images acquired from February 2013 to June 2013 over the site of Midi-Pyrenees (South West). The Normalized Difference Snow Index (NDSI) and Fraction of Snow Cover (SCF) are calculated on all dataset and the snow surface map and its evolution over the time is obtained. The distribution of snow cover is slightly larger using the Level 1C than in the Level 2A data. This information will be merged with climatic data and snow depth ground measures in order to derive the melt rate, the snow cover depletion rate and the snow water equivalent, and to analyze the groundwater level variations and their interaction with the landslide activity. 2015 IEEE.
BibTeX:
@conference{Facello2015766,
  author = {Facello, A. and Giordan, D. and Manconi, A.},
  title = {Analysis of snow cover in landslide prone areas: The example of Tena Valley, Central Pyrenees, Spain},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  volume = {2015-November},
  pages = {766-769},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962595677&doi=10.1109%2fIGARSS.2015.7325877&partnerID=40&md5=0dc2bb26f9571cfbee6319822a919d5c},
  doi = {10.1109/IGARSS.2015.7325877}
}
Fernandez-Moran R, Wigneron J-P, Lopez-Baeza E, Al-Yaari A, Coll-Pajaron A, Mialon A, Miernecki M, Parrens M, Salgado-Hernanz P, Schwank M, Wang S and Kerr Y (2015), "Roughness and vegetation parameterizations at L-band for soil moisture retrievals over a vineyard field", Remote Sensing of Environment. Vol. 170, pp. 269-279. Elsevier Inc..
Abstract: The capability of L-band radiometry to monitor surface soil moisture (SM) at global scale has been analyzed in numerous studies, mostly in the framework of the ESA SMOS and NASA SMAP missions. To retrieve SM from L-band radiometric observations, two significant effects have to be accounted for, namely soil roughness and vegetation optical depth. In this study, soil roughness effects on retrieved SM valueswere evaluated using brightness temperatures acquired by the L-band ELBARA-II radiometer, over a vineyard field at the Valencia Anchor Station (VAS) site during the year 2013. Different combinations of the values of themodel parameters used to account for soil roughness effects (HR, QR, NRH and NRV) in the L-MEB model were evaluated. The L-MEB model (L-band Microwave Emission of the Biosphere) is the forward radiative transfer model used in the SMOS soil moisture retrieval algorithm. In this model, HR parameterizes the intensity of roughness effects, QR accounts for polarization effects, and NRH and NRV parameterize the variations of the soil reflectivity as a function of the observation angle, θ, respectively for both H (Horizontal) and V (Vertical) polarizations. These evaluationswere made by comparing in-situ measurements of SM (used here as a reference) against SM retrievals derived from tower-based ELBARAII brightness temperatures mentioned above. The general retrieval approach consists of the inversion of L-MEB. Two specific configurations were tested: the classical 2-Parameter (2-P) retrieval configuration where SM and τNAD (vegetation optical depth at nadir) are retrieved, and a 3-Parameter (3-P) configuration, accounting for the additional effects of the vineyard vegetation structure. Using the 2-P configuration, it was found that setting NRp (p = H or V) equals to -1 provided the best SM estimations in terms of correlation and unbiased Root Mean Square Error (ubRMSE). The assumption NRV = NRH = -1 simplifies the L-MEB retrieval, since the two parameters τNAD and HR can then be grouped and retrieved as a single parameter (method here defined as the Simplified Retrieval Method (SRP)). The main advantage of the SRP method is that it is not necessary to calibrate HR before performing the SM retrievals. Using the 3-P configuration, the results improved, with respect to SM retrievals, in terms of correlation and ubRMSE, as the structural characteristics of the vineyards were better accounted for. However, this method still requires the calibration of HR, a disadvantage for operational applications. Finally, it was found that the use of in-situ roughness measurements to calibrate the roughness model parameters did not provide significant improvements in the SM retrievals as compared to the SRP method. 2015 Elsevier Inc.
BibTeX:
@article{Fernandez-Moran2015269,
  author = {Fernandez-Moran, R. and Wigneron, J.-P. and Lopez-Baeza, E. and Al-Yaari, A. and Coll-Pajaron, A. and Mialon, A. and Miernecki, M. and Parrens, M. and Salgado-Hernanz, P.M. and Schwank, M. and Wang, S. and Kerr, Y.H.},
  title = {Roughness and vegetation parameterizations at L-band for soil moisture retrievals over a vineyard field},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2015},
  volume = {170},
  pages = {269-279},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84943618524&doi=10.1016%2fj.rse.2015.09.006&partnerID=40&md5=e73e752d40c06aa4131fc6a9a93ea4c3},
  doi = {10.1016/j.rse.2015.09.006}
}
Fernandez-Moran R, Wigneron J-P, Lopez-Baeza E, Miernecki M, Salgado-Hernanz P, Coll M, Kerr Y and Schwank M (2015), "Towards a long-term dataset of ELBARA-II measurements assisting SMOS level-3 land product and algorithm validation at the Valencia Anchor Station [Validación a largo plazo de datos de nivel 3 de tierra de SMOS con medidas de ELBARA-II en la Valencia Anchor Station]", Revista de Teledeteccion. Vol. 2015(43), pp. 55-62. Asociacion Espanola de Teledeteccion.
Abstract: The Soil Moisture and Ocean Salinity (SMOS) mission was launched on 2nd November 2009 with the objective of providing global estimations of soil moisture and sea salinity. The main activity of the Valencia Anchor Station (VAS) is currently to assist in a long-term validation of SMOS land products. This study focus on a level 3 SMOS data validation with in situ measurements carried out in the period 2010-2012 over the VAS. ELBARA-II radiometer is placed in the VAS area, observing a vineyard field considered as representative of a major proportion of an area of 50×50 km, enough to cover a SMOS footprint. Brightness temperatures (TB) acquired by ELBARA-II have been compared to those observed by SMOS at the same dates and time. They were also used for the L-MEB model inversion to retrieve soil moisture (SM), which later on have been compared to those provided by SMOS as level 3 data. A good correlation between both TB datasets was found, improving year by year, mainly due to the decrease of precipitations in the analyzed period and the mitigation of radio frequency interferences at L-band. The larger homogeneity of the radiometer footprint as compared to SMOS explains the higher variability of its TB. Periods of more intense precipitation (spring and autumn) also presented higher SM, which corroborates the consistency of SM retrieved from ELBARA-II’s observations. However, the results show that SMOS level 3 data underestimate SM as compared to ELBARA-II’s, probably due to the influence of the small soil fraction which is not cultivated in vineyards. SMOS estimations in descending orbit (6 pm) had better quality (higher correlation, lower RMSE and bias) than the ones in ascending orbit (6 am, when there is a higher soil moisture). 2015, Asociacion Espanola de Teledeteccion. All rights reserved.
BibTeX:
@article{Fernandez-Moran201555,
  author = {Fernandez-Moran, R. and Wigneron, J.-P. and Lopez-Baeza, E. and Miernecki, M. and Salgado-Hernanz, P. and Coll, M.A. and Kerr, Y.H. and Schwank, M.},
  title = {Towards a long-term dataset of ELBARA-II measurements assisting SMOS level-3 land product and algorithm validation at the Valencia Anchor Station [Validación a largo plazo de datos de nivel 3 de tierra de SMOS con medidas de ELBARA-II en la Valencia Anchor Station]},
  journal = {Revista de Teledeteccion},
  publisher = {Asociacion Espanola de Teledeteccion},
  year = {2015},
  volume = {2015},
  number = {43},
  pages = {55-62},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84934767399&doi=10.4995%2fraet.2015.2297&partnerID=40&md5=52f3cce5aacf3b5790c310c4065e408f},
  doi = {10.4995/raet.2015.2297}
}
Frey O, Werner C, Schneebeli M, Macfarlane A and Wiesmann A (2015), "Enhancement of snowscat for tomographic observation capabilities", In European Space Agency, (Special Publication) ESA SP. Vol. SP-731 European Space Agency.
Abstract: The SnowScat device, a tower-mounted fully polarimetric scatterometer for measurements of the radar crosssection of snow at X-band up to Ku-band, has recently been enhanced to also support a tomographic profiling mode. The new tomographic profiling capability of SnowScat allows for performing high-resolution observations providing further insights into the complex electromagnetic interaction within snowpacks. In this paper, we present first results obtained from a series of tomographic profiles of a snowpack acquired with the enhanced SnowScat device at a test site of SLF in Davos, Switzerland, between Dec. 2014 and March 2015.
BibTeX:
@conference{Frey2015,
  author = {Frey, O. and Werner, C.L. and Schneebeli, M. and Macfarlane, A. and Wiesmann, A.},
  editor = {Ouwehand L.},
  title = {Enhancement of snowscat for tomographic observation capabilities},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  publisher = {European Space Agency},
  year = {2015},
  volume = {SP-731},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961821223&partnerID=40&md5=42e5855174f0f286cfac3a5ee59fd4ac}
}
Frey O, Werner C and Wiesmann A (2015), "Tomographic profiling of the structure of a snow pack at X-/Ku-Band using SnowScat in SAR mode", In 2015 European Radar Conference, EuRAD 2015 - Proceedings. , pp. 21-24. Institute of Electrical and Electronics Engineers Inc..
Abstract: The SnowScat device, a fully-polarimetric scatterometer originally designed to measure the radar cross-section of snow at a frequency range from 9.2 to 17.8 GHz (X-band to Ku-band), has recently been extended towards a high-resolution tomographic measurement mode. Such tomographic profiling observations provide further insights into the complex electromagnetic interaction within snowpacks, e.g., by revealing different layers, such as melt-freeze crusts, inside the snowpack. In this contribution, we report first results from an initial tomographic measurement campaign carried out at a test site in Davos, Switzerland, in winter 2014/2015. 2015 EuMA.
BibTeX:
@conference{Frey201521,
  author = {Frey, O. and Werner, C.L. and Wiesmann, A.},
  title = {Tomographic profiling of the structure of a snow pack at X-/Ku-Band using SnowScat in SAR mode},
  booktitle = {2015 European Radar Conference, EuRAD 2015 - Proceedings},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  pages = {21-24},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962891385&doi=10.1109%2fEuRAD.2015.7346227&partnerID=40&md5=ba4b1b5df9daaa178a39251f90a02e37},
  doi = {10.1109/EuRAD.2015.7346227}
}
Giordan D, Manconi A, Allasia P and Bertolo D (2015), "Brief Communication: On the rapid and efficient monitoring results dissemination in landslide emergency scenarios: The Mont de la Saxe case study", Natural Hazards and Earth System Sciences. Vol. 15(9), pp. 2009-2017. Copernicus GmbH.
Abstract: Straightforward communication of monitoring results is of major importance in emergency scenarios relevant to large slope instabilities. Here we describe the communication strategy developed for the Mont de La Saxe rockslide threatening La Palud and Entreves hamlets in the Courmayeur municipality (Aosta Valley, Italy). Starting from the definition of actions and needs of the landslide management team, including scientists, technicians, civil protection operators, decision makers, and politicians, we show that sharing and disseminating ad hoc information simplifies the understanding of the landslide evolution, as well as the correct communication of the level of criticality. 2015 Author(s).
BibTeX:
@article{Giordan20152009,
  author = {Giordan, D. and Manconi, A. and Allasia, P. and Bertolo, D.},
  title = {Brief Communication: On the rapid and efficient monitoring results dissemination in landslide emergency scenarios: The Mont de la Saxe case study},
  journal = {Natural Hazards and Earth System Sciences},
  publisher = {Copernicus GmbH},
  year = {2015},
  volume = {15},
  number = {9},
  pages = {2009-2017},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941194236&doi=10.5194%2fnhess-15-2009-2015&partnerID=40&md5=c8f30fe96e750b703c1cd9915c88688e},
  doi = {10.5194/nhess-15-2009-2015}
}
Giordan D, Manconi A, Facello A, Baldo M, Dell'Anese F, Allasia P and Dutto F (2015), "Brief Communication: The use of an unmanned aerial vehicle in a rockfall emergency scenario", Natural Hazards and Earth System Sciences. Vol. 15(1), pp. 163-169. Copernicus GmbH.
Abstract: In recent years, the use of unmanned aerial vehicles (UAVs) in civilian/commercial contexts are becoming increasingly common, as well as for applications concerning anthropic and natural disasters. In this paper, we present the first results of a research project aimed at defining a possible methodology for the use of micro-UAVs in emergency scenarios relevant to rockfall phenomena. To develop and support the method presented herein, the results relevant to a rockfall emergency occurred on 7 March 2014 in the San Germano municipality (north-western Italy) are presented and discussed.
BibTeX:
@article{Giordan2015163,
  author = {Giordan, D. and Manconi, A. and Facello, A. and Baldo, M. and Dell'Anese, F. and Allasia, P. and Dutto, F.},
  title = {Brief Communication: The use of an unmanned aerial vehicle in a rockfall emergency scenario},
  journal = {Natural Hazards and Earth System Sciences},
  publisher = {Copernicus GmbH},
  year = {2015},
  volume = {15},
  number = {1},
  pages = {163-169},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921914600&doi=10.5194%2fnhess-15-163-2015&partnerID=40&md5=481902691c4dff76bd799ebf0e42590d},
  doi = {10.5194/nhess-15-163-2015}
}
Giordan D, Manconi A, Tannant D and Allasia P (2015), "UAV: Low-cost remote sensing for high-resolution investigation of landslides", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2015-November, pp. 5344-5347. Institute of Electrical and Electronics Engineers Inc..
Abstract: The civilian use of small inexpensive mini- and micro-UAVs has increased dramatically in the past few years. UAVs can be used for natural hazards management. In this context, UAVs can be very useful for surveying and monitoring of active small landslides in urban environments. In this paper, a methodology for the data acquisition and processing that considers the landslide typology is presented and discussed. Two case studies from the northwest part of Italy are also described to illustrate the presented methodology. 2015 IEEE.
BibTeX:
@conference{Giordan20155344,
  author = {Giordan, D. and Manconi, A. and Tannant, D.D. and Allasia, P.},
  title = {UAV: Low-cost remote sensing for high-resolution investigation of landslides},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  volume = {2015-November},
  pages = {5344-5347},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962567735&doi=10.1109%2fIGARSS.2015.7327042&partnerID=40&md5=2cca1ef8dbf560c480d2dc0eebc8e375},
  doi = {10.1109/IGARSS.2015.7327042}
}
Hanssen R, Van Leijen F, Pierdicca N, Floury N and Wegmüller U (2015), "L-band multistatic radar interferometry for 3D deformation vector decomposition", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2015-November, pp. 4057-4060. Institute of Electrical and Electronics Engineers Inc..
Abstract: SAOCOM is an Argentinian L band system formed by two satellites (SAOCOM-1A and SAOCOM-1B). ESA is investigating the possible applications of a companion satellite (SAOCOM-CS) carrying a passive receiver working in concert with one of the SAOCOM-1 satellites. During the mission there will be cycles with a long along-track bistatic baseline, suitable for deformation monitoring. Together with the combination of ascending and descending orbits, this geometry will produce four measurements from different viewing geometries, enabling us to estimate the 3D motion vector. Here we investigate the sensitivity of such a configuration, and the opportunities for increasing the density of persistent scatterers. 2015 IEEE.
BibTeX:
@conference{Hanssen20154057,
  author = {Hanssen, R.F. and Van Leijen, F. and Pierdicca, N. and Floury, N. and Wegmüller, U.},
  title = {L-band multistatic radar interferometry for 3D deformation vector decomposition},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  volume = {2015-November},
  pages = {4057-4060},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962554178&doi=10.1109%2fIGARSS.2015.7326716&partnerID=40&md5=6f8af5a747337aa471fff8d20967d55d},
  doi = {10.1109/IGARSS.2015.7326716}
}
Hofmann D, Preuss G and Matzler C (2015), "Evidence for biological shaping of hair ice", Biogeosciences. Vol. 12(14), pp. 4261-4273. Copernicus GmbH.
Abstract: An unusual ice type, called hair ice, grows on the surface of dead wood of broad-leaf trees at temperatures slightly below 0°C. We describe this phenomenon and present physical, chemical, and biological investigations to gain insight in the properties and processes related to hair ice. Tests revealed that the biological activity of a winter-active fungus is required in the wood for enabling the growth of hair ice. We confirmed the fungus hypothesis originally suggested by Wegener (1918) by reproducing hair ice on wood samples. Treatment by heat and fungicide suppresses the formation of hair ice. Fruiting bodies of Asco- and Basidiomycota are identified on hair-ice-carrying wood. One species, Exidiopsis effusa (Ee), was present on all investigated samples. Both hair-ice-producing wood samples and those with killed fungus show essentially the same temperature variation, indicating that the heat produced by fungal metabolism is very small, that the freezing rate is not influenced by the fungus activity, and that ice segregation is the common mechanism of ice growth on the wood surface. The fungus plays the role of shaping the ice hairs and preventing them from recrystallisation. Melted hair ice indicates the presence of organic matter. Chemical analyses show a complex mixture of several thousand CHO(N,S) compounds similar to fulvic acids in dissolved organic matter (DOM). The evaluation reveals decomposed lignin as being the main constituent. Further work is needed to clarify its role in hair-ice growth and to identify the recrystallisation inhibitor. Author(s) 2015.
BibTeX:
@article{Hofmann20154261,
  author = {Hofmann, D. and Preuss, G. and Matzler, C.},
  title = {Evidence for biological shaping of hair ice},
  journal = {Biogeosciences},
  publisher = {Copernicus GmbH},
  year = {2015},
  volume = {12},
  number = {14},
  pages = {4261-4273},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937807540&doi=10.5194%2fbg-12-4261-2015&partnerID=40&md5=b0494ffc8b66a15cba3e1709f134da3b},
  doi = {10.5194/bg-12-4261-2015}
}
Jonard F, Weihermuller L, Schwank M, Jadoon K, Vereecken H and Lambot S (2015), "Estimation of Hydraulic properties of a sandy soil using ground-based active and passive microwave remote sensing", IEEE Transactions on Geoscience and Remote Sensing. Vol. 53(6), pp. 3095-3109. Institute of Electrical and Electronics Engineers Inc..
Abstract: In this paper, we experimentally analyzed the feasibility of estimating soil hydraulic properties from 1.4 GHz radiometer and 0.8-2.6 GHz ground-penetrating radar (GPR) data. Radiometer and GPR measurements were performed above a sand box, which was subjected to a series of vertical water content profiles in hydrostatic equilibrium with a water table located at different depths. A coherent radiative transfer model was used to simulate brightness temperatures measured with the radiometer. GPR data were modeled using full-wave layered medium Green's functions and an intrinsic antenna representation. These forward models were inverted to optimally match the corresponding passive and active microwave data. This allowed us to reconstruct the water content profiles, and thereby estimate the sand water retention curve described using the van Genuchten model. Uncertainty of the estimated hydraulic parameters was quantified using the Bayesian-based DREAM algorithm. For both radiometer and GPR methods, the results were in close agreement with in situ time-domain reflectometry (TDR) estimates. Compared with radiometer and TDR, much smaller confidence intervals were obtained for GPR, which was attributed to its relatively large bandwidth of operation, including frequencies smaller than 1.4 GHz. These results offer valuable insights into future potential and emerging challenges in the development of joint analyses of passive and active remote sensing data to retrieve effective soil hydraulic properties. 2015 IEEE.
BibTeX:
@article{Jonard20153095,
  author = {Jonard, F. and Weihermuller, L. and Schwank, M. and Jadoon, K.Z. and Vereecken, H. and Lambot, S.},
  title = {Estimation of Hydraulic properties of a sandy soil using ground-based active and passive microwave remote sensing},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  volume = {53},
  number = {6},
  pages = {3095-3109},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923192590&doi=10.1109%2fTGRS.2014.2368831&partnerID=40&md5=c5ede37c65797a49448594277201badc},
  doi = {10.1109/TGRS.2014.2368831}
}
Kadlecik P, Kajzar V, Nekvasilova Z, Wegmüller U and Dolezalova H (2015), "Evaluation of the subsidence based on dinsar and GPS measurements near Karvina, Czech Republic", Acta Universitatis Carolinae, Geographica. Vol. 50(1), pp. 51-61. Karolinum - Nakladatelstvi Univerzity Karlovy.
Abstract: The main impacts on the landscape due to coal mining in the Czech part of the Upper Silesian basin are ground subsidence and manmade landscape changes related to the mining. Two measurement techniques were used to determine the values of subsidence; these were then compared together to verify the results obtained. The first, differential SAR interferometry (dlnSAR), a remote sensing method, was applied by Gamma Remote Sensing in the frame of ESA GMES Project Terrafirma, using ALOS PALSAR data. The second was the GPS fast static method, which was provided by the Institute of Geonics AS CR. The GPS monitoring was established at a locality near Karviná in 2006. A comparison of the results is described on one subsidence depression created above a panel mined from February 2007 to May 2008. Aspects of the comparison applying to the subsidence measurements are discussed along with the advantages and disadvantages of both methods.
BibTeX:
@article{Kadlecik201551,
  author = {Kadlecik, P. and Kajzar, V. and Nekvasilova, Z. and Wegmüller, U. and Dolezalova, H.},
  title = {Evaluation of the subsidence based on dinsar and GPS measurements near Karvina, Czech Republic},
  journal = {Acta Universitatis Carolinae, Geographica},
  publisher = {Karolinum - Nakladatelstvi Univerzity Karlovy},
  year = {2015},
  volume = {50},
  number = {1},
  pages = {51-61},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84934326219&doi=10.14712%2f23361980.2015.86&partnerID=40&md5=4106f485376ed605317eaa9da57109fb},
  doi = {10.14712/23361980.2015.86}
}
Lanteri L, Bormioli D, Morelli M, Dutto F, Giordan D and Manconi A (2015), "Rockfall analysis during emergency scenarios", Engineering Geology for Society and Territory - Volume 5: Urban Geology, Sustainable Planning and Landscape Exploitation. , pp. 711-714. Springer International Publishing.
Abstract: In this paper we describe a procedure for the study and management of rockfall affected areas. During the MASSA project, we defined a procedure for the management of the first emergency phase after the gravitational phenomenon, describing what it could be done for a first analysis and monitoring of the instable areas. In particular, the developed methodology considered three important aspects that should begin during the first 48-72 h: (i) preliminary morphological/structural analysis; (ii) detection and monitoring of instable areas during the emergency phase; (iii) communication strategies for the event management and divulgation to the population. Starting from the defined methodology, we also describe the first results of the application of this method to the Quincinetto rockfall test site, Piedmont, Italy. Springer International Publishing Switzerland 2015.
BibTeX:
@book{Lanteri2015711,
  author = {Lanteri, L. and Bormioli, D. and Morelli, M. and Dutto, F. and Giordan, D. and Manconi, A.},
  title = {Rockfall analysis during emergency scenarios},
  journal = {Engineering Geology for Society and Territory - Volume 5: Urban Geology, Sustainable Planning and Landscape Exploitation},
  publisher = {Springer International Publishing},
  year = {2015},
  pages = {711-714},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84944607084&doi=10.1007%2f978-3-319-09048-1_138&partnerID=40&md5=61b0cd0a360ae347339a28aaa1226c5f},
  doi = {10.1007/978-3-319-09048-1_138}
}
Leinss S, Lemmetyinen J, Wiesmann A and Hajnsek I (2015), "Interferometric and polarimetric methods to determine SWE, fresh snow depth and the anisotropy of dry snow", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2015-November, pp. 4029-4032. Institute of Electrical and Electronics Engineers Inc..
Abstract: Dry snow can be considered as a transparent but refractive medium which causes a phase delay in the reflected signal of active radar remote sensing systems. Here, we analyze the phase delay to estimate Snow Water Equivalent (SWE), the depth of fresh snow and the anisotropic orientation of ice grains in the snow volume. SWE is determined from the integrated phase shift measured by differential interferometry. The temporal evolution of the snow anisotropy could be observed because different microwave polarizations show different propagation speeds in anisotropic snow. The depth of fresh snow as well as snow metamorphosis is discussed with respect to characteristic phase-shifts in the co-polar phase difference. Ground based radar observations from the Snow-scat instrument installed at a test site near Sodankyla, Finland, form the data basis for this paper. 2015 IEEE.
BibTeX:
@conference{Leinss20154029,
  author = {Leinss, S. and Lemmetyinen, J. and Wiesmann, A. and Hajnsek, I.},
  title = {Interferometric and polarimetric methods to determine SWE, fresh snow depth and the anisotropy of dry snow},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  volume = {2015-November},
  pages = {4029-4032},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962509241&doi=10.1109%2fIGARSS.2015.7326709&partnerID=40&md5=0d239760445ede7e996980efe897bd1d},
  doi = {10.1109/IGARSS.2015.7326709}
}
Leinss S, Wiesmann A, Lemmetyinen J and Hajnsek I (2015), "Snow Water Equivalent of Dry Snow Measured by Differential Interferometry", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 8(8), pp. 3773-3790. Institute of Electrical and Electronics Engineers.
Abstract: Large scale mapping of snow water equivalent (SWE) is a long-lasting request in many scientific and economical fields. Active and passive microwave remote sensing methods are explored, as local methods cannot be generalized due to the spatial inhomogeneity of the snow pack. Microwaves interact with snow by absorption, scattering, and refraction. For dry snow of a few meters depth and frequencies below 20 GHz, absorption and scattering in the snow volume are negligible compared with the backscattered energy from the underlying ground. The signal delay caused by refraction can be measured with differential radar interferometry, but phase wrapping errors and temporal decorrelation must be considered. We demonstrate that large ΔSWE can be accurately determined from dense time series of differential interferograms at X- and Ku-band by temporal integration. Lost phase cycles are reconstructed with a two-frequency approach. Temporal decorrelation is minimized by a temporal resolution of 4h. A linear function between ΔSWE and phase difference is derived, which deviates only a few percent from the exact solution and which depends negligibly on snow density and stratigraphy. ΔSWE retrieved from observations of the SnowScat instrument (SSI) were validated against observed SWE from different reference instruments, installed at a test site near the town of Sodankyla, Finland. An accuracy below ±6 mm SWE was achieved at frequencies of 10 and 16 GHz for up to 200 mm of ΔSWE. An exceptionally high temporal coherence was observed for up to 30 days for dry snow, whereas for wet snow it decayed within hours. 2008-2012 IEEE.
BibTeX:
@article{Leinss20153773,
  author = {Leinss, S. and Wiesmann, A. and Lemmetyinen, J. and Hajnsek, I.},
  title = {Snow Water Equivalent of Dry Snow Measured by Differential Interferometry},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2015},
  volume = {8},
  number = {8},
  pages = {3773-3790},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027922593&doi=10.1109%2fJSTARS.2015.2432031&partnerID=40&md5=238ee8339c485a24b0b9ec08f08c57e0},
  doi = {10.1109/JSTARS.2015.2432031}
}
Lemmetyinen J, Schwank M, Rautiainen K, Kontu A, Parkkinen T, Matzler C, Wiesmann A, Wegmüller U, Derksen C, Toose P, Roy A and Pulliainen J (2015), "Potential of L-band passive microwave radiometry for snow parameter retrieval", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2015-November, pp. 4033-4036. Institute of Electrical and Electronics Engineers Inc..
Abstract: Dry snow is conventionally considered as having minimal effect on microwave radiation at long wavelengths (such as L-band). However, dry snow affects observed microwave signatures even at these wavelengths through changes in impedance matching between soil and the overlying media, as well as through changes in the refraction angle at the soil interface. Exploiting these effects, the multi-angular, dual-polarized L-band observations of e.g. the European Space Agency's SMOS (Soil Moisture and Ocean Salinity) mission have the potential to derive snow properties, such as the density of the lowest layers of the snowpack in contact with the ground. This in turn, would have the potential to inform retrieval schemes of snow cover based on EO-data from other sensors. In addition, the theoretical studies demonstrate that the effect of dry snow on retrieval of other geophysical variables, such as soil moisture, is not negligible. In this study, we demonstrate the simultaneous retrieval of snow density and ground permittivity in dry snow conditions, using a multi-year dataset of tower-based L-band observations. We show that following predictions of the theoretical studies, the retrieved snow density matches that of the density measured for the lowest snow layers; dry snow cover is also shown to affect retrievals of ground permittivity by up to 40 %. 2015 IEEE.
BibTeX:
@conference{Lemmetyinen20154033,
  author = {Lemmetyinen, J. and Schwank, M. and Rautiainen, K. and Kontu, A. and Parkkinen, T. and Matzler, C. and Wiesmann, A. and Wegmüller, U. and Derksen, C. and Toose, P. and Roy, A. and Pulliainen, J.},
  title = {Potential of L-band passive microwave radiometry for snow parameter retrieval},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  volume = {2015-November},
  pages = {4033-4036},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962613692&doi=10.1109%2fIGARSS.2015.7326710&partnerID=40&md5=03d3c26c3cb5b39913cfe978bee66c31},
  doi = {10.1109/IGARSS.2015.7326710}
}
Lollino G, Manconi A, Clague J, Shan W and Chiarle M (2015), "Engineering geology for society and territory - Volume 1: Climate change and engineering geology", Engineering Geology for Society and Territory - Volume 1: Climate Change and Engineering Geology. , pp. 1-572. Springer International Publishing.
Abstract: This book is one out of 8 IAEG XII Congress volumes and deals with climate change affecting different natural processes and environments, such as slope dynamics, water courses, coastal and marine environments, hydrological and littoral processes and permafrost terrain. Due to climate change, major effects are also expected on territorial planning and infrastructure, particularly in extreme climate regions. The volume and its contents aim to analyze the role of engineering geology and the solutions it may offer with respect to the ongoing environmental changes. Contributions regard the modeling of both the factors and the effects induced by climate change. Potential impacts of the climate change on the common practice and routine work of engineering geologists are also analyzed, with particular attention to the risk assessment and mitigation procedures and to the adaptation measures adopted. The Engineering Geology for Society and Territory volumes of the IAEG XII Congress held in Torino from September 15-19, 2014, analyze the dynamic role of engineering geology in our changing world and build on the four main themes of the congress: environment, processes, issues and approaches. The congress topics and subject areas of the 8 IAEG XII Congress volumes are: Climate Change and Engineering Geology. Landslide Processes. River Basins, Reservoir Sedimentation and Water Resources. Marine and Coastal Processes. Urban Geology, Sustainable Planning and Landscape Exploitation. Applied Geology for Major Engineering Projects. Education, Professional Ethics and Public Recognition of Engineering Geology. Preservation of Cultural Heritage. Springer International Publishing Switzerland 2015.
BibTeX:
@book{Lollino20151a,
  author = {Lollino, G. and Manconi, A. and Clague, J. and Shan, W. and Chiarle, M.},
  title = {Engineering geology for society and territory - Volume 1: Climate change and engineering geology},
  journal = {Engineering Geology for Society and Territory - Volume 1: Climate Change and Engineering Geology},
  publisher = {Springer International Publishing},
  year = {2015},
  pages = {1-572},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945120831&doi=10.1007%2f978-3-319-09300-0&partnerID=40&md5=8c840f9d8bfdbc23de43b70dd3ad8945},
  doi = {10.1007/978-3-319-09300-0}
}
Lollino G, Manconi A, Giordan D, Allasia P and Baldo M (2015), "Infrastructure in geohazard contexts: The importance of automatic and near-real-time monitoring", Environmental Security of the European Cross-Border Energy Supply Infrastructure. , pp. 73-89. Springer Netherlands.
Abstract: The analysis and interpretation of ground deformation plays an important role in monitoring activities aimed at ensuring the safety of people and/or infrastructure in geohazard scenarios such as earthquakes, volcanic activity and landslides. Nowadays, a wide spectrum of instruments and methods is available, ranging from in-situ to remote sensing approaches. However, the research described here was primarily to develop automatic, and increasingly accurate, monitoring instruments, while acknowledging that the available tools for an efficient exploitation, understanding and interpretation of the measurements made still lack efficiency. In this work, three relevant geohazard case-studies are described where automatic and near-real-time systems allowed the monitoring of surface displacements and deep-seated deformation. The results demonstrate that the automatic and near-real-time acquisition of measurements is important but that this concept has to be extended also to the data processing and its communication. This is particularly important in critical geohazard scenarios, where monitoring activities are fundamental to support early warning systems. Springer Science+Business Media Dordrecht 2015.
BibTeX:
@book{Lollino201573,
  author = {Lollino, G. and Manconi, A. and Giordan, D. and Allasia, P. and Baldo, M.},
  title = {Infrastructure in geohazard contexts: The importance of automatic and near-real-time monitoring},
  journal = {Environmental Security of the European Cross-Border Energy Supply Infrastructure},
  publisher = {Springer Netherlands},
  year = {2015},
  pages = {73-89},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84943232880&doi=10.1007%2f978-94-017-9538-8_6&partnerID=40&md5=7df04ba85ce052c8ea565d14fe54064d},
  doi = {10.1007/978-94-017-9538-8_6}
}
Lollino G, Manconi A, Guzzetti F, Culshaw M, Bobrowsky P and Luino F (2015), "Engineering geology for society and territory - volume 5: Urban geology, sustainable planning and landscape exploitation", Engineering Geology for Society and Territory - Volume 5: Urban Geology, Sustainable Planning and Landscape Exploitation. , pp. 1-1400. Springer International Publishing.
Abstract: This book is one out of 8 IAEG XII Congress volumes, and deals with the theme of urban geology. Along with a rapidly growing world population, the wave of urban growth continues, causing cities to swell and new metropolitan centers to emerge. These global trends also open new ventures for underground city development. Engineering geology plays a major role in facing the increasing issues of the urban environment, such as: finding aggregates for construction works; providing adequate water supply and waste management; solving building problems associated to geological and geomorphological conditions; evaluating host rock conditions for underground constructions; preventing or mitigating geological and seismic hazards. Furthermore, this book illustrates recent advancements in sustainable land use planning, which includes conservation, protection, reclamation and landscape impact of open pit mining and alternative power generation.The Engineering Geology for Society and Territory volumes of the IAEG XII Congress held in Torino from September 15-19, 2014, analyze the dynamic role of engineering geology in our changing world and build on the four main themes of the congress: environment, processes, issues and approaches. The congress topics and subject areas of the 8 IAEG XII Congress volumes are:1. Climate Change and Engineering Geology2. Landslide Processes River Basins3. Reservoir Sedimentation and Water Resources4. Marine and Coastal Processes Urban Geology5. Sustainable Planning and Landscape Exploitation6. Applied Geology for Major Engineering Projects7. Education, Professional Ethics and Public Recognition of Engineering Geology8. Preservation of Cultural Heritage. Springer International Publishing Switzerland 2015.
BibTeX:
@book{Lollino20151b,
  author = {Lollino, G. and Manconi, A. and Guzzetti, F. and Culshaw, M. and Bobrowsky, P. and Luino, F.},
  title = {Engineering geology for society and territory - volume 5: Urban geology, sustainable planning and landscape exploitation},
  journal = {Engineering Geology for Society and Territory - Volume 5: Urban Geology, Sustainable Planning and Landscape Exploitation},
  publisher = {Springer International Publishing},
  year = {2015},
  pages = {1-1400},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84944538564&doi=10.1007%2f978-3-319-09048-1&partnerID=40&md5=4ab26b9dc302b61494c2c63078924482},
  doi = {10.1007/978-3-319-09048-1}
}
Magnard C, Small D and Meier E (2015), "Phase noise investigation of maximum likelihood estimation method for airborne multibaseline SAR interferometry", In International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives. Vol. 40,3W2, pp. 121-125. International Society for Photogrammetry and Remote Sensing.
Abstract: The phase estimation of cross-track multibaseline synthetic aperture interferometric data is usually thought to be very efficiently achieved using the maximum likelihood (ML) method. The suitability of this method is investigated here as applied to airborne single pass multibaseline data. Experimental interferometric data acquired with a Ka-band sensor were processed using (a) a ML method that fuses the complex data from all receivers and (b) a coarse-to-fine method that only uses the intermediate baselines to unwrap the phase values from the longest baseline. The phase noise was analyzed for both methods: in most cases, a small improvement was found when the ML method was used.
BibTeX:
@conference{Magnard2015121,
  author = {Magnard, C. and Small, D. and Meier, E.},
  editor = {Heipke C., Stilla U.},
  title = {Phase noise investigation of maximum likelihood estimation method for airborne multibaseline SAR interferometry},
  booktitle = {International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives},
  publisher = {International Society for Photogrammetry and Remote Sensing},
  year = {2015},
  volume = {40,3W2},
  pages = {121-125},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84925366150&doi=10.5194%2fisprsarchives-XL-3-W2-121-2015&partnerID=40&md5=20e04aa4ddad1ab986141b5e72b9fbce},
  doi = {10.5194/isprsarchives-XL-3-W2-121-2015}
}
Malnes E, Buanes A, Nagler T, Bippus G, Gustafsson D, Schiller C, Metsamaki S, Pulliainen J, Luojus K, Larsen H, Solberg R, Diamandi A and Wiesmann A (2015), "User requirements for the snow and land ice services - CryoLand", Cryosphere. Vol. 9(3), pp. 1191-1202. Copernicus GmbH.
Abstract: CryoLand (2011-2015) is a project carried out within the 7th Framework of the European Commission aimed at developing downstream services for monitoring seasonal snow, glaciers and lake/river ice primarily based on satellite remote sensing. The services target private and public users from a wide variety of application areas, and aim to develop sustainable services after the project is completed. The project has performed a thorough user requirement survey in order to derive targeted requirements for the service and provide recommendations for the design and priorities of the service. In this paper we describe the methods used, the major findings in this user survey, and how we used the results to design and specify the CryoLand snow and land ice service. The user requirement analysis shows that a European operational snow and land ice service is required and that there exists developed cryosphere products that can meet the specific needs. The majority of the users were mainly interested not only in the snow services, but also the lake/river ice products and the glacier products were desired. Author(s) 2015.
BibTeX:
@article{Malnes20151191,
  author = {Malnes, E. and Buanes, A. and Nagler, T. and Bippus, G. and Gustafsson, D. and Schiller, C. and Metsamaki, S. and Pulliainen, J. and Luojus, K. and Larsen, H.E. and Solberg, R. and Diamandi, A. and Wiesmann, A.},
  title = {User requirements for the snow and land ice services - CryoLand},
  journal = {Cryosphere},
  publisher = {Copernicus GmbH},
  year = {2015},
  volume = {9},
  number = {3},
  pages = {1191-1202},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930935219&doi=10.5194%2ftc-9-1191-2015&partnerID=40&md5=767ceae2ae17c93d6315ecb7a059eaa3},
  doi = {10.5194/tc-9-1191-2015}
}
Manconi A and Giordan D (2015), "Landslide early warning based on failure forecast models: The example of the Mt. de la Saxe rockslide, northern Italy", Natural Hazards and Earth System Sciences. Vol. 15(7), pp. 1639-1644. Copernicus GmbH.
Abstract: We apply failure forecast models by exploiting near-real-time monitoring data for the La Saxe rockslide, a large unstable slope threatening Aosta Valley in northern Italy. Starting from the inverse velocity theory, we analyze landslide surface displacements automatically and in near real time on different temporal windows and apply straightforward statistical methods to obtain confidence intervals on the estimated time of failure. Here, we present the result obtained for the La Saxe rockslide, a large unstable slope located in Aosta Valley, northern Italy. Based on this case study, we identify operational thresholds that are established on the reliability of the forecast models. Our approach is aimed at supporting the management of early warning systems in the most critical phases of the landslide emergency. Author(s) 2015.
BibTeX:
@article{Manconi20151639,
  author = {Manconi, A. and Giordan, D.},
  title = {Landslide early warning based on failure forecast models: The example of the Mt. de la Saxe rockslide, northern Italy},
  journal = {Natural Hazards and Earth System Sciences},
  publisher = {Copernicus GmbH},
  year = {2015},
  volume = {15},
  number = {7},
  pages = {1639-1644},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938405264&doi=10.5194%2fnhess-15-1639-2015&partnerID=40&md5=03c4bd3d3082b2a2da21276f71e5c9cc},
  doi = {10.5194/nhess-15-1639-2015}
}
Margottini C, Antidze N, Corominas J, Crosta G, Frattini P, Gigli G, Giordan D, Iwasaky I, Lollino G, Manconi A, Marinos P, Scavia C, Sonnessa A, Spizzichino D and Vacheishvili N (2015), "Landslide hazard, monitoring and conservation strategy for the safeguard of Vardzia Byzantine monastery complex, Georgia", Landslides. Vol. 12(1), pp. 193-204. Springer Verlag.
Abstract: This paper reports preliminary results of a feasibility project developed in cooperation with National Agency for Cultural Heritage Preservation of Georgia, and aimed at envisaging the stability conditions of the Vardzia monastery slope (rupestrian city cave in the south-western Georgia). The aim is the implementation of a low-impact monitoring system together with long-term mitigation/conservation policies. A field analysis was conducted to reconstruct geometry of the rocky cliff, characteristics of discontinuities, main failure modes, and volume of potential unstable blocks and geomechanical parameters. Instability processes are the combination of causative factors such as the following: lithology, frequency and orientation of discontinuities, slope orientation, physical and mechanical characteristics of slope-forming materials, and morphological and hydrological boundary conditions. The combined adoption of different survey techniques (e.g., 3D laser scanner, ground-based radar interferometry) could be the best solution in the interdisciplinary field of cultural heritage preservation policies. The collected data will be the basis for future activities to be completed in collaboration with local authorities for a complete hazard and risk characterization for the monastery site and the development of an early warning system to allow safe exploitation for touristic activities and for historical site preservation. 2015, Springer-Verlag Berlin Heidelberg.
BibTeX:
@article{Margottini2015193,
  author = {Margottini, C. and Antidze, N. and Corominas, J. and Crosta, G.B. and Frattini, P. and Gigli, G. and Giordan, D. and Iwasaky, I. and Lollino, G. and Manconi, A. and Marinos, P. and Scavia, C. and Sonnessa, A. and Spizzichino, D. and Vacheishvili, N.},
  title = {Landslide hazard, monitoring and conservation strategy for the safeguard of Vardzia Byzantine monastery complex, Georgia},
  journal = {Landslides},
  publisher = {Springer Verlag},
  year = {2015},
  volume = {12},
  number = {1},
  pages = {193-204},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84922447948&doi=10.1007%2fs10346-014-0548-z&partnerID=40&md5=80a419a428d513ab17bea7c3ad5385a6},
  doi = {10.1007/s10346-014-0548-z}
}
Metsamaki S, Pulliainen J, Salminen M, Luojus K, Wiesmann A, Solberg R, Bottcher K, Hiltunen M and Ripper E (2015), "Introduction to GlobSnow Snow Extent products with considerations for accuracy assessment", Remote Sensing of Environment. Vol. 156, pp. 96-108. Elsevier Inc..
Abstract: The European Space Agency's Data User Element (DUE) project GlobSnow was established to create a global database of Snow Extent and Snow Water Equivalent. The Snow Extent (SE) product portfolio provided within ESA DUE GlobSnow (2008-2014) is introduced and described, with a special focus on the Daily Fractional Snow Cover (DFSC) of the SE version 2.0 and its successor 2.1 released in 2013-2014. The fractional snow retrieval uses the SCAmod method designed ecpecially to enable accurate snow mapping including forests. The basics of the methodology are presented, as well as the cloud screening method applied in SE production. Considerations for future validations together with discussion on some current issues and potential inaccuracies are presented. One focus of the investigation is on the representativeness of reference FSC generated from Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM. +) data, with a particular interest in forested areas. Two methods for reference data generation are investigated. When comparing the GlobSnow Daily Fractional Snow Cover to these reference data, we try to identify how the comparison reflects the possible inaccuracies of the DFSC and to define the conditions where the reference data are not representative. It is obvious that the evaluation result strongly depends on the quality of the reference data, and that the two methods investigated cannot provide representative reference data for dense forests. For fully snow-covered dense conifer forest area in Finland, a Root Mean Squared Error of 20-30% was obtained from comparisons although DFSC indicated full snow cover correctly. These first evaluations would indicate a good performance of GlobSnow SE products in forests; however, this does not necessarily show up in validations due to the non-representativeness of the reference data. It is also concluded that GlobSnow SE products are sensitive to the representativeness of the applied SCAmod parameters and that FSC overestimations may occur in dense forests. GlobSnow SE products are available at www.globsnow.info/se/. 2014 Elsevier Inc.
BibTeX:
@article{Metsamaki201596,
  author = {Metsamaki, S. and Pulliainen, J. and Salminen, M. and Luojus, K. and Wiesmann, A. and Solberg, R. and Bottcher, K. and Hiltunen, M. and Ripper, E.},
  title = {Introduction to GlobSnow Snow Extent products with considerations for accuracy assessment},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2015},
  volume = {156},
  pages = {96-108},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907999764&doi=10.1016%2fj.rse.2014.09.018&partnerID=40&md5=c989574e145c0babc35d984cb9ad0a4f},
  doi = {10.1016/j.rse.2014.09.018}
}
Paul F, Bolch T, Kaab A, Nagler T, Nuth C, Scharrer K, Shepherd A, Strozzi T, Ticconi F, Bhambri R, Berthier E, Bevan S, Gourmelen N, Heid T, Jeong S, Kunz M, Lauknes T, Luckman A, Merryman Boncori J, Moholdt G, Muir A, Neelmeijer J, Rankl M, VanLooy J and Van Niel T (2015), "The glaciers climate change initiative: Methods for creating glacier area, elevation change and velocity products", Remote Sensing of Environment. Vol. 162, pp. 408-426. Elsevier Inc..
Abstract: Glaciers and their changes through time are increasingly obtained from a wide range of satellite sensors. Due to the often remote location of glaciers in inaccessible and high-mountain terrain, satellite observations frequently provide the only available measurements. Furthermore, satellite data provide observations of glacier characteristics that are difficult to monitor using ground-based measurements, thus complementing the latter. In the Glaciers_cci project of the European Space Agency (ESA), three of these characteristics are investigated in detail: glacier area, elevation change and surface velocity. We use (a) data from optical sensors to derive glacier outlines, (b) digital elevation models from at least two points in time, (c) repeat altimetry for determining elevation changes, and (d) data from repeat optical and microwave sensors for calculating surface velocity. For the latter, the two sensor types provide complementary information in terms of spatio-temporal coverage. While (c) and (d) can be generated mostly automatically, (a) and (b) require the intervention of an analyst. Largely based on the results of various round robin experiments (multi-analyst benchmark studies) for each of the products, we suggest and describe the most suitable algorithms for product creation and provide recommendations concerning their practical implementation and the required post-processing. For some of the products (area, velocity) post-processing can influence product quality more than the main-processing algorithm. 2013 Elsevier Inc.
BibTeX:
@article{Paul2015408,
  author = {Paul, F. and Bolch, T. and Kaab, A. and Nagler, T. and Nuth, C. and Scharrer, K. and Shepherd, A. and Strozzi, T. and Ticconi, F. and Bhambri, R. and Berthier, E. and Bevan, S. and Gourmelen, N. and Heid, T. and Jeong, S. and Kunz, M. and Lauknes, T.R. and Luckman, A. and Merryman Boncori, J.P. and Moholdt, G. and Muir, A. and Neelmeijer, J. and Rankl, M. and VanLooy, J. and Van Niel, T.},
  title = {The glaciers climate change initiative: Methods for creating glacier area, elevation change and velocity products},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2015},
  volume = {162},
  pages = {408-426},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84928489795&doi=10.1016%2fj.rse.2013.07.043&partnerID=40&md5=1fade622fe9648d57268e614b18346bd},
  doi = {10.1016/j.rse.2013.07.043}
}
Proksch M, Matzler C, Wiesmann A, Lemmetyinen J, Schwank M, Lowe H and Schneebeli M (2015), "MEMLS3&a: Microwave Emission Model of Layered Snowpacks adapted to include backscattering", Geoscientific Model Development. Vol. 8(8), pp. 2611-2626. Copernicus GmbH.
Abstract: The Microwave Emission Model of Layered Snowpacks (MEMLS) was originally developed for microwave emissions of snowpacks in the frequency range 5-100 GHz. It is based on six-flux theory to describe radiative transfer in snow including absorption, multiple volume scattering, radiation trapping due to internal reflection and a combination of coherent and incoherent superposition of reflections between horizontal layer interfaces. Here we introduce MEMLS3&a, an extension of MEMLS, which includes a backscatter model for active microwave remote sensing of snow. The reflectivity is decomposed into diffuse and specular components. Slight undulations of the snow surface are taken into account. The treatment of like- and cross-polarization is accomplished by an empirical splitting parameter q. MEMLS3&a (as well as MEMLS) is set up in a way that snow input parameters can be derived by objective measurement methods which avoid fitting procedures of the scattering efficiency of snow, required by several other models. For the validation of the model we have used a combination of active and passive measurements from the NoSREx (Nordic Snow Radar Experiment) campaign in Sodankyla, Finland. We find a reasonable agreement between the measurements and simulations, subject to uncertainties in hitherto unmeasured input parameters of the backscatter model. The model is written in Matlab and the code is publicly available for download through the following website: http://www.iapmw.unibe.ch/research/projects/snowtools/memls.html. Author(s) 2015.
BibTeX:
@article{Proksch20152611,
  author = {Proksch, M. and Matzler, C. and Wiesmann, A. and Lemmetyinen, J. and Schwank, M. and Lowe, H. and Schneebeli, M.},
  title = {MEMLS3&a: Microwave Emission Model of Layered Snowpacks adapted to include backscattering},
  journal = {Geoscientific Model Development},
  publisher = {Copernicus GmbH},
  year = {2015},
  volume = {8},
  number = {8},
  pages = {2611-2626},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940176762&doi=10.5194%2fgmd-8-2611-2015&partnerID=40&md5=d76e2277776becab5539aa3cb9ceadf4},
  doi = {10.5194/gmd-8-2611-2015}
}
Robson B, Nuth C, Dahl S, Holbling D, Strozzi T and Nielsen P (2015), "Automated classification of debris-covered glaciers combining optical, SAR and topographic data in an object-based environment", Remote Sensing of Environment. Vol. 170, pp. 372-387. Elsevier Inc..
Abstract: Satellite imagery is increasingly used to monitor glacier area changes and create glacier inventories. Robust and efficient pixel-based band ratios have proven to be accurate for automatically delineating clean glacier ice, however such classifications are restricted on debris-covered ice due to its spectral similarity with surrounding terrain. Object-Based Image Analysis (OBIA) has emerged as a new analysis technique within remote sensing. It offers many advantages over pixel-based classification techniques due to the ability to work with multiple data sources and handle data contextually and hierarchically. By making use of OBIA capabilities we automatically classify clean ice and debris-covered ice in the challenging area surrounding Mount Manaslu in Nepal using optical (Landsat 8), topographic (void-filled SRTM) and SAR coherence (ALOS PALSAR) data. Clean ice was classified with a mean accuracy of 93% whilst debris-covered ice was classified with an accuracy of 83% when compared to manually corrected outlines, providing a total glacier accuracy of 91%. With further developments in the classification, steep tributary sections of ice could be contextually included, raising the accuracy to over 94%. One prominent advantage of OBIA is that it allows some post-processing and correction of the glacier outlines automatically, reducing the amount of manual correction needed. OBIA incorporating SAR coherence data is recommended for future mapping of debris-covered ice. 2015 Elsevier Inc.
BibTeX:
@article{Robson2015372,
  author = {Robson, B.A. and Nuth, C. and Dahl, S.O. and Holbling, D. and Strozzi, T. and Nielsen, P.R.},
  title = {Automated classification of debris-covered glaciers combining optical, SAR and topographic data in an object-based environment},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2015},
  volume = {170},
  pages = {372-387},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84944065736&doi=10.1016%2fj.rse.2015.10.001&partnerID=40&md5=018606e86785d4a4c1bb4a4707c94990},
  doi = {10.1016/j.rse.2015.10.001}
}
Santoro M, Beaudoin A, Beer C, Cartus O, Fransson J, Hall R, Pathe C, Schmullius C, Schepaschenko D, Shvidenko A, Thurner M and Wegmüller U (2015), "Forest growing stock volume of the northern hemisphere: Spatially explicit estimates for 2010 derived from Envisat ASAR", Remote Sensing of Environment. Vol. 168, pp. 316-334. Elsevier Inc..
Abstract: This paper presents and assesses spatially explicit estimates of forest growing stock volume (GSV) of the northern hemisphere (north of 10°N) from hyper-temporal observations of Envisat Advanced Synthetic Aperture Radar (ASAR) backscattered intensity using the BIOMASAR algorithm. Approximately 70,000 ASAR images at a pixel size of 0.01° were used to estimate GSV representative for the year 2010. The spatial distribution of the GSV across four ecological zones (polar, boreal, temperate, subtropical) was well captured by the ASAR-based estimates. The uncertainty of the retrieved GSV was smallest in boreal and temperate forest (<30% for approximately 80% of the forest area) and largest in subtropical forest. ASAR-derived GSV averages at the level of administrative units were mostly in agreement with inventory-derived estimates. Underestimation occurred in regions of very high GSV (>300m3/ha) and fragmented forest landscapes. For the major forested countries within the study region, the relative RMSE between ASAR-derived GSV averages at provincial level and corresponding values from National Forest Inventory was between 12% and 45% (average: 29%). 2015 Elsevier Inc.
BibTeX:
@article{Santoro2015316,
  author = {Santoro, M. and Beaudoin, A. and Beer, C. and Cartus, O. and Fransson, J.E.S. and Hall, R.J. and Pathe, C. and Schmullius, C. and Schepaschenko, D. and Shvidenko, A. and Thurner, M. and Wegmüller, U.},
  title = {Forest growing stock volume of the northern hemisphere: Spatially explicit estimates for 2010 derived from Envisat ASAR},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2015},
  volume = {168},
  pages = {316-334},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938319734&doi=10.1016%2fj.rse.2015.07.005&partnerID=40&md5=859d12cca27db2263d40ce493fc6ca54},
  doi = {10.1016/j.rse.2015.07.005}
}
Santoro M, Eriksson L and Fransson J (2015), "Reviewing ALOS PALSAR backscatter observations for stem volume retrieval in Swedish forest", Remote Sensing. Vol. 7(4), pp. 4290-4317. MDPI AG.
Abstract: Between 2006 and 2011, the Advanced Land Observing Satellite (ALOS) Phased Array L-type Synthetic Aperture Radar (PALSAR) instrument acquired multi-temporal datasets under several environmental conditions and multiple configurations of look angle and polarization. The extensive archive of SAR backscatter observations over the forest test sites of Krycklan (boreal) and Remningstorp (hemi-boreal), Sweden, was used to assess the retrieval of stem volume at stand level. The retrieval was based on the inversion of a simple Water Cloud Model with gaps; single estimates of stem volume are then combined to obtain the final multi-temporal estimate. The model matched the relationship between the SAR backscatter and the stem volume under all configurations. The retrieval relative Root Mean Square Error (RMSE) differed depending upon environmental conditions, polarization and look angle. Stem volume was best retrieved in Krycklan using only HV-polarized data acquired under unfrozen conditions with a look angle of 34.3° (relative RMSE: 44.0%). In Remningstorp, the smallest error was obtained using only HH-polarized data acquired under predominantly frozen conditions with a look angle of 34.3° (relative RMSE: 35.1%). The relative RMSE was below 30% for stands >20 ha, suggesting high accuracy of ALOS PALSAR estimates of stem volumes aggregated at moderate resolution. 2015 by the authors; licensee MDPI, Basel, Switzerland.
BibTeX:
@article{Santoro20154290,
  author = {Santoro, M. and Eriksson, L.E.B. and Fransson, J.E.S.},
  title = {Reviewing ALOS PALSAR backscatter observations for stem volume retrieval in Swedish forest},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2015},
  volume = {7},
  number = {4},
  pages = {4290-4317},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937932908&doi=10.3390%2frs70404290&partnerID=40&md5=3f699bcdeb1352ff2e473ca97476828c},
  doi = {10.3390/rs70404290}
}
Santoro M, Wegmüller U, Lamarche C, Bontemps S, Defourny P and Arino O (2015), "Strengths and weaknesses of multi-year Envisat ASAR backscatter measurements to map permanent open water bodies at global scale", Remote Sensing of Environment. Vol. 171, pp. 185-201. Elsevier Inc..
Abstract: The mapping of water bodies at global scale has been undertaken primarily using multi-spectral optical Earth Observation data. Limitations of optical data associatedwith non-uniform and temporally variable spectral signatures suggested investigating alternative approaches towards a more consistent and reliable detection of water bodies. Multi-year (2005-2012) observations of SAR backscattered intensities at moderate resolution from the Envisat Advanced Synthetic Aperture Radar (ASAR) instrument were used in this study to generate an indicator of open permanent water bodies (SAR-WBI) for the year 2010 time frame and for all land surfaces excluding Antarctica and the Greenland ice sheet. A first map of potential water bodies with a spatial resolution of 150 m was obtained with a global detection algorithm based on a set of thresholds applied to multi-temporal metrics of the SAR backscatter (temporal variability, TV, and minimum backscatter, MB). Local refinements were then used to reduce systematic commission and omission errors (4.6% of the total area mapped) due to the similarity of TV and MB over open water bodies and other land surface types primarily in cold and arid environments. The refinement rules are here explained by means of a detailed signature analysis of the SAR backscatter in such environments. The accuracy of the SAR-WBIwas 80%when compared against 2078 manually interpreted footprints with a size of 150 × 150 m2. Omission errors were primarily observed along coast- and shorelines whereas commission errors were associated with (i) ephemeral water bodies, (ii) seasonally inundated areas, and (iii) an incorrect choice of the local refinement. 2015 Elsevier Inc.
BibTeX:
@article{Santoro2015185,
  author = {Santoro, M. and Wegmüller, U. and Lamarche, C. and Bontemps, S. and Defourny, P. and Arino, O.},
  title = {Strengths and weaknesses of multi-year Envisat ASAR backscatter measurements to map permanent open water bodies at global scale},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2015},
  volume = {171},
  pages = {185-201},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946542137&doi=10.1016%2fj.rse.2015.10.031&partnerID=40&md5=44f6814afd98dec0c446ca3bcae50ae3},
  doi = {10.1016/j.rse.2015.10.031}
}
Santoro M, Wegmüller U, Wiesmann A, Lamarche C, Bontemps S, Defourny P and Arino O (2015), "Assessing Envisat ASAR and Sentinel-1 multi-temporal observations to map open water bodies", In Proceedings of the 2015 IEEE 5th Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2015. , pp. 614-619. Institute of Electrical and Electronics Engineers Inc..
Abstract: C-band observations of the SAR backscatter from the Envisat ASAR (2005-2012) and Sentinel-1 (2014-ongoing) instruments are reviewed to understand their suitability to detect of open water bodies. The temporal variability (TV) and the minimum backscatter (MB) of ASAR backscatter were fed to a simple algorithm based on thresholds to obtain an indicator of water bodies globally with a spatial resolution of 150 m. Confusion occurred either in the case of irregular acquisitions of ASAR images or in cold and arid regions where the multi-temporal metrics based on the multi-year ASAR dataset were often similar to values obtained over open water bodies. With Sentinel-1, there are clear chances to improve the mapping of water bodies considering the dual-polarization capability, the higher spatial resolution and the more consistent observation strategy. First examples from a test site in Sweden show that average and minimum cross-polarized backscatter are suited for water body mapping. 2015 IEEE.
BibTeX:
@conference{Santoro2015614,
  author = {Santoro, M. and Wegmüller, U. and Wiesmann, A. and Lamarche, C. and Bontemps, S. and Defourny, P. and Arino, O.},
  title = {Assessing Envisat ASAR and Sentinel-1 multi-temporal observations to map open water bodies},
  booktitle = {Proceedings of the 2015 IEEE 5th Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2015},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  pages = {614-619},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957613901&doi=10.1109%2fAPSAR.2015.7306283&partnerID=40&md5=a44efb3e0f8779a43a182929f310ad01},
  doi = {10.1109/APSAR.2015.7306283}
}
Schmullius C, Thiel C, Pathe C and Santoro M (2015), "Radar time series for land cover and forest mapping", Remote Sensing and Digital Image Processing. Vol. 22, pp. 323-356. Springer International Publishing.
Abstract: Radar time series are powerful means to improve retrieval algorithms about land surface characteristics in the following ways: (i) as information for identification of land surface conditions, (ii) as source of multivariate statistics for mapping methodologies, (iii) to select the right scene(s) for dedicated retrieval procedures, or (iv) to train model parameters in physical retrievals. Albeit radar data from air- and spaceborne platforms have been investigated since 40 years, operational applications are limited - partly due to the non-intuitive handling of complex microwave backscatter signals, and partly due to restricted geometric and temporal resolutions or frequency and polarization constraints. This chapter gives an overview of 20 years of pilot projects performed by the authors and their collaborators with the goal of large-area radar data exploration. All studies lead to innovative pre-operational applications, several with promising discoveries that can now be realized with a new and expanding fleet of radar satellites. Four case studies for land cover, forest mapping, forest cover change and savannah monitoring conclude this chapter. Springer International Publishing Switzerland 2015.
BibTeX:
@article{Schmullius2015323,
  author = {Schmullius, C. and Thiel, C. and Pathe, C. and Santoro, M.},
  title = {Radar time series for land cover and forest mapping},
  journal = {Remote Sensing and Digital Image Processing},
  publisher = {Springer International Publishing},
  year = {2015},
  volume = {22},
  pages = {323-356},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84980010210&doi=10.1007%2f978-3-319-15967-6_16&partnerID=40&md5=4c92d89b74813b5378544b2d41c2d571},
  doi = {10.1007/978-3-319-15967-6_16}
}
Schwank M, Matzler C, Wiesmann A, Wegmüller U, Pulliainen J, Lemmetyinen J, Rautiainen K, Derksen C, Toose P and Drusch M (2015), "Snow Density and Ground Permittivity Retrieved from L-Band Radiometry: A Synthetic Analysis", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 8(8), pp. 3833-3845. Institute of Electrical and Electronics Engineers.
Abstract: A synthetic study was performed to determine the potential to retrieve dry-snow density and ground permittivity from multiangular L-band brightness temperatures. The thereto employed emission model was developed from parts of the 'microwave emission model of layered snowpacks' (MEMLS) coupled with components adopted from the 'L-band microwave emission of the biosphere' (L-MEB) model. The restriction to L-band made it possible to avoid scattering and absorption in the snow volume, leading to a rather simple formulation of our emission model. Parametric model studies revealed L-band signatures related to the mass density of the bottom layer of a dry snowpack. This gave rise to the presented analysis of corresponding retrieval performances based on measurements synthesized with the developed emission model. The question regarding the extent to which random noise translates into retrieval uncertainties was investigated. It was found that several classes of snow densities could be distinguished by retrievals based on L-band brightness temperatures with soil moisture and ocean salinity (SMOS)-typical data quality. Further synthetic retrievals demonstrated that propagation effects must be taken into account in dry snow even at L-band when retrieving permittivity of the underlying ground surface. Accordingly, current SMOS-based retrievals seam to underestimate actual ground permittivity by typically 30% as dry snow is wrongly considered as 'invisible.' Although experimental validation has not yet been performed, the proposed retrieval approach is seen as a promising step toward the full exploitation of L-band brightness temperatures available from current and future satellite Earth observation missions, especially over the cold regions of the Northern Hemisphere. 2008-2012 IEEE.
BibTeX:
@article{Schwank20153833,
  author = {Schwank, M. and Matzler, C. and Wiesmann, A. and Wegmüller, U. and Pulliainen, J. and Lemmetyinen, J. and Rautiainen, K. and Derksen, C. and Toose, P. and Drusch, M.},
  title = {Snow Density and Ground Permittivity Retrieved from L-Band Radiometry: A Synthetic Analysis},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2015},
  volume = {8},
  number = {8},
  pages = {3833-3845},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961945090&doi=10.1109%2fJSTARS.2015.2422998&partnerID=40&md5=6aa21a8daaaead83a5b4f0936b672ffc},
  doi = {10.1109/JSTARS.2015.2422998}
}
Siddique M, Hajnsek I, Wegmüller U and Frey O (2015), "Investigating the combined use of differential SAR tomography and PSI for spatio-temporal inversion", In 2015 Joint Urban Remote Sensing Event, JURSE 2015. Institute of Electrical and Electronics Engineers Inc..
Abstract: Persistent Scatterer Interferometry (PSI) inherently assumes a single temporally coherent scatterer inside a range-azimuth resolution cell. This restriction leads to the rejection of numerous persistent scatterer (PS) candidates, particularly in urban areas where layovers occur frequently. Moreover, in case of high-rise buildings, it is necessary to compensate the phase associated with thermal expansion in an iterative way. It is worthwhile to approach tomographic techniques to address these concerns. SAR tomography has the potential to separate scatterers in elevation, thus resolving layover. Differential SAR tomography additionally allows retrieval of deformation parameters, including a possible thermal expansion term. In this paper, we investigate the combined use of SAR tomographic approaches and PSI for elevation and deformation estimation. Results are presented for an interferometric time-series of 50 TerraSAR-X stripmap images acquired over Barcelona city. Spatio-temporal inversion of scatterers along the façade of a high-rise building is presented as a special case. 2015 IEEE.
BibTeX:
@conference{Siddique2015b,
  author = {Siddique, M.A. and Hajnsek, I. and Wegmüller, U. and Frey, O.},
  title = {Investigating the combined use of differential SAR tomography and PSI for spatio-temporal inversion},
  booktitle = {2015 Joint Urban Remote Sensing Event, JURSE 2015},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938894010&doi=10.1109%2fJURSE.2015.7120504&partnerID=40&md5=c5ebbe8d0efad3d89f46ce27858f397f},
  doi = {10.1109/JURSE.2015.7120504}
}
Siddique M, Hajnsek I, Wegmüller U and Frey O (2015), "Towards the integration of SAR tomography and PSI for improved deformation assessment in urban areas", In European Space Agency, (Special Publication) ESA SP. Vol. SP-731 European Space Agency.
Abstract: Persistent scatterer interferometry (PSI) typically rejects the range-azimuth pixels containing multiple scatterers, such as in a layover scenario. Since layovers occur frequently in urban areas, a significant number of candidates may get rejected. SAR tomography allows for resolving layover and has thus the potential to extend the spatial sampling of deformation measurements to layoveraffected areas. Using extended phase models, also taking into account temperature, an improved simultaneous estimation of elevation, deformation velocity, and temperature-induced scatterer displacement is possible. This paper explores the combined use of PSI and SAR tomography for deformation analysis in urban areas, using a multibaseline and multitemporal interferometric stack of stripmap TerraSAR-X images acquired over the city of Barcelona.
BibTeX:
@conference{Siddique2015a,
  author = {Siddique, M.A. and Hajnsek, I. and Wegmüller, U. and Frey, O.},
  editor = {Ouwehand L.},
  title = {Towards the integration of SAR tomography and PSI for improved deformation assessment in urban areas},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  publisher = {European Space Agency},
  year = {2015},
  volume = {SP-731},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961797224&partnerID=40&md5=bcf3d1064a504ae2ea3c987471325878}
}
Siddique M, Wegmüller U, Hajnsek I and Frey O (2015), "SAR tomography for spatio-temporal inversion of point-like scatterers in urban areas", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2015-November, pp. 5272-5275. Institute of Electrical and Electronics Engineers Inc..
Abstract: Persistent scatterer interferometry (PSI) assumes the presence of a single temporally coherent scatterer in a range-azimuth pixel. Multiple scatterers interfering in the same pixel, as for the case of a layover, are typically rejected. Conventional SAR tomography (3D SAR) is a means to separate the individual scatterers in layover. Advanced tomographic inversion approaches employing extended phase models additionally allow simultaneous retrieval of scatterer elevation and deformation parameters. In this way, SAR tomography can increase deformation sampling and thereby complement a PSI-based analysis. This paper investigates the use of tomography as an add-on to PSI for spatio-temporal inversion of single and double scatterers in urban areas. Results are provided on an interferometric stack of 50 stripmap TerraSAR-X images acquired over the city of Barcelona. 2015 IEEE.
BibTeX:
@conference{Siddique20155272,
  author = {Siddique, M.A. and Wegmüller, U. and Hajnsek, I. and Frey, O.},
  title = {SAR tomography for spatio-temporal inversion of point-like scatterers in urban areas},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  volume = {2015-November},
  pages = {5272-5275},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962505282&doi=10.1109%2fIGARSS.2015.7327024&partnerID=40&md5=e2dfbc7b75d848679e775726b40fd94e},
  doi = {10.1109/IGARSS.2015.7327024}
}
Strozzi T, Raetzo H, Wegmüller U, Papke J, Caduff R, Werner C and Wiesmann A (2015), "Satellite and Terrestrial Radar Interferometry for the Measurement of Slope Deformation", Engineering Geology for Society and Territory - Volume 5: Urban Geology, Sustainable Planning and Landscape Exploitation. , pp. 161-165. Springer International Publishing.
Abstract: Synergistic use of satellite and terrestrial radar interferometry was considered for the measurement of slope deformation in the Mattervalley (Canton of Valais, Switzerland). Highest rates of movement of more than 1cm/day were measured only with terrestrial radar interferometry, because of the large time interval between satellite SAR observations. Summer TerraSAR-X and Cosmo-SkyMed interferograms as well as terrestrial radar interferometry campaigns repeated with a time interval of a few days were jointly considered for the study of landslides moving at rates of dm/year. Persistent scatterer interferometric analyses conducted with ERS-1/2, ENVISAT, Radarsat-2, TerraSAR-X and Cosmo-Sky Med images were finally used to detect the slowest moving landslides, with rates of movement below a few cm/yr in the line-of-sight direction. . Springer International Publishing Switzerland 2015.
BibTeX:
@book{Strozzi2015161,
  author = {Strozzi, T. and Raetzo, H. and Wegmüller, U. and Papke, J. and Caduff, R. and Werner, C. and Wiesmann, A.},
  title = {Satellite and Terrestrial Radar Interferometry for the Measurement of Slope Deformation},
  journal = {Engineering Geology for Society and Territory - Volume 5: Urban Geology, Sustainable Planning and Landscape Exploitation},
  publisher = {Springer International Publishing},
  year = {2015},
  pages = {161-165},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84944573073&doi=10.1007%2f978-3-319-09048-1_32&partnerID=40&md5=7f3386ea00538d8b8107596f02df3c98},
  doi = {10.1007/978-3-319-09048-1_32}
}
Tanase M, Ismail I, Lowell K, Karyanto O and Santoro M (2015), "Detecting and quantifying forest change: The potential of existing C- and X-band radar datasets", PLoS ONE. Vol. 10(6) Public Library of Science.
Abstract: This paper evaluates the opportunity provided by global interferometric radar datasets for monitoring deforestation, degradation and forest regrowth in tropical and semi-arid environments. The paper describes an easy to implement method for detecting forest spatial changes and estimating their magnitude. The datasets were acquired within space-borne high spatial resolutions radar missions at near-global scales thus being significant for monitoring systems developed under the United Framework Convention on Climate Change (UNFCCC). The approach presented in this paper was tested in two areas located in Indonesia and Australia. Forest change estimation was based on differences between a reference dataset acquired in February 2000 by the Shuttle Radar Topography Mission (SRTM) and TanDEM-X mission (TDM) datasets acquired in 2011 and 2013. The synergy between SRTM and TDM datasets allowed not only identifying changes in forest extent but also estimating their magnitude with respect to the reference through variations in forest height. 2015 Tanase et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
BibTeX:
@article{Tanase2015,
  author = {Tanase, M.A. and Ismail, I. and Lowell, K. and Karyanto, O. and Santoro, M.},
  title = {Detecting and quantifying forest change: The potential of existing C- and X-band radar datasets},
  journal = {PLoS ONE},
  publisher = {Public Library of Science},
  year = {2015},
  volume = {10},
  number = {6},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938508124&doi=10.1371%2fjournal.pone.0131079&partnerID=40&md5=68848cfa0bbe740691390daa1b483da9},
  doi = {10.1371/journal.pone.0131079}
}
Torrero L, Seoli L, Molino A, Giordan D, Manconi A, Allasia P and Baldo M (2015), "The use of micro-uav to monitor active landslide scenarios", Engineering Geology for Society and Territory - Volume 5: Urban Geology, Sustainable Planning and Landscape Exploitation. , pp. 701-704. Springer International Publishing.
Abstract: We present a procedure to use micro-UAV (Unmanned Aerial Vehicles) to perform photogrammetry survey and monitoring analysis in landslide scenarios. The employed methodology is mainly composed of two phases: the first one is the UAV mission planning and execution, while the latter is the picture elaboration and alignment. The UAV used during all tests here described has been developed for photographic applications. Thanks to its –V— shape, propellers do not fall within camera field during normal flight operation and the eight motors configuration ensures more reliability in urban areas uses than a classical quadcopter configuration. The processing of the acquired photos relies on both standard photogrammetry procedure as well as innovative methods for photo alignment derived from computer vision algorithms. Examples of application are also provided to show the results and the potential of this methodology in real landslide scenarios. Springer International Publishing Switzerland 2015.
BibTeX:
@book{Torrero2015701,
  author = {Torrero, L. and Seoli, L. and Molino, A. and Giordan, D. and Manconi, A. and Allasia, P. and Baldo, M.},
  title = {The use of micro-uav to monitor active landslide scenarios},
  journal = {Engineering Geology for Society and Territory - Volume 5: Urban Geology, Sustainable Planning and Landscape Exploitation},
  publisher = {Springer International Publishing},
  year = {2015},
  pages = {701-704},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921923667&doi=10.1007%2f978-3-319-09048-1_136&partnerID=40&md5=c17587c5e1a0064efb76f5b1c5f03ef8},
  doi = {10.1007/978-3-319-09048-1_136}
}
Tosi L, Strozzi T, Da Lio C and Teatini P (2015), "Regional and local land subsidence at the Venice coastland by TerraSAR-X PSI", In Proceedings of the International Association of Hydrological Sciences. Vol. 372, pp. 199-205. Copernicus GmbH.
Abstract: Land subsidence occurred at the Venice coastland over the 2008-2011 period has been investigated by Persistent Scatterer Interferometry (PSI) using a stack of 90 TerraSAR-X stripmap images with a 3 m resolution and a 11-day revisiting time. The regular X-band SAR acquisitions over more than three years coupled with the very-high image resolution has significantly improved the monitoring of ground displacements at regional and local scales, e.g., the entire lagoon, especially the historical palaces, the MoSE large structures under construction at the lagoon inlets to disconnect the lagoon from the Adriatic Sea during high tides, and single small structures scattered within the lagoon environments. Our results show that subsidence is characterized by a certain variability at the regional scale with superimposed important local displacements. The movements range from a gentle uplift to subsidence rates of up to 35 mm yr-1. For instance, settlements of 30-35 mm yr-1 have been detected at the three lagoon inlets in correspondence of the MoSE works, and local sinking bowls up to 10 mm yr-1 connected with the construction of new large buildings or restoration works have been measured in the Venice and Chioggia historical centers. Focusing on the city of Venice, the mean subsidence of 1.1 ± 1.0 mm yr-1 confirms the general stability of the historical center. Author(s) 2015. CC Attribution 3.0 License.
BibTeX:
@conference{Tosi2015199,
  author = {Tosi, L. and Strozzi, T. and Da Lio, C. and Teatini, P.},
  title = {Regional and local land subsidence at the Venice coastland by TerraSAR-X PSI},
  booktitle = {Proceedings of the International Association of Hydrological Sciences},
  publisher = {Copernicus GmbH},
  year = {2015},
  volume = {372},
  pages = {199-205},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988457399&doi=10.5194%2fpiahs-372-199-2015&partnerID=40&md5=05c9fb3f9cd1f34a53f3d3a08ad65e6b},
  doi = {10.5194/piahs-372-199-2015}
}
Volksch I, Schwank M, Stahli M and Matzler C (2015), "Relief effects on the L-band emission of a bare soil", Remote Sensing. Vol. 7(11), pp. 14327-14359. MDPI AG.
Abstract: In a combined experimental and model study, we investigated effects of surface topography (relief) on the thermal L-band emission of a sandy soil. To this end, brightness temperatures of two adjacent footprint areas were measured quasi-simultaneously with an L-band radiometer at the observation angle of 55° relative to nadir for one year. One footprint featured a distinct relief in the form of erosion gullies with steep slopes, whereas the surface of the second footprint was smooth. Additionally, hydrometeorological variables, in situ soil moisture and temperature were measured, and digital terrain models of the two scenes were derived from terrestrial laser scanning. A facet model, taking into account the topography of the footprint surfaces as well as the antenna's directivity, was developed and brightness temperatures of both footprints were simulated based on the hydrometeorological and in situ soil data. We found that brightness temperatures of the footprint with the distinct surface relief were increased at horizontal and decreased at vertical polarization with respect to those of the plane footprint. The simulations showed that this is mainly due to modifications of local (facet) observation angles and due to polarization mixing caused by the pronounced relief. Measurements furthermore revealed that brightness temperatures of both areas respond differently to changing ambient conditions indicating differences in their hydrological properties. 2015 by the authors.
BibTeX:
@article{Volksch201514327,
  author = {Volksch, I. and Schwank, M. and Stahli, M. and Matzler, C.},
  title = {Relief effects on the L-band emission of a bare soil},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2015},
  volume = {7},
  number = {11},
  pages = {14327-14359},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84950105743&doi=10.3390%2frs71114327&partnerID=40&md5=513e9bd8f98b6ffb860fb709725f4512},
  doi = {10.3390/rs71114327}
}
Voytenko D, Dixon T, Howat I, Gourmelen N, Lembke C, Werner C, De La Pena S and Oddsson B (2015), "Multi-year observations of Breidamerkurjokull, a marine-terminating glacier in southeastern Iceland, using terrestrial radar interferometry", Journal of Glaciology. Vol. 61(225), pp. 42-54. International Glaciology Society.
Abstract: Terrestrial radar interferometry (TRI) is a new technique for studying ice motion and volume change of glaciers. TRI is especially useful for temporally and spatially dense measurements of highly dynamic glacial termini. We conducted a TRI survey of Breioamerkurjokull, a marine-terminating glacier in Iceland, imaging its terminus near the end of the melt season in 2011, 2012 and 2013. The ice velocities were as high as 5 m d-1, with the fastest velocities near the calving front. Retreat of the glacier over the 3 year observation period was accompanied by strong embayment formation. Iceberg tracking with the radar shows high current velocities near the embayment, probably indicating strong meltwater outflow and mixing with relatively warm lagoon water. 2015, International Glaciology Society. All rights reserved.
BibTeX:
@article{Voytenko201542,
  author = {Voytenko, D. and Dixon, T.H. and Howat, I.M. and Gourmelen, N. and Lembke, C. and Werner, C.L. and De La Pena, S. and Oddsson, B.},
  title = {Multi-year observations of Breidamerkurjokull, a marine-terminating glacier in southeastern Iceland, using terrestrial radar interferometry},
  journal = {Journal of Glaciology},
  publisher = {International Glaciology Society},
  year = {2015},
  volume = {61},
  number = {225},
  pages = {42-54},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84929412802&doi=10.3189%2f2015JoG14J099&partnerID=40&md5=b6ba1f95d3ed3fc6b99e14167ec0b916},
  doi = {10.3189/2015JoG14J099}
}
Wegmüller U, Santoro M, Werner C and Cartus O (2015), "On the estimation and interpretation of sentinel-1 TOPS InSAR coherence", In European Space Agency, (Special Publication) ESA SP. Vol. SP-731 European Space Agency.
Abstract: Sentinel-1 IWS acquisitions can be used for SAR interferometry. In our contribution the focus is on the S1 IWS InSAR coherence. For this we address in a first part the interferogram generation and coherence estimation. Then in a second part we use data examples to get a first impression on the potential of the S1 IWS InSAR coherence for landuse classification and to monitor temporal change.
BibTeX:
@conference{Wegmuller2015a,
  author = {Wegmüller, U. and Santoro, M. and Werner, C. and Cartus, O.},
  editor = {Ouwehand L.},
  title = {On the estimation and interpretation of sentinel-1 TOPS InSAR coherence},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  publisher = {European Space Agency},
  year = {2015},
  volume = {SP-731},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961777762&partnerID=40&md5=f51d24a6d4fcd5cac32f211591fa1210}
}
Wegmüller U, Strozzi T and Werner C (2015), "Earthquake damage mapping using the coherence of persistent scatterers", In European Space Agency, (Special Publication) ESA SP. Vol. SP-731 European Space Agency.
Abstract: After an Earthquake earth observation methods can support the damage assessment. In this contribution we describe an earthquake damage mapping methodology that is based on the coherence of persistent scatterers using a stack of ENVISAT ASAR images. Comparing the damage map generated for Christchurch, New Zeeland, after the Darfield Earthquake on 3-Sep-2010 with liquefaction maps resulting from in-situ assessments indicates a good potential of this methodology in this case.
BibTeX:
@conference{Wegmuller2015c,
  author = {Wegmüller, U. and Strozzi, T. and Werner, C.},
  editor = {Ouwehand L.},
  title = {Earthquake damage mapping using the coherence of persistent scatterers},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  publisher = {European Space Agency},
  year = {2015},
  volume = {SP-731},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961777960&partnerID=40&md5=a9ad296b3b575c70283c05270576cf03}
}
Wegmüller U and Werner C (2015), "Mitigation of thermal expansion phase in persistent scatterer interferometry in an urban environment", In 2015 Joint Urban Remote Sensing Event, JURSE 2015. Institute of Electrical and Electronics Engineers Inc..
Abstract: In an urban environment the differential phase due to thermal expansion of structures is relevant. Uncorrected, the thermal expansion phase leads to a loss of persistent scatterers and increased errors in the deformation time series. In the upper part of tall buildings the thermal expansion phase can vary strongly over time which may result in a complete lack of displacement information if uncompensated. The objective of our work was to estimate and mitigate the thermal expansion phase in our PSI processing. As a result it became possible to include tall buildings into the PSI solution and the accuracy of the solution was improved for all scatterers affected by thermal expansion. 2015 IEEE.
BibTeX:
@conference{wegmuller2015,
  author = {Wegmüller, U. and Werner, C.},
  title = {Mitigation of thermal expansion phase in persistent scatterer interferometry in an urban environment},
  booktitle = {2015 Joint Urban Remote Sensing Event, JURSE 2015},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938823390&doi=10.1109%2fJURSE.2015.7120505&partnerID=40&md5=2150c097bdb26859f4c5a6ad96742d26},
  doi = {10.1109/JURSE.2015.7120505}
}
Wegmüller U, Werner C, Strozzi T, Wiesmann A, Frey O and Santoro M (2015), "Sentinel-1 IWS mode support in the GAMMA software", In Proceedings of the 2015 IEEE 5th Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2015. , pp. 431-436. Institute of Electrical and Electronics Engineers Inc..
Abstract: First results using the new Sentinel-1 SAR look very promising, but the special interferometrie wide-swath (IWS) data acquired in the FOPS mode makes InSAR processing challenging. Fhe steep azimuth spectra ramp in each burst results in very stringent co-registration requirements. Combining the data of the individual bursts and sub-swaths into consistent mosaics requires careful 'bookkeeping' in the handling of the data and meta data and the large file sizes and high data throughputs require also a good performance. Considering these challenges good support from software is getting increasingly important. In this contribution we describe the Sentinel-1 support in the GAMMA Software, a high-level software package used by researchers, service providers and operational users in their SAR, InSAR and PSI work. 2015 IEEE.
BibTeX:
@conference{Wegmuller2015431,
  author = {Wegmüller, U. and Werner, C. and Strozzi, T. and Wiesmann, A. and Frey, O. and Santoro, M.},
  title = {Sentinel-1 IWS mode support in the GAMMA software},
  booktitle = {Proceedings of the 2015 IEEE 5th Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2015},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2015},
  pages = {431-436},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957687024&doi=10.1109%2fAPSAR.2015.7306242&partnerID=40&md5=214ec9f71b2f0e46a244cb8eb1811243},
  doi = {10.1109/APSAR.2015.7306242}
}
Wiesmann A, Caduff R and Matzler C (2015), "Terrestrial radar observations of dynamic changes in alpine snow", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 8(7), pp. 3665-3671. Institute of Electrical and Electronics Engineers.
Abstract: Remote sensing of snow with active and passive microwaves on terrestrial, aerial, and satellite platforms has a long tradition. However, the observation of dynamic processes on alpine slopes is difficult due to fixed satellite orbits and consequently given observation geometry and interval and in some cases, also the lack of spatial resolution. Furthermore, the interferometric phase can only be used for displacement measurements if the displacement direction is more or less in the line of sight direction and the observation interval is shorter than the decorrelation time. The use of a terrestrial radar interferometer allows to overcome some of these constraints thanks to the portability of the system, the possibility to make repeat acquisitions in short intervals, and the regional observation capability. In this study, the GPRI (GAMMA portable radar interferometer, [1]) was used that is easily deployable in the field, produces images at meter scale resolution, and allows repeat acquisitions within a minute. Results of two campaigns conducted in the Swiss Alps prove the potential of terrestrial radar to measure rapid and local changes in snow parameters such as changes in the liquid water content and sudden changes in the snowpack due to skiers and avalanches. Using standard interferometric techniques, it was also possible to compute a regional snow displacement map providing information about creeping snow locations, displacement rates, and history. 2015 IEEE.
BibTeX:
@article{Wiesmann20153665,
  author = {Wiesmann, A. and Caduff, R. and Matzler, C.},
  title = {Terrestrial radar observations of dynamic changes in alpine snow},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2015},
  volume = {8},
  number = {7},
  pages = {3665-3671},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939532992&doi=10.1109%2fJSTARS.2015.2400972&partnerID=40&md5=e0bca78bd2783c7e3de23b96e4c70f0a},
  doi = {10.1109/JSTARS.2015.2400972}
}
Blunden J. and Arndt Eds. DS (2014), "State of the climate in 2013", Bulletin of the American Meteorological Society. Vol. 95(7), pp. 1-279. American Meteorological Society.
Abstract: In 2013, the vast majority of the monitored climate variables reported here maintained trends established in recent decades. ENSO was in a neutral state during the entire year, remaining mostly on the cool side of neutral with modest impacts on regional weather patterns around the world. This follows several years dominated by the effects of either La Nina or El Nino events. According to several independent analyses, 2013 was again among the 10 warmest years on record at the global scale, both at the Earth's surface and through the troposphere. Some regions in the Southern Hemisphere had record or near-record high temperatures for the year. Australia observed its hottest year on record, while Argentina and New Zealand reported their second and third hottest years, respectively. In Antarctica, Amundsen-Scott South Pole Station reported its highest annual temperature since records began in 1957. At the opposite pole, the Arctic observed its seventh warmest year since records began in the early 20th century. At 20-m depth, record high temperatures were measured at some permafrost stations on the North Slope of Alaska and in the Brooks Range. In the Northern Hemisphere extratropics, anomalous meridional atmospheric circulation occurred throughout much of the year, leading to marked regional extremes of both temperature and precipitation. Cold temperature anomalies during winter across Eurasia were followed by warm spring temperature anomalies, which were linked to a new record low Eurasian snow cover extent in May. Minimum sea ice extent in the Arctic was the sixth lowest since satellite observations began in 1979. Including 2013, all seven lowest extents on record have occurred in the past seven years. Antarctica, on the other hand, had above-average sea ice extent throughout 2013, with 116 days of new daily high extent records, including a new daily maximum sea ice area of 19.57 million km2 reached on 1 October. ENSO-neutral conditions in the eastern central Pacific Ocean and a negative Pacific decadal oscillation pattern in the North Pacific had the largest impacts on the global sea surface temperature in 2013. The North Pacific reached a historic high temperature in 2013 and on balance the globally-averaged sea surface temperature was among the 10 highest on record. Overall, the salt content in nearsurface ocean waters increased while in intermediate waters it decreased. Global mean sea level continued to rise during 2013, on pace with a trend of 3.2 mm yr-1 over the past two decades. A portion of this trend (0.5 mm yr-1) has been attributed to natural variability associated with the Pacific decadal oscillation as well as to ongoing contributions from the melting of glaciers and ice sheets and ocean warming. Global tropical cyclone frequency during 2013 was slightly above average with a total of 94 storms, although the North Atlantic Basin had its quietest hurricane season since 1994. In the Western North Pacific Basin, Super Typhoon Haiyan, the deadliest tropical cyclone of 2013, had 1-minute sustained winds estimated to be 170 kt (87.5 m s-1) on 7 November, the highest wind speed ever assigned to a tropical cyclone. High storm surge was also associated with Haiyan as it made landfall over the central Philippines, an area where sea level is currently at historic highs, increasing by 200 mm since 1970. In the atmosphere, carbon dioxide, methane, and nitrous oxide all continued to increase in 2013. As in previous years, each of these major greenhouse gases once again reached historic high concentrations. In the Arctic, carbon dioxide and methane increased at the same rate as the global increase. These increases are likely due to export from lower latitudes rather than a consequence of increases in Arctic sources, such as thawing permafrost. At Mauna Loa, Hawaii, for the first time since measurements began in 1958, the daily average mixing ratio of carbon dioxide exceeded 400 ppm on 9 May. The state of these variables, along with dozens of others, and the 2013 climate conditions of regions around the world are discussed in further detail in this 24th edition of the State of the Climate series. 2014, American Meteorological Society. All rights reserved.
BibTeX:
@article{Blunden2014S1,
  author = {Blunden, J., and Arndt Eds., D. S.},
  title = {State of the climate in 2013},
  journal = {Bulletin of the American Meteorological Society},
  publisher = {American Meteorological Society},
  year = {2014},
  volume = {95},
  number = {7},
  pages = {1-279},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84910080574&doi=10.1175%2f2014BAMSStateoftheClimate.1&partnerID=40&md5=616bb425324b4ca206a31dfe2282c214},
  doi = {10.1175/2014BAMSStateoftheClimate.1}
}
Caduff R, Kos A, Schlunegger F, McArdell B and Wiesmann A (2014), "Terrestrial radar interferometric measurement of hillslope deformation and atmospheric disturbances in the Illgraben debris-flow catchment, Switzerland", IEEE Geoscience and Remote Sensing Letters. Vol. 11(2), pp. 434-438. Institute of Electrical and Electronics Engineers Inc..
Abstract: We describe a method for rapid identification and precise quantification of slope deformation using a portable radar interferometer. A rockslide with creep-like behavior was identified in the rugged and inaccessible headwaters of the Illgraben debris-flow catchment, located in the Central Swiss Alps. The estimated volume of the moving rock mass was approximately 0.5 × 10 6 m3 with a maximum daily (3-D) displacement rate of 3 mm. Fast scene acquisition in the order of 6 s/scene led to uniquely precise mapping of spatial and temporal variability of atmospheric phase delay. Observations led to a simple qualitative model for prediction of atmospheric disturbances using a simple model for solar radiation, which can be used for advanced campaign planning for short observation periods (hours to days). 2013 IEEE.
BibTeX:
@article{Caduff2014434,
  author = {Caduff, R. and Kos, A. and Schlunegger, F. and McArdell, B.W. and Wiesmann, A.},
  title = {Terrestrial radar interferometric measurement of hillslope deformation and atmospheric disturbances in the Illgraben debris-flow catchment, Switzerland},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2014},
  volume = {11},
  number = {2},
  pages = {434-438},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84896332706&doi=10.1109%2fLGRS.2013.2264564&partnerID=40&md5=ad25c7cabf1275431315dee44a2ab371},
  doi = {10.1109/LGRS.2013.2264564}
}
Caduff R and Rieke-Zapp D (2014), "Registration and visualisation of deformation maps from terrestrial radar interferometry using photogrammetry and structure from motion", Photogrammetric Record. Vol. 29(146), pp. 167 -186. Blackwell Publishing Ltd.
Abstract: This paper describes a general workflow for the registration of terrestrial radar interferometric data with 3D point clouds derived from terrestrial photogrammetry and structure from motion. After the determination of intrinsic and extrinsic orientation parameters, data obtained by terrestrial radar interferometry were projected on point clouds and then on the initial photographs. Visualisation of slope deformation measurements on photographs provides an easily understandable and distributable information product, especially of inaccessible target areas such as steep rock walls or in rockfall run-out zones. The suitability and error propagation of the referencing steps and final visualisation of four approaches are compared: (a) the classic approach using a metric camera and stereo-image photogrammetry;(b) images acquired with a metric camera, automatically processed using structure from motion; (c) images acquired with a digital compact camera, processed with structure from motion; and (d) a markerless approach, using images acquired with a digital compact camera using structure from motion without artificial ground control points. The usability of the completely markerless approach for the visualisation of high-resolution radar interferometry assists the production of visualisation products for interpretation. 2014 The Remote Sensing and Photogrammetry Society and John Wiley & Sons Ltd.
BibTeX:
@article{Caduff2014167,
  author = {Caduff, R. and Rieke-Zapp, D.},
  title = {Registration and visualisation of deformation maps from terrestrial radar interferometry using photogrammetry and structure from motion},
  journal = {Photogrammetric Record},
  publisher = {Blackwell Publishing Ltd},
  year = {2014},
  volume = {29},
  number = {146},
  pages = {167 -186},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84902526662&doi=10.1111%2fphor.12058&partnerID=40&md5=74348c6b53b2302b14d73fdebd807237},
  doi = {10.1111/phor.12058}
}
Canavero M, Murk A, Matzler C, Notel D and Huck J (2014), "Radiometric active indoor imaging in the W-band", Journal of Infrared, Millimeter, and Terahertz Waves. Vol. 35(2), pp. 218-241. Springer New York LLC.
Abstract: Millimeter wave passive imaging systems constitute a good compromise between resolution and penetration depth for a variety of imaging applications. In an outdoor scenario, the cold sky radiation, interacting with the reflectivity characteristics of the targets, constitutes the main source of contrast in the acquired images. In indoor applications such a source is not available, and higher thermal sensitivity is required. Alternatively, one has to provide an artificial illumination to the scene in order to increase its dynamic range. The implementation of an active source for a passive radiometer can, under certain conditions, increase the contrast of the images acquired and add extra information to the measurement. With such a setup, outdoor systems can be used for indoor observations (the absence of cold sky radiation is compensated with active illumination). The subject of our study is to better understand which kind of source and which setup can provide a diffuse illumination over the targets. This topic was investigated by conducting observations of various indoor scenes with two radiometers in the W-Band, using noise and continuous wave (CW) sources as illumination. In this paper we present the results achieved and our conclusions in order to provide an efficient illumination for indoor environment. 2013 Springer Science+Business Media New York.
BibTeX:
@article{Canavero2014218,
  author = {Canavero, M. and Murk, A. and Matzler, C. and Notel, D. and Huck, J.},
  title = {Radiometric active indoor imaging in the W-band},
  journal = {Journal of Infrared, Millimeter, and Terahertz Waves},
  publisher = {Springer New York LLC},
  year = {2014},
  volume = {35},
  number = {2},
  pages = {218-241},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894133339&doi=10.1007%2fs10762-013-0045-9&partnerID=40&md5=39acfd5749c70fd98bc59dc4a15388b8},
  doi = {10.1007/s10762-013-0045-9}
}
Cartus O, Kellndorfer J, Walker W, Franco C, Bishop J, Santos L and Fuentes J (2014), "A national, detailed map of forest aboveground carbon stocks in Mexico", Remote Sensing. Vol. 6(6), pp. 5559-5588. MDPI AG.
Abstract: A spatially explicit map of aboveground carbon stored in Mexico's forests was generated from empirical modeling on forest inventory and spaceborne optical and radar data. Between 2004 and 2007, the Mexican National Forestry Commission (CONAFOR) established a network of  26,000 permanent inventory plots in the frame of their national inventory program, the Inventario Nacional Forestal y de Suelos (INFyS). INFyS data served as model response for spatially extending the field-based estimates of carbon stored in the aboveground live dry biomass to a wall-to-wall map, with 30 × 30 m2 pixel posting using canopy density estimates derived from Landsat, L-Band radar data from ALOS PALSAR, as well as elevation information derived from the Shuttle Radar Topography Mission (SRTM) data set. Validation against an independent set of INFyS plots resulted in a coefficient of determination (R2) of 0.5 with a root mean square error (RMSE) of 14 t·C/ha in the case of flat terrain. The validation for different forest types showed a consistently low estimation bias (< 3 t·C/ha) and R2s in the range of 0.5 except for mangroves (R2 = 0.2). Lower accuracies were achieved for forests located on steep slopes (> 15°) with an R2 of 0.34. A comparison of the average carbon stocks computed from: (a) the map; and (b) statistical estimates from INFyS, at the scale of  650 km2 large hexagons (R2 of 0.78, RMSE of 5 t·C/ha) and Mexican states (R2 of 0.98, RMSE of 1.4 t·C/ha), showed strong agreement. 2014 by the authors.
BibTeX:
@article{Cartus20145559,
  author = {Cartus, O. and Kellndorfer, J. and Walker, W. and Franco, C. and Bishop, J. and Santos, L. and Fuentes, J.M.M.},
  title = {A national, detailed map of forest aboveground carbon stocks in Mexico},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2014},
  volume = {6},
  number = {6},
  pages = {5559-5588},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84922724254&doi=10.3390%2frs6065559&partnerID=40&md5=2085474396b1851ac4a9ba4bdfabc3f8},
  doi = {10.3390/rs6065559}
}
Carvalhais N, Forkel M, Khomik M, Bellarby J, Jung M, Migliavacca M, Mu M, Saatchi S, Santoro M, Thurner M, Weber U, Ahrens B, Beer C, Cescatti A, Randerson J and Reichstein M (2014), "Global covariation of carbon turnover times with climate in terrestrial ecosystems", Nature. Vol. 514(7521), pp. 213-217. Nature Publishing Group.
Abstract: The response of the terrestrial carbon cycle to climate change is among the largest uncertainties affecting future climate change projections. The feedback between the terrestrial carbon cycle and climate is partly determined by changes in the turnover time of carbon in land ecosystems, which in turn is an ecosystem property that emerges from the interplay between climate, soil and vegetation type. Here we present a global, spatially explicit and observation-based assessment of whole-ecosystem carbon turnover times that combines new estimates of vegetation and soil organic carbon stocks and fluxes. We find that the overall mean global carbon turnover time is 23-4+7 years (95 per cent confidence interval). On average, carbon resides in the vegetation and soil near the Equator for a shorter time than at latitudes north of 75° north (mean turnover times of 15 and 255 years, respectively). We identify a clear dependence of the turnover time on temperature, as expected from our present understanding of temperature controls on ecosystem dynamics. Surprisingly, our analysis also reveals a similarly strong association between turnover time and precipitation. Moreover, we find that the ecosystem carbon turnover times simulated by state-of-the-art coupled climate/carbon-cycle models vary widely and that numerical simulations, on average, tend to underestimate the global carbon turnover time by 36 per cent. The models show stronger spatial relationships with temperature than do observation-based estimates, but generally do not reproduce the strong relationships with precipitation and predict faster carbon turnover in many semi-arid regions. Our findings suggest that future climate/carbon-cycle feedbacks may depend more strongly on changes in the hydrological cycle than is expected at present and is considered in Earth system models. 2014 Macmillan Publishers Limited. All rights reserved.
BibTeX:
@article{Carvalhais2014213,
  author = {Carvalhais, N. and Forkel, M. and Khomik, M. and Bellarby, J. and Jung, M. and Migliavacca, M. and Mu, M. and Saatchi, S. and Santoro, M. and Thurner, M. and Weber, U. and Ahrens, B. and Beer, C. and Cescatti, A. and Randerson, J.T. and Reichstein, M.},
  title = {Global covariation of carbon turnover times with climate in terrestrial ecosystems},
  journal = {Nature},
  publisher = {Nature Publishing Group},
  year = {2014},
  volume = {514},
  number = {7521},
  pages = {213-217},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908348472&doi=10.1038%2fnature13731&partnerID=40&md5=c103d8571b7179065e61462932534f8d},
  doi = {10.1038/nature13731}
}
Demontoux F, Jonard F, Bircher S, Razafindratsima S, Schwank M, Wigneron J-P and Kerr Y (2014), "Integrated approach for effective permittivity estimation of multi-layered soils at L-Band", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3213-3216. Institute of Electrical and Electronics Engineers Inc..
Abstract: Microwave remote sensing instruments are an adequate way to provide soil moisture information at large scale. Microwave remote sensing data are linked to the electromagnetic properties of soil. In that context, the objective of this study is to develop an integrated approach to estimate effective electromagnetic properties of soils layers at different scale using groundpenetrating radar (GPR), L-band radiometer, dielectric laboratory measurements, modelling approaches and in situ measurements of essential state variables. 2014 IEEE.
BibTeX:
@conference{Demontoux20143213,
  author = {Demontoux, F. and Jonard, F. and Bircher, S. and Razafindratsima, S. and Schwank, M. and Wigneron, J.-P. and Kerr, Y.H.},
  title = {Integrated approach for effective permittivity estimation of multi-layered soils at L-Band},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2014},
  pages = {3213-3216},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84911371844&doi=10.1109%2fIGARSS.2014.6947162&partnerID=40&md5=f584dc4cd5d8ac41ca1883d64d71b237},
  doi = {10.1109/IGARSS.2014.6947162}
}
Dimitrov M, Vanderborght J, Kostov K, Jadoon K, Weihermuller L, Jackson T, Bindlish R, Pachepsky Y, Schwank M and Vereecken H (2014), "Soil hydraulic parameters and surface soil moisture of a tilled bare soil plot inversely derived from l-band brightness temperatures", Vadose Zone Journal. Vol. 13(1)
Abstract: We coupled a radiative transfer model and a soil hydrologic model (HYDRUS 1D) with an optimization routine to derive soil hydraulic parameters, surface roughness, and soil moisture of a tilled bare soil plot using measured brightness temperatures at 1.4 GHz (L-band), rainfall, and potential soil evaporation. The robustness of the approach was evaluated using five 28-d data sets representing different meteorological conditions. We considered two soil hydraulic property models: the unimodal Mualem-van Genuchten and the bimodal model of Durner. Microwave radiative transfer was modeled by three different approaches: the Fresnel equation with depth-averaged dielectric permittivity of either 2-or 5-cm-thick surface layers and a coherent radiative transfer model (CRTM) that accounts for vertical gradients in dielectric permittivity. Brightness temperatures simulated by the CRTM and the 2-cm-layer Fresnel model fitted well to the measured ones. L-band brightness temperatures are therefore related to the dielectric permittivity and soil moisture in a 2-cm-thick surface layer. The surface roughness parameter that was derived from brightness temperatures using inverse modeling was similar to direct estimates from laser profiler measurements. The laboratory-derived water retention curve was bimodal and could be retrieved consistently for the different periods from brightness temperatures using inverse modeling. A unimodal soil hydraulic property function underestimated the hydraulic conductivity near saturation. Surface soil moisture contents simulated using retrieved soil hydraulic parameters were compared with in situ measurements. Depth-specific calibration relations were essential to derive soil moisture from near-surface installed sensors. Soil Science Society of America 5585 Guilford Rd., Madison, WI 53711 USA.
BibTeX:
@article{Dimitrov2014,
  author = {Dimitrov, M. and Vanderborght, J. and Kostov, K.G. and Jadoon, K.Z. and Weihermuller, L. and Jackson, T.J. and Bindlish, R. and Pachepsky, Y. and Schwank, M. and Vereecken, H.},
  title = {Soil hydraulic parameters and surface soil moisture of a tilled bare soil plot inversely derived from l-band brightness temperatures},
  journal = {Vadose Zone Journal},
  year = {2014},
  volume = {13},
  number = {1},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84893025097&doi=10.2136%2fvzj2013.04.0075&partnerID=40&md5=473736077627d0a64ccfb1a3486a34ed},
  doi = {10.2136/vzj2013.04.0075}
}
Elefante S, Manconi A, Bonano M, De Luca C and Casu F (2014), "Three-dimensional ground displacements retrieved from SAR data in a landslide emergency scenario", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 2400-2403. Institute of Electrical and Electronics Engineers Inc..
Abstract: This work presents the Differential SAR Interferometry and pixel-offset analysis on the event landslide that struck Montescaglioso town (Matera, southern Italy) on December 3rd, 2013. The event occurred after adverse weather conditions that produced a ground displacement of several meters, causing a severe emergency situation. The analysis has shown the presence of two main directions of motion: a major and a minor movement along the South-SouthWest and South-SouthEast directions. The pixel-offset results are well in agreement with both the magnitude and the deformation mechanisms that have been identified and mapped during field observations. 2014 IEEE.
BibTeX:
@conference{Elefante20142400,
  author = {Elefante, S. and Manconi, A. and Bonano, M. and De Luca, C. and Casu, F.},
  title = {Three-dimensional ground displacements retrieved from SAR data in a landslide emergency scenario},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2014},
  pages = {2400-2403},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84911435975&doi=10.1109%2fIGARSS.2014.6946955&partnerID=40&md5=5cf71330f3a6d0a7a00fec48c09cd87e},
  doi = {10.1109/IGARSS.2014.6946955}
}
Fernandez-Moran R, Wigneron J-P, Lopez-Baeza E, Salgado-Hernanz P, Mialon A, Miernecki M, Alyaari A, Parrens M, Schwank M, Wang S, Coll-Pajaron A, Lawrence H and Kerr Y (2014), "Evaluating the impact of roughness in soil moisture and optical thickness retrievals over the VAS area", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1947-1950. Institute of Electrical and Electronics Engineers Inc..
Abstract: In this paper, roughness parameterizations providing best retrievals of soil moisture (SM) at L-band were evaluated. Different parameterizations were tested to find the best correlation R, bias and ubRMSE when comparing retrieved SM and in situ SM measurements carried out at the VAS (Valencia Anchor Station) over a vineyard field. Roughness measurements were always performed after the agricultural practices in the vineyard. These in situ data was used as input of the L-MEB (L-band Microwave Emission of the Biosphere) model, which permits the retrieval of SM and TAU (vegetation optical depth). In addition, a simplified method consisting on the retrieval of a parameter which combines the effects of roughness and TAU was tested. Significantly higher correlation (R=0.86) for SM was found using this method, while the absolute bias (-0.062) and RMSE (0.069) were slightly higher than for other roughness parameterizations. 2014 IEEE.
BibTeX:
@conference{Fernandez-Moran20141947,
  author = {Fernandez-Moran, R. and Wigneron, J.-P. and Lopez-Baeza, E. and Salgado-Hernanz, P.M. and Mialon, A. and Miernecki, M. and Alyaari, A. and Parrens, M. and Schwank, M. and Wang, S. and Coll-Pajaron, A. and Lawrence, H. and Kerr, Y.H.},
  title = {Evaluating the impact of roughness in soil moisture and optical thickness retrievals over the VAS area},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2014},
  pages = {1947-1950},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84911449299&doi=10.1109%2fIGARSS.2014.6946841&partnerID=40&md5=df75f6255d77f8127ea88544866fb2b1},
  doi = {10.1109/IGARSS.2014.6946841}
}
Frey O, Hajnsek I, Wegmüller U and Werner C (2014), "SAR tomography based 3-D point cloud extraction of point-like scatterers in urban areas", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1313-1316. Institute of Electrical and Electronics Engineers Inc..
Abstract: SAR tomography as an extension to persistent scatterer interferometry (PSI) approaches has the potential to improve the level of detail of retrievable information, in particular, in the case of layover scenarios in urban areas. In this paper, a processing approach is sketched that eventually allows for retrieving a 3-D point cloud of point-like scatterers based on subsequent PSI and SAR tomography processing of an interferometric stack of high-resolution spaceborne TerraSAR-X data acquired over the city of Barcelona between the years 2008 and 2012. Experimental results are presented in the form of (1) vertical tomographic slices of high-rise buildings and (2) a 3-D point cloud of a larger district of the city of Barcelona retrieved from the tomograms. 2014 IEEE.
BibTeX:
@conference{Frey20141313,
  author = {Frey, O. and Hajnsek, I. and Wegmüller, U. and Werner, C.L.},
  title = {SAR tomography based 3-D point cloud extraction of point-like scatterers in urban areas},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2014},
  pages = {1313-1316},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84911406703&doi=10.1109%2fIGARSS.2014.6946675&partnerID=40&md5=4458a73b32cd50b278f7494db365761d},
  doi = {10.1109/IGARSS.2014.6946675}
}
Frey O, Siddique M, Hajnsek I, Wegmüller U and Werner C (2014), "Combining SAR tomography and a PSI approach for highresolution 3-D imaging of an urban area", In Proc. European Conf. Synthetic Aperture Radar. Vol. Proceedings of the European Conference on Synthetic Aperture Radar, EUSAR, pp. 1045-1048.
Abstract: Combining persistent scatterer interferometry (PSI) and SAR tomography approaches has the potential to overcome layover scenarios in urban areas and may thus increase the level of detail of differential interferometric measurements of displacements in such environments. In this paper, we report the current status and results of our efforts to integrate SAR tomography into an operational interferometric point target analysis (IPTA) processing tool as an extension to the conventional persistent scatterer interferometry approach. In particular, the PSI and the SAR tomography processing approaches applied are highlighted. In addition, details in the form of tomographic slices of two high-rise buildings are presented as well as a 3-D point cloud reconstruction of parts of the city of Barcelona are shown, as extracted from an interferometric stack of high-resolution stripmap-mode SAR data at X-band acquired by the TerraSAR-X spaceborne SAR sensor. VDE VERLAG GMBH · Berlin · Offenbach, Germany.
BibTeX:
@conference{Frey20141045,
  author = {Frey, O. and Siddique, M.A. and Hajnsek, I. and Wegmüller, U. and Werner, C.L.},
  title = {Combining SAR tomography and a PSI approach for highresolution 3-D imaging of an urban area},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  year = {2014},
  volume = {Proceedings of the European Conference on Synthetic Aperture Radar, EUSAR},
  pages = {1045-1048},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84991661313&partnerID=40&md5=541a6d9972343965167febd50a535cee}
}
Frey O, Werner C and Wegmüller U (2014), "GPU-based parallelized time-domain back-projection processing for Agile SAR platforms", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1132-1135. Institute of Electrical and Electronics Engineers.
Abstract: Agile SAR platforms such as an automobile require a flexible SAR processing scheme to account for nonlinear sensor trajectories during the synthetic aperture. In this contribution, a parallelized implementation of a time-domain back-projection SAR focusing algorithm based on NVIDIA's CUDA GPU computing framework is presented and discussed using a car-borne SAR data set. The processing performance is assessed using different hardware. In addition, a pre-processing scheme is described that allows for full 3-D motion compensation, yet staying conveniently in conventional slant-range/azimuth geometry of single-look complex SAR images. 2014 IEEE.
BibTeX:
@conference{Frey20141132,
  author = {Frey, O. and Werner, C.L. and Wegmüller, U.},
  title = {GPU-based parallelized time-domain back-projection processing for Agile SAR platforms},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2014},
  pages = {1132-1135},
  url = {https://www.gamma-rs.ch/uploads/media/freyWernerWegmullerIGARSS2014GPUbasedTDBP.pdf},
  doi = {10.1109/IGARSS.2014.6946629}
}
Garcia-Davalillo J, Herrera G, Notti D, Strozzi T and Alvarez-Fernandez I (2014), "DInSAR analysis of ALOS PALSAR images for the assessment of very slow landslides: The Tena Valley case study", Landslides. Vol. 11(2), pp. 225-246. Springer Verlag.
Abstract: In this work we analyse the performance of advanced land observing satellite (ALOS) phased array type L-band syntetic aperture radar (PALSAR) images for mapping and monitoring of very slow landslides using conventional differential interferometry in the Tena Valley (Central Pyrenees, Spain). These results are compared with those retrieved in previous works where multi-band advanced differential interferometric synthetic aperture radar (DInSAR) analysis was performed for the same area using PSI techniques. The study area is largely underlain by slates (ca. 80 %) where large deep-seated very slow earth flows are dominant. The results reveal that DInSAR analysis is able to measure displacements of landslides with a greater spatial coverage than PSI analysis, but for a lower amount of them (nine against 51). Overall, the combination of the DInSAR and multi-band PSI analysis permitted to map and monitor 68 % of the landslides in Tena Valley. From this amount, 63 landslides are considered as active. The main advantage of DInSAR with respect to PSI analysis is the capability to detect faster movements (up to 145 cm year-1) derived from the 46 days interferograms. That is the case of Sextas and La Selva landslides where an acceleration of the moving mass was measured after intense rainfall periods producing major damages to linear infrastructures. The combination of measured displacement from ALOS interferograms, with the observed damages on the A-136 road, was useful to assess the potential damage that could cause these slow movements. In general, it is demonstrated that even though PSI analysis provides a better performance in terms of landslide mapping, L-band DInSAR analysis provides an added value for landslide hazard assessment through radar remote sensing. For this reason it is necessary to encourage the launch of new satellite missions similar to ALOS PALSAR that could operate with shorter revisiting time periods. 2013 Springer-Verlag Berlin Heidelberg.
BibTeX:
@article{GarciaDavalillo2014225,
  author = {Garcia-Davalillo, J.C. and Herrera, G. and Notti, D. and Strozzi, T. and Alvarez-Fernandez, I.},
  title = {DInSAR analysis of ALOS PALSAR images for the assessment of very slow landslides: The Tena Valley case study},
  journal = {Landslides},
  publisher = {Springer Verlag},
  year = {2014},
  volume = {11},
  number = {2},
  pages = {225-246},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897579101&doi=10.1007%2fs10346-012-0379-8&partnerID=40&md5=642c35472d7b027f174b404c79ee8ba8},
  doi = {10.1007/s10346-012-0379-8}
}
Gebhardt S, Wehrmann T, Ruiz M, Maeda P, Bishop J, Schramm M, Kopeinig R, Cartus O, Kellndorfer J, Ressl R, Santos L and Schmidt M (2014), "MAD-MEX: Automatic wall-to-wall land cover monitoring for the mexican REDD-MRV program using all landsat data", Remote Sensing. Vol. 6(5), pp. 3923-3943. MDPI AG.
Abstract: Estimating forest area at a national scale within the United Nations program of Reducing Emissions from Deforestation and Forest Degradation (REDD) is primarily based on land cover information using remote sensing technologies. Timely delivery for a country of a size like Mexico can only be achieved in a standardized and cost-effective manner by automatic image classification. This paper describes the operational land cover monitoring system for Mexico. It utilizes national-scale cartographic reference data, all available Landsat satellite imagery, and field inventory data for validation. Seven annual national land cover maps between 1993 and 2008 were produced. The classification scheme defined 9 and 12 classes at two hierarchical levels. Overall accuracies achieved were up to 76%. Tropical and temperate forest was classified with accuracy up to 78% and 82%, respectively. Although specifically designed for the needs of Mexico, the general process is suitable for other participating countries in the REDD+ program to comply with guidelines on standardization and transparency of methods and to assure comparability. However, reporting of change is ill-advised based on the annual land cover products and a combination of annual land cover and change detection algorithms is suggested. 2014 by the authors.
BibTeX:
@article{Gebhardt20143923,
  author = {Gebhardt, S. and Wehrmann, T. and Ruiz, M.A.M. and Maeda, P. and Bishop, J. and Schramm, M. and Kopeinig, R. and Cartus, O. and Kellndorfer, J. and Ressl, R. and Santos, L.A. and Schmidt, M.},
  title = {MAD-MEX: Automatic wall-to-wall land cover monitoring for the mexican REDD-MRV program using all landsat data},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2014},
  volume = {6},
  number = {5},
  pages = {3923-3943},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901486048&doi=10.3390%2frs6053923&partnerID=40&md5=ecfafa8261a2576851d9dc61d5816446},
  doi = {10.3390/rs6053923}
}
Gladstone R, Schafer M, Zwinger T, Gong Y, Strozzi T, Mottram R, Boberg F and Moore J (2014), "Importance of basal processes in simulations of a surging Svalbard outlet glacier", Cryosphere. Vol. 8(4), pp. 1393-1405. Copernicus GmbH.
Abstract: The outlet glacier of Basin 3 (B3) of Austfonna ice cap, Svalbard, is one of the fastest outlet glaciers in Svalbard, and shows dramatic changes since 1995. In addition to previously observed seasonal summer speed-up associated with the melt season, the winter speed of B3 has accelerated approximately fivefold since 1995. We use the Elmer/Ice full-Stokes model for ice dynamics to infer spatial distributions of basal drag for the winter seasons of 1995, 2008 and 2011. This "inverse" method is based on minimising discrepancy between modelled and observed surface velocities, using satellite remotely sensed velocity fields. We generate steady-state temperature distributions for 1995 and 2011. Frictional heating caused by basal sliding contributes significantly to basal temperatures of the B3 outlet glacier, with heat advection (a longer-timescale process than frictional heating) also being important in the steady state. <br><br> We present a sensitivity experiment consisting of transient simulations under present-day forcing to demonstrate that using a temporally fixed basal drag field obtained through inversion can lead to thickness change errors of the order of 2 m yearg -1. Hence it is essential to incorporate the evolution of basal processes in future projections of the evolution of B3. Informed by a combination of our inverse method results and previous studies, we hypothesise a system of processes and feedbacks involving till deformation and basal hydrology to explain both the seasonal accelerations (short residence time pooling of meltwater at the ice-till interface) and the ongoing interannual speed-up (gradual penetration of water into the till, reducing till strength). Author(s) 2014. CC Attribution 3.0 License.
BibTeX:
@article{Gladstone20141393,
  author = {Gladstone, R. and Schafer, M. and Zwinger, T. and Gong, Y. and Strozzi, T. and Mottram, R. and Boberg, F. and Moore, J.C.},
  title = {Importance of basal processes in simulations of a surging Svalbard outlet glacier},
  journal = {Cryosphere},
  publisher = {Copernicus GmbH},
  year = {2014},
  volume = {8},
  number = {4},
  pages = {1393-1405},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84905510744&doi=10.5194%2ftc-8-1393-2014&partnerID=40&md5=5bb8460deb1b6ee5441f34b955842305},
  doi = {10.5194/tc-8-1393-2014}
}
Haemmig C, Huss M, Keusen H, Hess J, Wegmüller U, Ao Z and Kulubayi W (2014), "Hazard assessment of glacial lake outburst floods from Kyagar glacier, Karakoram mountains, China", Annals of Glaciology. Vol. 55(66), pp. 34-44. International Glaciology Society.
Abstract: Kyagar glacier is located in the Chinese Karakoram mountains. The glacier tongue entirely blocks the riverbed in the upper Shaksgam valley and impounds a glacial lake, which was the source of several violent and disastrous glacial lake outburst floods (GLOFs). A GLOF early warning system was implemented between 2011 and 2013. We present an integrative analysis of the hazard potential of Kyagar lake, taking into account the ice flow dynamics of Kyagar glacier as well as the recent surface mass-balance response to climate change. Comparison of two high-resolution digital elevation models (DEMs) for the ice dam shows surface lowering rates of >5ma-1 between 2002 and 2011, leading to a significant reduction in the maximum potential lake volume. However, two DEMs covering the entire glacier for the period 2000-10 indicate mass gains in its central part, and flow speed measurements show an acceleration in this region. This pattern of local ice-thickness changes combined with varying ice flow velocities is typical for surge-type glaciers. The velocity of the glacier surface and of the ice dam between 2011 and 2012 are analyzed at high temporal and spatial resolution, based on feature tracking of synthetic aperture radar (SAR) images.
BibTeX:
@article{Haemmig201434,
  author = {Haemmig, C. and Huss, M. and Keusen, H. and Hess, J. and Wegmüller, U. and Ao, Z. and Kulubayi, W.},
  title = {Hazard assessment of glacial lake outburst floods from Kyagar glacier, Karakoram mountains, China},
  journal = {Annals of Glaciology},
  publisher = {International Glaciology Society},
  year = {2014},
  volume = {55},
  number = {66},
  pages = {34-44},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903198522&doi=10.3189%2f2014AoG66A001&partnerID=40&md5=a6d7f40c7fbcd71e2129cbf53b5e1492},
  doi = {10.3189/2014AoG66A001}
}
Jonard F, Demontoux F, Bircher S, Razafindratsima S, Schwank M, Weillermuller L, Lambot S, Wigneron J-P, Kerr Y and Vereecken H (2014), "Electromagnetic characterization of organic-rich soils at the microwave L-band with ground-penetrating radar, radiometry and laboratory measurements", In Proceedings of the 15th International Conference on Ground Penetrating Radar, GPR 2014. , pp. 202-207. Institute of Electrical and Electronics Engineers Inc..
Abstract: Microwave remote sensing of the environment strongly relies on knowledge of the soil electrical properties. In this study, we characterized organic-rich soils using remote ground-penetrating radar (GPR) and radiometer as well as resonant cavity and waveguide reference methods. Organic-rich soil samples were collected from the HOBE (Hydrological Observatory) test site in the Skjern River Catchment (Denmark) and set up at the TERENO (Terrestrial Environmental Observatories) controlled test site in Selhausen (Germany). GPR and L-band radiometer measurements were performed above the soils during two months in order to cover a wide range of soil moisture conditions. GPR data were processed using full-wave inversion based on layered media Green's functions and radiometer data were inverted using a two-stream radiative transfer model for estimating the soil electrical properties. Results were compared to reference measurements carried out at the IMS laboratory (Laboratoire de l'Integration du Materiau au Systeme, France) using two different methods, i.e., the small perturbation method with resonant cavity and the waveguide method. Relatively large differences were observed between the different estimation methods for the real part of the relative dielectric permittivity, while reasonable agreement were obtained with respect to its imaginary part. This was attributed to a higher sensitivity of the real part of the relative dielectric permittivity with respect to soil samples heterogeneities. This study provided valuable insights into the electrical characterization of organic soils to improve space-borne remote sensing data products. 2014 IEEE.
BibTeX:
@conference{Jonard2014202,
  author = {Jonard, F. and Demontoux, F. and Bircher, S. and Razafindratsima, S. and Schwank, M. and Weillermuller, L. and Lambot, S. and Wigneron, J.-P. and Kerr, Y. and Vereecken, H.},
  title = {Electromagnetic characterization of organic-rich soils at the microwave L-band with ground-penetrating radar, radiometry and laboratory measurements},
  booktitle = {Proceedings of the 15th International Conference on Ground Penetrating Radar, GPR 2014},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2014},
  pages = {202-207},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84919624837&doi=10.1109%2fICGPR.2014.6970414&partnerID=40&md5=eed851a6616a82ab977ed472bb3fdb94},
  doi = {10.1109/ICGPR.2014.6970414}
}
Kourkouli P, Wegmüller U, Teatini P, Tosi L, Strozzi T, Wiesmann A and Tansey K (2014), "Ground deformation monitoring over venice lagoon using combined DInSAR/PSI techniques", Engineering Geology for Society and Territory - Volume 4: Marine and Coastal Processes. , pp. 183-186. Springer International Publishing.
Abstract: Synthetic Aperture Radar Interferometric (InSAR) techniques are widely applied to detect ground displacements caused by both natural and anthropogenic effects. Such techniques are a powerful tool for monitoring the ground motion, however, they have limitations such as temporal and geometrical decorrelation. Persistent Scatterer Interferometry (PSI), a pixel based methodology, has been developed to overcome such constraints. Nevertheless, also with PSI poor spatial coverage is observed in many case studies, especially over natural environments. In this contribution, we propose a methodology using elements from InSAR and PSI techniques in order to improve the spatial coverage with valid information over natural landscapes. For testing the applicability of this methodology, we selected as a test area the Venice Lagoon and specifically an area covered by saltwater marshes. The synergistic approach shows a good potential to achieve a good spatial coverage over the study area. Springer International Publishing Switzerland 2014.
BibTeX:
@book{Kourkouli2014183,
  author = {Kourkouli, P. and Wegmüller, U. and Teatini, P. and Tosi, L. and Strozzi, T. and Wiesmann, A. and Tansey, K.},
  title = {Ground deformation monitoring over venice lagoon using combined DInSAR/PSI techniques},
  journal = {Engineering Geology for Society and Territory - Volume 4: Marine and Coastal Processes},
  publisher = {Springer International Publishing},
  year = {2014},
  pages = {183-186},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84948093675&doi=10.1007%2f978-3-319-08660-6_35&partnerID=40&md5=851762bbc16f04310dd1bb951bcfaf35},
  doi = {10.1007/978-3-319-08660-6_35}
}
Leinss S, Lemmetyinen J, Wiesmann A and Hajnsek I (2014), "Snow structure evolution measured by ground based polarimetric phase differences", In Proc. European Conf. Synthetic Aperture Radar. Vol. Proceedings of the European Conference on Synthetic Aperture Radar, EUSAR, pp. 908-911.
Abstract: Co-polar Phase Differences (CPD) obtained from a fully polarimetric ground based scatterometer operating at 9 to 18 GHz were compared with meteorological data and with spaceborne SAR acquisitions from TerraSAR-X and TanDEM-X. The temporal evolution of the CPD is discussed with respect to the changing microscopic structure of snow. The temporal resolution of 4 hours allowed a precise analysis with respect to snow fall and melt events. Radar reflection measurements were analyzed to gain insight into backscattering properties of dry and wet snow. VDE VERLAG GMBH · Berlin · Offenbach, Germany.
BibTeX:
@conference{Leinss2014908,
  author = {Leinss, S. and Lemmetyinen, J. and Wiesmann, A. and Hajnsek, I.},
  title = {Snow structure evolution measured by ground based polarimetric phase differences},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  year = {2014},
  volume = {Proceedings of the European Conference on Synthetic Aperture Radar, EUSAR},
  pages = {908-911},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84991705948&partnerID=40&md5=d2b9b967433b2c094496718e1abf6a50}
}
Lemmetyinen J, Pulliainen J, Kontu A, Wiesmann A, Matzler C, Rott H, Voglmeier K, Nagler T, Meta A, Coccia A, Schneebeli M, Proksch M, Davidson M, Schuttemeyer D, Lin C-C and Kern M (2014), "Observations of seasonal snow cover at X and Ku bands during the NoSREx campaign", In Proc. European Conf. Synthetic Aperture Radar. Vol. Proceedings of the European Conference on Synthetic Aperture Radar, EUSAR, pp. 900-903.
Abstract: Results from an experimental campaign, providing measurements of snow microwave backscatter over four winter seasons, are presented. The main dataset consists of tower-based scatterometer observations and coinciding measurements of snow, soil and atmospheric properties. In situ data includes measurements of snow SSA and snow microstructure using computer tomography during dedicated campaign periods. Airborne observations at X and Ku bands were collected at the test site during two seasons using the ESA SnowSAR instrument, covering typical land cover features of the boreal forest zone. We present the main findings of the experiment, relating the physical properties of snow to the measured backscatter. The tower based observations are applied to study the temporal evolution of the backscatter signal, including effects such as metamorphism of snow microstructure. The airborne data are used to study the effects of varying land cover on snow backscatter signatures, as well as to demonstrate the retrieval of Snow Water Equivalent from X/Ku band backscatter observations using the retrieval concept developed for CoReH2O. VDE VERLAG GMBH · Berlin · Offenbach, Germany.
BibTeX:
@conference{Lemmetyinen2014900,
  author = {Lemmetyinen, J. and Pulliainen, J. and Kontu, A. and Wiesmann, A. and Matzler, C. and Rott, H. and Voglmeier, K. and Nagler, T. and Meta, A. and Coccia, A. and Schneebeli, M. and Proksch, M. and Davidson, M. and Schuttemeyer, D. and Lin, C.-C. and Kern, M.},
  title = {Observations of seasonal snow cover at X and Ku bands during the NoSREx campaign},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  year = {2014},
  volume = {Proceedings of the European Conference on Synthetic Aperture Radar, EUSAR},
  pages = {900-903},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84991636692&partnerID=40&md5=3b8ce3d0da4e22226ae775999e5a6f86}
}
Lollino G, Manconi A, Locat J, Huang Y and Artigas M (2014), "Engineering Geology for Society and Territory-Volume 4: Marine and Coastal Processes", Engineering Geology for Society and Territory - Volume 4: Marine and Coastal Processes. , pp. 1-235. Springer International Publishing.
Abstract: This book is one out of 8 IAEG XII Congress volumes, and deals with the processes occurring on the coastal zone, which represents a critical interface between land and sea, as the contribution of the ocean to the provision of energy and mineral resources will likely increase in the coming decades. Several related topics fit into this volume, such as: coastal developments and infrastructures; dredging and beach re-nourishment; sediment erosion, transport and accumulation; geohazard assessment; seafloor uses; seabed mapping; exploration and exploitation of the seafloor, of the sub-seafloor, and of marine clean energies and climatic and anthropogenic impacts on coastal and marine environments. Examples of specific themes are coastal management and shore protection, taking into account storm-related events and natural and anthropogenic changes in the relative sea level, planning of waste disposal, remedial works for coastal pollution, seafloor pipeline engineering, slope stability analysis, or tsunami propagation and flooding. The Engineering Geology for Society and Territory volumes of the IAEG XII Congress held in Torino from September 15-19, 2014, analyze the dynamic role of engineering geology in our changing world and build on the four main themes of the congress: environment, processes, issues and approaches. The congress topics and subject areas of the 8 IAEG XII Congress volumes are: 1. Climate Change and Engineering Geology 2. Landslide Processes River Basins 3. Reservoir Sedimentation and Water Resources 4. Marine and Coastal Processes Urban Geology 5. Sustainable Planning and Landscape Exploitation 6. Applied Geology for Major Engineering Projects 7. Education, Professional Ethics and Public Recognition of Engineering Geology 8. Preservation of Cultural Heritage. Springer International Publishing Switzerland 2014.
BibTeX:
@book{Lollino20141,
  author = {Lollino, G. and Manconi, A. and Locat, J. and Huang, Y. and Artigas, M.C.},
  title = {Engineering Geology for Society and Territory-Volume 4: Marine and Coastal Processes},
  journal = {Engineering Geology for Society and Territory - Volume 4: Marine and Coastal Processes},
  publisher = {Springer International Publishing},
  year = {2014},
  pages = {1-235},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84948096390&doi=10.1007%2f978-3-319-08660-6&partnerID=40&md5=2ff6f9abccd3d7a5789e54ecc57dec7f},
  doi = {10.1007/978-3-319-08660-6}
}
Magnard C, Frioud M, Small D, Brehm T, Essen H and Meier E (2014), "Processing of MEMPHIS Ka-band multibaseline interferometric SAR data: From raw data to digital surface models", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 7(7), pp. 2927-2941. Institute of Electrical and Electronics Engineers.
Abstract: MEMPHIS is an experimental millimeter-wave synthetic aperture radar (SAR) system that acquires cross-track multibaseline interferometric data at high resolution in a single pass, using four receive horns. In this paper, we present the SAR system and navigation data, and propose a processing chain from the raw data input to a digital surface model (DSM) output. This processing chain includes full bandwidth reconstruction of the stepped-frequency SAR data, azimuth focusing with an Extended Omega-K algorithm, generation of interferograms for each available baseline, phase unwrapping using the multibaseline data, and phase-to-height conversion. The hardware and processing chain were validated through the analysis of experimental Ka-band data. The SAR image resolution was measured with point targets and found to be &2 and ∼15% coarser than the theoretical value in range and azimuth, respectively. The geolocation accuracy was typically better than 0.1 m in range and 0.2 m in azimuth. Observed depression angle-dependent interferometric phase errors were successfully removed using a correction function derived from the InSAR data. Investigation of the interferometric phase noise showed the utility of a multibaseline antenna setup; the number of looks and filter size used for the DSM generation were also derived from this analysis. The results showed that in grassland areas, the height difference between the ∼2m-resolution InSAR DSMs and the reference ALS models was 0±0.25 m. 2014 IEEE.
BibTeX:
@article{Magnard20142927,
  author = {Magnard, C. and Frioud, M. and Small, D. and Brehm, T. and Essen, H. and Meier, E.},
  title = {Processing of MEMPHIS Ka-band multibaseline interferometric SAR data: From raw data to digital surface models},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2014},
  volume = {7},
  number = {7},
  pages = {2927-2941},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84906946405&doi=10.1109%2fJSTARS.2014.2315896&partnerID=40&md5=c4792ca4c3b46b9fd59b0f1ff85f421e},
  doi = {10.1109/JSTARS.2014.2315896}
}
Manconi A, Casu F, Ardizzone F, Bonano M, Cardinali M, De Luca C, Gueguen E, Marchesini I, Parise M, Vennari C, Lanari R and Guzzetti F (2014), "Brief communication: Rapid mapping of landslide events: The 3 December 2013 Montescaglioso landslide, Italy", Natural Hazards and Earth System Sciences. Vol. 14(7), pp. 1835-1841. Copernicus GmbH.
Abstract: We present an approach to measure 3-D surface deformations caused by large, rapid-moving landslides using the amplitude information of high-resolution, X-band synthetic aperture radar (SAR) images. We exploit SAR data captured by the COSMO-SkyMed satellites to measure the deformation produced by the 3 December 2013 Montescaglioso landslide, southern Italy. The deformation produced by the deep-seated landslide exceeded 10 m and caused the disruption of a main road, a few homes and commercial buildings. The results open up the possibility of obtaining 3-D surface deformation maps shortly after the occurrence of large, rapid-moving landslides using high-resolution SAR data. 2014 Author(s).
BibTeX:
@article{Manconi20141835,
  author = {Manconi, A. and Casu, F. and Ardizzone, F. and Bonano, M. and Cardinali, M. and De Luca, C. and Gueguen, E. and Marchesini, I. and Parise, M. and Vennari, C. and Lanari, R. and Guzzetti, F.},
  title = {Brief communication: Rapid mapping of landslide events: The 3 December 2013 Montescaglioso landslide, Italy},
  journal = {Natural Hazards and Earth System Sciences},
  publisher = {Copernicus GmbH},
  year = {2014},
  volume = {14},
  number = {7},
  pages = {1835-1841},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84905003484&doi=10.5194%2fnhess-14-1835-2014&partnerID=40&md5=4e667075151cfccde696af2441e45ff2},
  doi = {10.5194/nhess-14-1835-2014}
}
McMillan M, Shepherd A, Gourmelen N, Dehecq A, Leeson A, Ridout A, Flament T, Hogg A, Gilbert L, Benham T, Van Den Broeke M, Dowdeswell J, Fettweis X, Noël B and Strozzi T (2014), "Rapid dynamic activation of a marine-based Arctic ice cap", Geophysical Research Letters. Vol. 41(24), pp. 8902-8909. Blackwell Publishing Ltd.
Abstract: We use satellite observations to document rapid acceleration and ice loss from a formerly slow-flowing, marine-based sector of Austfonna, the largest ice cap in the Eurasian Arctic. During the past two decades, the sector ice discharge has increased 45-fold, the velocity regime has switched from predominantly slow (  101 m/yr) to fast (  103 m/yr) flow, and rates of ice thinning have exceeded 25 m/yr. At the time of widespread dynamic activation, parts of the terminus may have been near floatation. Subsequently, the imbalance has propagated 50 km inland to within 8 km of the ice cap summit. Our observations demonstrate the ability of slow-flowing ice to mobilize and quickly transmit the dynamic imbalance inland; a process that we show has initiated rapid ice loss to the ocean and redistribution of ice mass to locations more susceptible to melt, yet which remains poorly understood. Key Points Recent dynamic activation of a formerly slow-flowing marine Arctic ice capImbalance has spread 50 km inland to within 8 km of the ice cap summitIce discharge has increased 45-fold, and thinning rates have exceeded 25 m/yr 2014. The Authors.
BibTeX:
@article{McMillan20148902,
  author = {McMillan, M. and Shepherd, A. and Gourmelen, N. and Dehecq, A. and Leeson, A. and Ridout, A. and Flament, T. and Hogg, A. and Gilbert, L. and Benham, T. and Van Den Broeke, M. and Dowdeswell, J.A. and Fettweis, X. and Noël, B. and Strozzi, T.},
  title = {Rapid dynamic activation of a marine-based Arctic ice cap},
  journal = {Geophysical Research Letters},
  publisher = {Blackwell Publishing Ltd},
  year = {2014},
  volume = {41},
  number = {24},
  pages = {8902-8909},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921844855&doi=10.1002%2f2014GL062255&partnerID=40&md5=010511d9290aa41e02587c98f7406528},
  doi = {10.1002/2014GL062255}
}
Miernecki M, Wigneron J-P, Lopez-Baeza E, Kerr Y, De Jeu R, De Lannoy G, Jackson T, O'Neill P, Schwank M, Moran R, Bircher S, Lawrence H, Mialon A, Al Bitar A and Richaume P (2014), "Comparison of SMOS and SMAP soil moisture retrieval approaches using tower-based radiometer data over a vineyard field", Remote Sensing of Environment. Vol. 154(1), pp. 89-101. Elsevier Inc..
Abstract: The objective of this study was to compare several approaches to soil moisture (SM) retrieval using l-band microwave radiometry. The comparison was based on a brightness temperature (TB) data set acquired since 2010 by the L-band radiometer ELBARA-II over a vineyard field at the Valencia Anchor Station (VAS) site. ELBARA-II, provided by the European Space Agency (ESA) within the scientific program of the SMOS (Soil Moisture and Ocean Salinity) mission, measures multiangular TB data at horizontal and vertical polarization for a range of incidence angles (30°-60°). Based on a three year data set (2010-2012), several SM retrieval approaches developed for spaceborne missions including AMSR-E (Advanced Microwave Scanning Radiometer for EOS), SMAP (Soil Moisture Active Passive) and SMOS were compared. The approaches include: the Single Channel Algorithm (SCA) for horizontal (SCA-H) and vertical (SCA-V) polarizations, the Dual Channel Algorithm (DCA), the Land Parameter Retrieval Model (LPRM) and two simplified approaches based on statistical regressions (referred to as 'Mattar' and 'Saleh'). Time series of vegetation indices required for three of the algorithms (SCA-H, SCA-V and 'Mattar') were obtained from MODIS observations. The SM retrievals were evaluated against reference SM values estimated from a multiangular 2-Parameter inversion approach. As no in situ SM data was used, the evaluation made here is relative to the use of this specific reference data set. The results obtained with the current base line algorithms developed for SMAP (SCA-H and -V) are in very good agreement with the 'reference' SM data set derived from the multi-angular observations (R2≈0.90, RMSE varying between 0.035 and 0.056m3/m3 for several retrieval configurations). This result showed that, provided the relationship between vegetation optical depth and a remotely-sensed vegetation index can be calibrated, the SCA algorithms can provide results very close to those obtained from multi-angular observations in this study area. The approaches based on statistical regressions provided similar results and the best accuracy was obtained with the 'Saleh' methods based on either bi-angular or bipolarization observations (R2≈0.93, RMSE≈0.035m3/m3). The LPRM and DCA algorithms were found to be slightly less successful in retrieving the 'reference' SM time series (R2≈0.75, RMSE≈0.055m3/m3). However, the two above approaches have the great advantage of not requiring any model calibrations previous to the SM retrievals. 2014 Elsevier Inc.
BibTeX:
@article{Miernecki201489,
  author = {Miernecki, M. and Wigneron, J.-P. and Lopez-Baeza, E. and Kerr, Y. and De Jeu, R. and De Lannoy, G.J.M. and Jackson, T.J. and O'Neill, P.E. and Schwank, M. and Moran, R.F. and Bircher, S. and Lawrence, H. and Mialon, A. and Al Bitar, A. and Richaume, P.},
  title = {Comparison of SMOS and SMAP soil moisture retrieval approaches using tower-based radiometer data over a vineyard field},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2014},
  volume = {154},
  number = {1},
  pages = {89-101},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908100906&doi=10.1016%2fj.rse.2014.08.002&partnerID=40&md5=c1587e09497666ec50112e095a48472e},
  doi = {10.1016/j.rse.2014.08.002}
}
Pantze A, Santoro M and Fransson J (2014), "Change detection of boreal forest using bi-temporal ALOS PALSAR backscatter data", Remote Sensing of Environment. Vol. 155, pp. 120-128. Elsevier Inc..
Abstract: Long-wavelength Synthetic Aperture Radar (SAR) satellite systems have the potential to increase the efficiency of forest mapping and monitoring, which today are based primarily on optical satellite systems. Here, we evaluate the effectiveness of using L-band SAR satellite images to detect and delineate clear-cuts in Swedish boreal forest. A set of computationally efficient techniques are combined in a fully automated unsupervised bi-temporal change detection approach that detects changes in SAR backscatter intensities. For radiometric normalization and initial change classification, we propose an iterative procedure consisting of successive polynomial based histogram matching and thresholding. Recently proposed methods for automatic SAR amplitude ratio thresholding and final change classification are adopted. The latter is a Markov random field based change detection method that exploits both spectral and spatial information from one or multiple SAR polarization channels. The change detection approach was applied to SAR images from the Japanese Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) acquired in Fine Beam Dual (FBD) mode (HH- and HV-polarizations) with a pixel size of 20. m (path data). Clear-cuts that took place between image acquisitions were clearly detected, and most errors were due to imperfect delineations of clear-cut edges. Pixel-wise clear-cut detection accuracies above 90% could be reached, with false alarm rates of approximately 10% or less. The results indicate that ALOS PALSAR path data are well suited for operational clear-cut detection in Swedish boreal forest. 2014 Elsevier Inc.
BibTeX:
@article{Pantze2014120,
  author = {Pantze, A. and Santoro, M. and Fransson, J.E.S.},
  title = {Change detection of boreal forest using bi-temporal ALOS PALSAR backscatter data},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2014},
  volume = {155},
  pages = {120-128},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909585663&doi=10.1016%2fj.rse.2013.08.050&partnerID=40&md5=d260295b4155adf748dbc9135d0151eb},
  doi = {10.1016/j.rse.2013.08.050}
}
Rautiainen K, Lemmetyinen J, Schwank M, Kontu A, Ménard C, Matzler C, Drusch M, Wiesmann A, Ikonen J and Pulliainen J (2014), "Detection of soil freezing from L-band passive microwave observations", Remote Sensing of Environment. Vol. 147, pp. 206-218. Elsevier Inc..
Abstract: We present a novel algorithm for detecting seasonal soil freezing processes using L-band microwave radiometry. L-band is the optimal choice of frequency for the monitoring of soil freezing, due to the inherent high contrast of the microwave signature between the frozen and thawed states of the soil medium. Dual-polarized observations of L-band brightness temperature at a range of observation angles were collected from a tower-based instrument, and evaluated against ancillary information on soil and snow properties over four winter seasons. During the first three winter periods the measurement site was located over mineral soil on a forest clearing, for the fourth winter the instrument was moved to a wetland site. Both sites are located in Sodankyla, Northern Finland. The test sites represent two environments typical for the northern boreal forest zone. The data were applied to derive an empirical relation between the onset and progress of soil freezing and the observed passive L-band signature. A retrieval algorithm was developed using the observations at the forest opening site. The algorithm exploits the perceived change in brightness temperature and the change in the relative difference between the signatures at horizontal and vertical polarization. With the collected experimental dataset, these features were linked optimally to the progress of soil freezing by choice of observation angle, polarization and temporal averaging. The wetland site observations provided the first opportunity for demonstrating the developed algorithm over a different soil type, giving a first estimate of the algorithm performance over larger heterogeneous targets. The future objective is to adapt the algorithm to L-band satellite observations. The present study is highly relevant for the development of freeze-thaw algorithms from current and future L-band satellite missions such as SMOS and SMAP. 2014 Elsevier Inc.
BibTeX:
@article{Rautiainen2014206,
  author = {Rautiainen, K. and Lemmetyinen, J. and Schwank, M. and Kontu, A. and Ménard, C.B. and Matzler, C. and Drusch, M. and Wiesmann, A. and Ikonen, J. and Pulliainen, J.},
  title = {Detection of soil freezing from L-band passive microwave observations},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2014},
  volume = {147},
  pages = {206-218},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897069346&doi=10.1016%2fj.rse.2014.03.007&partnerID=40&md5=7533f0105adf73c37e0cecdc2f232207},
  doi = {10.1016/j.rse.2014.03.007}
}
Santoro M and Wegmüller U (2014), "Multi-temporal synthetic aperture radar metrics applied to map open water bodies", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 7(8), pp. 3225-3238. Institute of Electrical and Electronics Engineers.
Abstract: Multi-temporal synthetic aperture radar (SAR) metrics are assessed to map open water bodies. High temporal variability and low minimum value in a time series of Envisat Advanced SAR (ASAR) Wide Swath Mode (WSM) backscatter measurements characterize open water bodies with respect to other land cover types. Confusion occurs in the case of steep terrain (slope angle > 10°), less than 10 backscatter observations and for mixed pixels with a water fraction. The behavior of the two SAR multi-temporal metrics is consistent at six study areas in Europe and Central Siberia. A simple thresholding algorithm applied to the multi-temporal SAR metrics to map open water bodies performs with overall accuracies above 90% in the case of pure pixels of water or land. The accuracy decreases when mixed pixels are accounted for in the reference dataset and for increasing land fraction in the reference samples. An overall accuracy of approximately 80% was obtained for a 50% threshold of the water fraction. Omissions of water areas occur mostly along shorelines. Specific conditions of the land surface can distort the minimum, causing commission in the water class. The use of a low order rank or percentile instead of the lowest backscatter value can reduce such commission error. 2013 IEEE.
BibTeX:
@article{Santoro20143225,
  author = {Santoro, M. and Wegmüller, U.},
  title = {Multi-temporal synthetic aperture radar metrics applied to map open water bodies},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers},
  year = {2014},
  volume = {7},
  number = {8},
  pages = {3225-3238},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907972496&doi=10.1109%2fJSTARS.2013.2289301&partnerID=40&md5=93c0f29b0a29d5c7666060e2e0550642},
  doi = {10.1109/JSTARS.2013.2289301}
}
Santoro M, Wegmüller U, Fransson J and Schmullius C (2014), "Regional mapping of forest growing stock volume with multitemporal ALOS PALSAR backscatter", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 2313-2316. Institute of Electrical and Electronics Engineers Inc..
Abstract: The paper presents advances in regional mapping of forest growing stock volume (GSV, unit: m3/ha) using multitemporal ALOS PALSAR images. For this, an approach based on the Water Cloud Model has been used. Fine Beam Dual (FBD) and Wide Beam (WB) mode backscatter data acquired during 2010 were inverted to GSV; the individual GSV estimates were then combined to form an improved estimate. Examples of regional mapping for the boreal, temperate and tropical zone are here presented. Estimates were obtained at 25 m resolution using FBD data only and at 75 m combining multi-looked FBD estimates and WB estimates. The inclusion of multi-temporal WB data served to improve the spatial characterization of GSV. At pixel level, the discrepancy with respect to other estimates from Earth Observation data was large (relative RMSE ∼ 90%). Aggregation to lower resolution (e.g., 1 km) increased the agreement and a relative RMSE mostly below 30% was obtained. 2014 IEEE.
BibTeX:
@conference{Santoro20142313,
  author = {Santoro, M. and Wegmüller, U. and Fransson, J.E.S. and Schmullius, C.},
  title = {Regional mapping of forest growing stock volume with multitemporal ALOS PALSAR backscatter},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2014},
  pages = {2313-2316},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84911366995&doi=10.1109%2fIGARSS.2014.6946933&partnerID=40&md5=dbc5ad8fdb6469a7d9e87f9b26df4935},
  doi = {10.1109/IGARSS.2014.6946933}
}
Schafer M, Gillet-Chaulet F, Gladstone R, Pettersson R, Pohjola V, Strozzi T and Zwinger T (2014), "Assessment of heat sources on the control of fast flow of Vestfonna ice cap, Svalbard", Cryosphere. Vol. 8(5), pp. 1951-1973. Copernicus GmbH.
Abstract: Understanding the response of fast flowing ice streams or outlet glaciers to changing climate is crucial in order to make reliable projections of sea level change over the coming decades. Motion of fast outlet glaciers occurs largely through basal motion governed by physical processes at the glacier bed, which are not yet fully understood. Various subglacial mechanisms have been suggested for fast flow but common to most of the suggested processes is the requirement of presence of liquid water, and thus temperate conditions.

We use a combination of modelling, field, and remote observations in order to study links between different heat sources, the thermal regime and basal sliding in fast flowing areas on Vestfonna ice cap. A special emphasis lies on Franklinbreen, a fast flowing outlet glacier which has been observed to accelerate recently. We use the ice flow model Elmer/Ice including a Weertman type sliding law and a Robin inverse method to infer basal friction parameters from observed surface velocities. Firn heating, i.e. latent heat release through percolation of melt water, is included in our model; its parameterisation is calibrated with the temperature record of a deep borehole. We found that strain heating is negligible, whereas friction heating is identified as one possible trigger for the onset of fast flow. Firn heating is a significant heat source in the central thick and slow flowing area of the ice cap and the essential driver behind the ongoing fast flow in all outlets.

Our findings suggest a possible scenario of the onset and maintenance of fast flow on the Vestfonna ice cap based on thermal processes and emphasise the role of latent heat released through refreezing of percolating melt water for fast flow. However, these processes cannot yet be captured in a temporally evolving sliding law. In order to simulate correctly fast flowing outlet glaciers, ice flow models not only need to account fully for all heat sources, but also need to incorporate a sliding law that is not solely based on the basal temperature, but also on hydrology and/or sediment physics. 2014 Author(s).
BibTeX:
@article{Schafer20141951,
  author = {Schafer, M. and Gillet-Chaulet, F. and Gladstone, R. and Pettersson, R. and Pohjola, V.A. and Strozzi, T. and Zwinger, T.},
  title = {Assessment of heat sources on the control of fast flow of Vestfonna ice cap, Svalbard},
  journal = {Cryosphere},
  publisher = {Copernicus GmbH},
  year = {2014},
  volume = {8},
  number = {5},
  pages = {1951-1973},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908246957&doi=10.5194%2ftc-8-1951-2014&partnerID=40&md5=561286a185736e52420687bf8febe4df},
  doi = {10.5194/tc-8-1951-2014}
}
Schwank M, Rautiainen K, Matzler C, Stahli M, Lemmetyinen J, Pulliainen J, Vehvilainen J, Kontu A, Ikonen J, Ménard C, Drusch M, Wiesmann A and Wegmüller U (2014), "Model for microwave emission of a snow-covered ground with focus on L band", Remote Sensing of Environment. Vol. 154(1), pp. 180-191. Elsevier Inc..
Abstract: Passive L-band (1-2 GHz) observables are sensitive to surface soil moisture and ocean salinity, which is the core of the "soil moisture and ocean salinity" (SMOS) mission of the European Space Agency (ESA). This work investigatesmicrowave emission processes that are important to link L-band brightness temperatureswith soil freeze/ thaw states and the presence and the state of snow. To this end, a ground snowradiative transfer (GS RT) model has been developed on the basis of the "Microwave EmissionModel of Layered Snowpacks" (MEMLS). Ourmodel sensitivity study revealed that L-band emission of a freezing ground can be affected significantly by dry snow, which has beenmostly disregarded in previous studies. Simulations suggest that even dry snowwithmostly negligible absorption at the L-band can impact L-band emission ofwinter landscapes significantly. We found that impedancematching and refraction caused by a dry snowpack can increase or decrease L-band emission depending on the polarization and the observation angle. Based on the performed sensitivity study, these RT processes can be compensatory at vertical polarization and the observation angle of 50°. This suggests the use of vertical polarized brightness temperatures measured at around 50° in order to achieve segregated information on soil-frost. Furthermore, our simulations demonstrate a significant sensitivity of L-band emission at horizontal polarization with respect to the density of the lowest snow layer as the result of refraction and impedance matching by the snowpack. 2014 Elsevier Inc.
BibTeX:
@article{Schwank2014180,
  author = {Schwank, M. and Rautiainen, K. and Matzler, C. and Stahli, M. and Lemmetyinen, J. and Pulliainen, J. and Vehvilainen, J. and Kontu, A. and Ikonen, J. and Ménard, C.B. and Drusch, M. and Wiesmann, A. and Wegmüller, U.},
  title = {Model for microwave emission of a snow-covered ground with focus on L band},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2014},
  volume = {154},
  number = {1},
  pages = {180-191},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84927710881&doi=10.1016%2fj.rse.2014.08.029&partnerID=40&md5=34757c9d93eb8c5b3e315da91ede50d3},
  doi = {10.1016/j.rse.2014.08.029}
}
Tanase M, Santoro M, Aponte C and De La Riva J (2014), "Polarimetric properties of burned forest areas at C- and L-band", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 7(1), pp. 267-276.
Abstract: Fully polarimetric C- and L-band synthetic aperture radar (SAR) data have been investigated to determine the relationship between polarimetric target decomposition components and forest burn severity over two sites located in a Mediterranean environment. The dependence of the polarimetric decomposition metrics on SAR acquisition geometry and environmental conditions was also analyzed at C-band. Multiple linear regression models with interactions (i.e., the incidence angle was included as a predictor variable and its interaction with the radar metrics was accounted for as a multiplicative effect) were used to quantify burn severity retrieval accuracy. According to our experiment, we found that for steep SAR acquisition geometries C-band polarimetric components related to surface scattering mechanisms had increased sensitivity to burn severity levels, while for datasets acquired with more grazing geometries the polarimetric components related to volume scattering and dihedral scattering mechanisms were more correlated with burn severity levels. At L-band only volume and dihedral scattering related decomposition components provided significant relationships with burn severity levels. Relatively low burn severity estimation errors (less than 20% of burn severity range) were obtained for all datasets, with L-band data presenting the highest sensitivity to fire effects. Using a single regression model provided sufficient accuracy for burn severity estimation when taking into account the local incidence angle. The use of fully polarimetric data improved the estimation accuracy of forest burn severity with respect to backscatter intensities by a small margin for our study sites. However, since backscatter intensity metrics already provide high retrieval accuracies, whatever improvement was bound to be low. 2013 IEEE.
BibTeX:
@article{Tanase2014267,
  author = {Tanase, M.A. and Santoro, M. and Aponte, C. and De La Riva, J.},
  title = {Polarimetric properties of burned forest areas at C- and L-band},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  year = {2014},
  volume = {7},
  number = {1},
  pages = {267-276},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84891749100&doi=10.1109%2fJSTARS.2013.2261053&partnerID=40&md5=be1d0840aaadfe680560bd4ca7a21541},
  doi = {10.1109/JSTARS.2013.2261053}
}
Teatini P, Tosi L and Strozzi T (2014), "Capability of X-band persistent scatterer interferometry to monitor land subsidence in the Venice lagoon", Engineering Geology for Society and Territory - Volume 4: Marine and Coastal Processes. , pp. 175-178. Springer International Publishing.
Abstract: Land subsidence is a widespread phenomenon, particularly relevant to natural areas such as wetlands, deltas, and lagoons characterized by low elevation with respect to the mean sea level. The possibility of mapping vertical displacements of large coastal lowlying areas at very high resolution began in the 2000s with the development of the Persistent Scatterer Interferometry (PSI). This synthetic aperture radar (SAR)-based methodology detects the displacements of man-made structures within the landscape, such as buildings, utility poles, and roadways. Experience with SAR data of the European Remote Sensing satellites ERS-1, ERS-2, and ENVISAT, characterized by a spatial resolution of about 20 m, a wavelength λ of the signal of 5.66 cm (C-band), and a repeat cycle of 35 days, suggested that persistent targets can be identified only for a fraction of the number of buildings or infrastructures larger than a few meters, and the precise position of the SAR scatterers are difficult to discern. With a very-high image resolution (about 3 m) and an acquisition repeatability never available in the past (between 11 and 16 days), the new generation of X-band (λ = 3.11 cm) SAR satellites has improved significantly the possibility of monitoring the movements of single small structures scattered within rural and natural environments. In this work, we present the PSI outcome in the Venice Lagoon using the German TerraSAR-X and the Italian COSMOSkyMed satellites. The investigated period covers the time interval 2008-2011. The outcomes of the two X-band analyses are compared both at the regional and the local scale in terms of target coverage and distribution and subsidence rates. Springer International Publishing Switzerland 2014.
BibTeX:
@book{Teatini2014175,
  author = {Teatini, P. and Tosi, L. and Strozzi, T.},
  title = {Capability of X-band persistent scatterer interferometry to monitor land subsidence in the Venice lagoon},
  journal = {Engineering Geology for Society and Territory - Volume 4: Marine and Coastal Processes},
  publisher = {Springer International Publishing},
  year = {2014},
  pages = {175-178},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84948104123&doi=10.1007%2f978-3-319-08660-6_33&partnerID=40&md5=b67bd6653d9f0388fd36baf4da04fb27},
  doi = {10.1007/978-3-319-08660-6_33}
}
Thurner M, Beer C, Santoro M, Carvalhais N, Wutzler T, Schepaschenko D, Shvidenko A, Kompter E, Ahrens B, Levick S and Schmullius C (2014), "Carbon stock and density of northern boreal and temperate forests", Global Ecology and Biogeography. Vol. 23(3), pp. 297-310.
Abstract: Aim: To infer a forest carbon density map at 0.01° resolution from a radar remote sensing product for the estimation of carbon stocks in Northern Hemisphere boreal and temperate forests. Location: The study area extends from 30°N to 80°N, covering three forest biomes - temperate broadleaf and mixed forests (TBMF), temperate conifer forests (TCF) and boreal forests (BFT) - over three continents (North America, Europe and Asia). Methods: This study is based on a recently available growing stock volume (GSV) product retrieved from synthetic aperture radar data. Forest biomass and spatially explicit uncertainty estimates were derived from the GSV using existing databases of wood density and allometric relationships between biomass compartments (stem, branches, roots, foliage). We tested the resultant map against inventory-based biomass data from Russia, Europe and the USA prior to making intercontinent and interbiome carbon stock comparisons. Results: Our derived carbon density map agrees well with inventory data at regional scales (r2=0.70-0.90). While 40.7±15.7 petagram of carbon (PgC) are stored in BFT, TBMF and TCF contain 24.5±9.4PgC and 14.5±4.8 PgC, respectively. In terms of carbon density, we found 6.21±2.07kgC m-2 retained in TCF and 5.80±2.21kgC m-2 in TBMF, whereas BFT have a mean carbon density of 4.00±1.54kgC m-2. Indications of a higher carbon density in Europe compared with the other continents across each of the three biomes could not be proved to be significant. Main conclusions: The presented carbon density and corresponding uncertainty map give an insight into the spatial patterns of biomass and stand as a new benchmark to improve carbon cycle models and carbon monitoring systems. In total, we found 79.8±29.9PgC stored in northern boreal and temperate forests, with Asian BFT accounting for 22.1±8.3PgC. 2013 The Authors.
BibTeX:
@article{Thurner2014297,
  author = {Thurner, M. and Beer, C. and Santoro, M. and Carvalhais, N. and Wutzler, T. and Schepaschenko, D. and Shvidenko, A. and Kompter, E. and Ahrens, B. and Levick, S.R. and Schmullius, C.},
  title = {Carbon stock and density of northern boreal and temperate forests},
  journal = {Global Ecology and Biogeography},
  year = {2014},
  volume = {23},
  number = {3},
  pages = {297-310},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84893876661&doi=10.1111%2fgeb.12125&partnerID=40&md5=25cc945d9ba5faf63fc95bc69770a28a},
  doi = {10.1111/geb.12125}
}
Tosi L, Teatini P, Strozzi T and Da Lio C (2014), "Relative land subsidence of the venice coastland, Italy", Engineering Geology for Society and Territory - Volume 4: Marine and Coastal Processes. , pp. 171-173. Springer International Publishing.
Abstract: The Venice coastland, Italy, is an emblematic case of a coastal area prone to progressive submersion by the rising of the sea. Although the city of Venice represents the most relevant case in the northern Adriatic coast, the loss in ground elevation with respect to the sea level, i.e. the relative land subsidence (RLS), is particularly important not only in sectors directly affected by the marine ingression but also in the in-land coastal plain. In this work we quantify the RLS occurred over the period 1992-2010 in the Venice coastland by the superimposition of the Adriatic sea level rise to the ground displacements assessed by the Interferometric Point Target Analysis performed on ERS-1/2 and ENVISAT scenes. Results show that the lowering of certain portions of the coastland relative to the mean sea level amounts to several centimeters, which are values particularly severe for the maintenance and management of the coastal area. Springer International Publishing Switzerland 2014.
BibTeX:
@book{Tosi2014171,
  author = {Tosi, L. and Teatini, P. and Strozzi, T. and Da Lio, C.},
  title = {Relative land subsidence of the venice coastland, Italy},
  journal = {Engineering Geology for Society and Territory - Volume 4: Marine and Coastal Processes},
  publisher = {Springer International Publishing},
  year = {2014},
  pages = {171-173},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84948082873&doi=10.1007%2f978-3-319-08660-6_32&partnerID=40&md5=3bb869be870efef162660e044eb6479b},
  doi = {10.1007/978-3-319-08660-6_32}
}
Walter T, Shirzaei M, Manconi A, Solaro G, Pepe A, Manzo M and Sansosti E (2014), "Possible coupling of Campi Flegrei and Vesuvius as revealed by InSAR time series, correlation analysis and time dependent modeling", Journal of Volcanology and Geothermal Research. Vol. 280, pp. 104-110. Elsevier.
Abstract: Volcanoes are often considered as isolated systems, however, evidences increase that adjacent volcanoes are directly coupled or may be closely related to remote triggers. At the Italian volcanoes Campi Flegrei and Vesuvius, as well as adjacent volcano-tectonic systems, all located in the Campania Volcanic Province with  . 2. million inhabitants, a new analysis of satellite radar data reveals allied deformation activity. Here we show that during the 16-year records from 1992 to 2008, identified episodes of deformation have occurred in correlation. Albeit differences in the quantity of deformation, the sign, frequency and rate of pressure changes at reservoirs beneath Campi Flegrei and Vesuvius can be very similar, allowing to infer that pressure changes originating from a magmatic or tectonic source external to the shallow volcano magma plumbing systems is a likely cause. Such a fluid-mechanical coupling sheds light on the earlier episodes of correlated eruptions and deformations occurring during the historical roman times. 2014 Elsevier B.V.
BibTeX:
@article{Walter2014104,
  author = {Walter, T.R. and Shirzaei, M. and Manconi, A. and Solaro, G. and Pepe, A. and Manzo, M. and Sansosti, E.},
  title = {Possible coupling of Campi Flegrei and Vesuvius as revealed by InSAR time series, correlation analysis and time dependent modeling},
  journal = {Journal of Volcanology and Geothermal Research},
  publisher = {Elsevier},
  year = {2014},
  volume = {280},
  pages = {104-110},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901585335&doi=10.1016%2fj.jvolgeores.2014.05.006&partnerID=40&md5=cc728517911345d4e5af73131e0472d5},
  doi = {10.1016/j.jvolgeores.2014.05.006}
}
Wiesmann A, Caduff R, Strozzi T, Papke J and Matzler C (2014), "Monitoring of dynamic changes in alpine snow with terrestrial radar imagery", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3662-3665. Institute of Electrical and Electronics Engineers Inc..
Abstract: Remote sensing of snow with active and passive microwaves on terrestrial, aircraft and satellite platforms has a long tradition. However, the observation of dynamic processes on alpine slopes is difficult to achieve by fixed orbits and flight schedules. Terrestrial radar interferometers allow to overcome some of these constraints due to the portability of the system, the possibility to make repeat acquisitions in minute intervals, and the local observation capability. Results in the Swiss Alps prove the potential of the methodology to measure rapid and local changes in snow parameters such as changes of the liquid water content, sudden mechanical impact on the snowpack due to skiers and avalanches. Using standard interferometric techniques a local snow displacement map was computed providing information about the spatial and temporal behavior of creeping snow. 2014 IEEE.
BibTeX:
@conference{Wiesmann20143662,
  author = {Wiesmann, A. and Caduff, R. and Strozzi, T. and Papke, J. and Matzler, C.},
  title = {Monitoring of dynamic changes in alpine snow with terrestrial radar imagery},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2014},
  pages = {3662-3665},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84911417045&doi=10.1109%2fIGARSS.2014.6947277&partnerID=40&md5=b072a7323e31d94eeed1dd67711bc64f},
  doi = {10.1109/IGARSS.2014.6947277}
}
Allasia P, Manconi A, Giordan D, Baldo M and Lollino G (2013), "ADVICE: A new approach for near-real-time monitoring of surface displacements in landslide hazard scenarios", Sensors (Switzerland). Vol. 13(7), pp. 8285-8302. MDPI AG.
Abstract: We present a new method for near-real-time monitoring of surface displacements due to landslide phenomena, namely ADVanced dIsplaCement monitoring system for Early warning (ADVICE). The procedure includes: (i) data acquisition and transfer protocols; (ii) data collection, filtering, and validation; (iii) data analysis and restitution through a set of dedicated software; (iv) recognition of displacement/velocity threshold, early warning messages via SMS and/or emails; (v) automatic publication of the results on a dedicated webpage. We show how the system evolved and the results obtained by applying ADVICE over three years into a real early warning scenario relevant to a large earthflow located in southern Italy. ADVICE has speed-up and facilitated the understanding of the landslide phenomenon, the communication of the monitoring results to the partners, and consequently the decision-making process in a critical scenario. Our work might have potential applications not only for landslide monitoring but also in other contexts, as monitoring of other geohazards and of complex infrastructures, as open-pit mines, buildings, dams, etc. 2013 by the authors; licensee MDPI, Basel, Switzerland.
BibTeX:
@article{Allasia20138285,
  author = {Allasia, P. and Manconi, A. and Giordan, D. and Baldo, M. and Lollino, G.},
  title = {ADVICE: A new approach for near-real-time monitoring of surface displacements in landslide hazard scenarios},
  journal = {Sensors (Switzerland)},
  publisher = {MDPI AG},
  year = {2013},
  volume = {13},
  number = {7},
  pages = {8285-8302},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879514742&doi=10.3390%2fs130708285&partnerID=40&md5=ecd3b7fb002a5035115bee5a879b7382},
  doi = {10.3390/s130708285}
}
Askne J, Fransson J, Santoro M, Soja M and Ulander L (2013), "Model-based biomass estimation of a hemi-boreal forest from multitemporal tanDEM-X acquisitions", Remote Sensing. Vol. 5(11), pp. 5574-5597. MDPI AG.
Abstract: Above-ground forest biomass is a significant variable in the terrestrial carbon budget, but is still estimated with relatively large uncertainty. Remote sensing methods can improve the characterization of the spatial distribution and estimation accuracy of biomass; in this respect, it is important to examine the potential offered by new sensors. To assess the contribution of the TanDEM-X mission, eighteen interferometric Synthetic Aperture Radar (SAR) image pairs acquired over the hemi-boreal test site of Remningstorp in Sweden were investigated. Three models were used for interpretation of TanDEM-X signatures and above-ground biomass retrieval: Interferometric Water Cloud Model (IWCM), Random Volume over Ground (RVoG) model, and a simple model based on penetration depth (PD). All use an allometric expression to relate above-ground biomass to forest height measured by TanDEM-X. The retrieval was assessed on 201 forest stands with a minimum size of 1 ha, and ranging from 6 to 267 Mg/ha (mean biomass of 105 Mg/ha) equally divided into a model training dataset and a validation test dataset. Biomass retrieved using the IWCM resulted in a Root Mean Square Error (RMSE) between 17% and 33%, depending on acquisition date and image acquisition geometry (angle of incidence, interferometric baseline, and orbit type). The RMSE in the case of the RVoG and the PD models were slightly higher. A multitemporal estimate of the above-ground biomass using all eighteen acquisitions resulted in an RMSE of 16% with R2 = 0.93. These results prove the capability of TanDEM-X interferometric data to estimate forest aboveground biomass in the boreal zone.. 2013 by the authors.
BibTeX:
@article{Askne20135574,
  author = {Askne, J.I.H. and Fransson, J.E.S. and Santoro, M. and Soja, M.J. and Ulander, L.M.H.},
  title = {Model-based biomass estimation of a hemi-boreal forest from multitemporal tanDEM-X acquisitions},
  journal = {Remote Sensing},
  publisher = {MDPI AG},
  year = {2013},
  volume = {5},
  number = {11},
  pages = {5574-5597},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84904625067&doi=10.3390%2frs5115574&partnerID=40&md5=42bf62db4f8e472dee46cd96c8626d9f},
  doi = {10.3390/rs5115574}
}
Burjack I, Santoro M and Schmullius C (2013), "Change analysis of sar based growing stock volume maps in northeast China for 2005 - 2010", In European Space Agency, (Special Publication) ESA SP. Vol. 704 SP
BibTeX:
@conference{Burjack2013,
  author = {Burjack, I. and Santoro, M. and Schmullius, C.},
  title = {Change analysis of sar based growing stock volume maps in northeast China for 2005 - 2010},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2013},
  volume = {704 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892684220&partnerID=40&md5=136c8e1604876e29fb07b46bfcc218bb}
}
Caduff R, Strozzi T and Wiesmann A (2013), "Successful application of terrestrial radar interferometry for the extensive measurement of extraordinary landslide movements in the area of Hintergraben (Obwalden) [Erfolgreicher Einsatz terrestrischer Radar-Interferometrie zur flachenhaften Vermessung von ausserordentlichen Hangrutschungsbewegungen im Gebiet Hintergraben (OW)]", Bulletin fuer Angewandte Geologie. Vol. 18(2), pp. 129-138. Ver. Schweizerischer Petroleum Geol. und Ing..
Abstract: Terrestrial radar interferometry allows precise detection and measurement of surface deformation related to mass movements. One of the known limitations of this technology is temporal decorrelation, affecting in particular its application in heavily vegetated areas. Based on the exceptional landslide activity in the area of Hintergraben (OWl in the Swiss Alpine Foreland we show in this study that an almost complete coverage of surface deformation can be achieved even over dense grassland with short acquisition time intervals of 3 minutes and selective post-processing. Two measurement campaigns performed on May 5 and 28, 2013 demonstrate the successful application of terrestrial radar interferometry for the measurement of surface displacement in the case of low grass-heigths (max. 20 cm) respectively grass-heights reaching 1 m. We show that surface deformation rates decreased from max. h0 cm/day to max. 10 cm/day in the 3 weeks period. The findings are in good agreement with punctual control measurements performed with tachymetry.
BibTeX:
@article{Caduff2013129,
  author = {Caduff, R. and Strozzi, T. and Wiesmann, A.},
  title = {Successful application of terrestrial radar interferometry for the extensive measurement of extraordinary landslide movements in the area of Hintergraben (Obwalden) [Erfolgreicher Einsatz terrestrischer Radar-Interferometrie zur flachenhaften Vermessung von ausserordentlichen Hangrutschungsbewegungen im Gebiet Hintergraben (OW)]},
  journal = {Bulletin fuer Angewandte Geologie},
  publisher = {Ver. Schweizerischer Petroleum Geol. und Ing.},
  year = {2013},
  volume = {18},
  number = {2},
  pages = {129-138},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85006643546&doi=10.5169%2fseals-391152&partnerID=40&md5=de16dc72f30a9b370fe3bee067fe2a38},
  doi = {10.5169/seals-391152}
}
De Michele M, Raucoules D, Wegmüller U and Bignami C (2013), "Synthetic aperture radar (sar) doppler anomaly detected during the 2010 merapi (Java, Indonesia) eruption", IEEE Geoscience and Remote Sensing Letters. Vol. 10(6), pp. 1319-1323.
Abstract: In this letter, we report the presence of a localized Doppler anomaly occurring during the focusing of a Radarsat-2 data set acquired on the Merapi volcano (Indonesia) during the devastating 2010 eruption. The Doppler anomaly is manifested as 3-km-wide bull's-eye-shaped azimuth pixel shifts between two subaperture images. The Doppler anomaly is centered on the summit-south flank of the Merapi volcano. The pixel shifts reach up to 11.6 m. Since the Merapi volcano was undergoing a large eruption during the data acquisition, it is possible that there is a volcano-related phenomenon that has delayed the radar signal so much to create measurable pixel offsets within a single synthetic aperture radar (SAR) data set, similar, but more extensive, to the signal generated by targets motions; similar, but less extensive, to the signal generated by ionospheric perturbations. It is known that the SAR signal is delayed as it passes through heterogeneous layers of the atmosphere, but this delay typically affects the SAR signal to a fraction of the phase cycle or few centimeters depending on the radar wavelength employed by the system. We investigate the source of this anomalous metric signal; we review the theoretical basis of SAR image focusing, and we try to provide a consistent physical framework to our observations. Our results are compatible with the SAR signal being perturbed during the actual process of image focusing by the presence of a contrasting medium located approximately between 6-and 12.5-km altitude, which we propose being associated with the presence of volcanic ash plume. 2013 IEEE.
BibTeX:
@article{DeMichele20131319,
  author = {De Michele, M. and Raucoules, D. and Wegmüller, U. and Bignami, C.},
  title = {Synthetic aperture radar (sar) doppler anomaly detected during the 2010 merapi (Java, Indonesia) eruption},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  year = {2013},
  volume = {10},
  number = {6},
  pages = {1319-1323},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84886584504&doi=10.1109%2fLGRS.2013.2239602&partnerID=40&md5=76f4cfd6a89aad8dc7c6e9b1db4ea270},
  doi = {10.1109/LGRS.2013.2239602}
}
Del Ventisette C, Ciampalini A, Manunta M, Calo F, Paglia L, Ardizzone F, Mondini A, Reichenbach P, Mateos R, Bianchini S, Garcia I, Fusi B, Deák Z, Rádi K, Graniczny M, Kowalski Z, Piatkowska A, Przylucka M, Retzo T, Strozzi T, Colombo D, Mora O, Sánchez F, Herrera G, Moretti S, Casagli N and Guzzetti F (2013), "Exploitation of large archives of ERS and ENVISAT C-band SAR data to characterize ground deformations", Remote Sensing. Vol. 5(8), pp. 3896-3917.
Abstract: In the last few years, several advances have been made in the use of radar images to detect, map and monitor ground deformations. DInSAR (Differential Synthetic Aperture Radar Interferometry) and A-DInSAR/PSI (Advanced DInSAR/Persistent Scatterers Interferometry) technologies have been successfully applied in the study of deformation phenomena induced by, for example, active tectonics, volcanic activity, ground water exploitation, mining, and landslides, both at local and regional scales. In this paper, the existing European Space Agency (ESA) archives (acquired as part of the FP7-DORIS project), which were collected by the ERS-1/2 and ENVISAT satellites operating in the microwave C-band, were analyzed and exploited to understand the dynamics of landslide and subsidence phenomena. In particular, this paper presents the results obtained as part of the FP7-DORIS project to demonstrate that the full exploitation of very long deformation time series (more than 15 years) can play a key role in understanding the dynamics of natural and human-induced hazards. 2013 by the authors.
BibTeX:
@article{DelVentisette20133896,
  author = {Del Ventisette, C. and Ciampalini, A. and Manunta, M. and Calo, F. and Paglia, L. and Ardizzone, F. and Mondini, A.C. and Reichenbach, P. and Mateos, R.M. and Bianchini, S. and Garcia, I. and Fusi, B. and Deák, Z.V. and Rádi, K. and Graniczny, M. and Kowalski, Z. and Piatkowska, A. and Przylucka, M. and Retzo, T. and Strozzi, T. and Colombo, D. and Mora, O. and Sánchez, F. and Herrera, G. and Moretti, S. and Casagli, N. and Guzzetti, F.},
  title = {Exploitation of large archives of ERS and ENVISAT C-band SAR data to characterize ground deformations},
  journal = {Remote Sensing},
  year = {2013},
  volume = {5},
  number = {8},
  pages = {3896-3917},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884691971&doi=10.3390%2frs5083896&partnerID=40&md5=a56fc85096ace5a9d5ad5572d5cf5d88},
  doi = {10.3390/rs5083896}
}
Frey O, Hajnsek I and Wegmüller U (2013), "Spaceborne SAR tomography in urban areas", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 69-72.
Abstract: Persistent scatterer interferometry relies on the assumption that only one dominant scatterer is present per range-azimuth resolution cell. If this criterion is not met the point target candidate is discarded during the iterative processing sequence. This one-scatterer assumption contrasts with the fact that in urban scenarios layover is an ubiquitous phenomenon, and, therefore two or even more scatterers per resolution cell occur frequently. SAR tomography has the potential to support persistent scatterer interferometry in urban areas by providing a means to identify and separate two scatterers in elevation direction. In this paper, we explore an interferometric stack consisting of 25 ENVISAT/ASAR SLC images over Bucharest using SAR tomography approaches combined with interferometric point target processing. Elevation profiles are extracted using beamforming and truncated singular value decomposition focusing approaches. 2013 IEEE.
BibTeX:
@conference{Frey201369,
  author = {Frey, O. and Hajnsek, I. and Wegmüller, U.},
  title = {Spaceborne SAR tomography in urban areas},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2013},
  pages = {69-72},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894263807&doi=10.1109%2fIGARSS.2013.6721094&partnerID=40&md5=67c9276491f73b730ca2c0ba1781a949},
  doi = {10.1109/IGARSS.2013.6721094}
}
Frey O, Santoro M, Werner C and Wegmüller U (2013), "DEM-based SAR pixel-area estimation for enhanced geocoding refinement and radiometric Normalization", IEEE Geoscience and Remote Sensing Letters. Vol. 10(1), pp. 48-52.
Abstract: Precise terrain-corrected georeferencing of synthetic aperture radar (SAR) images and derived products in range-Doppler coordinates is important with respect to several aspects, such as data interpretation, combination with other geodata products, and transformation of, e.g., terrain heights into SAR geometry as used in differential interferometric SAR (DInSAR) applications. For georeferencing, a lookup table is calculated and then refined based on a coregistration of the actual SAR image to a simulated SAR image. The impact of using two different implementations of such a simulator of topography-induced radar brightness, 1) an approach based on angular relationships and 2) a pixel-area-based method, is discussed in this letter. It is found that the pixel-area-based method leads to considerable improvements with regard to the robustness of georeferencing and also with regard to radiometric normalization in layover-affected areas. 2012 IEEE.
BibTeX:
@article{Frey201348,
  author = {Frey, O. and Santoro, M. and Werner, C.L. and Wegmüller, U.},
  title = {DEM-based SAR pixel-area estimation for enhanced geocoding refinement and radiometric Normalization},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  year = {2013},
  volume = {10},
  number = {1},
  pages = {48-52},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84887623092&doi=10.1109%2fLGRS.2012.2192093&partnerID=40&md5=1bbc732193929b74d40883764ef29f49},
  doi = {10.1109/LGRS.2012.2192093}
}
Frey O, Werner C, Wegmüller U, Wiesmann A, Henke D and Magnard C (2013), "A car-borne SAR and InSAR experiment", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 93-96. IEEE.
Abstract: In this contribution, a car-borne SAR and InSAR experiment is described. The slope of a valley was imaged by means of a single-pass InSAR system mounted on a car driving on roads along the bottom of the valley. The GAMMA portable radar interferometer GPRI-II hardware with a modified antenna configuration was used for data acquisition. The experimental setup (1), SAR imagery focused along a slightly curved sensor trajectory (2), and first interferometric results (3) obtained using this configuration are presented. 2013 IEEE.
BibTeX:
@conference{Frey201393,
  author = {Frey, O. and Werner, C.L. and Wegmüller, U. and Wiesmann, A. and Henke, D. and Magnard, C.},
  title = {A car-borne SAR and InSAR experiment},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE},
  year = {2013},
  pages = {93-96},
  url = {https://www.gamma-rs.ch/uploads/media/freyWernerWegmullerWiesmannHenkeMagnardIGARSS2013CARSAR.pdf},
  doi = {10.1109/IGARSS.2013.6721100}
}
Garcia-Davalillo J-C, Herrera G, Notti D, Hernandez-Ruiz M, Fernandez-Merodo J-A, Alvarez-Fernandez I, Gonzalez-Nicieza C, Strozzi T and Mora O (2013), "InSAR data for mapping and monitoring landslides in Tena valley", In Landslide Science and Practice: Early Warning, Instrumentation and Monitoring. Vol. 2, pp. 243-249.
Abstract: In the last 20 years the exploitation of satellite SAR interferometry has shown a considerable improvement due to the development of new InSAR PSI techniques and the availability of the new satellite sensors with higher spatial and temporal resolution. One of the most interesting applications is the possibility of mapping slow landslides processes. In this paper we present an analysis of the advantages and disadvantages of using L-, C- and Xband sensors for mapping and monitoring landslides in the Rio Gállego upper basin (Central Pyrenees, Spain) techniques. Springer-Verlag Berlin Heidelberg 2013.
BibTeX:
@conference{GarciaDavalillo2013243,
  author = {Garcia-Davalillo, J.-C. and Herrera, G. and Notti, D. and Hernandez-Ruiz, M. and Fernandez-Merodo, J.-A. and Alvarez-Fernandez, I. and Gonzalez-Nicieza, C. and Strozzi, T. and Mora, O.},
  title = {InSAR data for mapping and monitoring landslides in Tena valley},
  booktitle = {Landslide Science and Practice: Early Warning, Instrumentation and Monitoring},
  year = {2013},
  volume = {2},
  pages = {243-249},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84898060853&doi=10.1007%2f978-3-642-31445-2-31&partnerID=40&md5=4792fc91c99eb2b8cff2f6e66fb5efeb},
  doi = {10.1007/978-3-642-31445-2-31}
}
Giordan D, Allasia P, Manconi A, Baldo M, Santangelo M, Cardinali M, Corazza A, Albanese V, Lollino G and Guzzetti F (2013), "Morphological and kinematic evolution of a large earthflow: The Montaguto landslide, southern Italy", Geomorphology. Vol. 187, pp. 61-79.
Abstract: We studied the geomorphological evolution of the Montaguto landslide, a 3.1×103m long earthflow in the southern Apennines of Italy. Following an analysis of the different methods and techniques available to measure surface modifications caused by a large earthflow, we selected a combination of monitoring techniques compatible with the Montaguto case study. We exploited: (i) visual interpretation of aerial and satellite imagery, (ii) quantitative analysis of six digital elevation models (DEMs) covering the landslide area, and (iii) a large set of high-accuracy three-dimensional topographic measurements captured by three robotised total stations (RTSs). Integration of the results obtained from the different monitoring techniques allowed us to investigate the long (multi-decadal) and short (seasonal) term evolution of the Montaguto earthflow in the 58-year period (1954-2011). The examination of the available aerial, satellite and hill-shade images revealed a cyclic, long-term behaviour of mass movements of different types in the Rio Nocelle catchment occupied by the recent Montaguto earthflow. The combined analysis of the six DEMs allowed measuring the material eroded from the landslide crown area (V 1.4×106m3) and deposited in the landslide toe area (V 1.2×106m3) in the period from 2005 to June 2011. The analysis of a large set of high-accuracy topographic measurements revealed the kinematical characteristics of different sectors of the active earthflow, and allowed the reconstruction of the temporal and spatial evolution of the moving failure. The insights obtained are significant for the geo-mechanical modelling of similar earthflows, regional landslide mapping, and the evaluation of hazard and risk posed by large earthflows in southern Italy or similar physiographic regions. 2013 Elsevier B.V.
BibTeX:
@article{Giordan201361,
  author = {Giordan, D. and Allasia, P. and Manconi, A. and Baldo, M. and Santangelo, M. and Cardinali, M. and Corazza, A. and Albanese, V. and Lollino, G. and Guzzetti, F.},
  title = {Morphological and kinematic evolution of a large earthflow: The Montaguto landslide, southern Italy},
  journal = {Geomorphology},
  year = {2013},
  volume = {187},
  pages = {61-79},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84875485076&doi=10.1016%2fj.geomorph.2012.12.035&partnerID=40&md5=17fc3c027cdd4f474815dffb1be2728e},
  doi = {10.1016/j.geomorph.2012.12.035}
}
Grenerczy G and Wegmüller U (2013), "Deformation analysis of a burst red mud reservoir using combined descending and ascending pass ENVISAT ASAR data", Natural Hazards. Vol. 65(3), pp. 2205-2214.
Abstract: After the catastrophic failure of a red mud reservoir in Hungary, we performed a persistent scatterer radar interferometry (PSI) deformation analysis to investigate the stability and motion history of the entire area focusing on the dam walls of the collapsed structure. Our aim was to contribute to the better understanding of the disaster and, more importantly, to see whether it was possible to prognosticate and consequently prevent the failure of the reservoir and to help avoiding such occurrences worldwide. Our earlier data revealed that the surroundings were generally very stable over the investigated 8 years time interval, whereas significant continuous motions were detected on the embankments. After these first results, we continued our PSI deformation study with the processing and evaluation of the complete ascending pass ENVISAT dataset and later with the combination of the results of the two different observation geometries. From our descending and ascending data, it was possible to combine motions determined in line-of-sight directions and to investigate horizontal and vertical components allowing the estimation of 'total' velocity vectors, magnitude and directions, at those locations of the reservoir and on the entire study area where reflections from both projections were available. It was also possible to get information from several other segments of the embankments of the failed reservoir where the descending geometry was unfavorable. With the combination, the complete ENVISAT PSI analysis using both ascending and descending orbit data enabled us to constrain the role of the soil structure and to look at the differential uplift or subsidence due to swelling soil effect. It also enabled us to constrain the role of the deposited mud, slurry, and accumulated water, and the strength and design of the structure in the failure of the red mud reservoir. Models were also constructed to visualize the observed motions of the reservoir embankments and to highlight the location of strain and stress accumulation providing significant constraints on the natural and anthropogenic origin of the disaster. 2012 Springer Science+Business Media Dordrecht.
BibTeX:
@article{Grenerczy20132205,
  author = {Grenerczy, G. and Wegmüller, U.},
  title = {Deformation analysis of a burst red mud reservoir using combined descending and ascending pass ENVISAT ASAR data},
  journal = {Natural Hazards},
  year = {2013},
  volume = {65},
  number = {3},
  pages = {2205-2214},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871937028&doi=10.1007%2fs11069-012-0470-4&partnerID=40&md5=3fed848673da437d7d8bc8d11dba8be4},
  doi = {10.1007/s11069-012-0470-4}
}
Jakobsen P, Wegmüller U, Capes R and Pedersen S (2013), "Terrain subsidence detected by satellite radar scanning of the Copenhagen area, Denmark, and its relation to the tectonic framework", Geological Survey of Denmark and Greenland Bulletin. (28), pp. 25-28.
BibTeX:
@article{Jakobsen201325,
  author = {Jakobsen, P.R. and Wegmüller, U. and Capes, R. and Pedersen, S.A.S.},
  title = {Terrain subsidence detected by satellite radar scanning of the Copenhagen area, Denmark, and its relation to the tectonic framework},
  journal = {Geological Survey of Denmark and Greenland Bulletin},
  year = {2013},
  number = {28},
  pages = {25-28},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879516566&partnerID=40&md5=6c131f18eda5769902307f98fb7b6204}
}
Jones B, Gusmeroli A, Arp C, Strozzi T, Grosse G, Gaglioti B and Whitman M (2013), "Classification of freshwater ice conditions on the Alaskan Arctic Coastal Plain using ground penetrating radar and TerraSAR-X satellite data", International Journal of Remote Sensing. Vol. 34(23), pp. 8267-8279. Taylor and Francis Ltd..
Abstract: Arctic freshwater ecosystems have responded rapidly to climatic changes over the last half century. Lakes and rivers are experiencing a thinning of the seasonal ice cover, which may increase potential over-wintering freshwater habitat, winter water supply for industrial withdrawal, and permafrost degradation. Here, we combined the use of ground penetrating radar (GPR) and high-resolution (HR) spotlight TerraSAR-X (TSX) satellite data (1.25 m resolution) to identify and characterize floating ice and grounded ice conditions in lakes, ponds, beaded stream pools, and an alluvial river channel. Classified ice conditions from the GPR and the TSX data showed excellent agreement: 90.6% for a predominantly floating ice lake, 99.7% for a grounded ice lake, 79.0% for a beaded stream course, and 92.1% for the alluvial river channel. A GIS-based analysis of 890 surface water features larger than 0.01 ha showed that 42% of the total surface water area potentially provided over-wintering habitat during the 2012/2013 winter. Lakes accounted for 89% of this area, whereas the alluvial river channel accounted for 10% and ponds and beaded stream pools each accounted for <1%. Identification of smaller landscape features such as beaded stream pools may be important because of their distribution and role in connecting other water bodies on the landscape. These findings advance techniques for detecting and knowledge associated with potential winter habitat distribution for fish and invertebrates at the local scale in a region of the Arctic with increasing stressors related to climate and land use change. 2013 This work was authored as part of the Contributors' official duties as Employees of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under US Law.
BibTeX:
@article{Jones20138267,
  author = {Jones, B.M. and Gusmeroli, A. and Arp, C.D. and Strozzi, T. and Grosse, G. and Gaglioti, B.V. and Whitman, M.S.},
  title = {Classification of freshwater ice conditions on the Alaskan Arctic Coastal Plain using ground penetrating radar and TerraSAR-X satellite data},
  journal = {International Journal of Remote Sensing},
  publisher = {Taylor and Francis Ltd.},
  year = {2013},
  volume = {34},
  number = {23},
  pages = {8267-8279},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84886933697&doi=10.1080%2f2150704X.2013.834392&partnerID=40&md5=1995712d0acfeced62fe2ce085b76a5e},
  doi = {10.1080/2150704X.2013.834392}
}
Koffi E, Graham E and Matzler C (2013), "The water vapour flux above Switzerland and its role in the August 2005 extreme precipitation and flooding", Meteorologische Zeitschrift. Vol. 22(3), pp. 329-342.
Abstract: The water budget approach is applied to an atmospheric box above Switzerland (hereafter referred to as the "Swiss box") to quantify the atmospheric water vapour flux using ECMWF ERA-Interim reanalyses. The results confirm that the water vapour flux through the Swiss box is highly temporally variable, ranging from 1 to 5 × 107 kg/s during settled anticyclonic weather, but increasing in size by a factor of ten or more during high speed currents of water vapour. Overall, Switzerland and the Swiss box "import" more water vapour than it "exports", but the amount gained remains only a small fraction (1% to 5%) of the total available water vapour passing by. High inward water vapour fluxes are not necessarily linked to high precipitation episodes. The water vapour flux during the August 2005 floods, which caused severe damage in central Switzerland, is examined and an assessment is made of the computed water vapour fluxes compared to high spatio-temporal rain gauge and radar observations. About 25% of the incoming water vapour flux was stored in Switzerland. The computed water vapour fluxes from ECMWF data compare well with the mean rain gauge observations and the combined rain-gauge radar precipitation products. by Gebruder Borntraeger 2013.
BibTeX:
@article{Koffi2013329,
  author = {Koffi, E.N. and Graham, E. and Matzler, C.},
  title = {The water vapour flux above Switzerland and its role in the August 2005 extreme precipitation and flooding},
  journal = {Meteorologische Zeitschrift},
  year = {2013},
  volume = {22},
  number = {3},
  pages = {329-342},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84887830024&doi=10.1127%2f0941-2948%2f2013%2f0392&partnerID=40&md5=ffcb1febf24d1c8799c3a5f89d20bf48},
  doi = {10.1127/0941-2948/2013/0392}
}
Kos A, Strozzi T, Stockmann R, Wiesmann A and Werner C (2013), "Detection and characterization of rock slope instabilities using a portable radar interferometer (GPRI)", In Landslide Science and Practice: Early Warning, Instrumentation and Monitoring. Vol. 2, pp. 325-329.
Abstract: A portable radar interferomter was used to periodically monitor a rock wall, where millimeter-scale displacements (0.5-0.6 mm/month) on an unstable rock slab were detected. Preliminary interpretation of a radar images acquired over a 5 month period revealed evidence for combined toppling and buckling failure mechanisms on the rock slab. The rock wall of interest has a history of block fall activity, which directly endangers a roadway in Canton Graubunden, Switzerland. Springer-Verlag Berlin Heidelberg 2013.
BibTeX:
@conference{Kos2013325,
  author = {Kos, A. and Strozzi, T. and Stockmann, R. and Wiesmann, A. and Werner, C.},
  title = {Detection and characterization of rock slope instabilities using a portable radar interferometer (GPRI)},
  booktitle = {Landslide Science and Practice: Early Warning, Instrumentation and Monitoring},
  year = {2013},
  volume = {2},
  pages = {325-329},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84898073440&doi=10.1007%2f978-3-642-31445-2-42&partnerID=40&md5=dc39036747654a651913971b31c5aa9a},
  doi = {10.1007/978-3-642-31445-2-42}
}
Ling F, Li Z, Chen E, Huang Y, Tian X, Schmullius C, Leiterer R, Reiche J and Santoro M (2013), "Forest and non-forest mapping with envisat asar images", In European Space Agency, (Special Publication) ESA SP. Vol. 704 SP
Abstract: Envisat Advanced Synthetic Aperture Radar (ASAR) dual-polarization data are shown to be effective for regional forest monitoring. To this scope, an automatic SAR image preprocessing procedure was developed using SRTM DEM and Landsat TM image for geocoding in rugged terrain and smooth terrain areas, respectively. An object-oriented forest and non-forest classification method is then proposed based on the HH to HV intensity ratio and HV images of ASAR data at single acquisition in winter. The developed methods were applied to forest and non-forest mapping in Northeast China. The overall accuracy, the user's accuracy and the producer's accuracy of forest are 83.7%, 85.6% and 75.7% respectively. The results indicate that the proposed methods are promising for operational forest mapping at regional scale.
BibTeX:
@conference{Ling2013a,
  author = {Ling, F. and Li, Z. and Chen, E. and Huang, Y. and Tian, X. and Schmullius, C. and Leiterer, R. and Reiche, J. and Santoro, M.},
  title = {Forest and non-forest mapping with envisat asar images},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2013},
  volume = {704 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892720754&partnerID=40&md5=b9c3ffd31d228820cf9e8a1f4a1b5638}
}
Ling F, Li Z, Chen E, Huang Y, Tian X, Schmullius C, Leiterer R, Reiche J and Santoro M (2013), "Regional forest and non-forest mapping with envisat ASAR data", In European Space Agency, (Special Publication) ESA SP. Vol. 704 SP
BibTeX:
@conference{Ling2013b,
  author = {Ling, F. and Li, Z. and Chen, E. and Huang, Y. and Tian, X. and Schmullius, C. and Leiterer, R. and Reiche, J. and Santoro, M.},
  title = {Regional forest and non-forest mapping with envisat ASAR data},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2013},
  volume = {704 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892682072&partnerID=40&md5=f5658d27f26e82e1df2a86ef5458818d}
}
Manconi A, Allasia P, Giordan D, Baldo M and Lollino G (2013), "Monitoring the stability of infrastructures in an emergency scenario: The "costa Concordia" vessel wreck", In Global View of Engineering Geology and the Environment - Proceedings of the International Symposium and 9th Asian Regional Conference of IAEG. , pp. 587-591.
Abstract: We present a summary of the monitoring activities performed by CNR-IRPI during the emergency scenario relevant to the "Costa Concordia" ship stranding, occurred on January 13, 2012, near the coast of Il Giglio island, Italy. Two Robotized Total Stations (RTS) were deployed in different times in order to monitor the stability of the vessel during the Search and Rescue activities, as well as the fuel recovery accomplishment. RTS data have been considered as an important support for the early warning system set up to ensure the safety of the operators. The dataset and results herein included are unique, and represent a peculiar and concrete opportunity to test the efficiency of specific monitoring techniques, which were developed to control and study phenomena relevant to engineering geology activities, also in very peculiar structural health's monitoring, relevant to an unforeseen emergency scenario. 2013 Taylor & Francis Group, London.
BibTeX:
@conference{Manconi2013587,
  author = {Manconi, A. and Allasia, P. and Giordan, D. and Baldo, M. and Lollino, G.},
  title = {Monitoring the stability of infrastructures in an emergency scenario: The "costa Concordia" vessel wreck},
  booktitle = {Global View of Engineering Geology and the Environment - Proceedings of the International Symposium and 9th Asian Regional Conference of IAEG},
  year = {2013},
  pages = {587-591},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84890074884&partnerID=40&md5=1ec570f3a76ab95620082d6e7adf3452}
}
Manconi A, Allasia P, Giordan D, Baldo M, Lollino G, Corazza A and Albanese V (2013), "Landslide 3D surface deformation model obtained via RTS measurements", In Landslide Science and Practice: Early Warning, Instrumentation and Monitoring. Vol. 2, pp. 431-436.
Abstract: We present a new procedure that allows retrieving in near-real-time 3D surface deformation models starting from data acquired via Robotized Total Stations (RTS). The RTS measurements are first pre-processed and then implemented on 3D maps that include vector arrows representative of the intensities and of the real directions of motion in a given system of coordinates. The 3D surface deformation models are finally overlain on a DTM and/or on an updated picture of the monitored area. We discuss an example of application to an active large-scale landslide located in the area of Montaguto (southern Italy, ca. 100 km northeast from Naples). In this complex landslide scenario, the use of 3D representations of the surface deformation simplified the understanding of the evolution of the landslide phenomenon and received positive feedbacks from operators of the Italian Civil Protection Department. Springer-Verlag Berlin Heidelberg 2013.
BibTeX:
@conference{Manconi2013431,
  author = {Manconi, A. and Allasia, P. and Giordan, D. and Baldo, M. and Lollino, G. and Corazza, A. and Albanese, V.},
  title = {Landslide 3D surface deformation model obtained via RTS measurements},
  booktitle = {Landslide Science and Practice: Early Warning, Instrumentation and Monitoring},
  year = {2013},
  volume = {2},
  pages = {431-436},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84898070531&doi=10.1007%2f978-3-642-31445-2-56&partnerID=40&md5=5aa3c1b94a1f63d599e2f1bf920fd6a9},
  doi = {10.1007/978-3-642-31445-2-56}
}
Manunta M, Calo F, Ojha C, Ardizzone F, Guzzetti F, Mondini A, Reichenbach P, Bianchini S, Casagli N, Ciampalini A, Del Ventisette C, Moretti S, Garcia I, Herrera G, Mateos R, Fusi B, Graniczny M, Kowalski Z, Piatkowska A, Surala M, Retzo H, Strozzi T, Colombo D, Mora O and Sanchez C (2013), "The European DORIS downstream service as a multi-scale system for landslides and subsidence risk management", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 33-36.
Abstract: We focused on the joint exploitation of satellite and ground-based technologies in order to understand the kinematic behavior of landslides and subsidence phenomena relevant to different test sites in Europe. In this context, we efficiently exploited C-band and X-band satellite and ground-based SAR data for the investigation of the temporal and spatial pattern of ground deformations caused by natural and human-induced hazards. The present work has been conducted within the FP7-EU DORIS project. 2013 IEEE.
BibTeX:
@conference{Manunta201333,
  author = {Manunta, M. and Calo, F. and Ojha, C. and Ardizzone, F. and Guzzetti, F. and Mondini, A.C. and Reichenbach, P. and Bianchini, S. and Casagli, N. and Ciampalini, A. and Del Ventisette, C. and Moretti, S. and Garcia, I. and Herrera, G. and Mateos, R.M. and Fusi, B. and Graniczny, M. and Kowalski, Z. and Piatkowska, A. and Surala, M. and Retzo, H. and Strozzi, T. and Colombo, D. and Mora, O. and Sanchez, C.},
  title = {The European DORIS downstream service as a multi-scale system for landslides and subsidence risk management},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2013},
  pages = {33-36},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894288008&doi=10.1109%2fIGARSS.2013.6721085&partnerID=40&md5=206e8f0f3b4c89f71ccfcc7aa90e1054},
  doi = {10.1109/IGARSS.2013.6721085}
}
Santoro M, Cartus O, Fransson J, Shvidenko A, McCallum I, Hall R, Beaudoin A, Beer C and Schmullius C (2013), "Estimates of forest growing stock volume for sweden, central siberia, and quebec using envisat advanced synthetic aperture radar backscatter data", Remote Sensing. Vol. 5(9), pp. 4503-4532.
Abstract: A study was undertaken to assess Envisat Advanced Synthetic Aperture Radar (ASAR) ScanSAR data for quantifying forest growing stock volume (GSV) across three boreal regions with varying forest types, composition, and structure (Sweden, Central Siberia, and Quebec). Estimates of GSV were obtained using hyper-temporal observations of the radar backscatter acquired by Envisat ASAR with the BIOMASAR algorithm. In total, 5.3.106 km2 were mapped with a 0.01° pixel size to obtain estimates representative for the year of 2005. Comparing the SAR-based estimates to spatially explicit datasets of GSV, generated from forest field inventory and/or Earth Observation data, revealed similar spatial distributions of GSV. Nonetheless, the weak sensitivity of C-band backscatter to forest structural parameters introduced significant uncertainty to the estimated GSV at full resolution. Further discrepancies were observed in the case of different scales of the ASAR and the reference GSV and in areas of fragmented landscapes. Aggregation to 0.1° and 0.5° was then undertaken to generate coarse scale estimates of GSV. The agreement between ASAR and the reference GSV datasets improved; the relative difference at 0.5° was consistently within a magnitude of 20-30%. The results indicate an improvement of the characterization of forest GSV in the boreal zone with respect to currently available information. 2013 by the authors; licensee MDPI, Basel, Switzerland.
BibTeX:
@article{Santoro20134503,
  author = {Santoro, M. and Cartus, O. and Fransson, J.E.S. and Shvidenko, A. and McCallum, I. and Hall, R.J. and Beaudoin, A. and Beer, C. and Schmullius, C.},
  title = {Estimates of forest growing stock volume for sweden, central siberia, and quebec using envisat advanced synthetic aperture radar backscatter data},
  journal = {Remote Sensing},
  year = {2013},
  volume = {5},
  number = {9},
  pages = {4503-4532},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884676581&doi=10.3390%2frs5094503&partnerID=40&md5=fd5442b09f70efe874ce3b28cca3243c},
  doi = {10.3390/rs5094503}
}
Scherer D, Hall D, Hochschild V, Konig M, Winther J-G, Duguay C, Pivot F, Matzler C, Rau F, Seidel K, Solberg R and Walker A (2013), "Remote Sensing of Snow Cover", Remote Sensing in Northern Hydrology: Measuring Environmental Change. , pp. 7-38. American Geophysical Union.
Abstract: This chapter is dedicated to remote sensing of snow as one of the most important cryospheric components to be considered in Northern Hydrology. After a short introduction, general approaches in optical, thermal infrared, active and passive microwave, and airborne gamma remote sensing, including the most important systems, are presented and discussed. Then, specific applications of remote sensing of snow cover are shown, grouped by the respective snow properties, i.e., snow-covered area, liquid water content, snow water equivalent, snow reflectance, snow grain size, snow depth, and snow temperature. Finally, conclusions are drawn with respect to unresolved issues and future research needs. by the American Geophysical Union.
BibTeX:
@book{Scherer20137,
  author = {Scherer, D. and Hall, D.K. and Hochschild, V. and Konig, M. and Winther, J.-G. and Duguay, C.R. and Pivot, F. and Matzler, C. and Rau, F. and Seidel, K. and Solberg, R. and Walker, A.E.},
  title = {Remote Sensing of Snow Cover},
  journal = {Remote Sensing in Northern Hydrology: Measuring Environmental Change},
  publisher = {American Geophysical Union},
  year = {2013},
  pages = {7-38},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946839231&doi=10.1029%2f163GM03&partnerID=40&md5=51257c24c0624a567b5fec9cce6967b2},
  doi = {10.1029/163GM03}
}
Schlunegger F, Norton K and Caduff R (2013), "Hillslope Processes in Temperate Environments", Treatise on Geomorphology. Vol. 7, pp. 337-354. Elsevier Inc..
Abstract: In this chapter, we discuss the factors controlling the mechanisms and rates of hillslope failure in temperate environments with a major focus on the Swiss Alps. We frame this presentation by defining Alpine hillslopes as either strength- or transport-limited hillslopes. We organize this discussion into individual sections that outline how hillslope processes are related to (1) the mechanical strength and bedding orientation of bedrock, (2) the competition between channelized and hillslope processes, (3) hillslope-channel coupling relationships, and (4) fluvial erosion rates. We find that hillslope angles depend on bedrock strength along nonincised channels, but are not related to this parameter in inner gorges. We also find that valley flanks host deep-seated landslides where the bedrock dips parallel to the topographic slope. In the opposite case, the valley sides are dissected by a network of bedrock channels bordered by strength-limited hillslopes. In this chapter, we illustrate that a high ratio between sediment discharge on hillslopes and in channels explains the formation of smooth landscapes with low channel densities and long response times. This chapter considers the formation of strength-limited hillslopes as a consequence of an upslope-directed coupling between channels and hillslopes. The chapter also discusses that soil-mantled hillslopes occur where fluvial incision rates are less than weathering rates of bedrock, which are limited to 0.1-0.3mmyr-1. We finally present evidence for a decreasing trend of hillslope-derived sediment discharge during the Holocene, but predict an opposite trend in the nearest future as winters are warmer and wetter. 2013 Elsevier Inc. All rights reserved.
BibTeX:
@book{Schlunegger2013337,
  author = {Schlunegger, F. and Norton, K. and Caduff, R.},
  title = {Hillslope Processes in Temperate Environments},
  journal = {Treatise on Geomorphology},
  publisher = {Elsevier Inc.},
  year = {2013},
  volume = {7},
  pages = {337-354},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881089900&doi=10.1016%2fB978-0-12-374739-6.00183-4&partnerID=40&md5=f3ef34fe25cb9daf39321794313ac1c9},
  doi = {10.1016/B978-0-12-374739-6.00183-4}
}
Schmitt M, Magnard C, Stanko S, Ackermann C and Stilla U (2013), "Advanced high resolution SAR interferometry of urban areas with airborne millimetrewave radar", Photogrammetrie, Fernerkundung, Geoinformation. Vol. 2013(6), pp. 603-617.
Abstract: For rural and natural scenes, synthetic aperture radar interferometry (InSAR) has long been an operational technique for the generation of digital surface models. With the advent of sensors providing data in the decimetre resolution domain, also the analysis of densely built-up urban areas has become an increasingly important research topic. Due to the complexity of this kind of scenes, however, advanced interferometric techniques have to be employed. While usually satellite-borne stacks of multi-temporal data are collected in order to make use of differential SAR interferometry or the increasingly popular persistent scatterer technique, this article aims at the utilization of an airborne single-pass multi-baseline system working in the millimetrewave domain. Starting from the description of the exemplary German MEMPHIS sensor, the complete processing chain from the collection of necessary navigation data over the focusing of the raw SAR data to finally the application of sophisticated InSAR techniques is shown.
BibTeX:
@article{Schmitt2013603,
  author = {Schmitt, M. and Magnard, C. and Stanko, S. and Ackermann, C. and Stilla, U.},
  title = {Advanced high resolution SAR interferometry of urban areas with airborne millimetrewave radar},
  journal = {Photogrammetrie, Fernerkundung, Geoinformation},
  year = {2013},
  volume = {2013},
  number = {6},
  pages = {603-617},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84888409159&doi=10.1127%2f1432-8364%2f2013%2f0199&partnerID=40&md5=abd440f7c98a95b5189ce8bdd82a020e},
  doi = {10.1127/1432-8364/2013/0199}
}
Schmitt M, Maksymiuk O, Magnard C and Stilla U (2013), "Radargrammetric registration of airborne multi-aspect SAR data of urban areas", ISPRS Journal of Photogrammetry and Remote Sensing. Vol. 86, pp. 11-20. Elsevier B.V..
Abstract: In this paper, the registration of decimeter-resolution airborne multi-aspect SAR (MASAR) data of inner city areas by application of the radargrammetric rager equations is investigated. The geometrical model is adapted to linear flight trajectories and zero-Doppler processed SAR data, whereas the observed trajectory parameters are adjusted using a strict Gauss-Helmert model and known ground control points. The significance of the estimated corrections is examined and the most suitable set of free parameters is determined. Finally, the methodology is applied to real test data of an airborne campaign over the city of Munich, Germany, and the feasability of the proposed radargrammetric registration method is shown. 2013 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS).
BibTeX:
@article{Schmitt201311,
  author = {Schmitt, M. and Maksymiuk, O. and Magnard, C. and Stilla, U.},
  title = {Radargrammetric registration of airborne multi-aspect SAR data of urban areas},
  journal = {ISPRS Journal of Photogrammetry and Remote Sensing},
  publisher = {Elsevier B.V.},
  year = {2013},
  volume = {86},
  pages = {11-20},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884810643&doi=10.1016%2fj.isprsjprs.2013.09.003&partnerID=40&md5=ae9e56f4e0205a675411cfe37b0800fe},
  doi = {10.1016/j.isprsjprs.2013.09.003}
}
Schmullius C, Leiterer R, Burjack I, Traut K, Santoro M, Li Z and Ling F (2013), "Forest dragon 2: Final results of the european partners", In European Space Agency, (Special Publication) ESA SP. Vol. 704 SP
Abstract: The European contribution to the Forest DRAGON 2 focused on the evaluation of multi-temporal, multisensor and multi-scale Earth Observation images and data products within the vegetation ecosystem of Northeast China. The forest growing stock volume (GSV) map produced with ERS-1/2 coherence images for 1995-1998 and two GSV maps produced from Envisat ASAR ScanSAR data for 2005 and 2010 were inter-compared with respect to several datasets (in situ, EO images and EO data products) to assess the plausibility of the GSV estimates, the contribution to land cover mapping and the dynamics over time. For this purpose, a multi-source database was set up including in situ data and EO data products. Land use / land cover (LULC) datasets identified mis-classification of GSV in the ERS dataset primarily for cropland. An a posteriori correction of the GSV resulted in an increase of overall accuracy up to 7%. LULC products can also support the fine tuning of the algorithm to estimate GSV from ASAR data particularly in transition regions between forest and shrubland. The ASAR-based GSV estimates were consistent and highlighted areas of change. From the two ASAR maps, slight loss of volume from 2005 to 2010 was estimated.
BibTeX:
@conference{Schmullius2013,
  author = {Schmullius, C. and Leiterer, R. and Burjack, I. and Traut, K. and Santoro, M. and Li, Z.Y. and Ling, F.L.},
  title = {Forest dragon 2: Final results of the european partners},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2013},
  volume = {704 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892682819&partnerID=40&md5=01c4e33b793dd3d8f03ade4d72e7d154}
}
Stahli O, Murk A, Kampfer N, Matzler C and Eriksson P (2013), "Microwave radiometer to retrieve temperature profiles from the surface to the stratopause", Atmospheric Measurement Techniques. Vol. 6(9), pp. 2477-2494.
Abstract: TEMPERA (TEMPERature RAdiometer) is a new ground-based radiometer which measures in a frequency range from 51-57 GHz radiation emitted by the atmosphere. With this instrument it is possible to measure temperature profiles from ground to about 50 km. This is the first ground-based instrument with the capability to retrieve temperature profiles simultaneously for the troposphere and stratosphere. The measurement is done with a filterbank in combination with a digital fast Fourier transform spectrometer. A hot load and a noise diode are used as stable calibration sources. The optics consist of an off-axis parabolic mirror to collect the sky radiation. Due to the Zeeman effect on the emission lines used, the maximum height for the temperature retrieval is about 50 km. The effect is apparent in the measured spectra. The performance of TEMPERA is validated by comparison with nearby radiosonde and satellite data from the Microwave Limb Sounder on the Aura satellite. In this paper we present the design and measurement method of the instrument followed by a description of the retrieval method, together with a validation of TEMPERA data over its first year, 2012. 2013 Author(s).
BibTeX:
@article{Stahli20132477,
  author = {Stahli, O. and Murk, A. and Kampfer, N. and Matzler, C. and Eriksson, P.},
  title = {Microwave radiometer to retrieve temperature profiles from the surface to the stratopause},
  journal = {Atmospheric Measurement Techniques},
  year = {2013},
  volume = {6},
  number = {9},
  pages = {2477-2494},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884832899&doi=10.5194%2famt-6-2477-2013&partnerID=40&md5=c9bd21ea0a6341ef68d024fb5902a8c4},
  doi = {10.5194/amt-6-2477-2013}
}
Strozzi T, Ambrosi C and Raetzo H (2013), "Interpretation of aerial photographs and satellite SAR interferometry for the inventory of landslides", Remote Sensing. Vol. 5(5), pp. 2554-2570.
Abstract: An inventory of landslides with an indication of the state of activity is necessary in order to establish hazard maps. We combine interpretation of aerial photographs and information on surface displacement from satellite Synthetic Aperture Radar (SAR) interferometry for mapping landslides and intensity classification. Sketch maps of landslides distinguished by typology and depth, including geomorphological features, are compiled by stereoscopic photo-interpretation. Results achieved with differential SAR interferometry (InSAR) and Persistent Scatterer Interferometry (PSI) are used to estimate the state of activity of landslides around villages and in sparsely vegetated areas with numerous exposed rocks. For validation and possible extension of the inventory around vegetated areas, where InSAR and PSI failed to retrieve displacement information, traditional monitoring data such as topographic measurements and GPS are considered. Our results, covering extensive areas, are a valuable contribution towards the analysis of landslide hazards in areas where traditional monitoring techniques are sparse or unavailable. In this contribution we discuss our methodology for a study area around the deep-seated landslide in Osco in southern Switzerland. 2013 by the authors.
BibTeX:
@article{Strozzi20132554,
  author = {Strozzi, T. and Ambrosi, C. and Raetzo, H.},
  title = {Interpretation of aerial photographs and satellite SAR interferometry for the inventory of landslides},
  journal = {Remote Sensing},
  year = {2013},
  volume = {5},
  number = {5},
  pages = {2554-2570},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880336746&doi=10.3390%2frs5052554&partnerID=40&md5=afbb70d688d895b2cf4d474bbcbf0279},
  doi = {10.3390/rs5052554}
}
Strozzi T, Teatini P, Tosi L, Wegmüller U and Werner C (2013), "Land subsidence of natural transitional environments by satellite radar interferometry on artificial reflectors", Journal of Geophysical Research: Earth Surface. Vol. 118(2), pp. 1177-1191. Blackwell Publishing Ltd.
Abstract: Land subsidence is a widespread phenomenon, particularly relevant to transitional environments, such as wetlands, deltas, and lagoons, characterized by low elevation with respect to the mean sea level. Satellite synthetic aperture radar (SAR) interferometry offers the possibility to effectively and precisely measure land displacements for dry surfaces or anthropogenic structures, but difficulties arise in identifying long-term stable targets in natural transitional regions. In order to improve the coverage of satellite SAR interferometry in salt marshes within the Venice Lagoon (Italy), we installed a network of 57 Trihedral Corner Reflectors (TCRs). The TCRs were monitored by ENVISAT ASAR and TerraSAR-X acquisitions covering the time period from November 2006 to September 2011. The results show that the northern lagoon basin is subsiding at  3 mm/yr and that the central and southern portions are more stable. Larger subsidence rates, up to 6 mm/yr, are measured where surficial loads, such as artificial salt marshes or embankments, rise above the lagoon bottom. The accuracy of TerraSAR-X is greater than ENVISAT due to the shorter wavelength and higher spatial resolution in relationship to the size of the TCRs. The observations obtained in the Venice Lagoon indicate that SAR interferometry using a large network of artificial reflectors is an effective and powerful methodology to monitor land subsidence in transitional environments where the loss of elevation with respect to the mean sea level can yield significant morphological changes to the natural environment. Key Points Subsidence of natural transitional environments Radar interferometry on artificial corner reflectors Environment deterioration by loss of elevation relative to the mean sea level 2013. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Strozzi20131177,
  author = {Strozzi, T. and Teatini, P. and Tosi, L. and Wegmüller, U. and Werner, C.},
  title = {Land subsidence of natural transitional environments by satellite radar interferometry on artificial reflectors},
  journal = {Journal of Geophysical Research: Earth Surface},
  publisher = {Blackwell Publishing Ltd},
  year = {2013},
  volume = {118},
  number = {2},
  pages = {1177-1191},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880748858&doi=10.1002%2fjgrf.20082&partnerID=40&md5=be11e2bec5d7ae892b87a2f7fe98fa1a},
  doi = {10.1002/jgrf.20082}
}
Tian X, Li Z-Y, Chen E-X, Ling F-L, Cartus O, Santoro M and Schmullius C (2013), "Large-scale forest mapping based on ERS-1/2 and Envisat ASAR data", Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University. Vol. 35(1), pp. 7-15.
Abstract: In this paper, two kinds of forest map over Northeast China were produced by use of archived ERS-1/2 tandem data (1995-2000) and Envisat ASAR data (2005). As far as ERS-1/2 coherence model was concerned, a new approach was introduced, that allowed model training using the MODIS Vegetation Continuous Fields canopy cover product without further need for ground data. On basis of this method, the large-scale forest stem volume map (four classes: 0-20, > 20-50, > 50-80 and > 80 m3/hm2) was generated. As regards the Envisat ASAR data, the object-based classifier was applied to map the forest/non-forest areas automatically. The cross-comparisons were performed for these two kinds of map based on the land use map from Landsat TM-5 data acquired in 2005. The results show that these two satellite SAR data can be used for the large-scale forest mapping and their maps in current case will provide supports for the further analysis of forest change detection and the map updating.
BibTeX:
@article{Tian20137,
  author = {Tian, X. and Li, Z.-Y. and Chen, E.-X. and Ling, F.-L. and Cartus, O. and Santoro, M. and Schmullius, C.},
  title = {Large-scale forest mapping based on ERS-1/2 and Envisat ASAR data},
  journal = {Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University},
  year = {2013},
  volume = {35},
  number = {1},
  pages = {7-15},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84872766378&partnerID=40&md5=3eb62f46ba98f054a841a873e118ab4b}
}
Tosi L, Teatini P and Strozzi T (2013), "Natural versus anthropogenic subsidence of Venice", Scientific Reports. Vol. 3
Abstract: We detected land displacements of Venice by Persistent Scatterer Interferometry using ERS and ENVISAT C-band and TerraSAR-X and COSMO-SkyMed X-band acquisitions over the periods 1992-2010 and 2008-2011, respectively. By reason of the larger observation period, the C-band sensors was used to quantify the long-term movements, i.e. the subsidence component primarily ascribed to natural processes. The high resolution X-band satellites reveal a high effectiveness to monitor short-time movements as those induced by human activities. Interpolation of the two datasets and removal of the C-band from the X-band map allows discriminating between the natural and anthropogenic components of the subsidence. A certain variability characterizes the natural subsidence (0.9 ± 0.7âmm/yr), mainly because of the heterogeneous nature and age of the lagoon subsoil. The 2008 displacements show that man interventions are responsible for movements ranging from-10 to 2âmm/yr. These displacements are generally local and distributed along the margins of the city islands.
BibTeX:
@article{Tosi2013,
  author = {Tosi, L. and Teatini, P. and Strozzi, T.},
  title = {Natural versus anthropogenic subsidence of Venice},
  journal = {Scientific Reports},
  year = {2013},
  volume = {3},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885130906&doi=10.1038%2fsrep02710&partnerID=40&md5=8ca1e00610dc698f7162ac29bbf8f07f},
  doi = {10.1038/srep02710}
}
Traut K, Burjack I, Eberle J, Santoro M and Schmullius C (2013), "Creation of a forest dragon geoportal for validating forest growing stock volume maps", In European Space Agency, (Special Publication) ESA SP. Vol. 704 SP
BibTeX:
@conference{Traut2013,
  author = {Traut, K. and Burjack, I. and Eberle, J. and Santoro, M. and Schmullius, C.},
  title = {Creation of a forest dragon geoportal for validating forest growing stock volume maps},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2013},
  volume = {704 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892757683&partnerID=40&md5=72bb2810a46843c2fab8e70f6dbf980f}
}
Vassilopoulou S, Sakkas V, Wegmüller U and Capes R (2013), "Long term and seasonal ground deformation monitoring of Larissa Plain (Central Greece) by persistent scattering interferometry", Central European Journal of Geosciences. Vol. 5(1), pp. 61-76.
Abstract: The land subsidence which occurs at the Larissa Basin (Thessaly Plain, Central Greece) is due to various causes including aquifer system compaction. Deformation maps of high spatial resolution deduced by the Persistent Scattering Interferometry (PSI) technique (using radar scenes from ERS and ENVISAT satellites) for the period 1992-2006 were produced to study the spatial and temporal ground deformation. A developed GIS database (including geological, tectonic, morphological, hydrological, meteorological and watertable variation from wells in the area) offered the possibility of studying in detail the intense subsidence. The PSI based average deformation image clearly shows that subsidence generally takes place inside the Larissa Plain ranging from 5-250 mm. The largest amplitude rates (-25 mm/yr) are observed around the urban area of Larissa City (especially at Gianouli and Nikea villages), while the Larissa City center appears to be relatively stable with a tendency to subside. The rest of the plain regions seem to subside at moderate rates (about 5-10 mm/yr). The surrounding mountainous area is stable, or has slightly been uplifted with respect to the NE located reference point. It was found that there is a correlation between the seasonal water-table variation (deduced from wells data), the seasonal water demand for irrigation associated with specific types of cultivation (cotton fields), the monthly rainfall, and the observed subsidence rate in the rural regions of the Thessaly Plain. 2013 Versita Warsaw and Springer-Verlag Wien.
BibTeX:
@article{Vassilopoulou201361,
  author = {Vassilopoulou, S. and Sakkas, V. and Wegmüller, U. and Capes, R.},
  title = {Long term and seasonal ground deformation monitoring of Larissa Plain (Central Greece) by persistent scattering interferometry},
  journal = {Central European Journal of Geosciences},
  year = {2013},
  volume = {5},
  number = {1},
  pages = {61-76},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84875181204&doi=10.2478%2fs13533-012-0115-x&partnerID=40&md5=da516f2927375cbececcfe261e1ce3d1},
  doi = {10.2478/s13533-012-0115-x}
}
Wegmüller U, Strozzi T, Gruner U, Gisler C and Hauser M (2013), "Displacement measurements by means of satellite radar in the upper Reuss Valley in the North-South transport axis in the period 1992-2010 [Verschiebungsmessungen mittels Satellitenradar im Urner Reusstal oberhalb der Nord-Sued-Verkehrsachse im Zeitraum 1992 - 2010]", Bulletin fuer Angewandte Geologie. Vol. 18(2), pp. 139-153. Ver. Schweizerischer Petroleum Geol. und Ing..
Abstract: In a pilot project SAR interferometry was used to determine ground displacement measurements in the upper Reuss valley (Switzerland] between Sisikon and Wassen, with a special focus on the area of the Chli Windgaellen. In an interferometrie time series analysis on 82 acquisitions of the ERS and ENVISAT satellites between 1992 and 2010 terrain displacements were determined and used as input to geological interpretation. The method works without installation of measurement points and achieves for linear movements a precision of about 1 mm/year at a spatial resolution of about 20 m. The spatial coverage is limited by temporal decorrelation of the radar signals by vegetation and by radar specific imaging effects on steep slopes. The method can perfectly be used for the identification of large deformation areas and to monitor past and current movements, permitting to use it as an efficient component of an early warning system.
BibTeX:
@article{Wegmuller2013139,
  author = {Wegmüller, U. and Strozzi, T. and Gruner, U. and Gisler, C. and Hauser, M.},
  title = {Displacement measurements by means of satellite radar in the upper Reuss Valley in the North-South transport axis in the period 1992-2010 [Verschiebungsmessungen mittels Satellitenradar im Urner Reusstal oberhalb der Nord-Sued-Verkehrsachse im Zeitraum 1992 - 2010]},
  journal = {Bulletin fuer Angewandte Geologie},
  publisher = {Ver. Schweizerischer Petroleum Geol. und Ing.},
  year = {2013},
  volume = {18},
  number = {2},
  pages = {139-153},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85006359777&doi=10.5169%2fseals-391153&partnerID=40&md5=19f07ceb2172fece0c2cd598c47f4820},
  doi = {10.5169/seals-391153}
}
Barboux C, Delaloye R, Strozzi T, Lambiel C, Collet C and Raetzo H (2012), "Monitoring active rock glaciers in the Western Swiss Alps: Challenges of Differential Sar Interferometry and solutions to estimate annual and seasonal displacement rates", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 5210-5213.
Abstract: This paper describes a new method to monitor active rock glaciers using DInSAR technique with Terrasar-X data acquired with mode facing slope and 11 days time interval during late summers 2009 to 2011. Where the spatial distribution of the rock glacier surface deformation derived from the DInSAR data using conventional unwrapping processes fails due to the relative small size and the complex movement of some rock glaciers, a specific profile is here defined through the rock glacier and is used to analyze the DInSAR products along it. Firstly, the prerequisites to perform such analysis at local scale are given. Then a quantification and discussion of results are achieved through different examples of active rock glaciers encountered in Western Swiss Alps. 2012 IEEE.
BibTeX:
@conference{Barboux20125210,
  author = {Barboux, C. and Delaloye, R. and Strozzi, T. and Lambiel, C. and Collet, C. and Raetzo, H.},
  title = {Monitoring active rock glaciers in the Western Swiss Alps: Challenges of Differential Sar Interferometry and solutions to estimate annual and seasonal displacement rates},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {5210-5213},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873207972&doi=10.1109%2fIGARSS.2012.6352435&partnerID=40&md5=c4e7398379970a8f95458c06461af046},
  doi = {10.1109/IGARSS.2012.6352435}
}
Cartus O, Kellndorfer J, Rombach M and Walker W (2012), "Mapping canopy height and growing stock volume using airborne lidar, alos palsar and landsat ETM+", Remote Sensing. Vol. 4(11), pp. 3320-3345.
Abstract: We have investigated for forest plantations in Chile the stand-level retrieval of canopy height (CH) and growing stock volume (GSV) using Airborne Laser Scanner (ALS), ALOS PALSAR and Landsat. In a two-stage up-scaling approach, ensemble regression tree models (randomForest) were used to relate a suite of ALS canopy structure indices to stand-level in situ measurements of CH and GSV for 319 stands. The retrieval of CH and GSV with ALS yielded high accuracies with R2s of 0.93 and 0.81, respectively. A second set of randomForest models was developed using multi-temporal ALOS PALSAR intensities and repeat-pass coherences in two polarizations as well as Landsat data as predictor and stand-level ALS based estimates of CH and GSV as response variables. At three test sites, the retrieval of CH and GSV with PALSAR/Landsat reached promising accuracies with R2s in the range of 0.7 to 0.85. We show that the combined use of multi-temporal PALSAR intensity, coherence and Landsat yields higher retrieval accuracies than the retrieval with any of the datasets alone. Potential limitations for the large-area application of the fusion approach included (1) the low sensitivity of ALS first/last return data to forest horizontal structure, affecting the retrieval of GSV in less managed types of forest, and (2) the dense ALS sampling required to achieve high retrieval accuracies at larger scale. 2012 by the authors.
BibTeX:
@article{Cartus20123320,
  author = {Cartus, O. and Kellndorfer, J. and Rombach, M. and Walker, W.},
  title = {Mapping canopy height and growing stock volume using airborne lidar, alos palsar and landsat ETM+},
  journal = {Remote Sensing},
  year = {2012},
  volume = {4},
  number = {11},
  pages = {3320-3345},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870835634&doi=10.3390%2frs4113320&partnerID=40&md5=45859392a5c13f8d2bb7e30236c7ecc9},
  doi = {10.3390/rs4113320}
}
Cartus O, Santoro M and Kellndorfer J (2012), "Mapping forest aboveground biomass in the Northeastern United States with ALOS PALSAR dual-polarization L-band", Remote Sensing of Environment. Vol. 124, pp. 466-478.
Abstract: A method for regional scale mapping of aboveground forest biomass with Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) data is presented. A fully automated algorithm, exploiting the synergy of SAR and optical remote sensing for the calibration of a semi-empirical model (Santoro et al., 2011; Cartus et al., 2011), was adopted to map forest aboveground biomass with L-band HH and HV intensity in the northeastern United States. In the retrieval algorithm, a semi-empirical model is calibrated and inverted for each HH and HV image to estimate biomass at the pixel level. Where possible, biomass estimates for single images in a multi-temporal stack were combined in a weighted manner. A comparison with the National Biomass and Carbon Dataset, NBCD 2000 (Kellndorfer et al., in preparation), at different spatial scales indicated the feasibility of the automated biomass retrieval approach and confirmed previous findings that the retrieval accuracy for HV intensity is consistently better than that for HH intensity and depends on the imaging conditions. The weighted combination of the biomass estimates from each intensity image in a multi-temporal stack significantly improved the retrieval performance. Because of regional differences in the multi-temporal coverage with ALOS PALSAR dual polarization data (1-5 images for 2007/08) and the pronounced dependence of the retrieval for single images on the imaging conditions, the possibility of producing maps with consistent accuracy at high resolution was found to be limited. Accurate biomass estimates were obtained when aggregating the ALOS biomass maps at county scale and comparing the estimates to Forest Inventory and Analysis (FIA) county statistics (RMSE=12.9t/ha, R2=0.86). 2012 Elsevier Inc.
BibTeX:
@article{Cartus2012466,
  author = {Cartus, O. and Santoro, M. and Kellndorfer, J.},
  title = {Mapping forest aboveground biomass in the Northeastern United States with ALOS PALSAR dual-polarization L-band},
  journal = {Remote Sensing of Environment},
  year = {2012},
  volume = {124},
  pages = {466-478},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84863193261&doi=10.1016%2fj.rse.2012.05.029&partnerID=40&md5=a3e28524461e6659fd0481005bcafdbd},
  doi = {10.1016/j.rse.2012.05.029}
}
Dimitrov M, Kostov K, Jonard F, Jadoon K, Schwank M, Weihermuller L, Hermes N, Vanderborght J and Vereecken H (2012), "New improved algorithm for sky calibration of L-band radiometers JLBARA and ELBARA II", In 2012 12th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment, MicroRad 2012 - Proceedings.
Abstract: We propose a new algorithm for sky calibration of the L-band radiometers JLBARA and ELBARA II, introducing the effective transmissivities of the instruments. The suggested approach was tested using experimental data obtained at the Selhausen test site, Germany. It was shown that for JLBARA the effective transmissivities depend strongly on the air temperature and decrease with increasing air temperature, while for ELBARA II such strong dependence was not observed. It was also shown that the effective transmissivities account for the antenna and feed cable loss effects, and for the variations of the radiometer gain due to air temperature changes. The new calibration algorithm reduces significantly the bias of brightness temperature estimates for both radiometers, especially for JLBARA. 2012 IEEE.
BibTeX:
@conference{Dimitrov2012,
  author = {Dimitrov, M. and Kostov, K.G. and Jonard, F. and Jadoon, K.Z. and Schwank, M. and Weihermuller, L. and Hermes, N. and Vanderborght, J. and Vereecken, H.},
  title = {New improved algorithm for sky calibration of L-band radiometers JLBARA and ELBARA II},
  booktitle = {2012 12th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment, MicroRad 2012 - Proceedings},
  year = {2012},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860763004&doi=10.1109%2fMicroRad.2012.6185259&partnerID=40&md5=1531c1143f6e9b73e2f0d953366abec3},
  doi = {10.1109/MicroRad.2012.6185259}
}
Dixon T, Voytenko D, Lembke C, De La Pea S, Howat I, Gourmelen N, Werner C and Oddsson B (2012), "Emerging technology monitors ice-sea interface at outlet glaciers", Eos. Vol. 93(48), pp. 497-498.
Abstract: Recent melting in Greenland and Antarctica has led to concerns about the long-term stability of these ice sheets and their potential contributions to future sea level rise. Marine-terminating outlet glaciers play a key role in the dynamics of these ice sheets; recent mass losses are likely related to increased influx of warmer water to the base of outlet glaciers, as evidenced by the fact that changes in ocean currents, calving front retreats, glacial thinning, mass redistribution based on satellite gravity data, and accelerating coastal uplift are roughly concurrent [e.g., Holland et al., 2008; Wouters et al., 2008; Jiang et al., 2010; Straneo et al., 2012; Bevis et al., 2012]. However, collecting quantitative measurements within the dynamic environment of marine outlet glaciers is challenging. Oceanographic measurements are limited in iceberg-laden fjords. Measuring ice flow speeds near the calving front is similarly challenging; satellite methods lack temporal resolution (satellite revisit times are several days or longer), while GPS gives limited spatial resolution, a problem for assessing changes near the highly variable calving front. 2012. American Geophysical Union. All Rights Reserved.
BibTeX:
@article{Dixon2012497,
  author = {Dixon, T.H. and Voytenko, D. and Lembke, C. and De La Pea, S. and Howat, I. and Gourmelen, N. and Werner, C. and Oddsson, B.},
  title = {Emerging technology monitors ice-sea interface at outlet glaciers},
  journal = {Eos},
  year = {2012},
  volume = {93},
  number = {48},
  pages = {497-498},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870574116&doi=10.1029%2f2012EO480001&partnerID=40&md5=7d7217d76980af3289174af78ab493af},
  doi = {10.1029/2012EO480001}
}
Eriksson L, Fransson J, Soja M and Santoro M (2012), "Backscatter signatures of wind-thrown forest in satellite SAR images", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 6435-6438.
Abstract: Two field experiments have been conducted in Sweden to allow an evaluation of the backscatter signatures of wind-thrown forest from L-band, C-band and X-band Synthetic Aperture Radar. When the trees are felled the backscattered signal from TerraSAR-X (X-band) increase with about 1.5 dB, while for ALOS PALSAR (L-band) a decrease with the same amount is observed. Radar images with fine spatial resolution also show shadowing effects that should be possible to use for identification of storm felled forest. 2012 IEEE.
BibTeX:
@conference{Eriksson20126435,
  author = {Eriksson, L.E.B. and Fransson, J.E.S. and Soja, M.J. and Santoro, M.},
  title = {Backscatter signatures of wind-thrown forest in satellite SAR images},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {6435-6438},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873101723&doi=10.1109%2fIGARSS.2012.6352732&partnerID=40&md5=d0f0cabcf587e7a4b56eae874c918ea2},
  doi = {10.1109/IGARSS.2012.6352732}
}
Frey H, Paul F and Strozzi T (2012), "Compilation of a glacier inventory for the western Himalayas from satellite data: Methods, challenges, and results", Remote Sensing of Environment. Vol. 124, pp. 832-843.
Abstract: Due to their sensitive reaction to changes in climatic conditions, glaciers have been selected as an essential climate variable (ECV). Although a large amount of ice is located in the Himalayas, this region is yet only sparsely represented in global glacier databases. Accordingly, a sound and comprehensive change assessment or determination of water resources was not yet possible. In this study, we present a new glacier inventory for the western Himalayas, compiled from Landsat ETM+ scenes acquired between 2000 and 2002, coherence images from ALOS PALSAR image pairs, the SRTM digital elevation model (DEM) and the ASTER Global DEM (GDEM). Several specific challenges for glacier mapping were found in this region and addressed. They are related to debris cover, orographic clouds, locally variable snow conditions, and creeping permafrost features in cold-dry regions. Additional to seven topographic parameters that are obtained from the ASTER GDEM for each glacier, we also determined the relative amount of debris cover on the glacier surface. The inventory contains 11,400 glaciers larger than 0.02km2, which cover a total area of 9,310km2. Analysis of the inventory data revealed characteristic patterns of mean glacier elevation and relative debris cover amounts that might be related to the governing climatic conditions. The full dataset will be freely available in the GLIMS glacier database to foster further analyses and modeling of the glaciers in this region. 2012 Elsevier Inc.
BibTeX:
@article{Frey2012832,
  author = {Frey, H. and Paul, F. and Strozzi, T.},
  title = {Compilation of a glacier inventory for the western Himalayas from satellite data: Methods, challenges, and results},
  journal = {Remote Sensing of Environment},
  year = {2012},
  volume = {124},
  pages = {832-843},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864102237&doi=10.1016%2fj.rse.2012.06.020&partnerID=40&md5=7809343b96693af7a17b75f39860c94d},
  doi = {10.1016/j.rse.2012.06.020}
}
Frey O, Meier E and Hajnsek I (2012), "Towards a more reliable estimation of forest parameters from polarimetric SAR tomography data", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3110-3113.
Abstract: In this contribution, tomographic imagery obtained from estimating the 3-D localization and the polarimetric signature of backscattering sources within a forest environment from fully-polarimetric multibaseline SAR data at L- and P-bands are presented. Both, polarization diversity and spatial diversity were exploited jointly within the tomographic focusing to estimate the targets' localization and polarimetric signature. We thereby extend our recently proposed time-domain back-projection (TDBP)-based tomographic focusing approach. The tomographic slices obtained from polarimetric spectral estimation using MLBF, Capon, and MUSIC are opposed to the results previously obtained by tomographic focusing of the individual polarization channels. The results are briefly discussed with respect to potential advancements towards more reliable estimation of forest parameters from SAR tomography data. 2012 IEEE.
BibTeX:
@conference{Frey20123110,
  author = {Frey, O. and Meier, E. and Hajnsek, I.},
  title = {Towards a more reliable estimation of forest parameters from polarimetric SAR tomography data},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {3110-3113},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873147971&doi=10.1109%2fIGARSS.2012.6350767&partnerID=40&md5=146b724be5c2b473425d064715201fe2},
  doi = {10.1109/IGARSS.2012.6350767}
}
Frey O, Meier E and Hajnsek I (2012), "Tweaking baseline constellations for airborne SAR tomography and InSAR: An experimental study at L-and P-bands", In Proc. European Conf. Synthetic Aperture Radar. Vol. 2012-April, pp. 215-218. Institute of Electrical and Electronics Engineers Inc..
Abstract: A notable obstacle hindering widespread application of SAR tomography for 3D mapping of vegetation is the relatively large number of acquisitions that are needed to obtain a high resolution and a good rejection of spurious responses in the direction perpendicular to the line of sight. In this paper, we discuss the impact of different baseline constellations on 3-D mapping of vegetation volumes and the underlying topography in terms of tomographic focusing as well as classical single-baseline repeat-pass interferometry. The effects are studied using two airborne tomography data sets at L-and P-bands.
BibTeX:
@conference{Frey2012215,
  author = {Frey, O. and Meier, E. and Hajnsek, I.},
  title = {Tweaking baseline constellations for airborne SAR tomography and InSAR: An experimental study at L-and P-bands},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2012},
  volume = {2012-April},
  pages = {215-218},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85026213191&partnerID=40&md5=efbfbcafd78aa563efdb7ccaf8b18b01}
}
Frey O, Wegmüller U and Werner C (2012), "Terrain motion measurements over European urban areas using Persistent Scatterer Interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 7565-7568.
Abstract: In this contribution Persistent Scatterer Interferometry (PSI) processings done in the framework of the FP7 Project PanGEO over a number of European sites are presented. After a short introduction of the PanGEO project, we present the data used, the processing done and the results of the PSI analysis. The influence of specifics as the presence of large non-urban areas, significant topography, seasonal effects, special deformation characteristics, and the size of the available data stacks on the processing are highlighted. 2012 IEEE.
BibTeX:
@conference{Frey20127565,
  author = {Frey, O. and Wegmüller, U. and Werner, C.},
  title = {Terrain motion measurements over European urban areas using Persistent Scatterer Interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {7565-7568},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873109224&doi=10.1109%2fIGARSS.2012.6351911&partnerID=40&md5=6a67c0384041d145eb179995ddcf057b},
  doi = {10.1109/IGARSS.2012.6351911}
}
Graham E, N'Dri Koffi E and Matzler C (2012), "An observational study of air and water vapour convergence over the Bernese Alps, Switzerland, during summertime and the development of isolated thunderstorms", Meteorologische Zeitschrift. Vol. 21(6), pp. 561-574.
Abstract: The daytime summer phenomenon of the mesoscale transport of air and water vapour from the Swiss lowlands into the nearby western Alps, leading to orographic convection, is investigated using a range of independent observations. These observations are: Global Positioning System (GPS) integrated water vapour (IWV) data, the TROWARA microwave radiometer, MeteoSwiss ANETZ surface weather station data, the Payerne radiosonde, synoptic analyses for Switzerland and Europe, EUMETSAT and NOAA visible and infra-red satellite images, MeteoSwiss operational precipitation radar, photographs and webcam images including time-lapse cloud animations. The intention was to show, using GPS IWV data, that significant differences in IWV may occur between the Swiss plain and nearby Alps during small single-cell Alpine thunderstorm events, and that these may be attributable to regional airflow convergence. Two particular case studies are presented for closer examination: 20 June 2005 and 13 June 2006. On both days, fine and warm weather was followed by isolated orographic convection over the Alps in the afternoon and evening, producing thunderstorms. The thunderstorms investigated were generally small, local, discrete and shortlived phenomena. They were selected for study because of almost stationary position over orography, rendering easy observation because they remained contained within a particular mountain region before dissipating. The results show that large transfers of air and water vapour occur from the Swiss plain to the mountains on such days, with up to a 50% increase in GPS IWV values at individual Alpine stations, coincident with strong airflow convergence in the same locality. 2012 by Gebruer Borntraeger.
BibTeX:
@article{Graham2012561,
  author = {Graham, E. and N'Dri Koffi, E. and Matzler, C.},
  title = {An observational study of air and water vapour convergence over the Bernese Alps, Switzerland, during summertime and the development of isolated thunderstorms},
  journal = {Meteorologische Zeitschrift},
  year = {2012},
  volume = {21},
  number = {6},
  pages = {561-574},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874594002&doi=10.1127%2f0941-2948%2f2012%2f0347&partnerID=40&md5=982768345644c88c591c3f23cb0b33c1},
  doi = {10.1127/0941-2948/2012/0347}
}
Henke D, Magnard C, Frioud M, Small D, Meier E and Schaepman M (2012), "Moving-target tracking in single-channel wide-beam SAR", IEEE Transactions on Geoscience and Remote Sensing. Vol. 50(11 PART2), pp. 4735-4747. Institute of Electrical and Electronics Engineers Inc..
Abstract: A novel method for moving-target tracking using single-channel synthetic aperture radar (SAR) with a large antenna beamwidth is introduced and evaluated using a field experiment and real SAR data. The presented approach is based on subaperture SAR processing, image statistics, and multitarget unscented Kalman filtering. The method is capable of robustly detecting and tracking moving objects over time, providing information not only about the existence of moving targets but also about their trajectories in the image space while illuminated by the radar beam. We have successfully applied the method on an experimental data set using miniature SAR to accurately characterize the movement of vehicles on a highway section in the radar image space. 1980-2012 IEEE.
BibTeX:
@article{Henke20124735,
  author = {Henke, D. and Magnard, C. and Frioud, M. and Small, D. and Meier, E. and Schaepman, M.E.},
  title = {Moving-target tracking in single-channel wide-beam SAR},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2012},
  volume = {50},
  number = {11 PART2},
  pages = {4735-4747},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869496515&doi=10.1109%2fTGRS.2012.2191561&partnerID=40&md5=edc322e9a93876100f12eb7d4b940f2e},
  doi = {10.1109/TGRS.2012.2191561}
}
Jonard F, Weihermuller L, Schwank M, Jadoon K, Vereecken H and Lambot S (2012), "Estimating soil hydraulic properties using L-band radiometer and ground-penetrating radar", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 706-709.
Abstract: In this study, we experimentally analyze the feasibility of estimating the soil hydraulic properties from L-band radiometer and ground-penetrating radar (GPR) data. L-band radiometer and ultrawideband off-ground GPR measurements were performed above a sand box in hydrostatic equilibrium with a water table located at different depths. The results of the inversions showed that the radar and radiometer signals contain sufficient information to estimate the soil water retention curve and its related hydraulic parameters with a relatively good accuracy compared to time-domain reflectometry estimates. However, an accurate estimation of the hydraulic parameters was only obtained by considering the saturated water content parameter as known during the inversion. 2012 IEEE.
BibTeX:
@conference{Jonard2012706,
  author = {Jonard, F. and Weihermuller, L. and Schwank, M. and Jadoon, K.Z. and Vereecken, H. and Lambot, S.},
  title = {Estimating soil hydraulic properties using L-band radiometer and ground-penetrating radar},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {706-709},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873172004&doi=10.1109%2fIGARSS.2012.6351467&partnerID=40&md5=5672eb556aa8df81aeadf1de1ea3c229},
  doi = {10.1109/IGARSS.2012.6351467}
}
Kourkouli P, Strozzi T and Wegmüller U (2012), "Comparison of DInSAR and persistent scatterer interferometry for ground-motion monitoring in the Venice lagoon", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3919-3922.
Abstract: The city of Venice (Italy) and its surrounding lagoon constitutes a unique worldwide environment vulnerable to loss of surface elevation due to land subsidence and sea level rise. Locally, the city of Venice, shows a present general stability with rates averaging between -1 to +1 mm/year. This work presents results over Venice area, derived by the two interferometric techniques (DInSAR and Permanent Scatterers Interferometry). The use of the two techniques allows us to understand the complementarity of both techniques and their limitations. 2012 IEEE.
BibTeX:
@conference{Kourkouli20123919,
  author = {Kourkouli, P. and Strozzi, T. and Wegmüller, U.},
  title = {Comparison of DInSAR and persistent scatterer interferometry for ground-motion monitoring in the Venice lagoon},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {3919-3922},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873191691&doi=10.1109%2fIGARSS.2012.6350555&partnerID=40&md5=27de4279d40a572ecacb1b9b30d713eb},
  doi = {10.1109/IGARSS.2012.6350555}
}
Magnard C, Brehm T, Essen H and Meier E (2012), "High resolution MEMPHIS SAR data processing and applications", In Progress in Electromagnetics Research Symposium. , pp. 328-332.
Abstract: This paper focuses on MEMPHIS (Multi-frequency Experimental Monopulse High- resolution Interferometric SAR) data processing, possible applications using its various SAR modes and the results obtained. The processing chain used to focus MEMPHIS data is presented. To demonstrate the focusing quality, the signatures of corner reflectors were analyzed, revealing not only a high resolution, but also a very precise geometric positioning accuracy on the order of the resolution, in spite of MEMPHIS' experimental and portable design. Finally, applications and results using the various antennas are presented, such as the generation of digital surface models with the multi-baseline interferometric antenna along with a quality evaluation, as well as channel combinations of the polarimetric data.
BibTeX:
@conference{Magnard2012328,
  author = {Magnard, C. and Brehm, T. and Essen, H. and Meier, E.},
  title = {High resolution MEMPHIS SAR data processing and applications},
  booktitle = {Progress in Electromagnetics Research Symposium},
  year = {2012},
  pages = {328-332},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84868594572&partnerID=40&md5=9be975800957c18f8f209d8dc6c7d283}
}
Manconi A and Casu F (2012), "Joint analysis of displacement time series retrieved from SAR phase and amplitude: Impact on the estimation of volcanic source parameters", Geophysical Research Letters. Vol. 39(14) Blackwell Publishing Ltd.
Abstract: We study the impact of jointly analyzing the phase and amplitude information of a SAR dataset on the interpretation of the surface displacement over time in areas characterized by large dynamics. In particular, we compute the ground displacement time series over Fernandina and Sierra Negra calderas (Galápagos islands), by applying the Small BAseline Subset (SBAS) and the Pixel Offset (PO)-SBAS techniques to 25 ENVISAT SAR images acquired between 2003 and 2007, when both volcanoes experienced catastrophic eruptions. By merging the SBAS and PO-SBAS time series results the spatial density of measurements increased substantially. In addition, the joint analysis of the time series allows us to better constrain the temporal evolution of the magmatic source volume changes. Our results show that the joint use of the SBAS and PO-SBAS approaches may help for a more correct evaluation of large deformation affecting the Earth's surface caused by eruptions, earthquakes, and landslide phenomena. 2012. American Geophysical Union.
BibTeX:
@article{Manconi2012,
  author = {Manconi, A. and Casu, F.},
  title = {Joint analysis of displacement time series retrieved from SAR phase and amplitude: Impact on the estimation of volcanic source parameters},
  journal = {Geophysical Research Letters},
  publisher = {Blackwell Publishing Ltd},
  year = {2012},
  volume = {39},
  number = {14},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864444179&doi=10.1029%2f2012GL052202&partnerID=40&md5=b3ea153ff5452bf7cc50b1889e1bd496},
  doi = {10.1029/2012GL052202}
}
Manconi A, Giordan D, Allasia P, Baldo M and Lollino G (2012), "Surface displacements following the Mw 6.3 L'Aquila earthquake: One year of continuous monitoring via Robotized Total Station", Italian Journal of Geosciences. Vol. 131(3), pp. 403-409.
Abstract: We present the results of a continuous monitoring of the surface displacements following the April 6th 2009 L'Aquila earthquake in the area of Paganica village, central Italy. We considered 3-dimensional displacements measured via Robotized Total Station (RTS) installed the April 24th 2009 in the area of Paganica village (ca. 5 km ENE from L'Aquila town), where a water pipeline located within the urban centre was severely damaged. The monitoring system was set up in order to reveal potential post-seismic displacements that could cause further damages to the water pipeline. The RTS ran continuously for about one year, with sampling rates varying from 2 to 4 hours, and measured displacements at selected point targets. The revealed surface displacements are in agreement with the results of a DInSAR time series analysis relevant to satellite SAR data acquired over the same area and time period by the Italian satellite's constellation Cosmo-SkyMed. Moreover, despite the RTS monitored area was spatially limited, our analyses provide detailed feedbacks on fault processes following the L'Aquila earthquake. The aftershocks temporal evolution and the post-seismic displacements measured in the area show very similar exponential decays over time, with estimated cross-correlation coefficients values ranging from 0.86 to 0.97. The results of our time dependent modelling of the RTS measurements suggest that L'Aquila earthquake post-seismic displacements were dominated by the fault afterslip and/or fault creep, while poroelastic and viscoelastic processes had negligible effects. 2012 Societa Geologica Italiana, Roma.
BibTeX:
@article{Manconi2012403,
  author = {Manconi, A. and Giordan, D. and Allasia, P. and Baldo, M. and Lollino, G.},
  title = {Surface displacements following the Mw 6.3 L'Aquila earthquake: One year of continuous monitoring via Robotized Total Station},
  journal = {Italian Journal of Geosciences},
  year = {2012},
  volume = {131},
  number = {3},
  pages = {403-409},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84868627411&doi=10.3301%2fIJG.2012.13&partnerID=40&md5=439fd57201e577bebce96fdd280873b3},
  doi = {10.3301/IJG.2012.13}
}
Marzahn P, Rieke-Zapp D, Wegmüller U and Ludwig R (2012), "Multidimensional roughness characterization for microwave remote sensing applications using a simple photogrammetric acquisition system", In International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives. Vol. 39, pp. 423-428. International Society for Photogrammetry and Remote Sensing.
Abstract: Soil surface roughness, as investigated in this study, is a critical parameter in microwave remote sensing. As soil surface roughness is treated as a stationary single scale isotropic process in most backscattering models, the overall objective of this study was to better understand the role of soil surface roughness in the context of backscattering. Therefore a simple photogrametric acquisition setup was developed for the characterization of soil surface roughness. In addition several suited SAR images of different sensors (ERS-2 and TerraSAR-X) were acquired to quantify the impact of soil surface roughness on the backscattered signal. Major progress achieved in this work includes the much improved characterization of in-field soil surface roughness. Good progress was also made in the understanding of backscattering from bare surface in the case of directional scattering.
BibTeX:
@conference{Marzahn2012423,
  author = {Marzahn, P. and Rieke-Zapp, D. and Wegmüller, U. and Ludwig, R.},
  editor = {Shortis M., Mills J.},
  title = {Multidimensional roughness characterization for microwave remote sensing applications using a simple photogrammetric acquisition system},
  booktitle = {International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives},
  publisher = {International Society for Photogrammetry and Remote Sensing},
  year = {2012},
  volume = {39},
  pages = {423-428},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84924237581&partnerID=40&md5=ce8e7dfed698cfba2ca9e3afd92249e9}
}
Marzahn P, Wegmüller U, Mattia F and Ludwig R (2012), "'Flashing Fields' and the impact of soil surface roughness", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 6963-6966.
Abstract: In this paper the results of an additional campaign in the context of Flashing Fields are presented showing the impact of soil surface roughness on the directional backscattering. For the characterization of soil surface roughness a photogrametric measurement device was used and roughness was measured simultaneous to SAR observation made by ERS-2 and TerraSAR-X. As this study mainly confirmed and consolidated the findings of the previous Flashing Fields studies, major progress was made in in the understanding of the impact of soil surface roughness on the flashing phenomenon. It could be concluded, that besides the row orientation, certain roughness conditions could significantly alter the flashing effect. 2012 IEEE.
BibTeX:
@conference{Marzahn20126963,
  author = {Marzahn, P. and Wegmüller, U. and Mattia, F. and Ludwig, R.},
  title = {'Flashing Fields' and the impact of soil surface roughness},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {6963-6966},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873191097&doi=10.1109%2fIGARSS.2012.6351968&partnerID=40&md5=77014391ac8162963727fff0909c26a8},
  doi = {10.1109/IGARSS.2012.6351968}
}
Papke J, Strozzi T, Wiesmann A, Wegmüller U and Tate N (2012), "Rock glacier monitoring with spaceborne SAR in Graechen, Valais, Switzerland", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3911-3914.
Abstract: Spaceborne techniques to monitor the Earth and its processes have advanced significantly over the last thirty years. Sensor spatial resolutions have increased supporting more detailed measurements and shorter revisit times have given higher temporal resolutions. Notwithstanding such advances, understanding the Earth system as a whole remains challenging. The focus of this paper is on monitoring rock glaciers in a mountainous area in the municipality of Graechen, Valais, Switzerland using Envisat and TerraSAR-X data acquired in 2008, 2009 and 2010. Spaceborne Synthetic Aperture Radar interferometry (InSAR) is used to augment existing observations from borehole measurements, geodetic and photogrammetric methods. In the Graechen study area, significant phase differences are reliably observed in 11-day TerraSAR-X and 35-day Envisat differential interferograms related to movements of the 'Distelhorn' rock glacier and the Ritigraben rock glacier. The number of visible fringes are a relatively clear indication for seasonal variations in the movement of the rock glaciers, being about a quarter of a fringe faster in autumn (September/October) than in summer (June, July). 2012 IEEE.
BibTeX:
@conference{Papke20123911,
  author = {Papke, J. and Strozzi, T. and Wiesmann, A. and Wegmüller, U. and Tate, N.J.},
  title = {Rock glacier monitoring with spaceborne SAR in Graechen, Valais, Switzerland},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {3911-3914},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873180599&doi=10.1109%2fIGARSS.2012.6350557&partnerID=40&md5=c4dac17389e2c6c877b6c10ec3068daf},
  doi = {10.1109/IGARSS.2012.6350557}
}
Paul F, Bolch T, Kaab A, Nagler T, Shepherd A and Strozzi T (2012), "Satellite-based glacier monitoring in the ESA project Glaciers-CCI", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3222-3225.
Abstract: Glaciers and their changes have been in the focus of the public and the media over the past decade, as they reflect impacts of climate change in an extraordinarily clear and understandable way. They are thus considered as key indicators of climate change and play a most important role in globally coordinated climate-related monitoring programs like the Global Climate Observing System (GCOS). Glacier changes are widely reported with related adverse impacts when errors occur [4]. In consequence, all measurements must be performed with great care and should have been quality checked. Complementary to the field-based observations of changes in glacier length and mass on selected glaciers world-wide [12], satellite data offer the unique possibility to cover entire mountain ranges with a consistent method and thus help creating a more complete and representative picture of ongoing changes. From the large number of possible glacier observations that can be made with (repeat) satellite data, the Glaciers-cci project is focusing on three of them: Glacier area, elevation changes and velocity fields. The characteristics of the satellite sensors used to derive these three products are rather complimentary in regard to spectral properties (optical, microwave, LIDAR), spatial resolution, temporal coverage, repeat interval, etc. Glaciological studies greatly benefit from this wealth of data types and can utilize the different possibilities to derive specific properties of glaciers. 2012 IEEE.
BibTeX:
@conference{Paul20123222,
  author = {Paul, F. and Bolch, T. and Kaab, A. and Nagler, T. and Shepherd, A. and Strozzi, T.},
  title = {Satellite-based glacier monitoring in the ESA project Glaciers-CCI},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {3222-3225},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873131965&doi=10.1109%2fIGARSS.2012.6350738&partnerID=40&md5=923688a87daf414357019c1be0afe79b},
  doi = {10.1109/IGARSS.2012.6350738}
}
Santoro M, Pantze A, Fransson J, Dahlgren J and Persson A (2012), "Nation-wide clear-cut mapping in Sweden using ALOS PALSAR strip images", Remote Sensing. Vol. 4(6), pp. 1693-1715.
Abstract: Advanced Land Observing Satellite (ALOS) Phased Array L-band type Synthetic Aperture Radar (PALSAR) backscatter images with 50 m pixel size (strip images) at HV-polarization were used to map clear-cuts at a regional and national level in Sweden. For a set of 31 clear-cuts, on average 59.9% of the pixels within each clear-cut were correctly detected. When compared with a one-pixel edge-eroded version of the reference dataset, the accuracy increased to 88.9%. With respect to statistics from the Swedish Forest Agency, county-wise clear-felled areas were underestimated by the ALOS PALSAR dataset (between 25% and 60%) due to the coarse resolution. When compared with statistics from the Swedish National Forest Inventory, the discrepancies were larger, partly due to the estimation errors from the plot-wise forest inventory data. In Sweden, for the time frame of 2008-2010, the total area felled was estimated to be 140,618 ha, 172,532 ha and 194,586 ha using data from ALOS PALSAR, the Swedish Forest Agency and the Swedish National Forest Inventory, respectively. ALOS PALSAR strip images at HV-polarization appear suitable for detection of clear-felled areas at a national level; nonetheless, the pixel size of 50 m is a limiting factor for accurate delineation of clear-felled areas. 2012 by the authors.
BibTeX:
@article{Santoro20121693,
  author = {Santoro, M. and Pantze, A. and Fransson, J.E.S. and Dahlgren, J. and Persson, A.},
  title = {Nation-wide clear-cut mapping in Sweden using ALOS PALSAR strip images},
  journal = {Remote Sensing},
  year = {2012},
  volume = {4},
  number = {6},
  pages = {1693-1715},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865014962&doi=10.3390%2frs4061693&partnerID=40&md5=588006d0fe059fdd70e8c8195ad1c556},
  doi = {10.3390/rs4061693}
}
Santoro M, Schmullius C, Pathe C and Schwilk J (2012), "Pan-boreal mapping of forest growing stock volume using hyper-temporal Envisat ASAR ScanSAR backscatter data", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 7204-7207.
Abstract: Retrieval of forest growing stock volume (GSV) has been shown to be feasible with C-band backscatter data using hyper-temporal stacks. In this paper, we report on the generation of pan-boreal estimates of forest GSV representative for the year 2010 using Envisat ASAR ScanSAR backscatter measurements. More than 67,000 image strips acquired between October 2009 and February 2011 over the north American and the Eurasian continent have been multi-looked to 1 km pixel size, terrain geocoded to a pixel size of 0.01 degree, speckle filtered and corrected for slope-induced effects on the backscatter. Then, GSV has been retrieved with the BIOMASAR algorithm on a pixel-by-pixel basis. First results show the strong thematic accuracy of the GSV estimates due to the very large number of backscatter observations available and retained for retrieval. 2012 IEEE.
BibTeX:
@conference{Santoro20127204,
  author = {Santoro, M. and Schmullius, C. and Pathe, C. and Schwilk, J.},
  title = {Pan-boreal mapping of forest growing stock volume using hyper-temporal Envisat ASAR ScanSAR backscatter data},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {7204-7207},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873167000&doi=10.1109%2fIGARSS.2012.6352000&partnerID=40&md5=38cccb96ce02c79c33771d075299e8bb},
  doi = {10.1109/IGARSS.2012.6352000}
}
Santoro M and Wegmüller U (2012), "Multi-temporal SAR metrics applied to map water bodies", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 5230-5233.
Abstract: Multi-temporal synthetic aperture radar (SAR) metrics are investigated to assess their capability for mapping land cover types. The temporal variability and the minimum backscatter in a time series of Envisat Advanced SAR (ASAR) Wide Swath Mode (WSM) backscatter measurements present unique features over water surfaces with respect to other land cover types. A simple thresholding algorithm applied to these metrics is then presented to detect water bodies. Results from six study areas in Europe and Central Siberia show consistency of the behavior of the multi-temporal metrics over 'water' and 'land' areas regardless of the specific region. Water body detection accuracies are mostly above 90%, omissions occurring when a water body has a size similar to the pixel size of the SAR image. 2012 IEEE.
BibTeX:
@conference{Santoro20125230,
  author = {Santoro, M. and Wegmüller, U.},
  title = {Multi-temporal SAR metrics applied to map water bodies},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {5230-5233},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873136700&doi=10.1109%2fIGARSS.2012.6352430&partnerID=40&md5=019d57c62dd13bab2aedc84c4839c3e6},
  doi = {10.1109/IGARSS.2012.6352430}
}
Schafer M, Zwinger T, Christoffersen P, Gillet-Chaulet F, Laakso K, Pettersson R, Pohjola V, Strozzi T and Moore J (2012), "Sensitivity of basal conditions in an inverse model: Vestfonna ice cap, Nordaustlandet/Svalbard", Cryosphere. Vol. 6(4), pp. 771-783.
Abstract: The dynamics of Vestfonna ice cap (Svalbard) are dominated by fast-flowing outlet glaciers. Its mass balance is poorly known and affected dynamically by these fast-flowing outlet glaciers. Hence, it is a challenging target for ice flow modeling. Precise knowledge of the basal conditions and implementation of a good sliding law are crucial for the modeling of this ice cap. Here we use the full-Stokes finite element code Elmer/Ice to model the 3-D flow over the whole ice cap. We use a Robin inverse method to infer the basal friction from the surface velocities observed in 1995. Our results illustrate the importance of the basal friction parameter in reproducing observed velocity fields. We also show the importance of having variable basal friction as given by the inverse method to reproduce the velocity fields of each outlet glacier-a simple parametrization of basal friction cannot give realistic velocities in a forward model. We study the robustness and sensitivity of this method with respect to different parameters (mesh characteristics, ice temperature, errors in topographic and velocity data). The uncertainty in the observational parameters and input data proved to be sufficiently small as not to adversely affect the fidelity of the model. 2012 Author(s).
BibTeX:
@article{Schafer2012771,
  author = {Schafer, M. and Zwinger, T. and Christoffersen, P. and Gillet-Chaulet, F. and Laakso, K. and Pettersson, R. and Pohjola, V.A. and Strozzi, T. and Moore, J.C.},
  title = {Sensitivity of basal conditions in an inverse model: Vestfonna ice cap, Nordaustlandet/Svalbard},
  journal = {Cryosphere},
  year = {2012},
  volume = {6},
  number = {4},
  pages = {771-783},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867469539&doi=10.5194%2ftc-6-771-2012&partnerID=40&md5=1169257fa42e53a38cf26ae24f438ed7},
  doi = {10.5194/tc-6-771-2012}
}
Schwank M, Wigneron J-P, López-Baeza E, Volksch I, Matzler C and Kerr Y (2012), "L-band radiative properties of vine vegetation at the MELBEX III SMOS cal/val site", IEEE Transactions on Geoscience and Remote Sensing. Vol. 50(5 PART 1), pp. 1587-1601.
Abstract: Radiative properties at 1.4 GHz of vine vegetation are investigated by measuring brightness temperatures with the ETH L-band Radiometer II (ELBARA II) operated on a tower at the Mediterranean Ecosystem L-band Characterisation Experiment III (MELBEX III) field site in Spain. To this aim, experiments with and without a reflecting foil placed under the vines were performed for the vegetation winter and summer states, respectively, to provide prevailingly information on vegetation transmissivities. The resulting parameters, which can be considered as ground truth for the MELBEX III vineyard, were retrieved from brightness temperature at horizontal and vertical polarization measured at observation angles between 30° and 60°. These MELBEX III ground-truth values are representative for the Mediterranean Soil Moisture and Ocean Salinity (SMOS) Valencia Anchor Station (VAS) and therefore valuable for the corresponding calibration and validation activities over the VAS site. Likewise, quantifying the uncertainties of the measured brightness temperatures was also important, particularly as several equivalent ELBARA II instruments are currently operative in ongoing SMOS-related field campaigns. 2012 IEEE.
BibTeX:
@article{Schwank20121587,
  author = {Schwank, M. and Wigneron, J.-P. and López-Baeza, E. and Volksch, I. and Matzler, C. and Kerr, Y.H.},
  title = {L-band radiative properties of vine vegetation at the MELBEX III SMOS cal/val site},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2012},
  volume = {50},
  number = {5 PART 1},
  pages = {1587-1601},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860313055&doi=10.1109%2fTGRS.2012.2184126&partnerID=40&md5=0a7950b1af64b0fae582a57b0e65f8f1},
  doi = {10.1109/TGRS.2012.2184126}
}
Strozzi T, Wegmüller U, Werner C and Kos A (2012), "TerraSAR-X interferometry for surface deformation monitoring on periglacial area", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 5214-5217.
Abstract: Arctic and mountainous periglacial areas are subject to intense freezing cycles and characterized by remarkable surface displacement. We used TerraSAR-X interferometry to analyze the seasonal surface displacement on two regions in Alaska and Switzerland. In both cases, TerraSAR-X interferograms with an 11 days time interval are computed in series in order to maximize coherence. Seasonal subsidence maps highlight surface displacements of several centimeters while time-series show non-linear behaviors of the movements. 2012 IEEE.
BibTeX:
@conference{Strozzi20125214,
  author = {Strozzi, T. and Wegmüller, U. and Werner, C. and Kos, A.},
  title = {TerraSAR-X interferometry for surface deformation monitoring on periglacial area},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {5214-5217},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873145915&doi=10.1109%2fIGARSS.2012.6352434&partnerID=40&md5=0c3cf832880966459d96c35b523d3217},
  doi = {10.1109/IGARSS.2012.6352434}
}
Strozzi T, Werner C, Wiesmann A and Wegmüller U (2012), "Topography mapping with a portable real-aperture radar interferometer", IEEE Geoscience and Remote Sensing Letters. Vol. 9(2), pp. 277-281.
Abstract: In this letter, the requirements to derive topography from a portable terrestrial radar interferometer are introduced, the instrument design and the relationship between interferometric phase shift and surface topography are explained, and two examples of topographic maps from measurements at the Rhone glacier and Grabengufer rock glacier in Switzerland are presented. In the first case, an external digital elevation model was used to assess the error of topography mapping with the portable radar interferometer and to analyze ice surface changes of the glacier in the last 14 years. We found that the height error standard deviation is about 3 m within a distance of 2 km from the sensor and observed massive thinning of the Rhone glacier. In the second case, we used the terrestrial radar interferometer in order to measure the height difference between August 2009 and March 2010 over the rock glacier as a consequence of its destabilization. 2006 IEEE.
BibTeX:
@article{Strozzi2012277,
  author = {Strozzi, T. and Werner, C. and Wiesmann, A. and Wegmüller, U.},
  title = {Topography mapping with a portable real-aperture radar interferometer},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  year = {2012},
  volume = {9},
  number = {2},
  pages = {277-281},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856955434&doi=10.1109%2fLGRS.2011.2166751&partnerID=40&md5=45cbdeada90f9057faef265761562c50},
  doi = {10.1109/LGRS.2011.2166751}
}
Strozzi T, Wiesmann A, Kaab A, Joshi S and Mool P (2012), "Glacial lake mapping with very high resolution satellite SAR data", Natural Hazards and Earth System Science. Vol. 12(8), pp. 2487-2498.
Abstract: Floods resulting from the outbursts of glacial lakes are among the most far-reaching disasters in high mountain regions. Glacial lakes are typically located in remote areas and space-borne remote sensing data are an important source of information about the occurrence and development of such lakes. Here we show that very high resolution satellite Synthetic Aperture Radar (SAR) data can be employed for reliably mapping glacial lakes. Results in the Alps, Pamir and Himalaya using TerraSAR-X and Radarsat-2 data are discussed in comparison to in-situ information, and high-resolution satellite optical and radar imagery. The performance of the satellite SAR data is best during the snow- and ice-free season. In the broader perspective of hazard management, the detection of glacial lakes and the monitoring of their changes from very high-resolution satellite SAR intensity images contributes to the initial assessment of hazards related to glacial lakes, but a more integrated, multi-level approach needs also to include other relevant information such as glacier outlines and outline changes or the identification of unstable slopes above the lake and the surrounding area, information types to which SAR analysis techniques can also contribute. Author(s) 2012.
BibTeX:
@article{Strozzi20122487,
  author = {Strozzi, T. and Wiesmann, A. and Kaab, A. and Joshi, S. and Mool, P.},
  title = {Glacial lake mapping with very high resolution satellite SAR data},
  journal = {Natural Hazards and Earth System Science},
  year = {2012},
  volume = {12},
  number = {8},
  pages = {2487-2498},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865241098&doi=10.5194%2fnhess-12-2487-2012&partnerID=40&md5=242c774c9f053872d54662f2b525de07},
  doi = {10.5194/nhess-12-2487-2012}
}
Teatini P, Tosi L and Strozzi T (2012), "Comment on "Recent subsidence of the Venice Lagoon from continuous GPS and interferometric synthetic aperture radar" by Y. Bock, S. Wdowinski, A. Ferretti, F. Novali, and A. Fumagalli", Geochemistry, Geophysics, Geosystems. Vol. 13(1) Blackwell Publishing Ltd.
BibTeX:
@article{Teatini2012,
  author = {Teatini, P. and Tosi, L. and Strozzi, T.},
  title = {Comment on "Recent subsidence of the Venice Lagoon from continuous GPS and interferometric synthetic aperture radar" by Y. Bock, S. Wdowinski, A. Ferretti, F. Novali, and A. Fumagalli},
  journal = {Geochemistry, Geophysics, Geosystems},
  publisher = {Blackwell Publishing Ltd},
  year = {2012},
  volume = {13},
  number = {1},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864571427&doi=10.1029%2f2012GC004191&partnerID=40&md5=0ab9855b2d02f407d3815461e52b1a89},
  doi = {10.1029/2012GC004191}
}
Teatini P, Tosi L, Strozzi T, Carbognin L, Cecconi G, Rosselli R and Libardo S (2012), "Resolving land subsidence within the Venice Lagoon by persistent scatterer SAR interferometry", Physics and Chemistry of the Earth. Vol. 40-41, pp. 72-79.
Abstract: Land subsidence is a severe geologic hazard threatening the lowlying transitional coastal areas worldwide. Monitoring land subsidence has been significantly improved over the last decade by space borne earth observation techniques based on Synthetic Aperture Radar (SAR) interferometry. Within the INLET Project, funded by Magistrato alle Acque di Venezia - Venice Water Authority (VWA) and Consorzio Venezia Nuova (CVN), we use Interferometric Point Target Analysis (IPTA) to characterize the ground displacements within the Venice Lagoon. IPTA measures the movement of backscattering point targets (PTs) at the ground surface that persistently reflect radar signals emitted by the SAR system at different passes. For this study 80 ERS-1/2 and 44 ENVISAT SAR scenes recorded from 1992 to 2005 and from 2003 to 2007, respectively, have been processed. Highly reliable displacement measurements have been detected for thousands of PTs located on the lagoon margins, along the littorals, in major and small islands, and on single structures scattered within the lagoon. On the average, land subsidence ranges from less than 1. mm/year to 5. mm/year, with some PTs that exhibit values also larger than 10. mm/year depending on both the local geologic conditions and the anthropic activities. A network of a few tens of artificial square trihedral corner reflectors (TCRs) has been established before summer 2007 in order to monitor land subsidence in the inner lagoon areas where " natural" reflectors completely lack (e.g., on the salt marshes). The first interferometric results on the TCRs appear very promising. 2010 Elsevier Ltd.
BibTeX:
@article{Teatini201272,
  author = {Teatini, P. and Tosi, L. and Strozzi, T. and Carbognin, L. and Cecconi, G. and Rosselli, R. and Libardo, S.},
  title = {Resolving land subsidence within the Venice Lagoon by persistent scatterer SAR interferometry},
  journal = {Physics and Chemistry of the Earth},
  year = {2012},
  volume = {40-41},
  pages = {72-79},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858804914&doi=10.1016%2fj.pce.2010.01.002&partnerID=40&md5=5a1fb223f4333ffa771cc04dcf94cbe6},
  doi = {10.1016/j.pce.2010.01.002}
}
Tosi L, Strozzi T and Teatini P (2012), "Cosmo-skymed versus TerraSAR-X -based interferometry for monitoring the mose settlements at the Venice lagoon inlets", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 2837-2840.
Abstract: The modern approach of studying ground movements is aimed at distinguishing regional land subsidence and local consolidation processes, as well as long- and short- term displacements. With a very-high resolution images and a repeatability acquisitions never available in the past the new generation of SAR satellites provides helps to reach these achievements. In this work we compare the capability of Cosmo-SkyMed and TerraSAR-X for detecting the displacement of jetties, breakwaters, locks, and an artificial island which are under construction in the Venice lagoon inlets, Italy, as part of the anti-flood project MOSE Cosmo-SkyMed and TerraSAR-X have been also used to provide an updated quantification of the subsidence rates of the Venice and Chioggia historical centers. 2012 IEEE.
BibTeX:
@conference{Tosi20122837,
  author = {Tosi, L. and Strozzi, T. and Teatini, P.},
  title = {Cosmo-skymed versus TerraSAR-X -based interferometry for monitoring the mose settlements at the Venice lagoon inlets},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {2837-2840},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873151016&doi=10.1109%2fIGARSS.2012.6350841&partnerID=40&md5=b984dc7659ffb7cccbc4bc997a16272c},
  doi = {10.1109/IGARSS.2012.6350841}
}
Tosi L, Teatini P, Bincoletto L, Simonini P and Strozzi T (2012), "Integrating Geotechnical and Interferometric SAR Measurements for Secondary Compressibility Characterization of Coastal Soils", Surveys in Geophysics. Vol. 33(5), pp. 907-926.
Abstract: Persistent scatterer interferometry (PSI) provides a new perspective to monitor the movements of coastal structures due to long-term consolidation using satellite-borne remote sensors. The method has the advantages of detecting the displacements at a very high spatial (from 1 to a few meters) and temporal (from 10 to 30 days) resolution. Cost-effective monitoring of complex and large (some kilometer long) structures can be done over long time (up to 10 years) intervals and at large scales (tens times tens km 2) of investigation. Here, these measurements are integrated with geotechnical, site-specific measurements to characterize in a unique framework the long-term compressibility of coastal soils over large areas. The approach is tested on the 60-km-long coastland of the Venice Lagoon, Italy. An accurate quantification of the movements of coastal infrastructures at the Venice coastland is carried out by PSI using ENVISAT ASAR and TerraSAR-X images acquired from April 2003 to December 2009 and from March 2008 to January 2009, respectively. Several nearshore and offshore structures were constructed over the decades to protect Venice and its coastal environment from sea storms and high tides. Long jetties were built at the lagoon inlets since the end of the 18th century, significantly reinforced between 1994 and 1997, and finally reshaped since 2003 in the framework of the MOSE construction (i. e., the project of mobile barriers for the temporarily closure of the lagoon to the sea). The measured displacements range from a few mm/year for the structures older than 10 years to 50-70 mm/year for those realized a few years ago. The PSI measurements are combined with the outcome of a detailed geomechanical characterization of the lagoon subsoil obtained by a field-scale experiment started at the end of 2002 and monitored to 2008. The use of the stress-strain properties derived from the trial embankment and the actual lithostratigraphy below the coastal structures, which is available from several piezocone profiles and boreholes, allows for the computation of secondary compression (consolidation) rates that match very well the PSI-derived movements. The results provide important information on the potential of using PSI to characterizing geotechnical properties (magnitude and distribution) of coastal deposits, as well as to estimate the expected time-dependent geomechanical response of coastal structures or other large constructions. 2012 Springer Science+Business Media B.V.
BibTeX:
@article{Tosi2012907,
  author = {Tosi, L. and Teatini, P. and Bincoletto, L. and Simonini, P. and Strozzi, T.},
  title = {Integrating Geotechnical and Interferometric SAR Measurements for Secondary Compressibility Characterization of Coastal Soils},
  journal = {Surveys in Geophysics},
  year = {2012},
  volume = {33},
  number = {5},
  pages = {907-926},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864307146&doi=10.1007%2fs10712-012-9186-y&partnerID=40&md5=d5cf6a85974ae7deb914a4bbd5fdea50},
  doi = {10.1007/s10712-012-9186-y}
}
Voytenko D, Dixon T, Werner C, Gourmelen N, Howat I, Tinder P and Hooper A (2012), "Monitoring a glacier in southeastern Iceland with the portable Terrestrial Radar Interferometer", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3230-3232.
Abstract: Terrestrial Radar Interferometry (TRI) has several advantages for measuring glacier velocity. These ground-based systems alleviate problems associated with the long revisit times of satellites, and provide higher spatial sampling compared to GPS-based approaches. TRI is the technique of choice for rapidly moving glaciers, especially their terminal zones, which tend to exhibit high spatial and temporal variability. In this study, we use the Gamma Portable Radar Interferometer (GPRI) to measure the velocity of Breidamerkurjokull, a marine-terminating outlet glacier on the southeastern coast of Iceland, and compare it to TerraSAR-X data taken shortly after. We document significant temporal and spatial variability of ice velocity within 800 meters of the calving front. 2012 IEEE.
BibTeX:
@conference{Voytenko20123230,
  author = {Voytenko, D. and Dixon, T.H. and Werner, C. and Gourmelen, N. and Howat, I.M. and Tinder, P.C. and Hooper, A.},
  title = {Monitoring a glacier in southeastern Iceland with the portable Terrestrial Radar Interferometer},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {3230-3232},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873181924&doi=10.1109%2fIGARSS.2012.6350736&partnerID=40&md5=30ac039b0bc533782f8b7359d50598e9},
  doi = {10.1109/IGARSS.2012.6350736}
}
Wegmüller U, Frey O and Werner C (2012), "Point density reduction in persistent scatterer interferometry", In Proc. European Conf. Synthetic Aperture Radar. Vol. 2012-April, pp. 673-676. Institute of Electrical and Electronics Engineers Inc..
Abstract: Persistent Scatterer Interferometry (PSI) is widely used to determine ground deformation rates and histories. The data sets processed are increasing in size due to larger areas considered, higher resolution, and higher point densities. Working with lists of several million points and related networks reduces the computational efficiency. In this paper a method to adaptively reduce the size of the point list is presented. Considering the local point density and a point quality measure points are removed such that the density is significantly reduced in areas of very high density while maintaining the available density in areas of lower density. The main PSI processing is then done for the reduced point list. Later on the result obtained for the reduced list is expanded to the full point list. In several cases this methodology improves the processing efficiency significantly.
BibTeX:
@conference{Wegmuller2012673,
  author = {Wegmüller, U. and Frey, O. and Werner, C.},
  title = {Point density reduction in persistent scatterer interferometry},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2012},
  volume = {2012-April},
  pages = {673-676},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85007454984&partnerID=40&md5=4df125ef75a9b65769eb57ec8d1ea407}
}
Wegmüller U, Strozzi T, Delaloye R and Raetzo H (2012), "Landslide mapping in Switzerland with ENVISAT ASAR", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1829-1832.
Abstract: In the frame of the IGARSS 2012 special session on ENVISAT the landslide mapping activities in Switzerland using ENVISAT ASAR data are presented. Between 2005 and 2010 the building up of a well suited archive over the Swiss Alps was realized through programming of all IS2 mode data during the snow free period. In recent years DINSAR and PSI based landslide inventory and monitoring products started to play an important role in the updating of hazard maps. 2012 IEEE.
BibTeX:
@conference{Wegmuller20121829,
  author = {Wegmüller, U. and Strozzi, T. and Delaloye, R. and Raetzo, H.},
  title = {Landslide mapping in Switzerland with ENVISAT ASAR},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {1829-1832},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873156068&doi=10.1109%2fIGARSS.2012.6351155&partnerID=40&md5=5bc5bf057e2965fead5be6ac3fe7d445},
  doi = {10.1109/IGARSS.2012.6351155}
}
Wegmüller U, Strozzi T and Werner C (2012), "Ionospheric path delay estimation using split-beam interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3631-3634.
Abstract: Azimuth spectrum band-pass filtering has been applied successfully for estimation of along-track ground displacement [1] as well as for other applications, such as the identification of directional scattering [2] and the coherence estimation for long-baseline pairs [3]. Particularly L-band split-beam interferograms have shown another phase component related to along-track variations in the ionospheric path delay. In our work we present methodologies to identify and quantify ionospheric path delays affecting an interferogram using the corresponding split-beam interferogram. 2012 IEEE.
BibTeX:
@conference{Wegmuller20123631,
  author = {Wegmüller, U. and Strozzi, T. and Werner, C.},
  title = {Ionospheric path delay estimation using split-beam interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2012},
  pages = {3631-3634},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873206223&doi=10.1109%2fIGARSS.2012.6350630&partnerID=40&md5=f90de27c5ad9ec680081a9b351c04d4f},
  doi = {10.1109/IGARSS.2012.6350630}
}
Wegmüller U, Strozzi T, Wiesmann A, Werner CL, Frey O, Caduff R and Kos A (2012), "Hangrutschungskartierung mittels Radar Interferometrie", Geomatik Schweiz. Vol. 110(9)
Abstract: Insbesondere durch die ERS-1, ERS-2 und ENVISAT ASAR Sensoren der Europäischen Raumfahrtsagentur ESA hat sich in den letzten 20 Jahren die SAR Interferometrie Methode sehr stark entwickelt. Ein wichtiger Anwendungsbereich ist die Kartierung von Geländebewegungen. Innerhalb der Schweiz wird die SAR Interferometrie Methodevor allem für die Kartierung von Hangrutschungen eingesetzt. Hangrutschungsinformation wird momentan für die Erstellung der Gefahrenhinweiskarten durch die Kantone benötigt. Angesichts einer wahrscheinlichen Zunahme der Hangrutschungs- undFelssturzgefahren durch die Klimaerwärmung und daraus resultierenden sekundärenVeränderungen, wie der Reduktion des Alpinen Permafrosts und des Gletscherrückzugs, kann mit einem zunehmenden Informationsbedarf gerechnet werden.
BibTeX:
@article{wegmullerStrozziWiesmannWernerFreyCaduffKosGEOMATIK2012DInSAR,
  author = {Wegmüller, Urs and Strozzi, Tazio and Wiesmann, Andreas and Werner, Charles L. and Frey, Othmar and Caduff, Rafael and Kos, Andrew},
  title = {Hangrutschungskartierung mittels Radar Interferometrie},
  journal = {Geomatik Schweiz},
  year = {2012},
  volume = {110},
  number = {9},
  url = {http://doi.org/10.5169/seals-309305}
}
Werner C, Wiesmann A, Strozzi T, Kos A, Caduff R and Wegmüller U (2012), "The GPRI multi-mode differential interferometric radar for ground-based observations", In Proc. European Conf. Synthetic Aperture Radar. Vol. 2012-April, pp. 304-307. Institute of Electrical and Electronics Engineers Inc..
Abstract: We describe the Gamma Portable Radar Interferometer (GPRI), an instrument designed to perform ground-based radar interferometry to measure surface deformation with an accuracy > 0.2 mm and generate digital elevation models (DEMs). Ground-based interferometric observations are complementary to spaceborne or airborne SAR based measurements because they can be acquired continuously in order to track rapid deformation and mitigate the effects of temporal decorrelation and atmospheric phase variability. Results from test cases are shown including the Aletsch glacier, Aletschwald, and Konthaus bridge in Bern.
BibTeX:
@conference{Werner2012304,
  author = {Werner, C. and Wiesmann, A. and Strozzi, T. and Kos, A. and Caduff, R. and Wegmüller, U.},
  title = {The GPRI multi-mode differential interferometric radar for ground-based observations},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2012},
  volume = {2012-April},
  pages = {304-307},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85009715660&partnerID=40&md5=31ab22f41de461eea2cac471fce1392e}
}
Wigneron J-P, Schwank M, Baeza E, Kerr Y, Novello N, Millan C, Moisy C, Richaume P, Mialon A, Al Bitar A, Cabot F, Lawrence H, Guyon D, Calvet J-C, Grant J, Casal T, de Rosnay P, Saleh K, Mahmoodi A, Delwart S and Mecklenburg S (2012), "First evaluation of the simultaneous SMOS and ELBARA-II observations in the Mediterranean region", Remote Sensing of Environment. Vol. 124, pp. 26-37.
Abstract: The SMOS (Soil Moisture and Ocean Salinity) mission was launched on November 2, 2009. Over the land surfaces, simultaneous retrievals of surface soil moisture (SM) and vegetation characteristics made from the multi-angular and dual polarization SMOS observations are now available from Level-2 (L2) products delivered by the European Space Agency (ESA). Therefore, first analyses evaluating the SMOS observations in terms of Brightness Temperatures (TB) and L2 products (SM and vegetation optical depth TAU) can be carried out over several calibration/validation (cal/val) sites selected by ESA over all continents. This study is based on SMOS observations and in situ measurements carried out in 2010 over one of the main SMOS cal/val sites in Europe: the VAS (Valencia Anchor Station) site in the region of Utiel-Requena, close to Valencia, Spain. The main vegetation types in the region are vineyards, orchards and natural Mediterranean vegetation. The SMOS observations were analyzed in conjunction with those carried out by the L-band ELBARA-II radiometer over a vineyard which is considered as representative of the main land use of the VAS site. Time series of TB and retrievals of SM and TAU based on both the SMOS (L2 products) and the ELBARA-II observations were compared and evaluated against in situ measurements. A good agreement was found between the time variations in TB and in the retrieved SM values computed over the site from the SMOS and ELBARA-II observations (the determination coefficient R 2 was >0.88 for the TB values and R 2>0.64 for the retrieved SM values). However, it was found that the SMOS L2 SM products underestimated the SM values retrieved from ELBARA-II by  0.2m 3/m 3. It is likely this offset can be partially explained by differences between the observed scenes: while the ELBARA-II footprint includes a single vineyard, the heterogeneous SMOS footprint includes not only a large number of vineyards but also a natural Mediterranean vegetation with persistent leaves overlaying rocky soils. The time variations in TAU retrieved from the ELBARA-II observations were found to be closely related to those of the NDVI (Normalized Difference Vegetation Index) vegetation index obtained from MODIS (Moderate Resolution Imaging Spectroradiometer) (R 2=0.61) and revealed the vegetation cycle over the year. Conversely, the time variations in the SMOS Level-2 TAU product did not reveal any trends in relation to the vegetation development over the site. 2012 Elsevier Inc.
BibTeX:
@article{Wigneron201226,
  author = {Wigneron, J.-P. and Schwank, M. and Baeza, E.L. and Kerr, Y. and Novello, N. and Millan, C. and Moisy, C. and Richaume, P. and Mialon, A. and Al Bitar, A. and Cabot, F. and Lawrence, H. and Guyon, D. and Calvet, J.-C. and Grant, J.P. and Casal, T. and de Rosnay, P. and Saleh, K. and Mahmoodi, A. and Delwart, S. and Mecklenburg, S.},
  title = {First evaluation of the simultaneous SMOS and ELBARA-II observations in the Mediterranean region},
  journal = {Remote Sensing of Environment},
  year = {2012},
  volume = {124},
  pages = {26-37},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861333665&doi=10.1016%2fj.rse.2012.04.014&partnerID=40&md5=76ead5b0f40e4ea23acfaac572a3543f},
  doi = {10.1016/j.rse.2012.04.014}
}
Brocard E, Schneebeli M and Matzler C (2011), "Detection of cirrus clouds using infrared radiometry", IEEE Transactions on Geoscience and Remote Sensing. Vol. 49(2), pp. 595-602.
Abstract: The detection of low-level clouds from ground-based infrared (IR) radiometry is usually based on the IR brightness temperature (IRBT) contrast between the warm clouds and the cold clear-sky background. This method works as long as the brightness temperature contrast subsists. It is not the case for cirrus clouds, which are usually optically thin and exhibit a low brightness temperature, comparable to that of clear sky in similar atmospheric conditions. In this paper, we propose a detection scheme to discriminate between clear sky and cirrus sky based on the fluctuations of the IRBT rather than on the absolute IRBT values. For this, we use the detrended fluctuation analysis (DFA) method on IRBT data when no liquid clouds were present. We compute the exponent α for nine IRBT time series covering clear- and cirrus-sky situations. We find that, for the fluctuation range of 1-5 min, α ≃ 0.1 for clear sky, α ≃ 0.5 for stratiform cirrus layers, and α ≃ 1 for broken cirrus layers. We suggest a threshold value of α = 0.25 for the discrimination between clear sky and cirrus sky. We also examine the relationship between DFA and the classical spectral analysis and find that spectral analysis could be an alternative to the DFA method in detecting the presence of cirrus clouds. 2006 IEEE.
BibTeX:
@article{Brocard2011595,
  author = {Brocard, E. and Schneebeli, M. and Matzler, C.},
  title = {Detection of cirrus clouds using infrared radiometry},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2011},
  volume = {49},
  number = {2},
  pages = {595-602},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79151471813&doi=10.1109%2fTGRS.2010.2063033&partnerID=40&md5=e56cde8cf5b983dc9eb1a3ed8aedda86},
  doi = {10.1109/TGRS.2010.2063033}
}
Cartus O, Santoro M, Schmullius C and Li Z (2011), "Large area forest stem volume mapping in the boreal zone using synergy of ERS-1/2 tandem coherence and MODIS vegetation continuous fields", Remote Sensing of Environment. Vol. 115(3), pp. 931-943.
Abstract: ERS-1/2 tandem coherence was reported to have high potential for the mapping of boreal forest stem volume (e.g. Santoro et al., 2002, 2007a; Wagner et al., 2003; Askne & Santoro, 2005). Large-scale application of the data for forest stem volume mapping, however, is hindered by the variability of coherence with meteorological and environmental acquisition conditions. The traditional way of stem volume retrieval is based on the training of models, relating coherence to stem volume, with the aid of forest inventory data which is generally available for a few small test sites but not for large areas. In this paper a new approach is presented that allows model training using the MODIS Vegetation Continuous Fields canopy cover product (Hansen et al., 2003) without further need for ground data. A comparison of the new approach with the traditional regression-based and ground-data dependent model training is presented in this paper for a multi-seasonal ERS-1/2 tandem dataset covering several well known Central Siberian forest sites. As a test scenario for large-area application, the approach was applied to a multi-seasonal ERS-1/2 tandem dataset of 223 ERS-1 and ERS-2 image pairs covering Northeast China ( 1.5millionkm2) to map four stem volume classes (0-20, 20-50, 50-80, and >80m3/ha). 2010 Elsevier Inc.
BibTeX:
@article{Cartus2011931,
  author = {Cartus, O. and Santoro, M. and Schmullius, C. and Li, Z.},
  title = {Large area forest stem volume mapping in the boreal zone using synergy of ERS-1/2 tandem coherence and MODIS vegetation continuous fields},
  journal = {Remote Sensing of Environment},
  year = {2011},
  volume = {115},
  number = {3},
  pages = {931-943},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651428989&doi=10.1016%2fj.rse.2010.12.003&partnerID=40&md5=55f8d0c5d614938d64eafa0821870111},
  doi = {10.1016/j.rse.2010.12.003}
}
Casu F, Manconi A, Pepe A and Lanari R (2011), "Deformation time-series generation in areas characterized by large displacement dynamics: The SAR amplitude pixel-offset SBAS technique", IEEE Transactions on Geoscience and Remote Sensing. Vol. 49(7), pp. 2752-2763.
Abstract: We exploit the amplitude information of a sequence of synthetic aperture radar (SAR) images, acquired at different times, in order to generate displacement time-series in areas characterized by large and/or rapid deformation, the size of which is on the order of the image's pixel dimensions. We follow the same rationale of the Small BAseline Subset (SBAS) differential SAR interferometry (DInSAR) approach, by coupling the available SAR images into pairs characterized by a small separation between the acquisition orbits. We exploit the amplitudes of the selected image pairs in order to calculate the relative across-track (range) and along-track (azimuth) pixel-offsets (PO). Finally, we apply the SBAS inversion strategy to retrieve the range and azimuth displacement time-series. This approach, referred to as pixel-offset (PO-) SBAS technique, has been applied to a set of 25 ENVISAT SAR observations of the Sierra Negra caldera, Galpagos Islands, spanning the 20032007 time interval. The retrieved deformation time-series show the capability of the technique to detect and measure the large displacements affecting the inner part of the caldera that, in correspondence to the October 2005 eruption, reached several meters. Moreover, by comparing the PO-SBAS results to continuous GPS measurements, we estimate that the accuracy of the PO-SBAS time-series is on the order of 1/30th of a pixel for both range and azimuth directions. 2011 IEEE.
BibTeX:
@article{Casu20112752,
  author = {Casu, F. and Manconi, A. and Pepe, A. and Lanari, R.},
  title = {Deformation time-series generation in areas characterized by large displacement dynamics: The SAR amplitude pixel-offset SBAS technique},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2011},
  volume = {49},
  number = {7},
  pages = {2752-2763},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79959733508&doi=10.1109%2fTGRS.2010.2104325&partnerID=40&md5=d25eceab52c1f3bde54992e7ae251be7},
  doi = {10.1109/TGRS.2010.2104325}
}
Dimitrov M, Vanderborght J, Jadoon K, Schwank M, Weihermueller L and Vereecken H (2011), "Closed loop brightness temperature data inversion for the retrieval of soil hydraulic properties", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1219-1222.
Abstract: We combined the radiative transfer approach to simulate L-band brightness temperatures at 1.4 GHz with a hydrological simulator (HYDRUS 1D) and a global optimization routine SCE-UA to estimate the Mualem van Genuchten (MVG) soil hydraulic parameters from time-lapse L-band brightness temperatures and in situ soil moisture measurements at different depths. The measurements were collected from a bare soil plot, prepared after ploughing. First, we briefly described the coupled inversion procedure and compared the results with measured brightness temperatures and in-situ soil moisture data. Second, estimated soil hydraulic parameters were compared with laboratory derived ones. The results suggest that the proposed method is promising for the effective characterization of the soil hydraulic properties and the determination of soil moisture within the top soil layer. 2011 IEEE.
BibTeX:
@conference{Dimitrov20111219,
  author = {Dimitrov, M. and Vanderborght, J. and Jadoon, K.Z. and Schwank, M. and Weihermueller, L. and Vereecken, H.},
  title = {Closed loop brightness temperature data inversion for the retrieval of soil hydraulic properties},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2011},
  pages = {1219-1222},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80955150909&doi=10.1109%2fIGARSS.2011.6049418&partnerID=40&md5=7c2cd7743b1d58523faadaf4bd3c93a2},
  doi = {10.1109/IGARSS.2011.6049418}
}
Frey O and Meier E (2011), "3-D time-domain SAR imaging of a forest using airborne multibaseline data at L-and P-bands", IEEE Transactions on Geoscience and Remote Sensing. Vol. 49(10 PART 1), pp. 3660-3664.
Abstract: In this paper, a time-domain back-projection based tomographic processing approach to a 3-D reconstruction grid is detailed, with the focusing in the third dimension being either modified versions of multilook standard beamforming, robust Capon beamforming, or multiple signal classification. The novel feature of the proposed approach compared to previous synthetic aperture radar (SAR) tomography approaches is that it allows for an approximation-free height-dependent calculation of the sample covariance matrix by exploiting the azimuth-focused data on the 3-D reconstruction grid. The method is applied to experimental multibaseline quad-pol SAR data at L-and P-bands acquired by German Aerospace Center's (DLR) E-SAR sensor: Tomographic images of a partially forested area, including a 3-D voxel plot that visualizes the very high level of detail of the tomographic image, are shown, and an analysis of the focusing performance is given for the full as well as reduced synthetic aperture in the normal direction. 2011 IEEE.
BibTeX:
@article{Frey20113660,
  author = {Frey, O. and Meier, E.},
  title = {3-D time-domain SAR imaging of a forest using airborne multibaseline data at L-and P-bands},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2011},
  volume = {49},
  number = {10 PART 1},
  pages = {3660-3664},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80053575857&doi=10.1109%2fTGRS.2011.2128875&partnerID=40&md5=5cca2b5db6982d3e938f2ae090b9fff2},
  doi = {10.1109/TGRS.2011.2128875}
}
Frey O and Meier E (2011), "Analyzing tomographic SAR data of a forest with respect to frequency, polarization, and focusing technique", IEEE Transactions on Geoscience and Remote Sensing. Vol. 49(10), pp. 3648-3659.
Abstract: Forest canopies are semitransparent to microwaves at both L-and P-bands. Thus, a number of scattering sources and different types of scattering mechanisms may contribute to a single range cell of a synthetic aperture radar (SAR) image. By appropriately combining the SAR data of multiple parallel flight paths, a large 2-D aperture is synthesized, which allows for tomographic imaging of the 3-D structure of such semitransparent media and the underlying ground. A separate paper deals with the actual tomographic imaging part that leads to the 3-D data cube. In particular, three focusing techniques are described and analyzed: multilook beamforming, robust Capon beamforming, and multiple signal classification beamforming. In this paper, the resulting data products obtained by tomographically focusing two airborne multibaseline SAR data sets of a partially forested area, one at L-band and another at P-band, are subject to a detailed analysis with respect to the location and the type of backscattering sources. In particular, the following aspects are investigated: 1) The forest structure, as obtained from the vertical profiles of intensities at sample plot locations within the forest, is compared to the height distribution of the top of the forest canopy, as derived from airborne laser scanning data, and profiles are presented for all polarimetric channels and focusing techniques, as well as at both frequencies; 2) the type and location of scattering mechanisms are analyzed as functions of height for the two frequencies, namely, L-and P-bands, and using the polarimetric channels, as well as the Pauli and Cloude-Pottier decompositions thereof; and 3) the accuracy of the ground elevation estimation obtained from the different focusing techniques and the two frequencies is assessed with the help of a lidar-derived digital elevation model. 2011 IEEE.
BibTeX:
@article{Frey20113648,
  author = {Frey, Othmar and Meier, E.},
  title = {Analyzing tomographic SAR data of a forest with respect to frequency, polarization, and focusing technique},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2011},
  volume = {49},
  number = {10},
  pages = {3648-3659},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80053571947&doi=10.1109%2fTGRS.2011.2125972&partnerID=40&md5=235dc7e32ff82cd05f01e984be26d31d},
  doi = {10.1109/TGRS.2011.2125972}
}
Frey O and Meier E (2011), "Characterizing the Backscattering Properties of a Forest by Polarimetric SAR Tomography at L- and P-Bands", In Proc. PolInSAR, 5th Int. Workshop on Science and Applications of SAR Polarimetry and Polarimetric Interferometry. Frascati, Italy, January, 2011.
BibTeX:
@inproceedings{freyMeierPolInsAR2011:Tomo,
  author = {Othmar Frey and Erich Meier},
  title = {Characterizing the Backscattering Properties of a Forest by Polarimetric SAR Tomography at L- and P-Bands},
  booktitle = {Proc. PolInSAR, 5th Int. Workshop on Science and Applications of SAR Polarimetry and Polarimetric Interferometry},
  year = {2011}
}
Frey O, Meier E and Hajnsek I (2011), "On the sensitivity of measured backscattering properties to variations of incidence angle and baselines in tomographic SAR data", In 2011 3rd International Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2011. , pp. 571-574.
Abstract: SAR tomography at L- and P-bands reveals 3-D structural information of forested areas. A drawback, however, are the large number of samples, i.e. overflights, typically used for such configurations. Based on two fully-polarimetric tomographic SAR data sets, at L- and P-bands, we analyze the sensitivity of backscattering from a forest volume as measured by means of SAR tomography with respect to (1) a reduction of the total baseline by subsequently reducing the number of baselines, and (2), with respect to a variation of the incidence angle. In this paper, an excerpt of this sensitivity analysis is presented and discussed. 2011 KIEES.
BibTeX:
@conference{Frey2011571,
  author = {Frey, O. and Meier, E. and Hajnsek, I.},
  title = {On the sensitivity of measured backscattering properties to variations of incidence angle and baselines in tomographic SAR data},
  booktitle = {2011 3rd International Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2011},
  year = {2011},
  pages = {571-574},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-83755182710&partnerID=40&md5=672b6aa8ad16d98dede786a2b84dd7df}
}
Graham E, Sarazin M and Matzler C (2011), "Using re-analysis model data to analyse climate trends related to the astroclimatology of Paranal and La Silla", In Revista Mexicana de Astronomia y Astrofisica: Serie de Conferencias. Vol. 41, pp. 12-15.
Abstract: This paper consists of a summary of the results of two separate research exercises. In the first part, the relationship between astronomical night-time viewing statistics (Seeing and Photometric Night Fraction) from ESO Paranal-La Silla observatories and thirty-five ERA-40 and NCEP-NCEP re-analyses variables (available with the FriOWL software) were examined for correlation, using data from the re-analysis model gridpoint closest to the two observatories. The results confirm that the photometric night fraction datasets of both observatories are better described than are the seeing datasets. The strongest relationships are found at La Silla due to its more southerly, baroclinic location. Interestingly, the NOAA outgoing longwave radiation (OLR) dataset performs equally well, or better than its equivalent ERA40 re-analyses cloud cover dataset. In second part of this study, the FriOWL tool was used in an analysis of the climatology of northern Chile region, to help determine the cause of a deterioration in astronomical seeing conditions at Paranal from 1998 onwards. The results show that an exceptional increase in lOOOhPa geopotential height has occurred to the south-east of Paranal over the 1998-2007 period, when compared to the previous nine-year period. This increase is not replicated at the 700, 500 or 200 hPa levels, however. A shift south in the axis of near-surface geopotential heights from 21°S to 25-27°S has also occurred over the same period. Furthermore, there appears to be a link between phase shifts of the Interdecadal Pacific Oscillation, and atmospheric circulation anomalies over the Pacific region. 2011: Instituto de Astronomía, UNAM - Astronomical Site Testing Data in Chile Ed. M. Cure, A. Otárola, J. Marín, & M. Sarazin.
BibTeX:
@conference{Graham201112,
  author = {Graham, E. and Sarazin, M. and Matzler, C.},
  title = {Using re-analysis model data to analyse climate trends related to the astroclimatology of Paranal and La Silla},
  booktitle = {Revista Mexicana de Astronomia y Astrofisica: Serie de Conferencias},
  year = {2011},
  volume = {41},
  pages = {12-15},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878312608&partnerID=40&md5=c067dec3f4a34f8c41a97aca91a4afb8}
}
Grenerczy G and Wegmüller U (2011), "Persistent scatterer interferometry analysis of the embankment failure of a red mud reservoir using ENVISAT ASAR data", Natural Hazards. Vol. 59(2), pp. 1047-1053.
Abstract: On October 4, 2010, the embankment of No. 10 red mud-waste product during bauxite refining-reservoir of MAL Co. Ltd. alumina plant collapsed. Around 700 000 cubic meter of alkaline slurry with 11-13 pH value flooded three nearby settlements. Ten people were killed, 123 wounded, and about 350 houses were damaged or became uninhabitable in one of the biggest industrial and ecological catastrophe in modern history of Hungary. Synthetic aperture radar interferometry (InSAR) is the only geodetic technique that can reveal the past stability and motion history of the broken reservoir. We performed a persistent scatterer InSAR (PSI) analysis to contribute to the better understanding of the disaster. The key question we address in this study is whether there were signs prior to October 4th event which may have prognosticated the disaster. The PSI results could reveal if the dam was stable in the past without prior signs of the failure or there were definite indications of deformation before the collapse and proper monitoring of motions could have highlighted the risk and the disaster may have been prevented. This is a rare event and its PSI study is unique and may be critical in understanding it and helping to prevent other similar occurrences. 2011 Springer Science+Business Media B.V.
BibTeX:
@article{Grenerczy20111047,
  author = {Grenerczy, G. and Wegmüller, U.},
  title = {Persistent scatterer interferometry analysis of the embankment failure of a red mud reservoir using ENVISAT ASAR data},
  journal = {Natural Hazards},
  year = {2011},
  volume = {59},
  number = {2},
  pages = {1047-1053},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80053563595&doi=10.1007%2fs11069-011-9816-6&partnerID=40&md5=e1e745dd74bb5eeb26ad5745d5c559cc},
  doi = {10.1007/s11069-011-9816-6}
}
Guglielmino F, Bignami C, Bonforte A, Briole P, Obrizzo F, Puglisi G, Stramondo S and Wegmüller U (2011), "Analysis of satellite and in situ ground deformation data integrated by the SISTEM approach: The April 3, 2010 earthquake along the Pernicana fault (Mt. Etna - Italy) case study", Earth and Planetary Science Letters. Vol. 312(3-4), pp. 327-336.
Abstract: Etna is known worldwide as one of the most studied and monitored active volcanoes. Flank instability along the eastern and southern portions of Mt. Etna has been observed and measured thanks to geodetic networks and InSAR data analysis. The spreading area is bordered to the north by the east-west Pernicana Fault System (PFS) whose dynamics is often linked with the eruptive activity, as recently observed during the 2002-2003 eruption. A seismic sequence occurred from April 2-3, 2010, along the PFS with very shallow (a few hundred meters) mainshocks of magnitude 4.3 and 3.6. Explosions and ash emissions at the summit craters followed this swarm culminating a few days later (April 7-8). Despite their small magnitude, the earthquakes caused damage and significant surface fracturing along the PFS. In order to investigate and measure the deformations in the near field of the earthquakes, the SISTEM integration approach has been exploited. The SISTEM enabled integrating geodetic in situ ground deformation measurements (GPS and leveling) with satellite interferometric measurements (ENVISAT and ALOS), in order to obtain high resolution 3D displacement maps, allowing to overcome the limitations of each technique and take advantage of the particular features of each of them. The integrated ground deformation field evidenced that the medium behave elastically. We inverted the SISTEM results using an optimization algorithm based on the Genetic Algorithm (GA) in order to model the kinematics of the PFS associated to seismic swarm; the results are in good agreement with the field evidence and improved the knowledge on the kinematics of the PFS and Mt. Etna's unstable flank. 2011 Elsevier B.V.
BibTeX:
@article{Guglielmino2011327,
  author = {Guglielmino, F. and Bignami, C. and Bonforte, A. and Briole, P. and Obrizzo, F. and Puglisi, G. and Stramondo, S. and Wegmüller, U.},
  title = {Analysis of satellite and in situ ground deformation data integrated by the SISTEM approach: The April 3, 2010 earthquake along the Pernicana fault (Mt. Etna - Italy) case study},
  journal = {Earth and Planetary Science Letters},
  year = {2011},
  volume = {312},
  number = {3-4},
  pages = {327-336},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-81255166168&doi=10.1016%2fj.epsl.2011.10.028&partnerID=40&md5=ded9f6748fdc31b40608f6d683cd0b78},
  doi = {10.1016/j.epsl.2011.10.028}
}
Hocke K, Kampfer N, Gerber C and Matzler C (2011), "A complete long-term series of integrated water vapour from ground-based microwave radiometers", International Journal of Remote Sensing. Vol. 32(3), pp. 751-765. Taylor and Francis Ltd..
Abstract: Integrated water vapour (IWV) is the vertical column density of atmospheric water vapour. IWV can be determined from microwave radiances measured by multi-channel radiometers on the ground or in space. Both quality and quantity of IWV measurements have rapidly increased during the past 10 to 20 years. Global maps and time series of IWV give evidence for a strong spatio-temporal variability of atmospheric water vapour, playing a key role in weather prediction and climate-change research. We analyse the relationships between microwave radiances and IWV using long-term observations of two radiometers at Bern, Switzerland. The first radiometer (Tropospheric Water Vapour Radiometer; TROWARA) measures 21 and 31 GHz radiances and permits the accurate retrieval of IWV. The long-term series of the TROWARA have some data gaps that possibly influence the trend analysis. On the other hand, the series of 142 GHz radiance of the second radiometer (Ground-based Millimeter-wave Ozone Spectrometer; GROMOS) are almost complete. The 142 GHz radiance is more affected by integrated cloud liquid water (ILW) than the 21 and 31 GHz radiances. The coincident radiometer data of GROMOS and TROWARA are utilized for exploration of the relationship between 142 GHz radiance, IWV and ILW. The IWV is calculated from the 142 GHz radiance of GROMOS when TROWARA data are not available. Thus, we can derive a complete series of IWV above Bern from 1994 to 2009. The combination of both series and the trend analysis are performed by means of multiple linear regression and bootstrapping. The observations indicate a positive trend up to +10% decade-1 of IWV in summer and a negative trend of about -15% decade-1 in winter. 2011 Taylor & Francis.
BibTeX:
@article{Hocke2011751,
  author = {Hocke, K. and Kampfer, N. and Gerber, C. and Matzler, C.},
  title = {A complete long-term series of integrated water vapour from ground-based microwave radiometers},
  journal = {International Journal of Remote Sensing},
  publisher = {Taylor and Francis Ltd.},
  year = {2011},
  volume = {32},
  number = {3},
  pages = {751-765},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952400280&doi=10.1080%2f01431161.2010.517792&partnerID=40&md5=c87e067eba743ff5010a8b0105a2520c},
  doi = {10.1080/01431161.2010.517792}
}
Jonard F, Weihermuller L, Jadoon K, Schwank M, Vereecken H and Lambot S (2011), "Mapping field-scale soil moisture with L-band radiometer and ground-penetrating radar over bare soil", IEEE Transactions on Geoscience and Remote Sensing. Vol. 49(8), pp. 2863-2875.
Abstract: Accurate estimates of surface soil moisture are essential in many research fields, including agriculture, hydrology, and meteorology. The objective of this study was to evaluate two remote-sensing methods for mapping the soil moisture of a bare soil, namely, L-band radiometry using brightness temperature and ground-penetrating radar (GPR) using surface reflection inversion. Invasive time-domain reflectometry (TDR) measurements were used as a reference. A field experiment was performed in which these three methods were used to map soil moisture after controlled heterogeneous irrigation that ensured a wide range of water content. The heterogeneous irrigation pattern was reasonably well reproduced by both remote-sensing techniques. However, significant differences in the absolute moisture values retrieved were observed. This discrepancy was attributed to different sensing depths and areas and different sensitivities to soil surface roughness. For GPR, the effect of roughness was excluded by operating at low frequencies (0.2-0.8 GHz) that were not sensitive to the field surface roughness. The root mean square (rms) error between soil moisture measured by GPR and TDR was 0.038 m3 · m-3. For the radiometer, the rms error decreased from 0.062 (horizontal polarization) and 0.054 (vertical polarization) to 0.020 m3 · m-3 (both polarizations) after accounting for roughness using an empirical model that required calibration with reference TDR measurements. Monte Carlo simulations showed that around 20% of the reference data were required to obtain a good roughness calibration for the entire field. It was concluded that relatively accurate measurements were possible with both methods, although accounting for surface roughness was essential for radiometry. 2011 IEEE.
BibTeX:
@article{Jonard20112863,
  author = {Jonard, F. and Weihermuller, L. and Jadoon, K.Z. and Schwank, M. and Vereecken, H. and Lambot, S.},
  title = {Mapping field-scale soil moisture with L-band radiometer and ground-penetrating radar over bare soil},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2011},
  volume = {49},
  number = {8},
  pages = {2863-2875},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960907712&doi=10.1109%2fTGRS.2011.2114890&partnerID=40&md5=a30221b2cdbf4af873bee37cd14ecb66},
  doi = {10.1109/TGRS.2011.2114890}
}
Jonard F, Weihermuller L, Schwank M, Vereecken H and Lambot S (2011), "Soil moisture retrieval using L-band radiometer and ground-penetrating radar", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3093-3096.
Abstract: The objective of this study was to evaluate two remote-sensing methods for mapping the surface soil moisture of a bare soil, namely L-band radiometry using brightness temperature and ground-penetrating radar (GPR) using surface reflection inversion. Invasive time-domain reflectometry (TDR) measurements were used as a reference. A field experiment was performed in which these three methods were used to map soil moisture after controlled heterogeneous irrigation that ensured a wide range of water content. The heterogeneous irrigation pattern was reasonably well reproduced by both remote-sensing techniques. For GPR, the effect of roughness was excluded by operating at low frequencies (0.2-0.8 GHz) that were not sensitive to the field surface roughness. For the radiometer, the effect of roughness was accounted for using an empirical model that required calibration with the reference TDR measurements. The root mean square (RMS) error between soil moisture measured by GPR and TDR was 0.038 m3 m- while the RMS error between radiometer (horizontal and vertical polarizations)- and TDR-derived soil water content was 0.020 m 3 m-3. These results suggest that both remote-sensing techniques are promising for field-scale mapping of surface soil moisture over bare soils. 2011 IEEE.
BibTeX:
@conference{Jonard20113093,
  author = {Jonard, F. and Weihermuller, L. and Schwank, M. and Vereecken, H. and Lambot, S.},
  title = {Soil moisture retrieval using L-band radiometer and ground-penetrating radar},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2011},
  pages = {3093-3096},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80955159758&doi=10.1109%2fIGARSS.2011.6049872&partnerID=40&md5=bbc4cceff16407eaf117b952941e5edd},
  doi = {10.1109/IGARSS.2011.6049872}
}
Lemmetyinen J, Pulliainen J, Arslan A, Kontu A, Rautiainen K, Vehvilainen J, Wiesmann A, Nagler T, Rott H, Davidson M, Schuettemeyer D and Kern M (2011), "Analysis of active and passive microwave observations from the NoSREx campaign", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 2737-2740.
Abstract: The acquisition of Snow Water Equivalent (SWE) at spatial resolutions higher than those of the present methods relying on inversion of coarse-scale passive microwave observations is a possible application for space-borne SAR imagery. The presented experimental campaign NoSREx (Nordic Snow Radar Experiment) was initiated to contribute to the knowledge of snowpack backscattering and emission properties, in particular, to help develop methods to retrieve SWE from high-resolution two-frequency SAR observations (at X and Ku band). Another objective was to provide data for studies exploring the synergistic use of active and passive microwave observations for monitoring of snow properties. The NoSREx campaign began in November 2009, and has recently concluded a second winter period of observations. 2011 IEEE.
BibTeX:
@conference{Lemmetyinen20112737,
  author = {Lemmetyinen, J. and Pulliainen, J. and Arslan, A. and Kontu, A. and Rautiainen, K. and Vehvilainen, J. and Wiesmann, A. and Nagler, T. and Rott, H. and Davidson, M. and Schuettemeyer, D. and Kern, M.},
  title = {Analysis of active and passive microwave observations from the NoSREx campaign},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2011},
  pages = {2737-2740},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80955139550&doi=10.1109%2fIGARSS.2011.6049780&partnerID=40&md5=30b209adc2c8c2271127e46ecaf18110},
  doi = {10.1109/IGARSS.2011.6049780}
}
Parde M, J.-P. W, Zribi M, Kerr Y, Fanise P, Calvet J-C, Albergel C, Albitar A, Cabot F, Demontoux F, Jacquette E, Lopez-Baeza E, Mialon A, Moisy C, Novello N, Richaume P, Saleh K, Schwank M, Waldteufel P, Zakharova E and Dechambre M (2011), "Retrievals of soil moisture and optical depth from CAROLS", In Progress in Electromagnetics Research Symposium. , pp. 80-84.
Abstract: We propose in this paper to evaluate a method to retrieve soil moisture (SM) and vegetation optical thickness, in areas of unknown roughness and unknown vegetation water content in view of operational applications, by using airborne Tb measurements acquired in South-West of France. Results are compared to in situ measurements, manual and automatic ones included in SMOSmania network, in the South-West of France.
BibTeX:
@conference{Parde201180,
  author = {Parde, M. and Wigneron J.-P. and Zribi, M. and Kerr, Y. and Fanise, P. and Calvet, J.-C. and Albergel, C. and Albitar, A. and Cabot, F. and Demontoux, F. and Jacquette, E. and Lopez-Baeza, E. and Mialon, A. and Moisy, C. and Novello, N. and Richaume, P. and Saleh, K. and Schwank, M. and Waldteufel, P. and Zakharova, E. and Dechambre, M.},
  title = {Retrievals of soil moisture and optical depth from CAROLS},
  booktitle = {Progress in Electromagnetics Research Symposium},
  year = {2011},
  pages = {80-84},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84055184129&partnerID=40&md5=d62ed9503f9179f1552cbabf09b6a774}
}
Pettersson R, Christoffersen P, Dowdeswell J, Pohjola V, Hubbard A and Strozzi T (2011), "Ice Thickness and Basal Conditions of Vestfonna Ice Cap, Eastern Svalbard", Geografiska Annaler, Series A: Physical Geography. Vol. 93(4), pp. 311-322.
Abstract: We combined ground-based pulsed radar data collected in 2008-2009 with airborne radio-echo sounding data acquired in 1983 and 1986 over Vestfonna ice cap, Svalbard. The airborne dataset mainly covers the fast-flowing outlet glaciers and the marginal zone, while the ground-based data explicitly cover the interior part of the ice cap. The data presented here are thus the first complete estimate of bed topography and ice thickness. The subglacial landscape undulates with elevations between -160 and +410m above sea level. The mean ice thickness is 186m and the total ice area and volume are 2402km2 and 442±0.6km3, respectively. This is a much smaller volume than those derived from empirical volume-area scaling relationships currently used to estimate regional-to-global glacier volumes. This difference may depend on local conditions for Vestfonna and emphasizes the need to include more volume observations in the derivations of volume-area scaling parameters. We also derive basal reflectivity as a proxy for thermal conditions at the bed. Basal reflectivity values suggest that fast-flowing outlet glaciers are underlain by temperate conditions. The geometric boundaries and basal conditions for Vestfonna will be critical additions to the development of numerical models of the ice cap and to the estimation of more accurate area-volume scaling parameters. The authors 2011. Geografiska Annaler: Series A, Physical Geography 2011 Swedish Society for Anthropology and Geography.
BibTeX:
@article{Pettersson2011311,
  author = {Pettersson, R. and Christoffersen, P. and Dowdeswell, J.A. and Pohjola, V.A. and Hubbard, A. and Strozzi, T.},
  title = {Ice Thickness and Basal Conditions of Vestfonna Ice Cap, Eastern Svalbard},
  journal = {Geografiska Annaler, Series A: Physical Geography},
  year = {2011},
  volume = {93},
  number = {4},
  pages = {311-322},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-83055166294&doi=10.1111%2fj.1468-0459.2011.00438.x&partnerID=40&md5=794a5de6ab77b19dca220e1054d8ae31},
  doi = {10.1111/j.1468-0459.2011.00438.x}
}
Pohjola V, Christoffersen P, Kolondra L, Moore J, Pettersson R, Schafer M, Strozzi T and Reijmer C (2011), "Spatial Distribution and Change in the Surface Ice-Velocity Field of Vestfonna Ice Cap, Nordaustlandet, Svalbard, 1995-2010 Using Geodetic and Satellite Interferometry Data", Geografiska Annaler, Series A: Physical Geography. Vol. 93(4), pp. 323-335.
Abstract: During 2007 we launched a geodetic campaign on the Svalbard ice cap Vestfonna in order to estimate the velocity field of the ice cap. This was done within the frame of the IPY project KINNVIKA. We present here the velocity measurements derived from our campaigns 2007-2010 and compare the geodetic measurements against InSAR velocity fields from satellite platforms from 1995/96 and 2008. We find the spatial distribution of ice speeds from the InSAR is in good agreement within the uncertainty limits with our geodetic measurements. We observe no clear indication of seasonal ice speed differences, but we find a speed-up of the outlet glacier Franklinbreen between the InSAR campaigns, and speculate the outlet is having a surge phase. The authors 2011. Geografiska Annaler: Series A, Physical Geography 2011 Swedish Society for Anthropology and Geography.
BibTeX:
@article{Pohjola2011323,
  author = {Pohjola, V.A. and Christoffersen, P. and Kolondra, L. and Moore, J.C. and Pettersson, R. and Schafer, M. and Strozzi, T. and Reijmer, C.H.},
  title = {Spatial Distribution and Change in the Surface Ice-Velocity Field of Vestfonna Ice Cap, Nordaustlandet, Svalbard, 1995-2010 Using Geodetic and Satellite Interferometry Data},
  journal = {Geografiska Annaler, Series A: Physical Geography},
  year = {2011},
  volume = {93},
  number = {4},
  pages = {323-335},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-83055169887&doi=10.1111%2fj.1468-0459.2011.00441.x&partnerID=40&md5=b6429873a51f16d1bc99d9598d2bc2bc},
  doi = {10.1111/j.1468-0459.2011.00441.x}
}
Riesen P, Strozzi T, Bauder A, Wiesmann A and Funk M (2011), "Short-term surface ice motion variations measured with a ground-based portable real aperture radar Interferometer", Journal of Glaciology. Vol. 57(201), pp. 53-60.
Abstract: We report measurements using a portable real aperture radar (Gamma Portable Radar Interferometer (GPRI)) for interferometric imaging of the surface ice motion on Gornergletscher, Switzerland, during the drainage of the adjacent ice-marginal lake Gornersee. The GPRI tracked the surface ice motion in line of sight over an area of ∼3 km2 down-glacier of Gornersee almost continuously during the drainage event. The displacement maps derived from the acquired interferograms capture the spatial distribution of the surface ice motion. Due to fast acquisition times of the microwave images, the GPRI was able to record sub-daily variations of the ice displacements, most likely caused by the impact of the Gornersee drainage on the ice motion of Gornergletscher. In situ point measurements of the ice displacement agree reasonably well with the results obtained by the GPRI and highlight the use of the GPRI for high-resolution measurements of glacier surface ice motion.
BibTeX:
@article{Riesen201153,
  author = {Riesen, P. and Strozzi, T. and Bauder, A. and Wiesmann, A. and Funk, M.},
  title = {Short-term surface ice motion variations measured with a ground-based portable real aperture radar Interferometer},
  journal = {Journal of Glaciology},
  year = {2011},
  volume = {57},
  number = {201},
  pages = {53-60},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79958851547&doi=10.3189%2f002214311795306718&partnerID=40&md5=fba331e211206fb476eeb14e864963eb},
  doi = {10.3189/002214311795306718}
}
Santoro M, Beer C, Cartus O, Schmullius C, Shvidenko A, McCallum I, Wegmüller U and Wiesmann A (2011), "Retrieval of growing stock volume in boreal forest using hyper-temporal series of Envisat ASAR ScanSAR backscatter measurements", Remote Sensing of Environment. Vol. 115(2), pp. 490-507.
Abstract: Methods for the estimation of forest growing stock volume (GSV) are a major topic of investigation in the remote sensing community. The boreal zone contains almost 30% of global forest by area but measurements of forest resources are often outdated. Although past and current spaceborne synthetic aperture radar (SAR) backscatter data are not optimal for forest-related studies, a multi-temporal combination of individual GSV estimates can improve the retrieval as compared to the single-image case. This feature has been included in a novel GSV retrieval approach, hereafter referred to as the BIOMASAR algorithm. One innovative aspect of the algorithm is its independence from in situ measurements for model training. Model parameter estimates are obtained from central tendency statistics of the backscatter measurements for unvegetated and dense forest areas, which can be selected by means of a continuous tree canopy cover product, such as the MODIS Vegetation Continuous Fields product. In this paper, the performance of the algorithm has been evaluated using hyper-temporal series of C-band Envisat Advanced SAR (ASAR) images acquired in ScanSAR mode at 100m and 1km pixel size. To assess the robustness of the retrieval approach, study areas in Central Siberia (Russia), Sweden and Quebec (Canada) have been considered. The algorithm validation activities demonstrated that the automatic approach implemented in the BIOMASAR algorithm performed similarly to traditional approaches based on in situ data. The retrieved GSV showed no saturation up to 300m3/ha, which represented almost the entire range of GSV at the study areas. The relative root mean square error (RMSE) was between 34.2% and 48.1% at 1km pixel size. Larger errors were obtained at 100m because of local errors in the reference datasets. Averaging GSV estimates over neighboring pixels improved the retrieval statistics substantially. For an aggregation factor of 10×10pixels, the relative RMSE was below 25%, regardless of the original resolution of the SAR data. 2010 Elsevier Inc.
BibTeX:
@article{Santoro2011490,
  author = {Santoro, M. and Beer, C. and Cartus, O. and Schmullius, C. and Shvidenko, A. and McCallum, I. and Wegmüller, U. and Wiesmann, A.},
  title = {Retrieval of growing stock volume in boreal forest using hyper-temporal series of Envisat ASAR ScanSAR backscatter measurements},
  journal = {Remote Sensing of Environment},
  year = {2011},
  volume = {115},
  number = {2},
  pages = {490-507},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650875602&doi=10.1016%2fj.rse.2010.09.018&partnerID=40&md5=87625818a6dee66014cfd92a9fdd52d6},
  doi = {10.1016/j.rse.2010.09.018}
}
Schmitt M, Magnard C, Brehm T and Stilla U (2011), "Towards airborne single pass decimeter resolution SAR interferometry over urban areas", Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). Vol. 6952 LNCS, pp. 197-208.
Abstract: Airborne cross-track Synthetic Aperture Radar interferometers have the capability of deriving three-dimensional topographic information with just a single pass over the area of interest. In order to get a highly accurate height estimation, either a large interferometric baseline or a high radar frequency has to be used. The utilization of a millimeter wave SAR allows precise height estimation even for short baselines. Combined with a spatial resolution in the decimeter range, this enables the mapping of urban areas from airborne platforms. The side-looking SAR imaging geometry, however, leads to disturbing effects like layover and shadowing, which is even intensified by the shallow looking angle caused by the relatively low altitudes of airborne SAR systems. To solve this deficiency, enhanced InSAR processing strategies relying on multi-aspect and multi-baseline data, respectively, are shown to be necessary. 2011 Springer-Verlag.
BibTeX:
@article{Schmitt2011197,
  author = {Schmitt, M. and Magnard, C. and Brehm, T. and Stilla, U.},
  title = {Towards airborne single pass decimeter resolution SAR interferometry over urban areas},
  journal = {Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)},
  year = {2011},
  volume = {6952 LNCS},
  pages = {197-208},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80054014373&doi=10.1007%2f978-3-642-24393-6_17&partnerID=40&md5=35be4398f2c1af10c60f6378787decc7},
  doi = {10.1007/978-3-642-24393-6_17}
}
Schneebeli M and Matzler C (2011), "A radiative transfer model for an idealized and non-scattering atmosphere and its application for ground-based remote sensing", Journal of Quantitative Spectroscopy and Radiative Transfer. Vol. 112(5), pp. 883-892.
Abstract: Inversion of tropospheric profiles from ground-based microwave measurements requires a simple and accurate model for calculating the brightness temperatures as received by the radiometer. In the first part, an analytic solution of the radiative transfer equation is derived for an exponentially decaying absorption coefficient and a linear temperature gradient. Based on the obtained analytic expressions, a discretized radiative transfer scheme is developed in the second part. The new scheme incorporates the generic behavior of the atmosphere with the effect that brightness temperatures can be modeled more accurately and with fewer grid points compared to commonly used radiative transfer schemes. The brightness temperature modeling accuracy was improved by a factor of six. The results suggest that the model could be employed for the retrieval of temperature and humidity profiles. 2010 Elsevier Ltd.
BibTeX:
@article{Schneebeli2011883,
  author = {Schneebeli, M. and Matzler, C.},
  title = {A radiative transfer model for an idealized and non-scattering atmosphere and its application for ground-based remote sensing},
  journal = {Journal of Quantitative Spectroscopy and Radiative Transfer},
  year = {2011},
  volume = {112},
  number = {5},
  pages = {883-892},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79451471808&doi=10.1016%2fj.jqsrt.2010.10.018&partnerID=40&md5=60d7b0a143f6713cb5a68977c29b86f9},
  doi = {10.1016/j.jqsrt.2010.10.018}
}
Schneebeli M and Matzler C (2011), "Spatiotemporal behavior of integrated water vapor", IEEE Geoscience and Remote Sensing Letters. Vol. 8(5), pp. 948-952.
Abstract: A time series of the hemispheric distribution of integrated water vapor (IWV) measured with the All-Sky Multi Wavelength Radiometer is analyzed by means of empirical orthogonal functions (EOFs). The data were acquired in February 2007 at the Zimmerwald Observatory in Switzerland. It is shown that the analysis of temporally demeaned time series yields information about passing fronts. With EOF analysis of the spatially demeaned time series, information about the spatial distribution of IWV is obtained. Our results also indicate that water vapor behaves like a conservative and passive tracer within the examined sampling volume and with the given temporal sampling resolution of 12 min. 2011 IEEE.
BibTeX:
@article{Schneebeli2011948,
  author = {Schneebeli, M. and Matzler, C.},
  title = {Spatiotemporal behavior of integrated water vapor},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  year = {2011},
  volume = {8},
  number = {5},
  pages = {948-952},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80052341299&doi=10.1109%2fLGRS.2011.2144562&partnerID=40&md5=2d2f7ec46334ec761500285eccc1554c},
  doi = {10.1109/LGRS.2011.2144562}
}
Schneebeli M, Wolf S, Kunert N, Eugster W and Matzler C (2011), "Relating the X-band opacity of a tropical tree canopy to sapflow, rain interception and dew formation", Remote Sensing of Environment. Vol. 115(8), pp. 2116-2125.
Abstract: During summer and autumn 2007, a 11. GHz microwave radiometer was deployed in an experimental tree plantation in Sardinilla, Panama. The opacity of the tree canopy was derived from incoming brightness temperatures received on the ground. A collocated eddy-covariance flux tower measured water vapor fluxes and meteorological variables above the canopy. In addition, xylem sapflow of trees was measured within the flux tower footprint. We observed considerable diurnal differences between measured canopy opacities and modeled theoretical opacities that were closely linked to xylem sapflow. It is speculated that dielectric changes in the leaves induced by the sapflow are causing the observed diurnal changes. In addition, canopy intercepted rain and dew formation also modulated the diurnal opacity cycle. With an enhanced canopy opacity model accounting for water deposited on the leaves, we quantified the influence of canopy stored water (i.e. intercepted water and dew) on the opacity. A time series of dew formation and rain interception was directly monitored during a period of two weeks. We found that during light rainfall up to 60% of the rain amount is intercepted by the canopy whereas during periods of intense rainfall only 4% were intercepted. On average, 0.17. mm of dew was formed during the night. Dew evaporation contributed 5% to the total water vapor flux measured above the canopy. 2011 Elsevier Inc.
BibTeX:
@article{Schneebeli20112116,
  author = {Schneebeli, M. and Wolf, S. and Kunert, N. and Eugster, W. and Matzler, C.},
  title = {Relating the X-band opacity of a tropical tree canopy to sapflow, rain interception and dew formation},
  journal = {Remote Sensing of Environment},
  year = {2011},
  volume = {115},
  number = {8},
  pages = {2116-2125},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79957691036&doi=10.1016%2fj.rse.2011.04.016&partnerID=40&md5=bf7c405aab16f6de233cefaa22d16ce9},
  doi = {10.1016/j.rse.2011.04.016}
}
Stahli O, Matzler C, Murk A and Kampfer N (2011), "A surface-based imaging method for water vapor and liquid clouds using a scanning radiometer at 91 GHz", IEEE Transactions on Geoscience and Remote Sensing. Vol. 49(9), pp. 3273-3280.
Abstract: The Scanning Polarimetric Imaging RAdiometer a 91 GHz with an angular resolution of 0.5 circ was used to investigate the dynamics of the atmosphere. We introduced a new imaging method by continuously scanning the sky over a range of elevation angles in a fixed azimuth direction. The measurements were realized during three different situations: clear sky, sky with water clouds, and sky with cirrus clouds. In most situations, the scan direction was nearly parallel to the mean atmospheric flow. Particularly interesting structures were found in the images with water clouds. In contrast, cirrus clouds are highly transparent. Simulations of the applied imaging method helped to interpret the cloud images, particularly concerning the cloud movement. Characteristic shapes were identified as signatures of motions along the scan line, which were used to estimate the horizontal velocity of water clouds. It was also possible to estimate the integrated water vapor from the clear sky images. They allow a visualization of water vapor parcels. Some of these images contain similar signatures as the clouds, indicating advection of water vapor along the scan line. In the future, we plan to extend these measurements and to combine them with multifrequency observations. 2011 IEEE.
BibTeX:
@article{Stahli20113273,
  author = {Stahli, O. and Matzler, C. and Murk, A. and Kampfer, N.},
  title = {A surface-based imaging method for water vapor and liquid clouds using a scanning radiometer at 91 GHz},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2011},
  volume = {49},
  number = {9},
  pages = {3273-3280},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80052329808&doi=10.1109%2fTGRS.2011.2160269&partnerID=40&md5=cafae5e293c9de4ecfeb5a4707ea4a84},
  doi = {10.1109/TGRS.2011.2160269}
}
Strozzi T, Delaloye R, Poffet D, Hansmann J and Loew S (2011), "Surface subsidence and uplift above a headrace tunnel in metamorphic basement rocks of the Swiss Alps as detected by satellite SAR interferometry", Remote Sensing of Environment. Vol. 115(6), pp. 1353-1360.
Abstract: Surface subsidence associated with the construction of a headrace tunnel in the Swiss Alps at more than 2000 m above sea level (a.s.l.) has been detected at two locations with satellite differential Synthetic Aperture Radar (SAR) interferometry. At the first location, a subsidence trough of about 4 cm in the satellite line-of-sight direction following the headrace tunnel axes has been measured between August 1995 and August 1996. Similar values from SAR data of ascending and descending orbits indicate displacements in the vertical direction of the movement. In the second case, a symmetric cone of depression with a maximum displacement of about 4 cm between 1995 and 1997 has been observed above the tunnel. Differences in the results from satellite SAR data of ascending and descending orbits indicate that the direction of displacement in this second case was not entirely vertical. Large-scale consolidation associated with pore-pressure reduction in the rock mass arising from tunnel drainage at about 200-400 m depth beneath the topographical surface is believed to be the contributing mechanism (Zangerl et al., 2008a, 2008b). Evidence for this process is based on pore pressure recordings in nearby deep wells. In both areas, the subsidence was followed by a small uplift of about one centimeter between 1997 and 1999, after the tunnel was cased with permeable concrete segments. This partial recovery is also visible in pore pressure records and can be related to the elastic components of rock mass deformation. 2011 Elsevier Inc.
BibTeX:
@article{Strozzi20111353,
  author = {Strozzi, T. and Delaloye, R. and Poffet, D. and Hansmann, J. and Loew, S.},
  title = {Surface subsidence and uplift above a headrace tunnel in metamorphic basement rocks of the Swiss Alps as detected by satellite SAR interferometry},
  journal = {Remote Sensing of Environment},
  year = {2011},
  volume = {115},
  number = {6},
  pages = {1353-1360},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953166717&doi=10.1016%2fj.rse.2011.02.001&partnerID=40&md5=5a56c9e16b287e4237e0d65922455bbb},
  doi = {10.1016/j.rse.2011.02.001}
}
Tanase M, de la Riva J, Santoro M, Pérez-Cabello F and Kasischke E (2011), "Sensitivity of SAR data to post-fire forest regrowth in Mediterranean and boreal forests", Remote Sensing of Environment. Vol. 115(8), pp. 2075-2085.
Abstract: Disturbed forests may need decades to reach a mature stage and optically-based vegetation indices are usually poorly suited for monitoring purposes due to the rapid saturation of the signal with increasing canopy cover. Spaceborne synthetic aperture radar (SAR) data provide an alternate monitoring approach since the backscattered microwave energy is sensitive to the vegetation structure. Images from two regions in Spain and Alaska were used to analyze SAR metrics (cross-polarized backscatter and co-polarized interferometric coherence) from regrowing forests previously affected by fire. TerraSAR-X X-band backscatter showed the lowest sensitivity to forest regrowth, with the average backscatter increasing by 1-2. dB between the most recent fire scar and the unburned forest. Increased sensitivity (around 3-4. dB) was observed for C-band Envisat Advanced Synthetic Aperture (ASAR) backscatter. The Advanced Land Observing Satellite (ALOS) Phased Array-type L-band Synthetic Aperture Radar (PALSAR) L-band backscatter presented the highest dynamic range from unburned to recently burned forests (approximately 8. dB). The interferometric coherence showed low sensitivity to forest regrowth at all SAR frequencies. For Mediterranean forests, five phases of forest regrowth were discerned whereas for boreal forest, up to four different regrowth phases could be discerned with L-band SAR data. In comparison, the Normalized Difference Vegetation Index (NDVI) provided reliable differentiation only for the most recent development stages. The results obtained were consistent in both environments. 2011 Elsevier Inc.
BibTeX:
@article{Tanase20112075,
  author = {Tanase, M. and de la Riva, J. and Santoro, M. and Pérez-Cabello, F. and Kasischke, E.},
  title = {Sensitivity of SAR data to post-fire forest regrowth in Mediterranean and boreal forests},
  journal = {Remote Sensing of Environment},
  year = {2011},
  volume = {115},
  number = {8},
  pages = {2075-2085},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79957624015&doi=10.1016%2fj.rse.2011.04.009&partnerID=40&md5=e9744288c78f2275834aba9d2022a5ba},
  doi = {10.1016/j.rse.2011.04.009}
}
Teatini P, Tosi L and Strozzi T (2011), "Quantitative evidence that compaction of Holocene sediments drives the present land subsidence of the Po Delta, Italy", Journal of Geophysical Research: Solid Earth. Vol. 116(8) Blackwell Publishing Ltd.
Abstract: Deltas are highly dynamic coastal systems that over the last few decades have generally experienced a substantial area loss caused by trapping of river sediments in upland drainage basins as well as land subsidence due to natural and anthropogenic causes. A major example is the Po Delta in the Mediterranean in northeastern Italy. This area has experienced as much as 3 m of land subsidence from the 1930s to the 1970s primarily because of the extraction of gas-bearing waters. However, present subsidence rates are largely unknown and the ground settlement is supposedly controlled by natural long-term deep processes. We have combined radar Interferometric Point Target Analysis (IPTA) with previous geomorphological investigations on aerial/satellite images and seismic surveys, and geochronological data from core samples and geomechanical in situ tests, to assess the current sinking of the delta and to understand the processes controlling the vertical movement. The high density of the measurable point targets (more than 15,000) allows characterization of the spatial variation in the vertical land motions (VLM), ranging from -1 to -15 mm/yr. We find that subsidence rates are significantly correlated with the age of highly compressible Holocene deposits that compose the shallowest 30-40 m of the sedimentary sequence. A typical log-type consolidation equation applicable at the scale of the entire delta has been obtained. We conclude that the consolidation of late Holocene sediments is the major cause of the present land subsidence in the Po River delta. This finding has significant impact on the understanding of many other modern deltas that were formed in the lower Holocene epoch. Copyright 2011 by the American Geophysical Union.
BibTeX:
@article{Teatini2011,
  author = {Teatini, P. and Tosi, L. and Strozzi, T.},
  title = {Quantitative evidence that compaction of Holocene sediments drives the present land subsidence of the Po Delta, Italy},
  journal = {Journal of Geophysical Research: Solid Earth},
  publisher = {Blackwell Publishing Ltd},
  year = {2011},
  volume = {116},
  number = {8},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80052309695&doi=10.1029%2f2010JB008122&partnerID=40&md5=9c747f5089914a39703454d212c92842},
  doi = {10.1029/2010JB008122}
}
Triebnig G, Diamandi A, Hall R, Malnes E, Marklund L, Metsamaki S, Nagler T, Pulliainen J, Rott H, Schiller C, Solberg R and Wiesmann A (2011), "CryoLand - GMES service snow and land ice - Interoperability, service integration and user access", IFIP Advances in Information and Communication Technology. Vol. 359 AICT, pp. 341-348. Springer New York LLC.
Abstract: The CryoLand project implements and validates a standardized and sustainable service on snow and land ice monitoring as a Downstream Service of GMES. It will provide geospatial product coverages of seasonal snow (snow extent, snow mass, melt state), glaciers (area, snow / ice extent, ice velocities, glacier dammed lakes), and lake / river ice (extent, temporal variations, snow burden) derived from Earth observation (EO) satellite data. Processing lines and a service infrastructure will be developed on top of existing Web service environments supporting the publication, provision and chaining of involved geospatial data services. The CryoLand service architecture commits INSPIRE, OGC, and OASIS standards specifically respecting HMA and GENESIS frameworks. User information services offering discovery, view and download functions will be provided. 2011 IFIP International Federation for Information Processing.
BibTeX:
@article{Triebnig2011341,
  author = {Triebnig, G. and Diamandi, A. and Hall, R. and Malnes, E. and Marklund, L. and Metsamaki, S. and Nagler, T. and Pulliainen, J. and Rott, H. and Schiller, C. and Solberg, R. and Wiesmann, A.},
  title = {CryoLand - GMES service snow and land ice - Interoperability, service integration and user access},
  journal = {IFIP Advances in Information and Communication Technology},
  publisher = {Springer New York LLC},
  year = {2011},
  volume = {359 AICT},
  pages = {341-348},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960797950&doi=10.1007%2f978-3-642-22285-6_37&partnerID=40&md5=0a808261d251dd743ffff49a1c4e313b},
  doi = {10.1007/978-3-642-22285-6_37}
}
Volksch I, Schwank M and Matzler C (2011), "L-band reflectivity of a furrowed soil surface", IEEE Transactions on Geoscience and Remote Sensing. Vol. 49(6 PART 1), pp. 1957-1966.
Abstract: In a combined experimental and model study, we investigated the thermal L-band signatures of a sandy soil with periodic topography (furrows) with dimensions close to the observation wavelength of 21 cm. Measurements were carried out with a radiometer mounted on a tower and aimed at a soil box with an artificially prepared furrowed soil surface. Corresponding reflectivities were derived from brightness temperature measurements performed under dry and moist conditions, with the furrow direction either along or perpendicular to the plane of incidence. Results showed that the furrows had a pronounced effect on the reflectivity, depending on the polarization of the observed radiance, the direction of the furrows, and the soil moisture. A physical reflectivity model for dielectric periodic surfaces was used to explain the soil reflectivities measured for the different furrow directions and soil-water contents. Using this model improved the agreement between the measured and modeled reflectivities considerably compared to the Fresnel reflectivities. The observed dependence of soil reflectivity on furrow orientation and soil moisture could be reproduced by the reflectivity model. The quantitative agreement with the observed reflectivities was further improved by using a simple empirical approach to consider the small-scale heterogeneity of the top soil layer. 2011 IEEE.
BibTeX:
@article{Volksch20111957,
  author = {Volksch, I. and Schwank, M. and Matzler, C.},
  title = {L-band reflectivity of a furrowed soil surface},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2011},
  volume = {49},
  number = {6 PART 1},
  pages = {1957-1966},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79957650214&doi=10.1109%2fTGRS.2010.2091720&partnerID=40&md5=f5ef0229775a846e056531d6f6b0691b},
  doi = {10.1109/TGRS.2010.2091720}
}
Wegmüller U, Santoro M, Mattia F, Balenzano A, Satalino G, Marzahn P, Fischer G, Ludwig R and Floury N (2011), "Progress in the understanding of narrow directional microwave scattering of agricultural fields", Remote Sensing of Environment. Vol. 115(10), pp. 2423-2433.
Abstract: Directional microwave scattering, as investigated in this study, is characterized by a strong and narrow scattering pattern that varies strongly for only minor aspect angle changes. As was noted already in the past directional scattering is relevant for applications and cannot just be ignored. The overall objective of our work was to better understand directional scattering. Suited space- and airborne SAR data over several agricultural sites together with related in-situ information were collected for this purpose. Directional scattering was identified by comparison of backscattering acquired with only slightly different aspect angles as available from ERS-ENVISAT pairs with significantly different Doppler Centroids or by comparing azimuth spectrum sub-bands with slightly different Doppler Centroid. Major progress achieved in this work includes the much improved experimental evidence available and significant improvements in the understanding of the scatter phenomenon through the developed scatter model. Good progress was also made in the detection of directional scattering. 2011 Elsevier Inc.
BibTeX:
@article{Wegmuller20112423,
  author = {Wegmüller, U. and Santoro, M. and Mattia, F. and Balenzano, A. and Satalino, G. and Marzahn, P. and Fischer, G. and Ludwig, R. and Floury, N.},
  title = {Progress in the understanding of narrow directional microwave scattering of agricultural fields},
  journal = {Remote Sensing of Environment},
  year = {2011},
  volume = {115},
  number = {10},
  pages = {2423-2433},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960741618&doi=10.1016%2fj.rse.2011.04.026&partnerID=40&md5=ed0c4e32b3965e14692c2421dc777c66},
  doi = {10.1016/j.rse.2011.04.026}
}
Wegmüller U, Werner CL, Frey O, Strozzi T and Santoro M (2011), "Multi-pass ERS-ENVISAT cross-interferometry methods and results", In Proc. FRINGE 2011. Frascati, Italy, September, 2011.
Abstract: ERS-ENVISAT Tandem (EET) cross-interferometry (CInSAR) pairs are characterized by long 2km baselines and short 28 minute time intervals. Over some sites multiple pairs are available. In our work we discuss multi-pass interferometric techniques and investigate for several applications, including DEM generation, mapping of fast motions and grounding line mapping for Antarctic ice sheets, the use of multiple EET pairs.
BibTeX:
@inproceedings{wegmullerWernerFreyStrozziSantoro2011,
  author = {Urs Wegmüller and Charles L. Werner and Othmar Frey and Tazio Strozzi and Maurizio Santoro},
  title = {Multi-pass ERS-ENVISAT cross-interferometry methods and results},
  booktitle = {Proc. FRINGE 2011},
  year = {2011}
}
Werner CL, Wegmüller U, Frey O and Santoro M (2011), "Interferometric processing of PALSAR Wide-Beam SCANSAR Data", In Proc. FRINGE 2011. Frascati, Italy, September, 2011.
Abstract: Processing of ScanSAR data for interferometric applications requires careful attention to the phase and position accuracy to obtain interferometric products with high correlation and continuous phase across the bursts. We describe an interferometric processing system developed for ScanSAR data acquired by the ALOS PALSAR instrument able to produce differential interferometric products with 350 km swath width that are without visible phase discontinuities between ScanSAR beams.
BibTeX:
@inproceedings{wernerWegmullerFreySantoro2011,
  author = {Charles L. Werner and Urs Wegmüller and Othmar Frey and Maurizio Santoro},
  title = {Interferometric processing of PALSAR Wide-Beam SCANSAR Data},
  booktitle = {Proc. FRINGE 2011},
  year = {2011}
}
Wiesmann A and Gruner U (2011), "Radar interferometry in use for monitoring the stability of extensive cliffs [Radar-lnterferometrie im Einsatz fuer die Stabilitaetsueberwachung von grossflaechigen Felswaenden]", Bulletin fuer Angewandte Geologie. Vol. 16(1), pp. 51-55. Ver. Schweizerischer Petroleum Geol. und Ing..
Abstract: Radar interferometry is widely used for monitoring terrain movement from space. With the availability of portable terrestrial radar interferometers this technique is now also applied locally. The terrestrial radar interferometry allows to image the movement along the line of sight of large rockwatls with-in mm accuracy. This new technique is currently used at several locations in Switzerland as an early warning system to detect rock movements along important traffic lines.
BibTeX:
@article{Wiesmann201151,
  author = {Wiesmann, A. and Gruner, U.},
  title = {Radar interferometry in use for monitoring the stability of extensive cliffs [Radar-lnterferometrie im Einsatz fuer die Stabilitaetsueberwachung von grossflaechigen Felswaenden]},
  journal = {Bulletin fuer Angewandte Geologie},
  publisher = {Ver. Schweizerischer Petroleum Geol. und Ing.},
  year = {2011},
  volume = {16},
  number = {1},
  pages = {51-55},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85016254716&doi=10.5169%2fseals-327741&partnerID=40&md5=3b5bce8d9207448bf4a41800008b896f},
  doi = {10.5169/seals-327741}
}
Zacharias S, Bogena H, Samaniego L, Mauder M, Fuss R, Putz T, Frenzel M, Schwank M, Baessler C, Butterbach-Bahl K, Bens O, Borg E, Brauer A, Dietrich P, Hajnsek I, Helle G, Kiese R, Kunstmann H, Klotz S, Munch J, Papen H, Priesack E, Schmid H, Steinbrecher R, Rosenbaum U, Teutsch G and Vereecken H (2011), "A network of terrestrial environmental observatories in Germany", Vadose Zone Journal. Vol. 10(3), pp. 955-973.
Abstract: Multi compartment and multiscale long-term observation and research are important prerequisites to tackling the scientific challenges resulting from climate and global change. Long-term monitoring programs are cost intensive and require high analytical standards, however, and the gain of knowledge often requires longer observation times. Nevertheless, several environmental research networks have been established in recent years, focusing on the impact of climate and land use change on terrestrial ecosystems. From 2008 onward, a network of Terrestrial Environmental Observatories (TERENO) has been established in Germany as an interdisciplinary research program that aims to observe and explore the long-term ecological, social, and economic impacts of global change at the regional level. State-of-the-art methods from the field of environmental monitoring, geophysics, and remote sensing will be used to record and analyze states and fluxes for different environmental compartments from groundwater through the vadose zone, surface water, and biosphere, up to the lower atmosphere. Soil Science Society of America.
BibTeX:
@article{Zacharias2011955,
  author = {Zacharias, S. and Bogena, H. and Samaniego, L. and Mauder, M. and Fuss, R. and Putz, T. and Frenzel, M. and Schwank, M. and Baessler, C. and Butterbach-Bahl, K. and Bens, O. and Borg, E. and Brauer, A. and Dietrich, P. and Hajnsek, I. and Helle, G. and Kiese, R. and Kunstmann, H. and Klotz, S. and Munch, J.C. and Papen, H. and Priesack, E. and Schmid, H.P. and Steinbrecher, R. and Rosenbaum, U. and Teutsch, G. and Vereecken, H.},
  title = {A network of terrestrial environmental observatories in Germany},
  journal = {Vadose Zone Journal},
  year = {2011},
  volume = {10},
  number = {3},
  pages = {955-973},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860394701&doi=10.2136%2fvzj2010.0139&partnerID=40&md5=e66c6b14c4135d41b997b02d62d80fde},
  doi = {10.2136/vzj2010.0139}
}
Bitelli G, Bonsignore F, Carbognin L, Ferretti A, Strozzi T, Teatini P, Tosi L and Vittuari L (2010), "Radar interferometry-based mapping of the present land subsidence along the low-lying northern Adriatic coast of Italy", In IAHS-AISH Publication. Vol. 339, pp. 279-286.
Abstract: The northern Adriatic coastal area, Italy (from the Veneto region northward, and to the Romagna region to the south), is characterized by low-lying environments such as lagoons, e.g. those of Venice and of the Valli di Comacchio, wetlands and deltas, such as that of the Po River delta, and reclaimed farmland and beaches subjected to marked anthropogenic pressure. The coastal area is characterized by an elevation generally well below the mean sea level (down to -4 m m.s.l.) and never exceeds 2 m above m.s.l. Man-induced land subsidence has greatly affected the whole coastal area over the 20th century, and especially from the 1950s and the 1970s, when over-exploitation of subsurface fluids was responsible for the occurrence of general lowering. Although the sinking rates have significantly decreased over the last decades, land subsidence is still a process threatening the entire coastal environment. In this study we report a recent investigation aimed at mapping the vertical displacements recorded in the period 1992-2000 on the 20-30 km wide and 250-km long coastal area from the Tagliamento River to the north, to the town of Rimini to the south. Measurements have been carried out by Persistent Scatterer Interferometry (PSI) using levelling and GPS records to reference the interferometric solution. The results identify the variability of the ground movements that are presently occurring along the northern Adriatic coastline. Substantially stable areas, the most important of which are the cities of Venice and Ravenna and their surroundings, contrast with subsidence rates of more than 10 mm/year recorded in some parts of the Po River delta and to the south. The observed land displacements have been associated with the geological features of the study region, i.e. tectonics and differential consolidation of the Middle-Upper Pleistocene and Holocene deposits, and to anthropogenic activities, mainly groundwater withdrawal from the Upper Pleistocene-Holocene alluvial deposits and more locally peatland oxidation in reclaimed areas and gas exploitation from Plio-Pleistocene reservoirs. Copyright 2010 IAHS Press.
BibTeX:
@conference{Bitelli2010279,
  author = {Bitelli, G. and Bonsignore, F. and Carbognin, L. and Ferretti, A. and Strozzi, T. and Teatini, P. and Tosi, L. and Vittuari, L.},
  title = {Radar interferometry-based mapping of the present land subsidence along the low-lying northern Adriatic coast of Italy},
  booktitle = {IAHS-AISH Publication},
  year = {2010},
  volume = {339},
  pages = {279-286},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952634892&partnerID=40&md5=cda540d47c48ba65ecc2ed9a1f083338}
}
Casu F, Manconi A, Pepe A, Manzo M and Lanari R (2010), "Advances in the generation of deformation time series from SAR data sequences in areas affected by large dynamics", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 2618-2621.
Abstract: We propose advances on the generation of deformation time series in areas affected by large deformation dynamics, where the exploitation of the differential SAR phase can be strongly limited by severe misregistration errors or by very high fringe rates. First, to overcome the former issue, we present an extension of the amplitude-based Pixel-Offset (PO) analyses by applying the Small BAseline Subset (SBAS) strategy, in order to move from the investigation of single (large) deformation events to that of dynamic phenomena. Secondly, to handle the high fringe rate interferograms, we subtract from them properly generated synthetic deformation models allowing us to reduce the fringe rate, thus helping the phase unwrapping step. The proposed approaches have been tested on ASAR-ENVISAT data acquired on Galápagos Islands and validated via continuous GPS measurements. 2010 IEEE.
BibTeX:
@conference{Casu20102618,
  author = {Casu, F. and Manconi, A. and Pepe, A. and Manzo, M. and Lanari, R.},
  title = {Advances in the generation of deformation time series from SAR data sequences in areas affected by large dynamics},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2010},
  pages = {2618-2621},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650908640&doi=10.1109%2fIGARSS.2010.5651926&partnerID=40&md5=35cc5413748c3ca755c4314073db1e3c},
  doi = {10.1109/IGARSS.2010.5651926}
}
Eriksson L, Borenas K, Dierking W, Berg A, Santoro M, Pemberton P, Lindh H and Karlson B (2010), "Evaluation of new spaceborne SAR sensors for sea-ice monitoring in the Baltic Sea", Canadian Journal of Remote Sensing. Vol. 36, pp. S56-S73.
Abstract: In this study, synthetic aperture radar (SAR) data from the Advanced Land Observing Satellite (ALOS) and the Envisat, RADARSAT-2, and TerraSAR-X satellites were compared to evaluate their usefulness for sea-ice monitoring in the Baltic Sea. Radar signature characteristics at different frequencies, polarizations, and spatial resolutions are presented for three examples from 2009. C-band like-polarization data, which have been used for operational sea-ice mapping since the early 1990s, serve as a reference. Advantages and disadvantages were identified for the different SAR systems and imaging modes. One conclusion is that cross-polarized data improve the discrimination between sea ice and open water. Another observation is that it is easier to identify ice ridges in L-band data than in images from shorter wavelengths. The information content of X- and C-band images is largely equivalent, whereas L-band data provide complementary information. L-band SAR also seems to be less sensitive to wet snow cover on the ice. 2010, Taylor & Francis Group, LLC. All rights reserved.
BibTeX:
@article{Eriksson2010S56,
  author = {Eriksson, L.E.B. and Borenas, K. and Dierking, W. and Berg, A. and Santoro, M. and Pemberton, P. and Lindh, H. and Karlson, B.},
  title = {Evaluation of new spaceborne SAR sensors for sea-ice monitoring in the Baltic Sea},
  journal = {Canadian Journal of Remote Sensing},
  year = {2010},
  volume = {36},
  pages = {S56-S73},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956154903&doi=10.5589%2fm10-020&partnerID=40&md5=995d135b5b3a54e25679ec13b5cc6d34},
  doi = {10.5589/m10-020}
}
Fransson J, Pantze A, Eriksson L, Soja M and Santoro M (2010), "Mapping of wind-thrown forests using satellite SAR images", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1242-1245.
Abstract: The study focuses on investigation and evaluation of wind-thrown forest mapping using satellite remotely sensed data from three synthetic aperture radar (SAR) sensors. The study is carried out at Remningstorp, a test site in the south of Sweden dominated by coniferous forest, where trees were manual felled to simulate wind-thrown forest. The satellite data consisted of time series of HH polarized SAR images acquired by the Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR), Radarsat-2 (C-band) and TerraSAR-X (X-band). The results from visual interpretation of SAR images acquired before and after the simulated wind-throw together with corresponding ratio images show that ALOS PALSAR HH polarized intensity images are not able to detect wind-thrown forest, probably due to too coarse spatial resolution. In contrast, the wind-thrown forest is clearly visible in the Radarsat-2 and TerraSAR-X HH polarized images, implying that it may be possible to develop a new application using these SAR data for mapping of wind-thrown forests. 2010 IEEE.
BibTeX:
@conference{Fransson20101242,
  author = {Fransson, J.E.S. and Pantze, A. and Eriksson, L.E.B. and Soja, M.J. and Santoro, M.},
  title = {Mapping of wind-thrown forests using satellite SAR images},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2010},
  pages = {1242-1245},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650860742&doi=10.1109%2fIGARSS.2010.5654183&partnerID=40&md5=43bd5a67d70c1f8ec716a56f66dcfc06},
  doi = {10.1109/IGARSS.2010.5654183}
}
Frey O and Meier E (2010), "3D SAR imaging of a forest using airborne MB-SAR data at L- and P-band: Data processing and analysis", In Proc. European Conf. Synthetic Aperture Radar. , pp. 166-169. Institute of Electrical and Electronics Engineers Inc..
Abstract: Using a time-domain back-projection based focusing algorithm in combination with three tomographic focusing techniques (multilook standard beamforming, robust Capon beamforming, and MUSIC) a 3D volume containing a forested area has been tomographically imaged at L- and P-band. In this paper, we present further results and insights obtained by processing and analyzing these data sets with respect to the localization of the scattering sources using the three different focusing techniques, as well as for both, the two frequency bands and the different polarimetric channels. VDE VERLAG GMBH · Berlin · Offenbach.
BibTeX:
@conference{Frey2010166,
  author = {Frey, O. and Meier, E.},
  title = {3D SAR imaging of a forest using airborne MB-SAR data at L- and P-band: Data processing and analysis},
  booktitle = {Proc. European Conf. Synthetic Aperture Radar},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2010},
  pages = {166-169},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84985863702&partnerID=40&md5=5777ed82ebfcd1c421bce22a41b9f00b}
}
Frey O and Meier E (2010), "Analyzing tomographic SAR data of a forest with respect to frequency, polarization, and focusing technique", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 150-153.
Abstract: In this paper, two fully-polarimetric tomographic SAR data sets of a forested area, at L-band and P-band, are analyzed with respect to the localization of scattering sources and scattering mechanisms. In particular, the 3D SAR data is examined regarding the performance of three different tomographic focusing techniques multilook standard beamforming, robust Capon beamforming, and MUSIC, as well as for both, the two frequency bands and the different polarimetric channels. 2010 IEEE.
BibTeX:
@conference{Frey2010150,
  author = {Frey, O. and Meier, E.},
  title = {Analyzing tomographic SAR data of a forest with respect to frequency, polarization, and focusing technique},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2010},
  pages = {150-153},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650861110&doi=10.1109%2fIGARSS.2010.5654438&partnerID=40&md5=d8849c800d27702cec9cdd9838503b32},
  doi = {10.1109/IGARSS.2010.5654438}
}
Jehle M, Frey O, Small D and Meier E (2010), "Measurement of ionospheric tec in spaceborne sar data", IEEE Transactions on Geoscience and Remote Sensing. Vol. 48(6), pp. 2460-2468.
Abstract: The propagation of spaceborne radar signals operating at L-band frequency or below can be seriously affected by the ionosphere. At high states of solar activity, Faraday rotation (FR) and signal path delays disturb radar polarimetry and reduce resolution in range and azimuth. While these effects are negligible at X-band, FR and the frequency-dependent path delays can become seriously problematic starting at L-band. For quality assurance and calibration purposes, existing L-band or potential spaceborne P-band missions require the estimation of the ionospheric state before or during the data take. This paper introduces two approaches for measuring the ionospheric total electron content (TEC) from single-polarized spaceborne SAR data. The two methods are demonstrated using simulations. Both methods leverage knowledge of the frequency-dependent path delay through the ionosphere: The first estimates TEC from the phase error of the filter mismatch, while the second gauges path-delay differences between up and down chirps. FR, mean (direct current) offsets, and noise contributions are also considered in the simulations. Finally, possibilities for further methodological improvements are discussed. 2006 IEEE.
BibTeX:
@article{Jehle20102460,
  author = {Jehle, M. and Frey, O. and Small, D. and Meier, E.},
  title = {Measurement of ionospheric tec in spaceborne sar data},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2010},
  volume = {48},
  number = {6},
  pages = {2460-2468},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77952586225&doi=10.1109%2fTGRS.2010.2040621&partnerID=40&md5=d79bc651dbc78a466d1d8ba5c74c5d21},
  doi = {10.1109/TGRS.2010.2040621}
}
Lanari R, Berardino P, Bonano M, Casu F, Manconi A, Manunta M, Manzo M, Pepe A, Pepe S, Sansosti E, Solaro G, Tizzani P and Zeni G (2010), "Surface displacements associated with the L'Aquila 2009 Mw 6.3 earthquake (central Italy): New evidence from SBAS-DInSAR time series analysis", Geophysical Research Letters. Vol. 37(20) Blackwell Publishing Ltd.
Abstract: We investigate the surface displacements in the area affected by the April 2009 L'Aquila earthquake (Central Italy) through an advanced DInSAR analysis. In particular, we apply the SBAS approach to retrieve deformation maps and displacement time series from ENVISAT data acquired between February 2003 and October 2009 and from COSMO-SkyMed data relevant to the six-month interval following the earthquake. Our analysis shows no evidence of pre-seismic surface deformation at the 35-day temporal sampling of the ENVISAT sensor. On the other hand, by benefiting of the high spatial resolution and temporal sampling of the COSMO-SkyMed satellites, we measure post-seismic displacements at an unprecedented level of detail for a DInSAR analysis. This allows us to identify three main areas continuing to deform after the earthquake. In addition, our modeling shows that post-seismic displacements are very likely related to the fault afterslip, since their decay times are on the order of 10 1-102 days. 2010 by the American Geophysical Union.
BibTeX:
@article{Lanari2010,
  author = {Lanari, R. and Berardino, P. and Bonano, M. and Casu, F. and Manconi, A. and Manunta, M. and Manzo, M. and Pepe, A. and Pepe, S. and Sansosti, E. and Solaro, G. and Tizzani, P. and Zeni, G.},
  title = {Surface displacements associated with the L'Aquila 2009 Mw 6.3 earthquake (central Italy): New evidence from SBAS-DInSAR time series analysis},
  journal = {Geophysical Research Letters},
  publisher = {Blackwell Publishing Ltd},
  year = {2010},
  volume = {37},
  number = {20},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78049326388&doi=10.1029%2f2010GL044780&partnerID=40&md5=57f8baa52caffba79c9bc476f21a56e4},
  doi = {10.1029/2010GL044780}
}
Leiterer R, Reiche J, Cartus O, Santoro M, Schmullius C and Li Z (2010), "Multiscale comparison of ERS -1/2 tandem forest growing stock maps with existing landcover products", In European Space Agency, (Special Publication) ESA SP. Vol. 684 SP
Abstract: The purpose of this poster is to show a useful approach for determining the quality of forest growing stock (6SV) maps derived from ERS-1/2 tandem data. For the validation of the large-area maps, a special cross-comparison design based on freely available Earth Observation land cover (LC) products had to be developed due to unavailability of in situ measurements. A multiscale comparative assessment design, linking quality flags and LC products such as GlobCover, MODIS VCF, GLC2000 and AVHRR LC, has been applied. The sampling design, based on the FAO FRA2010 sampling design and the Degree Confluence Project, uses a 1 degree sampling grid with 10 × 10 km sample plots. The method provides appropriate information about plausibility and quality of the ERS forest GSV maps. Since similar global data sets will be available in the future (e.g. within the framework of ESA Sentinel programme), the developed approach is well suitable for scale and thematic independent accuracy assessment applications.
BibTeX:
@conference{Leiterer2010,
  author = {Leiterer, R. and Reiche, J. and Cartus, O. and Santoro, M. and Schmullius, C. and Li, Z.},
  title = {Multiscale comparison of ERS -1/2 tandem forest growing stock maps with existing landcover products},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2010},
  volume = {684 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79851470476&partnerID=40&md5=2ce724d3896fa7401d14e54367f33ad4}
}
Loew A and Schwank M (2010), "Calibration of a soil moisture model over grassland using L-band microwave radiometry", International Journal of Remote Sensing. Vol. 31(19), pp. 5163-5177. Taylor and Francis Ltd..
Abstract: Land surface models are widely used to simulate water and energy fluxes at the land surface. To perform realistic simulations, an appropriate model parameterization and calibration is required. The present paper investigates the general potential of using L-band microwave radiometer data for the calibration of a simple soil wetness model. A ground based L-band radiometer was used to measure the dual polarized microwave emission from a grass covered area throughout the vegetation period in 2004. It was found that L-band microwave data provided a robust proxy for surface soil moisture conditions for the used data set which is consistent with previous findings. The microwave data is used for the calibration of a simple soil moisture model. Using the L-band data resulted in improved simulation skills of surface soil water dynamics as well as a better representation of deeper soil water storage. The correlation r between the soil moisture model estimates and the actual soil moisture was improved from r = 0.16(-0.42) to r = 0.90(0.54) for the surface and (root zone) soil water content, respectively. The results of the study reveal the general potential of using L-band microwave radiometry for an improved parameterization of land surface models which might be an interesting application for proposed and recent L-band microwave satellite missions such as the NASA Soil Moisture Active/Passive (SMAP) and the European Soil Moisture and Ocean Salinity Mission (SMOS). 2010 Taylor & Francis.
BibTeX:
@article{Loew20105163,
  author = {Loew, A. and Schwank, M.},
  title = {Calibration of a soil moisture model over grassland using L-band microwave radiometry},
  journal = {International Journal of Remote Sensing},
  publisher = {Taylor and Francis Ltd.},
  year = {2010},
  volume = {31},
  number = {19},
  pages = {5163-5177},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857941265&doi=10.1080%2f01431160903260981&partnerID=40&md5=e6066b7e4fdc8a1bd646e27a12698988},
  doi = {10.1080/01431160903260981}
}
Magnard C, Meier E, Small D, Essen H and Brehm T (2010), "Processing of MEMPHIS millimeter wave multi-baseline InSAR data", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 4302-4305.
Abstract: This paper presents a processing method for multi-baseline interferometric data acquired with the MEMPHIS airborne sensor. The processing method ingests the SAR raw data from each receiver and extends up to the generation of digital elevation models (DEMs). Critical steps include the correction of the azimuth phase undulations, the multi-baseline processing and the phase-to-DEM conversion. Methods for resolving the various hurdles were adapted to the MEMPHIS sensor and are presented here. The results obtained for a data take over a test site near Zurich, Switzerland are shown; these results are in a good agreement with comparable LIDAR products. 2010 IEEE.
BibTeX:
@conference{Magnard20104302,
  author = {Magnard, C. and Meier, E. and Small, D. and Essen, H. and Brehm, T.},
  title = {Processing of MEMPHIS millimeter wave multi-baseline InSAR data},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2010},
  pages = {4302-4305},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650859939&doi=10.1109%2fIGARSS.2010.5650372&partnerID=40&md5=e0ec65b348d6090fb63e0f8da5059a3a},
  doi = {10.1109/IGARSS.2010.5650372}
}
Manconi A, Walter T, Manzo M, Zeni G, Tizzani P, Sansosti E and Lanari R (2010), "On the effects of 3-D mechanical heterogeneities at Campi Flegrei caldera, southern Italy", Journal of Geophysical Research: Solid Earth. Vol. 115(8) Blackwell Publishing Ltd.
Abstract: Campi Flegrei caldera, located near the highly populated city of Naples, southern Italy, is characterized by long-term subsidence punctuated by fast uplift phases. Most of the interpretations of the ground deformation are still based on standard models that assume the lithosphere to behave as a homogeneous half-space. However, several geophysical investigations show the presence of vertical and lateral heterogeneities, especially in the shallow subsurface, which might have an effect on the interpretation of the surface displacements. Our 3-D finite element models, constrained by seismic tomography to take into account the realistic distribution of mechanical heterogeneities, demonstrate that at Campi Flegrei the assessment of the source location is independent of the consideration of 3-D heterogeneities, while the evaluation of its strength is overestimated. Thus, we propose an approach that still allows use of standard homogeneous half-space models but accounts for 3-D heterogeneity effects. This procedure, applied to the deformation field revealed by Differential Synthetic Aperture Radar Interferometry (DInSAR) over the past 16 years, provides new insights for the understanding of the ground displacements observed at Campi Flegrei caldera. This work provides an approach for a quantitative evaluation of the effects of mechanical heterogeneities on surface deformation. Analogous procedures can be also applied in other volcanic areas where, similar to Campi Flegrei caldera, a priori information on the mechanical heterogeneities distribution is available. Copyright 2010 by the American Geophysical Union.
BibTeX:
@article{Manconi2010,
  author = {Manconi, A. and Walter, T.R. and Manzo, M. and Zeni, G. and Tizzani, P. and Sansosti, E. and Lanari, R.},
  title = {On the effects of 3-D mechanical heterogeneities at Campi Flegrei caldera, southern Italy},
  journal = {Journal of Geophysical Research: Solid Earth},
  publisher = {Blackwell Publishing Ltd},
  year = {2010},
  volume = {115},
  number = {8},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955879078&doi=10.1029%2f2009JB007099&partnerID=40&md5=f371e348b6b1631154385aaa0cb3bb4e},
  doi = {10.1029/2009JB007099}
}
Manzo M, Berardino P, Bonano M, Casu F, Lanari R, Manconi A, Manunta M, Pepe A, Pepe S, Sansosti E, Solaro G, Tizzani P and Zeni G (2010), "Full exploitation of the SBAS-DInSAR algorithm in active seismogenetic scenarios", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1206-1209.
Abstract: We perform a full exploitation of the Differential SAR Interferometry (DInSAR) algorithm referred to as Small BAseline Subset (SBAS) technique to investigate long term surface deformation occurring in extended, seismogenetic areas. To this aim we benefit of the SBAS technique capability to work in multi-frame and multi-sensor scenarios in order to improve the spatial and temporal coverage, as well as to employ new generation SAR sensors to increase the temporal sampling of the retrieved time series. In this work we apply the SBAS algorithm to analyze the temporal evolution of the detected displacements affecting three different seismogenetic scenarios by means of deformation time series retrieved through data acquired by European (ERS-1/2, ENVISAT) and Italian (COSMO-SkyMed) satellites. In particular, we focus on the analysis of the deformation patterns associated with the activity of the San Andreas (SAF, California, USA), the North Anatolian (NAF, Turkey) and the Paganica (PF, Abruzzo, Central Italy) Faults. The achieved results provide a clear idea of the surface deformation retrieval capability of the SBAS procedure. 2010 IEEE.
BibTeX:
@conference{Manzo20101206,
  author = {Manzo, M. and Berardino, P. and Bonano, M. and Casu, F. and Lanari, R. and Manconi, A. and Manunta, M. and Pepe, A. and Pepe, S. and Sansosti, E. and Solaro, G. and Tizzani, P. and Zeni, G.},
  title = {Full exploitation of the SBAS-DInSAR algorithm in active seismogenetic scenarios},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2010},
  pages = {1206-1209},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650861513&doi=10.1109%2fIGARSS.2010.5654188&partnerID=40&md5=4af0dcfd22a868fedc8d6bd73a7bc539},
  doi = {10.1109/IGARSS.2010.5654188}
}
Matzler C, Rosenkranz P and Cermak J (2010), "Microwave absorption of supercooled clouds and implications for the dielectric properties of water", Journal of Geophysical Research Atmospheres. Vol. 115(23) Blackwell Publishing Ltd.
Abstract: The absorption of liquid clouds was determined in the frequency range from 21 to 31 GHz and over the temperature range from 246 to 279 K. The information was derived from continuous surface-based microwave and infrared radiometer observations at Bern, Switzerland, from 2006 to 2010 and using satellite data for cloud-top temperature. The results indicate that common dielectric models of liquid water are inaccurate at temperatures below 265 K, possibly owing to the poor representation of the main relaxation frequency of water. The best agreement with our observations is found for a model published in report form in 1995. Part of the scatter in the temperature dependence of the analyzed data can be explained by correlated fluctuations in water vapor and liquid water. The results are relevant for remote sensing of supercooled clouds using passive and active microwave techniques and, more generally, for the physics of water. Copyright 2010 by the American Geophysical Union.
BibTeX:
@article{Matzler2010,
  author = {Matzler, C. and Rosenkranz, P.W. and Cermak, J.},
  title = {Microwave absorption of supercooled clouds and implications for the dielectric properties of water},
  journal = {Journal of Geophysical Research Atmospheres},
  publisher = {Blackwell Publishing Ltd},
  year = {2010},
  volume = {115},
  number = {23},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650013251&doi=10.1029%2f2010JD014283&partnerID=40&md5=fc52e91dc6521fcae0f14eada7b715b3},
  doi = {10.1029/2010JD014283}
}
Murka A, Stahli O, Matzler C, Canavero M, Oechslin R, Wellig P, Notel D and Essen H (2010), "Polarimetric imaging with the 91GHz Radiometer SPIRA", In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 7837
Abstract: The Scanning Polarimetric Imaging Radiometer (SPIRA) is a passive microwave imaging system operating around 91 GHz. It consists of a two orthogonally polarized receiver channels and an analog adding correlator network with 2 GHz bandwidth, which can measure all four Stokes parameters simultaneously by scanning the scene with an offset parabolic reector on an elevation over azimuth scanner. In October 2008 the SPIRA instrument has participated in the joint Swiss-German Radiometer Experiment Thun where it has been operated in parallel with two PMMW systems of Fraunhofer Institut fur Hochfrequenzphysik und Radartechnik and an IR camera. During this measurement campaign different camouage kits, vehicles and persons with hidden threats have been observed together with reference objects. This paper gives an overview of the three different instruments and discusses selected images of the joint measurement campaign. 2010 SPIE.
BibTeX:
@conference{Murka2010,
  author = {Murka, A. and Stahli, O. and Matzler, C. and Canavero, M. and Oechslin, R. and Wellig, P. and Notel, D. and Essen, H.},
  title = {Polarimetric imaging with the 91GHz Radiometer SPIRA},
  booktitle = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2010},
  volume = {7837},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649805600&doi=10.1117%2f12.865150&partnerID=40&md5=a87f6fb484bb7fd60afe77e9781d9ef2},
  doi = {10.1117/12.865150}
}
Pantze A, Fransson J and Santoro M (2010), "Forest change detection from L-band satellite SAR images using iterative histogram matching and thresholding together with data fusion", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1226-1229.
Abstract: In this study, we assess the efficiency of using L-band satellite SAR for forest change monitoring, by applying a combination of change detection techniques to SAR backscatter intensity images acquired over Swedish forest. We use a bi-temporal change detection approach based on image rationing. Histogram based techniques are used both for radiometric normalization and thresholding. For a final classification step, we evaluate a data fusion based change detection method that exploits the spatial and spectral information from one or multiple SAR channels. Pre-applied filters are also evaluated as alternatives to tackle low resolution and speckle. HH and HV polarized Fine Beam Dual images, acquired 34 degrees off nadir (FBD34) by the Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR), are used to find clear-cuts in Swedish boreal forest. Our results show that clear-cuts can be clearly extracted from L-band SAR data. 2010 IEEE.
BibTeX:
@conference{Pantze20101226,
  author = {Pantze, A. and Fransson, J.E.S. and Santoro, M.},
  title = {Forest change detection from L-band satellite SAR images using iterative histogram matching and thresholding together with data fusion},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2010},
  pages = {1226-1229},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650906663&doi=10.1109%2fIGARSS.2010.5650677&partnerID=40&md5=67a8b894e916064d72f0cb34a9e0d29f},
  doi = {10.1109/IGARSS.2010.5650677}
}
Pulliainen J, Lemmetyinen J, Kontu A, Arslan A, Wiesmann A, Nagler T, Rott H, Davidson M, Schuettemeyer D and Kern M (2010), "Observing seasonal snow changes in the boreal forest area using active and passive microwave measurements", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 2375-2378.
Abstract: We present initial results from an experimental campaign aiming to acquire a comprehensive, full-snow season dataset of simultaneous backscatter and brightness temperature measurements of snow covered ground. The campaign is a part of Phase A activities in support of the proposed CoReH2O mission, aiming both to contribute to investigations on interpreting snow properties from active microwave observations, and to explore the possibilities for synergistic use of active measurements with existing passive microwave instruments. The campaign period covers the winter season of 2009-2010. Microwave observations are complemented by detailed in situ data of snow cover properties. 2010 IEEE.
BibTeX:
@conference{Pulliainen20102375,
  author = {Pulliainen, J. and Lemmetyinen, J. and Kontu, A. and Arslan, A. and Wiesmann, A. and Nagler, T. and Rott, H. and Davidson, M. and Schuettemeyer, D. and Kern, M.},
  title = {Observing seasonal snow changes in the boreal forest area using active and passive microwave measurements},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2010},
  pages = {2375-2378},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650907769&doi=10.1109%2fIGARSS.2010.5653105&partnerID=40&md5=ea7a3624a01581d4ba5e4231637326fd},
  doi = {10.1109/IGARSS.2010.5653105}
}
Santoro M, Fransson J, Eriksson L and Ulander L (2010), "Clear-Cut Detection in Swedish Boreal Forest Using Multi-Temporal ALOS PALSAR Backscatter Data", IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. Vol. 3(4), pp. 618-631.
Abstract: An extensive dataset of images acquired by the Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) is investigated for clear-cut detection in the county of Vasterbotten, Sweden. Strong forest/non-forest contrast and temporal consistency were found for the Fine Beam Dual HV-polarized backscatter in summer/fall. In consequence of a clear-cut between image acquisitions, the HV-backscatter dropped in most cases between 2 and 3 dB. Thus, a simple thresholding algorithm that exploits the temporal consistency of time series of HV-backscatter measurements has been developed for clear-cut detection. The detection algorithm was applied at pixel level to ALOS PALSAR strip images with a pixel size of 50 m. The performance of the detection algorithm was tested with three different threshold values (2.0, 2.5 and 3.0 dB). The classification accuracy increased from 57.4% to 78.2% for decreasing value of the threshold. Conversely, the classification error increased from 3.0% to 9.7%. For about 90% of the clear-felled polygons used for accuracy assessment the proportion of pixels correctly detected as clear-felled was above 50% when using a threshold value of 2.0 dB. For the threshold values of 2.5 and 3.0 dB the corresponding figures were 80% and 65%, respectively. The total area classified as clear-felled during the time frame of the ALOS PALSAR data differed by 5% compared to an estimate of notified fellings for the same period of time when using a detection threshold of 2.5 dB. The performance of the simple detection algorithm is reasonable when aiming at detecting clear-cuts, whereas there are shortcomings in terms of delineation. 2010, IEEE.
BibTeX:
@article{Santoro2010618,
  author = {Santoro, M. and Fransson, J.E.S. and Eriksson, L.E.B. and Ulander, L.M.H.},
  title = {Clear-Cut Detection in Swedish Boreal Forest Using Multi-Temporal ALOS PALSAR Backscatter Data},
  journal = {IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  year = {2010},
  volume = {3},
  number = {4},
  pages = {618-631},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650498131&doi=10.1109%2fJSTARS.2010.2048201&partnerID=40&md5=8ced1dfbde504b6fbd64133451bad204},
  doi = {10.1109/JSTARS.2010.2048201}
}
Santoro M, Wegmüller U and Askne J (2010), "Signatures of ERS-Envisat interferometric SAR coherence and phase of short vegetation: An analysis in the case of maize fields", IEEE Transactions on Geoscience and Remote Sensing. Vol. 48(4 PART 1), pp. 1702-1713.
Abstract: Interferometric observations between the European Remote Sensing, ERS-2, synthetic aperture radar (SAR) and the Envisat Advanced SAR (ASAR) are unique since they are characterized by a short repeat-pass interval (28 min) and a perpendicular baseline of approximately 2 km. In vegetated areas, this configuration should preserve from strong temporal decorrelation and enhance the sensitivity of coherence and SAR interferometric (InSAR) phase to volumes with small heights. This assumption could be tested with the data acquired during the dedicated ERS-Envisat Tandem mission on October 15, 2007, over the Seeland region, Switzerland. Five maize fields and one sunflower field presented lower coherence and offsets of the interferometric phase, i.e. height, with respect to neighboring bare fields. To gain understanding on the interferometric signatures, the interferometric water cloud model was used to simulate coherence and InSAR height for the maize fields. Both the coherence and the In-SAR height present clear dependence upon vegetation height and exhibit strong consistency. Simulations showed that the modeled coherence and InSAR height are most sensitive to the two-way attenuation and the temporal coherence of the vegetation. The best correspondence between the observed and modeled InSAR parameters was obtained with two-way attenuation values between 2 and 4 dB/m (corresponding to an extinction between 1 and 2 dB/m) and high temporal coherence of the vegetation (above 0.6), with this being due to the very stable conditions of the weather during the 28-min interval between image acquisitions. 2009 IEEE.
BibTeX:
@article{Santoro20101702,
  author = {Santoro, M. and Wegmüller, U. and Askne, J.I.H.},
  title = {Signatures of ERS-Envisat interferometric SAR coherence and phase of short vegetation: An analysis in the case of maize fields},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2010},
  volume = {48},
  number = {4 PART 1},
  pages = {1702-1713},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-82455217253&doi=10.1109%2fTGRS.2009.2034257&partnerID=40&md5=267371a19d5e53bf07ed36e090457837},
  doi = {10.1109/TGRS.2009.2034257}
}
Schmullius C, Reiche J, Leiterer R, Cartus O, Santoro M, Wegmüller U, Li Z, Tian X and Ling F (2010), "Forest DRAGON 2: Mid-term results of the European partners", In European Space Agency, (Special Publication) ESA SP. Vol. 684 SP
Abstract: One of the main objectives of the Forest DRAGON 2 project is the evaluation of the Forest DRAGON 1 large area forest growing stock volume (GSV) maps generated for Northeast and Southeast China, based on ERS-1/2 tandem coherence data from the mid 1990s. A special cross-comparison design mainly based on freely available Earth Observation products has been developed in consequence of lack of extensive in situ measurements. A reasonable agreement above 70 % between the forest GSV maps and the EO products in terms of forest/non-forest could be achieved for NE and SE China. The assessment of forest cover and structure changes in China from the mid 1990s into the current decade is addressed by a pilot study at the regions of Daxinganling and Xiaoxinganling. A one-year stack (2007) of Envisat ASAR GMM data has been processed at 1-km pixel size with the BIOMASAR algorithm to obtain continuous GSV. Accordingly, the ERS-1/2 tandem data has been reprocessed to 1 km to allow an intercomparison of the two products, which in turn allowed observing scaling effects on the forest GSV. Preliminary results show plausible detection of forest cover changes.
BibTeX:
@conference{Schmullius2010,
  author = {Schmullius, C. and Reiche, J. and Leiterer, R. and Cartus, O. and Santoro, M. and Wegmüller, U. and Li, Z.Y. and Tian, X. and Ling, F.L.},
  title = {Forest DRAGON 2: Mid-term results of the European partners},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2010},
  volume = {684 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79851490948&partnerID=40&md5=6cf9f322ba600444c888da772cdc8309}
}
Schwank M, Voksch I, Wigneron J-P, Kerr Y, Mialon A, De Rosnay P and Matzler C (2010), "Comparison of two bare-soil reflectivity models and validation with L-band radiometer measurements", IEEE Transactions on Geoscience and Remote Sensing. Vol. 48(1), pp. 325-337.
Abstract: The emission of bare soils at microwave L-band (1-2 GHz) frequencies is known to be correlated with surface soil moisture. Roughness plays an important role in determining soil emissivity although it is not clear which roughness length scales are most relevant. Small-scale (i.e., smaller than the resolution limit) inhomogeneities across the soil surface and with soil depth caused by both spatially varying soil properties and topographic features may affect soil emissivity. In this paper, roughness effects were investigated by comparing measured brightness temperatures of well-characterized bare soil surfaces with the results from two reflectivity models. The selected models are the air-to-soil transition model and Shi's parameterization of the integral equation model (IEM). The experimental data taken from the Surface Monitoring of the Soil Reservoir Experiment (SMOSREX) consist of surface profiles, soil permittivities and temperatures, and brightness temperatures at 1.4 GHz with horizontal and vertical polarizations. The types of correlation functions of the rough surfaces were investigated as required to evaluate Shi's parameterization of the IEM. The correlation functions were found to be clearly more exponential than Gaussian. Over the experimental period, the diurnalmean root mean square (rms) height decreased, while the correlation length and the type of correlation function did not change. Comparing the reflectivity models with respect to their sensitivities to the surface rms height and correlation length revealed distinct differences. Modeled reflectivities were tested against reflectivities derived from measured brightness, which showed that the two models perform differently depending on the polarization and the observation angle. 2009 IEEE.
BibTeX:
@article{Schwank2010325,
  author = {Schwank, M. and Voksch, I. and Wigneron, J.-P. and Kerr, Y.H. and Mialon, A. and De Rosnay, P. and Matzler, C.},
  title = {Comparison of two bare-soil reflectivity models and validation with L-band radiometer measurements},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2010},
  volume = {48},
  number = {1},
  pages = {325-337},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-73249125600&doi=10.1109%2fTGRS.2009.2026894&partnerID=40&md5=a864b0b266de7a0ad01db64d32a88aec},
  doi = {10.1109/TGRS.2009.2026894}
}
Schwank M, Wiesmann A, Werner C, Matzler C, Weber D, Murk A, Volksch I and Wegmüller U (2010), "ELBARA II, an L-band radiometer system for soil moisture research", Sensors. Vol. 10(1), pp. 584-612.
Abstract: L-band (1-2 GHz) microwave radiometry is a remote sensing technique that can be used to monitor soil moisture, and is deployed in the Soil Moisture and Ocean Salinity (SMOS) Mission of the European Space Agency (ESA). Performing ground-based radiometer campaigns before launch, during the commissioning phase and during the operative SMOS mission is important for validating the satellite data and for the further improvement of the radiative transfer models used in the soil-moisture retrieval algorithms. To address these needs, three identical L-band radiometer systems were ordered by ESA. They rely on the proven architecture of the ETH L-Band radiometer for soil moisture research (ELBARA) with major improvements in the microwave electronics, the internal calibration sources, the data acquisition, the user interface, and the mechanics. The purpose of this paper is to describe the design of the instruments and the main characteristics that are relevant for the user. 2010 by the authors.
BibTeX:
@article{Schwank2010584,
  author = {Schwank, M. and Wiesmann, A. and Werner, C. and Matzler, C. and Weber, D. and Murk, A. and Volksch, I. and Wegmüller, U.},
  title = {ELBARA II, an L-band radiometer system for soil moisture research},
  journal = {Sensors},
  year = {2010},
  volume = {10},
  number = {1},
  pages = {584-612},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953671888&doi=10.3390%2fs100100584&partnerID=40&md5=b4b7004199aed6469e07d042028c0fb6},
  doi = {10.3390/s100100584}
}
Stahli O, Matzler C, Murk A and Kampfer N (2010), "Sky measurements with the imaging polarimeter SPIRA at 91 GHz", In 11th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment, MicroRad 2010 - Proceedings. , pp. 181-186.
Abstract: The Scanning Polarimetric Imaging RAdiometer SPIRA at 91 GHz with an angular resolution of 0.5° was used to investigate the dynamics of the atmosphere. We introduced a new imaging method by continuously scanning the sky over a range of elevation angles in a fixed azimuth direction. The measurements were realized during three different situations: clear sky, sky with water clouds and sky with cirrus clouds. Especially interesting structures were found in the images with water clouds. In contrast, cirrus clouds are highly transparent. Simulations of the applied imaging method helped to interpret the cloud images, especially concerning the cloud movement. Curves with an S shape are signatures of motions along the scan line. By extracting the observed shape from such curves we estimated the horizontal velocity of water clouds. It was also possible to estimate the Integrated Water Vapor (IWV) from the clear sky images. They allow a visualization of water vapor parcels. Some of these images contain S curves as well indicating advection of water vapor along the scan line. In future we plan to extend these measurements and to combine with multi-frequency observations. 2010 IEEE.
BibTeX:
@conference{Stahli2010181,
  author = {Stahli, O. and Matzler, C. and Murk, A. and Kampfer, N.},
  title = {Sky measurements with the imaging polarimeter SPIRA at 91 GHz},
  booktitle = {11th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment, MicroRad 2010 - Proceedings},
  year = {2010},
  pages = {181-186},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77958083166&doi=10.1109%2fMICRORAD.2010.5559564&partnerID=40&md5=9a7a31fdb3b18f3e33546a54fbc60aac},
  doi = {10.1109/MICRORAD.2010.5559564}
}
Strozzi T, Delaloye R, Kaab A, Ambrosi C, Perruchoud E and Wegmüller U (2010), "Combined observations of rock mass movements using satellite SAR interferometry, differential GPS, airborne digital photogrammetry, and airborne photography interpretation", Journal of Geophysical Research: Earth Surface. Vol. 115(1) Blackwell Publishing Ltd.
Abstract: Recent global warming, through the related retreat of mountain glaciers, causes a growing number of different slope instabilities requiring accurate and cost·effective monitoring. We investigate the potential of combined remote sensing observations from satellite and airborne microwave and optical sensors for an efficient survey of mountainous ground displacements. The evolution of a paraglacial deep·seated rock mass movement due to glacier retreat in the Swiss Alps has been observed between 1976 and 2008 with satellite synthetic aperture radar (SAR) interferometry, differential GPS, and airborne digital photogram metry. Analysis of differential SAR interferograms revealed an acceleration of the landslide from ·4 cm/yr in the slope·parallel direction during the mid·1990s to more than 30 cm/yr in the summer of 2008. Differential GPS surveys performed between the summers of 2007 and 2008 indicate seasonal variations of the landslide activity. The photogrammetric analysis revealed no significant movement (i.e., <1 cm/yr) between 1976 and 1995 and provides an overview of the total displacement between 1995 and 2006 with high spatial resolution. In situ and airborne photography interpretation suggests that the landslide was activated at earliest by the end of the Last Glaciation but without any significant long·lasting activity during the Holocene and that the exponentially increasing reactivation since the 1990s is the result of ongoing debutressing of the valley flank due to the glacier retreat in combination with strong precipitation and snowmelt events. We conclude that the employed remote sensing techniques complement each other well within a landslide hazard assessment procedure. Copyright 2010 by the American Geophysical Union.
BibTeX:
@article{Strozzi2010,
  author = {Strozzi, T. and Delaloye, R. and Kaab, A. and Ambrosi, C. and Perruchoud, E. and Wegmüller, U.},
  title = {Combined observations of rock mass movements using satellite SAR interferometry, differential GPS, airborne digital photogrammetry, and airborne photography interpretation},
  journal = {Journal of Geophysical Research: Earth Surface},
  publisher = {Blackwell Publishing Ltd},
  year = {2010},
  volume = {115},
  number = {1},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77952712367&doi=10.1029%2f2009JF001311&partnerID=40&md5=1768e792f70fa950f461e5f676ffaec6},
  doi = {10.1029/2009JF001311}
}
Strozzi T, Tosi L, Teatini P, Wegmüller U, Santoro M and Carbognin L (2010), "Advanced monitoring techniques for mapping land displacement on the Venice coastland with satellite SAR data", In IAHS-AISH Publication. Vol. 339, pp. 249-254.
Abstract: In this contribution we review the monitoring techniques applied during the last 20 years in the Venice coastland for the control of land subsidence, with particular emphasis on satellite Synthetic Aperture Radar (SAR) interferometry using images acquired by the ERS-1/2, ENVISAT and TerraSAR-X sensors. Copyright 2010 IAHS Press.
BibTeX:
@conference{Strozzi2010249,
  author = {Strozzi, T. and Tosi, L. and Teatini, P. and Wegmüller, U. and Santoro, M. and Carbognin, L.},
  title = {Advanced monitoring techniques for mapping land displacement on the Venice coastland with satellite SAR data},
  booktitle = {IAHS-AISH Publication},
  year = {2010},
  volume = {339},
  pages = {249-254},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952669313&partnerID=40&md5=6515431025e71735eeab346d2024d584}
}
Tanase M, Pérez-Cabello F, De La Riva J and Santoro M (2010), "TerraSAR-X data for burn severity evaluation in mediterranean forests on sloped terrain", IEEE Transactions on Geoscience and Remote Sensing. Vol. 48(2), pp. 917-929.
Abstract: TerraSAR-X (TSX) dual-polarized synthetic aperture radar (SAR) data from a test site in Spain have been investigated to determine the relationship between forest burn severity and SAR backscatter. The role of the local incidence angle on the backscatter coefficient has been also studied. Burn severity was estimated by means of composition burn index plots and the remotely sensed differenced normalized burn ratio index. To infer the potential of the TSX data for burn severity assessment, the determination coefficients obtained from linear regression analysis have been used. At horizontal transmit horizontal receive (HH) polarization, backscatter increased for slopes oriented toward the sensor and areas affected by high burn severity, whereas, at horizontal transmit vertical receive (HV) polarization, higher backscatter occurred for slopes oriented away from the sensor in areas of low burn severity. The dependence of the backscatter coefficient on topography for areas affected by forest fire has been confirmed. The HH backscatter presented a clear descending trend with the increase in local incidence angle, whereas the HV backscatter presented an ascending trend. The determination coefficients showed that, at HH polarization, better estimates of burn severity are obtained at low local incidence angles, whereas, for HV polarization, the best estimates are obtained at high local incidence angles. The dual-polarized X-band SAR data showed potential for burn severity estimation in the Mediterranean environment if local incidence angle is accounted for. 2009 IEEE.
BibTeX:
@article{Tanase2010917,
  author = {Tanase, M.A. and Pérez-Cabello, F. and De La Riva, J. and Santoro, M.},
  title = {TerraSAR-X data for burn severity evaluation in mediterranean forests on sloped terrain},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2010},
  volume = {48},
  number = {2},
  pages = {917-929},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-76349115821&doi=10.1109%2fTGRS.2009.2025943&partnerID=40&md5=994ca70c8c6f0221d5db691d18918594},
  doi = {10.1109/TGRS.2009.2025943}
}
Tanase M, Santoro M, De La Riva J, Pérez-Cabello F and Le Toan T (2010), "Sensitivity of X-, C-, and L-band SAR backscatter to burn severity in Mediterranean pine forests", IEEE Transactions on Geoscience and Remote Sensing. Vol. 48(10), pp. 3663-3675.
Abstract: Synthetic aperture radar (SAR) data at X-, C-, and L-bands have been investigated to determine the relationship between backscatter and forest burn severity over three sites in Spain. The dependence of SAR backscatter on local incidence angle and environmental conditions has been analyzed. At HH and VV polarizations, the backscatter increased with burn severity for X- and C-bands, whereas it decreased for L-band. Cross-polarized (HV) backscatter decreased with burn severity for all frequencies. Determination coefficients were used to quantify the relationship between radar backscatter and burn severity for given intervals of local incidence angle. For X- and C-band copolarized data, higher determination coefficients were observed for slopes oriented toward the sensors, whereas for cross-polarized data, the determination coefficients were higher for slopes oriented away from the sensor. At L-band, the association strength of cross-polarized data to burn severity was high for all local incidence angles. C- and L-band cross-polarized backscatter showed better potential for burn severity estimation in the Mediterranean environment when the local incidence angle is accounted for. The small dynamic range observed for X-band data could hinder its use in forests affected by fires. 2006 IEEE.
BibTeX:
@article{Tanase20103663,
  author = {Tanase, M.A. and Santoro, M. and De La Riva, J. and Pérez-Cabello, F. and Le Toan, T.},
  title = {Sensitivity of X-, C-, and L-band SAR backscatter to burn severity in Mediterranean pine forests},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2010},
  volume = {48},
  number = {10},
  pages = {3663-3675},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77957013646&doi=10.1109%2fTGRS.2010.2049653&partnerID=40&md5=5258c9adfbcfe406c81b0f8e45fe6b7e},
  doi = {10.1109/TGRS.2010.2049653}
}
Tanase M, Santoro M, Wegmüller U, de la Riva J and Pérez-Cabello F (2010), "Properties of X-, C- and L-band repeat-pass interferometric SAR coherence in Mediterranean pine forests affected by fires", Remote Sensing of Environment. Vol. 114(10), pp. 2182-2194.
Abstract: Synthetic Aperture Radar (SAR) data has been investigated to determine the relationship between burn severity and interferometric coherence at three sites affected by forest fires in a hilly Mediterranean environment. Repeat-pass SAR images were available from the TerraSAR-X, ERS-1/2, Envisat ASAR and ALOS PALSAR sensors. Coherence was related to measurements of burn severity (Composite Burn Index) and remote sensing estimates expressed by the differenced normalized burn ratio (dNBR) index. In addition, the effects of topography and weather on coherence estimates were assessed. The analysis for a given range of local incidence angle showed that the co-polarized coherence increases with the increase of burn severity at X- and C-band whereas cross-polarized coherence was practically insensitive to burn severity. Higher sensitivity to burn severity was found at L-band for both co- and cross-polarized channels. The association strength between coherence and burn severity was strongest for images acquired under stable, dry environmental conditions. When the local incidence angle is accounted for the determination coefficients increased from 0.6 to 0.9 for X- and C-band. At L-band the local incidence angle had less influence on the association strength to burn severity. 2010 Elsevier Inc.
BibTeX:
@article{Tanase20102182,
  author = {Tanase, M.A. and Santoro, M. and Wegmüller, U. and de la Riva, J. and Pérez-Cabello, F.},
  title = {Properties of X-, C- and L-band repeat-pass interferometric SAR coherence in Mediterranean pine forests affected by fires},
  journal = {Remote Sensing of Environment},
  year = {2010},
  volume = {114},
  number = {10},
  pages = {2182-2194},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955307541&doi=10.1016%2fj.rse.2010.04.021&partnerID=40&md5=1d03e198dd282b561e803de81f6f743b},
  doi = {10.1016/j.rse.2010.04.021}
}
Tizzani P, Manconi A, Zeni G, Pepe A, Manzo M, Camacho A and Fernández J (2010), "Long-term versus short-term deformation processes at Tenerife (Canary Islands)", Journal of Geophysical Research: Solid Earth. Vol. 115(12) Blackwell Publishing Ltd.
Abstract: Several geophysical investigations have identified that the Tenerife volcanic complex is affected by crustal deformation processes occurring at timescales of millions of years. Recently, space-based geodetic observations have also detected a short-term surface deformation, characterized by a broad subsidence pattern with maximum ground velocities of about 4 mm yr-1. For the purpose of investigating the relationship between these long-term and short-term deformation processes, we performed an advanced fluid dynamic analysis (FDA). We first carried out a standard dimensionless FDA to discriminate the deformation style of Tenerife and found that, at million year timescales, basement flexure mainly controls its long-term structural evolution. Secondly, to highlight the driving forces of the short-term deformation process, we simulated a numerical FDA based on finite element models that include topography as well as vertical and lateral material heterogeneities. Our results show that the recent surface deformation is mainly caused by a progressive sagging of the denser (less viscous) core of the island onto the weaker (but more viscous) lithosphere. Moreover, over periods comparable to the hypothesized age of loading of the oceanic crust beneath Tenerife, this tendency would result in a total flexure of about 3-4 km, which is in agreement with independent estimations based on geophysical analyses. Our study shows that a unitary physical model may explain both the deformation recorded in deep geological structures and the current active ground deformation processes occurring at the Tenerife volcano. Copyright 2010 by the American Geophysical Union.
BibTeX:
@article{Tizzani2010,
  author = {Tizzani, P. and Manconi, A. and Zeni, G. and Pepe, A. and Manzo, M. and Camacho, A. and Fernández, J.},
  title = {Long-term versus short-term deformation processes at Tenerife (Canary Islands)},
  journal = {Journal of Geophysical Research: Solid Earth},
  publisher = {Blackwell Publishing Ltd},
  year = {2010},
  volume = {115},
  number = {12},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650508767&doi=10.1029%2f2010JB007735&partnerID=40&md5=077115ee130fef01118bbeae6dd9cb48},
  doi = {10.1029/2010JB007735}
}
Tosi L, Teatini P, Strozzi T, Carbognin L, Brancolini G and Rizzetto F (2010), "Ground surface dynamics in the northern Adriatic coastland over the last two decades", Rendiconti Lincei. Vol. 21(SUPPL. 1), pp. 115-129.
Abstract: Abstract During most of the past century, spirit leveling was the only technique for providing high-precision data for the assessment of land subsidence in the northern Adriatic coastland. Only at the end of the 1990s did global positioning system methods, both continuous (CGPS) and differential (DGPS), begin to be used for ground movement measurements with a sufficient accuracy. Since the beginning of the new millennium, space-borne observation techniques based on synthetic aperture radar (SAR) interferometry also have been used to detect ground displacements, i.e., subsidence and uplift, in the Venice coastland. Differential InSAR (DInSAR), first, and interferometric point target analysis (IPTA), at a later stage, have been applied to measure and map displacements occurring since 1992 when SAR data first became available. The capability of SAR interferometry to measure ground vertical movements in large areas at millimetric accuracy has significantly improved the knowledge of the phenomenon. In particular, comprehensive maps of the vertical displacements have revealed the high spatial variability characterizing the ground movements in the Venice region. A general land stability has been detected in the central part of the study area, including the major cities of Venice, Padova and Treviso, with scattered local bowls of subsidence of up to 2-3 mm/year. Conversely, land settlement has appeared as a widespread phenomenon in the northern and southern coast with rates of up to 5 and 15 mm/year, respectively. Uplift rates ranging up to 2 mm/year have been measured in two different large areas located north of Treviso and south of Padova, respectively, whereas higher values are restricted to the eastern sector of the Euganean Hills. Springer-Verlag 2010.
BibTeX:
@article{Tosi2010115,
  author = {Tosi, L. and Teatini, P. and Strozzi, T. and Carbognin, L. and Brancolini, G. and Rizzetto, F.},
  title = {Ground surface dynamics in the northern Adriatic coastland over the last two decades},
  journal = {Rendiconti Lincei},
  year = {2010},
  volume = {21},
  number = {SUPPL. 1},
  pages = {115-129},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864307047&doi=10.1007%2fs12210-010-0084-2&partnerID=40&md5=18534fd687965dc5eba924b3981cf85b},
  doi = {10.1007/s12210-010-0084-2}
}
Volksch I, Schwank M and Matzler C (2010), "L-band reflectivity of a wire grid above a dielectric surface", IEEE Geoscience and Remote Sensing Letters. Vol. 7(3), pp. 601-605.
Abstract: We investigated the influence of a wire grid above a paved ground on thermal brightness at 1.4 GHz. Reflectivities were derived from dual-polarized brightness temperature measurements for different grid orientations and wire spacings between 2.5 and 20 cm. For spacings larger than a quarter of a wavelength (≈5 cm), the grid had no impact on the observed reflectivities. A physical model was used to analyze the experimental results. 2010 IEEE.
BibTeX:
@article{Volksch2010601,
  author = {Volksch, I. and Schwank, M. and Matzler, C.},
  title = {L-band reflectivity of a wire grid above a dielectric surface},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  year = {2010},
  volume = {7},
  number = {3},
  pages = {601-605},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954624641&doi=10.1109%2fLGRS.2010.2042786&partnerID=40&md5=2c894de2936dc1662d07a26e42aaccc6},
  doi = {10.1109/LGRS.2010.2042786}
}
Walter T, Manzo M, Manconi A, Solaro G, Lanari R, Motagh M, Woith H, Parolai S, Shirzaei M, Zschau J, Baris S and Ansal A (2010), "Satellite monitoring of hazards: A Focus on Istanbul, Turkey", Eos. Vol. 91(36), pp. 313-314.
BibTeX:
@article{Walter2010313,
  author = {Walter, T.R. and Manzo, M. and Manconi, A. and Solaro, G. and Lanari, R. and Motagh, M. and Woith, H. and Parolai, S. and Shirzaei, M. and Zschau, J. and Baris, S. and Ansal, A.},
  title = {Satellite monitoring of hazards: A Focus on Istanbul, Turkey},
  journal = {Eos},
  year = {2010},
  volume = {91},
  number = {36},
  pages = {313-314},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956834901&doi=10.1029%2f2010EO360001&partnerID=40&md5=61c9734ea2de41c81484c2978f663adf},
  doi = {10.1029/2010EO360001}
}
Wegmüller U, Santoro M, Werner C, Strozzi T and Wiesmann A (2010), "Estimation of ICE thickness of tundra lakes using ERS - ENVISAT cross-interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 316-319.
Abstract: ERS-ENVISAT cross-interferometry is a unique tool for a number of applications since it combines a short repeat-pass interval (28 minutes) with a long perpendicular baseline (2 km). In the present work a methodology to use the cross-interferogram phase to map the ice thickness of frozen tundra lakes and northern rivers. After presenting the methodology used examples over sites in northern Canada and Siberia are shown. For one site the results could be compared to in-situ measurements and showed good correspondence. 2010 IEEE.
BibTeX:
@conference{Wegmuller2010316,
  author = {Wegmüller, U. and Santoro, M. and Werner, C. and Strozzi, T. and Wiesmann, A.},
  title = {Estimation of ICE thickness of tundra lakes using ERS - ENVISAT cross-interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2010},
  pages = {316-319},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650883825&doi=10.1109%2fIGARSS.2010.5649026&partnerID=40&md5=efa851f5e313c016b78b144a1f0e37bf},
  doi = {10.1109/IGARSS.2010.5649026}
}
Wegmüller U, Walter D, Spreckels V and Werner C (2010), "Nonuniform ground motion monitoring with TerraSAR-X persistent scatterer interferometry", IEEE Transactions on Geoscience and Remote Sensing. Vol. 48(2), pp. 895-904.
Abstract: In the past, the application of Persistent Scatterer Interferometry (PSI) was primarily possible in the case of slow (less than a few centimeters per year) uniform movements. In this paper, we show how PSI permits the monitoring of relatively fast (including rates up to > 50cm/year) and nonuniform movements using TerraSAR-X repeat observations over deep-level mining. To enable this, parts of the PSI methodology were adapted to the special characteristics of the example studied. Apart from a description of the methodology used and the result achieved, error considerations and a validation of the result with in situ measurements are included. 2009 IEEE.
BibTeX:
@article{Wegmuller2010895,
  author = {Wegmüller, U. and Walter, D. and Spreckels, V. and Werner, C.L.},
  title = {Nonuniform ground motion monitoring with TerraSAR-X persistent scatterer interferometry},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2010},
  volume = {48},
  number = {2},
  pages = {895-904},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-76349121786&doi=10.1109%2fTGRS.2009.2030792&partnerID=40&md5=2a8c3d2403aa8c6ed9b3b9cfcc0bc2e7},
  doi = {10.1109/TGRS.2009.2030792}
}
Werner C, Wiesmann A, Strozzi T, Schneebeli M and Matzler C (2010), "The SnowScat ground-based polarimetric scatterometer: Calibration and initial measurements from davos Switzerland", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 2363-2366.
Abstract: We present the first results from calibration of the SnowScat scatterometer that operated at Weissfluhjoch during the Winter season of 2009. The instrument has been designed to operate in severe alpine environments. SnowScat has acquired a data set that will be used for validation of SWE retrieval algorithms in support of the CoReH20 mission. Processing and calibration of the entire Weissfluhjoch data set is ongoing. 2010 IEEE.
BibTeX:
@conference{Werner20102363,
  author = {Werner, C. and Wiesmann, A. and Strozzi, T. and Schneebeli, M. and Matzler, C.},
  title = {The SnowScat ground-based polarimetric scatterometer: Calibration and initial measurements from davos Switzerland},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2010},
  pages = {2363-2366},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650872313&doi=10.1109%2fIGARSS.2010.5649015&partnerID=40&md5=e17f631b8587a3b48d8dddfa7ae9880d},
  doi = {10.1109/IGARSS.2010.5649015}
}
Askne J and Santoro M (2009), "Automatic model-based estimation of boreal forest stem volume from repeat pass C-band InSAR coherence", IEEE Transactions on Geoscience and Remote Sensing. Vol. 47(2), pp. 513-516.
Abstract: C-band repeat pass interferometric synthetic aperture radar coherence can provide high-accuracy estimates of boreal forest stem volume in spite of environmental dependence. Typically, the retrieval methods require a data set of in situ measurements for training the model linking coherence to stem volume. The drawback is the need for such data and the incapacity to take into account spatial variations of environmental conditions. Here, we demonstrate a model training method that does not require reference data. For the investigated case, the relative root mean square error of stem volume is 18% or as good as obtained using the traditional training method with in situ data. 2009 IEEE.
BibTeX:
@article{Askne2009513,
  author = {Askne, J.I.H. and Santoro, M.},
  title = {Automatic model-based estimation of boreal forest stem volume from repeat pass C-band InSAR coherence},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2009},
  volume = {47},
  number = {2},
  pages = {513-516},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-59849129083&doi=10.1109%2fTGRS.2008.2009764&partnerID=40&md5=a70572738aeca1d120d8b8aaccc81cf5},
  doi = {10.1109/TGRS.2008.2009764}
}
Brocard E, Schneebeli M and Matzler C (2009), "Deriving winds at cloud-base height with an infrared camera", IEEE Transactions on Geoscience and Remote Sensing. Vol. 47(10), pp. 3319-3325.
Abstract: An uncooled commercial infrared camera is used to retrieve horizontal winds at cloud-base height. The camera is equipped with a microbolometer array of 320 × 240 pixels covering a field of view of 32° × 24°. It operates in the atmospheric window from 7.5 to 14 μm. In this wavelength range, the camera has day and night measurement capabilities, independent of the illumination conditions. Optically thick clouds appear as blackbody radiators and offer a large brightness temperature contrast with the much colder clear-sky background. We develop a method to follow the infrared structures in the clouds as they pass through the field of view of the camera. Taking a picture every 6 s, the angular velocity of the cloud base is calculated as the ratio of t angular displacement of the cloud structures between two pictures over the elapsed time. To transform the angular velocity into a metric velocity, we use the temperature profile retrieved by a microwave radiometer called All-Sky MUlti-WAvelength Radiometer. The case study of September 10, 2007 is shown. The retrieved wind is of 18.0 ± 2.4 m/s at an altitude of 4164 ± 546 m above the instrument, blowing from northwest. These results agree well with radiosondings launched in the vicinity of the experiment site. 2009 IEEE.
BibTeX:
@article{Brocard20093319,
  author = {Brocard, E. and Schneebeli, M. and Matzler, C.},
  title = {Deriving winds at cloud-base height with an infrared camera},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2009},
  volume = {47},
  number = {10},
  pages = {3319-3325},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70350622982&doi=10.1109%2fTGRS.2009.2021158&partnerID=40&md5=c22b23311b1c0b5360b63613a31f9199},
  doi = {10.1109/TGRS.2009.2021158}
}
Frey O, Magnard C, Ruegg M and Meier E (2009), "Focusing of airborne synthetic aperture radar data from highly nonlinear flight tracks", IEEE Transactions on Geoscience and Remote Sensing. Vol. 47(6), pp. 1844-1858. IEEE.
Abstract: Standard focusing of data from synthetic aperture radar (SAR) assumes a straight recording track of the sensor platform. Small nonli neari ties of airborne platform tracks are corrected for during a motion-compensation step while maintaining the assumption of a linear flight path. This paper describes the processing of SAR data acquired from nonlinear tracks, typical of sensors mounted on small aircraft or drones flying at low altitude. Such aircraft do not fly along straight tracks, but the trajectory depends on topography, influences of weather and wind, or the shape of areas of interest such as rivers or traffic routes. Two potential approaches for processing SAR data from such highly nonlinear flight tracks are proposed, namely, a patchwise frequency-domain processing and mosaicking technique and a time-domain back-projection-based technique. Both are evaluated with the help of experimental data featuring tracks with altitude changes, a double bend, a 90° curve, and a linear flight track. In order to assess the quality of the focused data, close-ups of amplitude images are compared, impulse response functions of a point target are analyzed, and the coherence is evaluated. The experimental data were acquired by the German Aerospace Center's E-SAR L-band system. 2008 IEEE.
BibTeX:
@article{Frey20091844,
  author = {Frey, O. and Magnard, C. and Ruegg, M. and Meier, E.},
  title = {Focusing of airborne synthetic aperture radar data from highly nonlinear flight tracks},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {IEEE},
  year = {2009},
  volume = {47},
  number = {6},
  pages = {1844-1858},
  url = {https://www.gamma-rs.ch/uploads/media/freyMagnardRueeggMeierTGRS2009Tracks.pdf},
  doi = {10.1109/TGRS.2008.2007591}
}
Gambolati G, Teatini P, Ferronato M, Strozzi T, Tosi L and Putti M (2009), "On the uniformity of anthropogenic Venice uplift", Terra Nova. Vol. 21(6), pp. 467-473.
Abstract: A programme of Venice uplift because of seawater injection into a 600-800 m deep brackish aquifer underlying the lagoon has recently been advanced. As the actual spatial variability of the hydro-geological parameters is to a large extent unknown, a controversial issue concerns the 25-30 cm heave prediction with the possible generation of differential displacements that might jeopardize the integrity of the architectural patrimony. It is shown that significant differential displacements have occurred in Venice in the past and are still presently occurring as evidenced by SAR interferometry. The results of a stochastic analysis addressing the variability of the hydraulic conductivity of the injected formation indicate that even a highly uneven aquifer expansion does not migrate to ground surface because of the smoothing effect exerted by the overburden. The predicted differential displacements are well below the values Venice is experiencing. Any . a priori alarmism appears to be unfounded and unjustified. 2009 Blackwell Publishing Ltd.
BibTeX:
@article{Gambolati2009467,
  author = {Gambolati, G. and Teatini, P. and Ferronato, M. and Strozzi, T. and Tosi, L. and Putti, M.},
  title = {On the uniformity of anthropogenic Venice uplift},
  journal = {Terra Nova},
  year = {2009},
  volume = {21},
  number = {6},
  pages = {467-473},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-71049192387&doi=10.1111%2fj.1365-3121.2009.00903.x&partnerID=40&md5=204ab9b474044998ccae4de3f94a6560},
  doi = {10.1111/j.1365-3121.2009.00903.x}
}
Grant J, Van De Griend A, Schwank M and Wigneron J-P (2009), "Observations and modeling of a pine forest floor at L-band", IEEE Transactions on Geoscience and Remote Sensing. Vol. 47(7), pp. 2024-2034.
Abstract: Recent studies of passive L-band observations over forests have shown that the average canopy transmissivity in temperate coniferous and deciduous forests is on the order of 0.40.5. Although the canopy would therefore be expected to transmit a reasonable amount of ground emission, the total emission observed above the canopy shows very little variation with varying soil moisture content. Moist litter present on the forest floor is known to obscure the soil emission. Therefore, more knowledge on the L-band radiative properties of litter and understory layers is needed to better understand the emission of the whole forest system. In order to contribute toward this issue, a field experiment was conducted in a pine forest in southwest France. Radiometric observations were done on the canopy and on different configurations of the forest floor, following sequential stripping of each forest floor layer. In combination with a long-term data set of above-canopy observations, this resulted in emissivity values of bare soil, soillitter, soillittergrass, and soillittergrasscanopy configurations for a range of soil and litter moisture values. Calculations involved the use of the Wilheit and L-MEB models. The sensitivity to soil moisture was found to be substantially suppressed by the presence of a grass understory and litter. This corroborates the low correlation between soil moisture and L-band brightness temperature measured above the canopy. Several results of recent modeling and laboratory studies are also confirmed by this paper, which is, to our knowledge, the first to use in situ experimental data in this context. 2006 IEEE.
BibTeX:
@article{Grant20092024,
  author = {Grant, J.P. and Van De Griend, A.A. and Schwank, M. and Wigneron, J.-P.},
  title = {Observations and modeling of a pine forest floor at L-band},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2009},
  volume = {47},
  number = {7},
  pages = {2024-2034},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67651155801&doi=10.1109%2fTGRS.2008.2010252&partnerID=40&md5=98d05aa8f8b17a73006bc7e031538cec},
  doi = {10.1109/TGRS.2008.2010252}
}
Groisman PY, Clark E, Kattsov V, Lettenmaier D, Sokolik I, Aizen V, Cartus O, Chen J, Conard S, Katzenberger J, Krankina O, Kukkonen J, Machida T, Maksutov S, Ojima D, Qi J, Romanovsky V, Santoro M, Schmullius C, Shiklomanov A, Shimoyama K, Shugart HH, Shuman JK, Sofiev MA, Sukhinin AL, Vorosmarty C, Walker D and Wood EF (2009), "The Northern Eurasia Earth Science Partnership: An example of science applied to societal needs", Bulletin of the American Meteorological Society. Vol. 90(5), pp. 671-688.
Abstract: Northern Eurasia, the largest land-mass in the northern extratropics, accounts for 20% of the global land area. However, little is known about how the biogeochemical cycles, energy and water cycles, and human activities specific to this carbon-rich, cold region interact with global climate. A major concern is that changes in the distribution of land-based life, as well as its interactions with the environment, may lead to a self-reinforcing cycle of accelerated regional and global warming. With this as its motivation, the Northern Eurasian Earth Science Partnership Initiative (NEESPI) was formed in 2004 to better understand and quantify feedbacks between northern Eurasian and global climates. The first group of NEESPI projects has mostly focused on assembling regional databases, organizing improved environmental monitoring of the region, and studying individual environmental processes. That was a starting point to addressing emerging challenges in the region related to rapidly and simultaneously changing climate, environmental, and societal systems. More recently, the NEESPI research focus has been moving toward integrative studies, including the development of modeling capabilities to project the future state of climate, environment, and societies in the NEESPI domain. This effort will require a high level of integration of observation programs, process studies, and modeling across disciplines. 2009 American Meteorological Society.
BibTeX:
@article{Groisman2009671,
  author = {Groisman, Pavel Y. and Clark, E.A. and Kattsov, V.M. and Lettenmaier, D.P. and Sokolik, I.N. and Aizen, V.B. and Cartus, O. and Chen, J. and Conard, S. and Katzenberger, J. and Krankina, O. and Kukkonen, J. and Machida, T. and Maksutov, S. and Ojima, D. and Qi, J. and Romanovsky, V.E. and Santoro, M. and Schmullius, C.C. and Shiklomanov, A.I. and Shimoyama, K. and Shugart, H. H. and Shuman, J. K. and Sofiev, M. A. and Sukhinin, A. L. and Vorosmarty, C. and Walker, D. and Wood, E. F.},
  title = {The Northern Eurasia Earth Science Partnership: An example of science applied to societal needs},
  journal = {Bulletin of the American Meteorological Society},
  year = {2009},
  volume = {90},
  number = {5},
  pages = {671-688},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-68949213032&doi=10.1175%2f2008BAMS2556.1&partnerID=40&md5=a36d212e2fb60b80f3c7ca079cabf93a},
  doi = {10.1175/2008BAMS2556.1}
}
Loew A, Schwank M and Schlenz F (2009), "Assimilation of an L-band microwave soil moisture proxy to compensate for uncertainties in precipitation data", IEEE Transactions on Geoscience and Remote Sensing. Vol. 47(8), pp. 2606-2616.
Abstract: The accuracy of hydrological model simulations is dependent on the reliability of model input data like, for example, meteorological information or land cover and soil information. Uncertainties of simulations of soil water fluxes are hereby directly related to the accuracy of available precipitation data. As precipitation is characterized by small temporal and spatial correlation lengths, the uncertainties in precipitation data increase with decreasing density of available precipitation gauges. As soil moisture directly depends on precipitation dynamics, its variation can be used as a proxy for precipitation variability. Remote sensing techniques allow for monitoring of surface soil moisture dynamics at different spatiotemporal scales. In particular, low-frequency microwave data are most sensitive to soil moisture dynamics. This paper investigates the potential of integrating L-band (12 GHz) microwave radiometer data into a simple model for soil wetness to compensate for uncertainties in a priori information of precipitation. The study is based on a short-term ground-based L-band radiometer data set over grassland. A high correlation between the microwave signature and surface soil moisture was found, which is consistent with previous findings. An analytical data assimilation scheme for the integration of that information into a soil wetness model, based on an antecedent precipitation index (API), was established. The results revealed that the data assimilation filter adds or removes an amount of water partially compensating for the actual precipitation error. The correlation coefficient between the filter update and the actual precipitation error was found to be 0.6 ≤ r ≤ 0.8, and the model simulations did show a better coincidence with in situ soil moisture records when integrating the microwave data. The results indicate high potential for use of L-band microwave data to compensate for uncertainties in precipitation data. 2006 IEEE.
BibTeX:
@article{Loew20092606,
  author = {Loew, A. and Schwank, M. and Schlenz, F.},
  title = {Assimilation of an L-band microwave soil moisture proxy to compensate for uncertainties in precipitation data},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2009},
  volume = {47},
  number = {8},
  pages = {2606-2616},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67949118792&doi=10.1109%2fTGRS.2009.2014846&partnerID=40&md5=16694e3be0ab65d3317b4c90aa11d8b6},
  doi = {10.1109/TGRS.2009.2014846}
}
Manconi A, Longpe M-A, Walter T, Troll V and Hansteen T (2009), "The effects of flank collapses on volcano plumbing systems", Geology. Vol. 37(12), pp. 1099-1102.
Abstract: The growth of large volcanoes is commonly interrupted by episodes of flank collapse that may be accompanied by catastrophic debris avalanches, explosive eruptions, and tsunamis. El Hierro, the youngest island of the Canary Archipelago, has been repeatedly affected by such mass-wasting events in the last 1 Ma. Our field observations and petrological data suggest that the largest and most recent of these fl ank collapses - the El Golfo landslide - likely influenced the magma plumbing system of the island, leading to the eruption of higher proportions of denser and less evolved magmas. The results of our numerical simulations indicate that the El Golfo landslide generated pressure changes exceeding 1 MPa down to upper-mantle depths, with local amplification in the surroundings and within the modeled magma plumbing system. Stress perturbations of that order might drastically alter feeding system processes, such as degassing, transport, differentiation, and mixing of magma batches. 2009 Geological Society of America.
BibTeX:
@article{Manconi20091099,
  author = {Manconi, A. and Longpe, M.-A. and Walter, T.R. and Troll, V.R. and Hansteen, T.H.},
  title = {The effects of flank collapses on volcano plumbing systems},
  journal = {Geology},
  year = {2009},
  volume = {37},
  number = {12},
  pages = {1099-1102},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-72149083573&doi=10.1130%2fG30104A.1&partnerID=40&md5=135231ffb36769c550d6f650da6b5da6},
  doi = {10.1130/G30104A.1}
}
Matzler C, Koffi E and Berne A (2009), "Monitoring rain rate with data from networks of microwave transmission links", In European Conference on Antennas and Propagation, EuCAP 2009, Proceedings. , pp. 907-910.
Abstract: Monitoring microwave attenuation (20 to 45 GHz) of directional transmission links is a method to derive rain rate at high time resolution and in near-real time. Raindrops falling through a propagation path of a microwave link attenuate the transmitted signal quasi linearly with rain rate, allowing the estimation of path-averaged rain intensity. These data are valuable for meteorology, hydrology, agriculture, flood control, and others. The application to entire networks of commercial links would be a cost-effective method to fill data gaps where precipitation-radar data are either distorted or missing, such as large cities, valleys in mountain areas and developing countries. We will review the feasibility of the method and report on activities for setting up a project in Switzerland.
BibTeX:
@conference{Matzler2009907,
  author = {Matzler, C. and Koffi, E. and Berne, A.},
  title = {Monitoring rain rate with data from networks of microwave transmission links},
  booktitle = {European Conference on Antennas and Propagation, EuCAP 2009, Proceedings},
  year = {2009},
  pages = {907-910},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349866417&partnerID=40&md5=ad8e463aed8d8f845b212bb594d62c73}
}
Matzler C and Morland J (2009), "Refined physical retrieval of integrated water vapor and cloud liquid for microwave radiometer data", IEEE Transactions on Geoscience and Remote Sensing. Vol. 47(6), pp. 1585-1594.
Abstract: Monitoring atmospheric water is essential for the understanding of the dynamic processes of the atmosphere and for the assessment of wave-propagation properties. Microwave radiometers, in combination with a thermal infrared channel, have the potential to fulfill these tasks. This paper is focused on the surface-based system TROWARA with microwave channels at 21.3 and 31.5 GHz. TROWARA has been used for tropospheric water measurements at Bern since 1994 together with a standard meteo station. So far, emphasis has been put on integrated water vapor (IWV) measurements, particularly for climate studies, but integrated liquid water (ILW) has been retrieved as well. We report on methodological advances with the data analysis. First, the original algorithm was replaced by a new statistical retrieval based on the simulations of TROWARA data using radiosonde profiles. Second, in a physical refinement, the cause of the variable ILW bias has been identified, and a method for its reduction to the level of 0.001 to 0.005 mm has been developed and tested. The bias is mainly a result of the variable water-vapor influence on absorption at 31 GHz. The bias correction also influences the IWV retrieval. The refined physical retrieval includes the temperature dependence of cloud absorption based on a recent dielectric model of water. The three algorithms (original, new, and refined) have been compared for two years of data. The applications of the refined algorithm are focused on physical processes, such as the development of supercooled clouds. Future advances will include precipitation measurements. 2008 IEEE.
BibTeX:
@article{Matzler20091585,
  author = {Matzler, C. and Morland, J.},
  title = {Refined physical retrieval of integrated water vapor and cloud liquid for microwave radiometer data},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2009},
  volume = {47},
  number = {6},
  pages = {1585-1594},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349159362&doi=10.1109%2fTGRS.2008.2006984&partnerID=40&md5=742e8e92f43897c40dab30f98709b72d},
  doi = {10.1109/TGRS.2008.2006984}
}
Morland J, Coen C, Hocke K, Jeannet P and Matzler C (2009), "Tropospheric water vapour above Switzerland over the last 12 years", Atmospheric Chemistry and Physics. Vol. 9(16), pp. 5975-5988. Copernicus GmbH.
Abstract: Integrated Water vapour (IWV) has been measured since 1994 by the TROWARA microwave radiometer in Bern, Switzerland. Homogenization techniques were used to identify and correct step changes in IWV related to instrument problems. IWV from radiosonde, GPS and sun photometer (SPM) was used in the homogenisation process as well as partial IWV columns between valley and mountain weather stations. The average IWV of the homogenized TROWARA time series was 14.4mm over the 1996-2007 period, with maximum and minimum monthly average values of 22.4mm and 8mm occurring in August and January, respectively. A weak diurnal cycle in TROWARA IWV was detected with an amplitude of 0.32 mm, a maximum at 21:00UT and a minimum at 11:00 UT. For 1996- 2007, TROWARA trends were compared with those calculated from the Payerne radiosonde and the closest ECMWF grid point to Bern. Using least squares analysis, the IWV time series of radiosondes at Payerne, ECMWF, and TROWARA showed consistent positive trends from 1996 to 2007. The radiosondes measured an IWV trend of 0.45±0.29%/y, the TROWARA radiometer observed a trend of 0.39±0.44%/y, and ECMWF operational analysis gave a trend of 0.25±0.34%/y. Since IWV has a strong and variable annual cycle, a seasonal trend analysis (Mann-Kendall analysis) was also performed. The seasonal trends are stronger by a factor 10 or so compared to the full year trends above. The positive IWV trends of the summer months are partly compensated by the negative trends of the winter months. The strong seasonal trends of IWV on regional scale underline the necessity of long-term monitoring of IWV for detection, understanding, and forecast of climate change effects in the Alpine region. 2009 Author(s).
BibTeX:
@article{Morland20095975,
  author = {Morland, J. and Coen, C.M. and Hocke, K. and Jeannet, P. and Matzler, C.},
  title = {Tropospheric water vapour above Switzerland over the last 12 years},
  journal = {Atmospheric Chemistry and Physics},
  publisher = {Copernicus GmbH},
  year = {2009},
  volume = {9},
  number = {16},
  pages = {5975-5988},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80052018647&doi=10.5194%2facp-9-5975-2009&partnerID=40&md5=01cf741f122f847377720a058a1da2ca},
  doi = {10.5194/acp-9-5975-2009}
}
Pantze A, Krantz A, Fransson J, Olsson H, Santoro M, Eriksson L and Ulander L (2009), "Mapping and monitoring clear-cuts in Swedish forest using ALOS Palsar satellite images", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. III589-III592.
Abstract: This study presents results for observing forest changes in Sweden using multi-temporal L-band satellite data and is a part of the JAXA's ALOS Kyoto and Carbon Initiative. An extensive dataset of images acquired by the Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) is investigated for clear-cut detection in boreal forests in northern Sweden (Lat. 64°14' N, Long. 19°50' E). Strong forest/non-forest contrast and temporal consistency were found for the Fine Beam Dual HV-polanzed backscatter during unfrozen conditions. Thus, a simple thresholding algorithm that exploits the temporal consistency of pair-wise HV-backscatter measurements has been developed for clear-cut detection. When applied to an image pair acquired during favorable weather conditions, the detection algorithm identified 76% of the clear-cut pixels within a reference layer, with zero erroneously detected pixels. With further refinement the developed methodology can be an option to present operational alternatives for clear-cut detection. 2009 IEEE.
BibTeX:
@conference{Pantze2009,
  author = {Pantze, A. and Krantz, A.H. and Fransson, J.E.S. and Olsson, H. and Santoro, M. and Eriksson, L.E.B. and Ulander, L.M.H.},
  title = {Mapping and monitoring clear-cuts in Swedish forest using ALOS Palsar satellite images},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2009},
  volume = {3},
  pages = {III589-III592},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77950933238&doi=10.1109%2fIGARSS.2009.5417826&partnerID=40&md5=c41e75d5cf095d0c49566e5879e82585},
  doi = {10.1109/IGARSS.2009.5417826}
}
Parcharidis I, Foumelis M, Kourkouli P and Wegmüller U (2009), "Persistent Scatterers InSAR to detect ground deformation over Rio-Antirio area (Western Greece) for the period 1992-2000", Journal of Applied Geophysics. Vol. 68(3), pp. 348-355.
Abstract: The aim of this paper is to detect ground deformation detection in the Rio-Antirio area (Western Greece), between 1992 and 2000. The construction of Rio-Antirio bridge, commenced in year 2000 and completed in 2004 when its operation was launched, demands the study of the historic deformation of the broader area. The Interferometric Point Target Analysis (IPTA) was applied using a dataset of 42 ERS-1 and 2 scenes. Two separate IPTA processing were performed using different reference points for Rio and Antirio respectively. It would not be possible to unwrap the entire scenes using a single reference point because of the presence of the sea water mass between Rio and Antirio. The majority of the point targets show subsidence for the area of Rio ranging between - 1.8 mm/year and - 6.2 mm/year and for the Antirio area stability or subsidence rates of less than 2 mm/year. Additionally, the deformation history for a number of point targets for both areas was investigated. The detected subsidence of the coastal plains and specially this of Rio could be attributed to the presence of active faults as the area is located over the hanging wall of the fault zone. 2008 Elsevier B.V. All rights reserved.
BibTeX:
@article{Parcharidis2009348,
  author = {Parcharidis, I. and Foumelis, M. and Kourkouli, P. and Wegmüller, U.},
  title = {Persistent Scatterers InSAR to detect ground deformation over Rio-Antirio area (Western Greece) for the period 1992-2000},
  journal = {Journal of Applied Geophysics},
  year = {2009},
  volume = {68},
  number = {3},
  pages = {348-355},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349257144&doi=10.1016%2fj.jappgeo.2009.02.005&partnerID=40&md5=1a5eff1379e3561be5668934b7c2f8be},
  doi = {10.1016/j.jappgeo.2009.02.005}
}
Rommen B, Mika A, Gale L, Zelle H, Hanssen R, Liu S, Matzler C, Morland J, Wegmüller U, Werner C and Santoro M (2009), "The ESA METAWAVE project: Correcting for atmospheric water vapour effects in InSAR products", In European Conference on Antennas and Propagation, EuCAP 2009, Proceedings. , pp. 3428-3432.
Abstract: In many cases, the largest uncertainty in Synthetic Aperture Radar Interferometry (InSAR) is a range delay caused by the presence of atmospheric water vapour resulting in a phase disturbance. This limits the accuracy of InSAR products such as digital elevation models (DEMs) and terrain subsidence maps. The quality of these products could be dramatically improved if atmospheric water vapour effects could be corrected for. The ESA METAWAVE (Mitigation of Electromagnetic Transmission errors induced by Atmospheric WAter Vapour Effects) project primarily aims at improving the accuracy of InSAR products by correcting for atmospheric effects in novel ways.
BibTeX:
@conference{Rommen20093428,
  author = {Rommen, B. and Mika, A. and Gale, L. and Zelle, H. and Hanssen, R. and Liu, S. and Matzler, C. and Morland, J. and Wegmüller, U. and Werner, C. and Santoro, M.},
  title = {The ESA METAWAVE project: Correcting for atmospheric water vapour effects in InSAR products},
  booktitle = {European Conference on Antennas and Propagation, EuCAP 2009, Proceedings},
  year = {2009},
  pages = {3428-3432},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349868447&partnerID=40&md5=04b617312be1e0df6c115542d8747ef9}
}
Ruch J, Manconi A, Zeni G, Solaro G, Pepe A, Shirzaei M, Walter T and Lanari R (2009), "Stress transfer in the Lazufre volcanic area, central Andes", Geophysical Research Letters. Vol. 36(22)
Abstract: We generated a 13-year InSAR time series from 1995-2008 to investigate the spatiotemporal characteristics of two neighboring volcano's deformations for the Lazufre volcanic area, central Andes. The data reveal two scales of uplift initiating during the observation time: (1) a largescale uplift started in 1997 that shows an increase of the mean uplift rate of up to 3.2 cm/yr, now affecting several eruptive centers situated in an area larger than 1800 km2 and (2) a small-scale uplift located at Lastarria volcano, which is the only volcano to show strong fumarolic activity in decades, with most of the clear deformation apparently not observed before 2000. Both the large and small uplift signals can be explained by magmatic or hydrothermal sources located at about 13 km and 1 km deep, respectively. To test a possible relationship, we use numerical modeling and estimate that the depth inflating source increased the tensile stress close to the shallow source. We discuss how the deep inflating source may have disturbed the shallow one and triggered the observed deformation at Lastarria. Copyright 2009 by the American Geophysical Union.
BibTeX:
@article{Ruch2009,
  author = {Ruch, J. and Manconi, A. and Zeni, G. and Solaro, G. and Pepe, A. and Shirzaei, M. and Walter, T.R. and Lanari, R.},
  title = {Stress transfer in the Lazufre volcanic area, central Andes},
  journal = {Geophysical Research Letters},
  year = {2009},
  volume = {36},
  number = {22},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-72049125591&doi=10.1029%2f2009GL041276&partnerID=40&md5=d6b304c78bc114984a99e433d44566ba},
  doi = {10.1029/2009GL041276}
}
Santoro M, Fransson J, Eriksson L, Magnusson M, Ulander L and Olsson H (2009), "Signatures of ALOS PALSAR L-band backscatter in Swedish Forest", IEEE Transactions on Geoscience and Remote Sensing. Vol. 47(12), pp. 4001-4019.
Abstract: The Phased Array type L-band Synthetic Aperture Radar onboard the Advanced Land Observing Satellite has, since its launch, been acquiring an extensive data set of images over two forest test sites in Sweden. The sites of Remningstorp (Lat. 58°30′ N, Long. 13°40′ E) in the south and Krycklan (Lat. 64°14′ N, Long. 19°50′ E) in the north of Sweden are characterized by hemiboreal and boreal forests, respectively. In this paper, we have investigated the signatures of standwise backscatter measurements from forests with different growth stages in relation to polarization, environmental conditions, image viewing geometry, and spatial resolution. The HV backscatter presented stronger sensitivity to the forest growth stage than the HH and VV backscatter. Under unfrozen conditions, the dynamic range of fine-beam data acquired at 34.3 ° was 89 dB for the HV polarization and 67 dB for the HH polarization. At 21.5 °, in the polarimetric mode, the dynamic range was 6, 7, and 9 dB at VV, HH, and HV polarizations, respectively. Regardless of the specific polarization, the backscatter was temporally consistent under unfrozen conditions, with a small increase of backscatter in regrowing young forest for wet conditions. Under thawing and frozen conditions, repeated measurements were available only for the HH backscatter at 34.3 °. For thawing conditions, the backscatter level was similar to the unfrozen conditions even though the signatures differed depending on temperature dynamics, snow-cover properties, and precipitation. Under frozen conditions, the signatures varied depending on temperature. For images acquired when the temperature was well below the freezing point, the backscatter was low, and the dynamic range was small (24 dB); nonetheless, the measurements were consistent. Images acquired when temperature was close to the freezing point presented a behavior similar to unfrozen conditions. The sensitivity of the backscatter to the image viewing geometry for different growth stages was studied for data acquired under dry unfrozen conditions. The backscatter difference increased for increasing look angle because of the increase in volume scattering and the decrease of ground-surface backscatter. The largest difference was observed at 41.5 ° with 2.54-dB difference for the HH and 45-dB difference for the HV case. Loss of spatial resolution (2050 m) did not have any effect on the backscatter signatures in Krycklan, whereas in Remningstorp, the smallest stands were affected. 2009 IEEE.
BibTeX:
@article{Santoro20094001,
  author = {Santoro, M. and Fransson, J.E.S. and Eriksson, L.E.B. and Magnusson, M. and Ulander, L.M.H. and Olsson, H.},
  title = {Signatures of ALOS PALSAR L-band backscatter in Swedish Forest},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2009},
  volume = {47},
  number = {12},
  pages = {4001-4019},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70549112128&doi=10.1109%2fTGRS.2009.2023906&partnerID=40&md5=38d0a289462e9c19ed8bfc77fc6528e6},
  doi = {10.1109/TGRS.2009.2023906}
}
Santoro M, Fransson J, Eriksson L, Magnusson M, Ulander L, Olsson H and Krantz A (2009), "Investigations on forestry applications in Sweden using ALOS PALSAR", In European Space Agency, (Special Publication) ESA SP. Vol. 664 SP
Abstract: An extensive dataset of ALOS PALSAR L-band synthetic aperture radar (SAR) backscatter images is investigated for clear-cut detection and stem volume retrieval in Swedish forest. Data are available for local test sites (Remningstorp and Krycklan) and for the counties of Vasterbotten and Vastra Gotaland. Thanks to the strong forest/non-forest contrast and the temporal consistency of HV-polarized backscatter in summer/fall, a simple thresholding algorithm seems to be sufficient for clear-cut detection (threshold: 3 dB). First results for the period summer 2007/fall 2008 appear promising. The relationship between SAR backscatter and stem volume was investigated for the HH-polarized data in Fine Beam mode. Significant differences occur for frozen and unfrozen environmental conditions. The behaviour is however opposite at the two local test sites. Multi-temporal combination of images acquired under frozen conditions in Remningstorp performed best with RMSE equal to 97 m3/ha (relative RMSE: 29%). In Krycklan the highest accuracy was achieved when six images acquired under unfrozen conditions were combined resulting in a RMSE of 44 m3/ha (relative RMSE: 41%).
BibTeX:
@conference{Santoro2009,
  author = {Santoro, M. and Fransson, J.E.S. and Eriksson, L.E.B. and Magnusson, M. and Ulander, L.M.H. and Olsson, H. and Krantz, A.},
  title = {Investigations on forestry applications in Sweden using ALOS PALSAR},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2009},
  volume = {664 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955170852&partnerID=40&md5=22cbf57d5b7f6e2a48e9b0a4a4038eff}
}
Schneebeli M and Matzler C (2009), "A calibration scheme for microwave radiometers using tipping curves and kalman filtering", IEEE Transactions on Geoscience and Remote Sensing. Vol. 47(12), pp. 4201-4209.
Abstract: Calibration of microwave radiometers is a critical task and remains a key issue for the accuracy of brightness-temperature measurements. The tipping-curve calibration method is a well-established technique for ground-based microwave radiometers measuring at frequencies where the opacity of the atmosphere is low. This method relies on the known relationship between the tipping angles of the radiometer and the atmospheric opacity at those angles. Atmospheric inhomogeneities slightly disturb this relationship and therefore lead to calibration errors. The calibration scheme presented in this paper uses the determined tipping-calibration accuracy and incorporates the statistical behavior of radiometer gain and system-temperature variations in a Kalman filter framework. In this paper, a calibration simulation is set up to test the capability of the proposed scheme by reconstructing simulated brightness temperatures first. Moreover, the technique is applied to experimental data. The calibration quality is evaluated with the detrended-fluctuation-analysis method. Model and experimental results show that the calibration accuracy can be increased by a factor of two or even higher. Finally, we apply the calibration technique to a microwave radiometer with internal calibration, resulting in a reduction of the calibration noise. 2009 IEEE.
BibTeX:
@article{Schneebeli20094201,
  author = {Schneebeli, M. and Matzler, C.},
  title = {A calibration scheme for microwave radiometers using tipping curves and kalman filtering},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2009},
  volume = {47},
  number = {12},
  pages = {4201-4209},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70549096082&doi=10.1109%2fTGRS.2009.2023784&partnerID=40&md5=1cf19ed428b7296608cb365d82cba48c},
  doi = {10.1109/TGRS.2009.2023784}
}
Strozzi T, Teatini P and Tosi L (2009), "TerraSAR-X reveals the impact of the mobile barrier works on Venice coastland stability", Remote Sensing of Environment. Vol. 113(12), pp. 2682-2688.
Abstract: Land subsidence and eustacy concurred to make the relative sea level in Venice (Italy) 23 cm higher over the last century. In order to protect the city and its lagoon environment from increased flooding, a series of mobile barriers are under construction at the three inlets of Lido, Malamocco, and Chioggia connecting the Adriatic Sea to the inner water body. Since 2003 work has been proceeding with the reinforcement and extension of the existing jetties and the construction of breakwaters, harbors, and a small island within the Lido inlet. We detected significant local settlements of a few centimeters between March 2008 and January 2009 at the three inlets induced by the construction works through an interferometric analysis of 30 satellite radar images acquired by the new German TerraSAR-X mission. On a more regional scale we observe that the city of Venice and the other major urban settlements on the lagoon littorals are not impacted by subsidence during this period. The very high spatial resolution of 3 m and the short repeat-time interval of 11 days of TerraSAR-X enable the investigation of displacements with an unprecedented observed level of details, opening new perspectives to geodynamic's research and civil engineering sectors for the monitoring of large infrastructures with potential vulnerability to terrain motion. 2009 Elsevier Inc. All rights reserved.
BibTeX:
@article{Strozzi20092682,
  author = {Strozzi, T. and Teatini, P. and Tosi, L.},
  title = {TerraSAR-X reveals the impact of the mobile barrier works on Venice coastland stability},
  journal = {Remote Sensing of Environment},
  year = {2009},
  volume = {113},
  number = {12},
  pages = {2682-2688},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70350029061&doi=10.1016%2fj.rse.2009.08.001&partnerID=40&md5=00ccf2b58e103f2600c936c2848031e0},
  doi = {10.1016/j.rse.2009.08.001}
}
Strozzi T, Tosi L, Teatini P, Werner C and Wegmüller U (2009), "Monitoring land subsidence within the Venice Lagoon with SAR interferometry on trihedral corner reflectors", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. IV33-IV36.
Abstract: Before the summer of 2007 58 square Trihedral Corner Reflectors (TCR) were installed in salt marshes within the Venice Lagoon where anthropogenic structures completely lack or few constructions are scattered at a distance from one another too large to reliably resolve the radar phase ambiguity on ERS and ENVISAT interferometric point target analysis. An optimal TCR network has been established taking into account the location of "natural" point targets in ERS and ENVISAT SAR interferometric analyses and keeping to a value of about 1 km the maximum distance between the TCR or between an "artificial" and the adjacent "natural" reflectors. In this contribution we discuss the set-up of the TCR, their backscattering intensity response on ENVISAT ASAR and TerraSAR-X images, and the approach followed to measure the ground displacement in areas of particular interest within the Venice Lagoon. 2009 IEEE.
BibTeX:
@conference{Strozzi2009b,
  author = {Strozzi, T. and Tosi, L. and Teatini, P. and Werner, C. and Wegmüller, U.},
  title = {Monitoring land subsidence within the Venice Lagoon with SAR interferometry on trihedral corner reflectors},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2009},
  volume = {4},
  pages = {IV33-IV36},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77951293688&doi=10.1109%2fIGARSS.2009.5417602&partnerID=40&md5=97d5d5cb684c8189d2f50b06c144db0f},
  doi = {10.1109/IGARSS.2009.5417602}
}
Strozzi T, Wegmüller U, Werner C, Wiesmann A, Delaloye R and Raetzo H (2009), "Survey of landslide activity and rockglaciers movement in the Swiss Alps with TerraSAR-X", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. III53-III56.
Abstract: Four TerraSAR-X stripmap mode scenes acquired during the late summer of 2008 in the Oberwallis region in the Swiss Alps have been interferometrically analyzed for the survey of the activity of unstable slopes. Differential interferometry was applied using a high precision external Digital Elevation Model (DEM). Position, extent, contour, and approximate velocity of unstable slopes were determined for a large area. Selected results representing rockglacier movement and landslide activity are discussed and compared with insitu information and interferograms derived from ENVISAT ASAR, JERS-1 SAR and ALOS PASLSAR data. This application strongly benefits from the higher spatial resolution of the TerraSAR-X data in comparison to the C- and L-band sensors used in the past, because many of the instabilities are of relatively small size. 2009 IEEE.
BibTeX:
@conference{Strozzi2009c,
  author = {Strozzi, T. and Wegmüller, U. and Werner, C. and Wiesmann, A. and Delaloye, R. and Raetzo, H.},
  title = {Survey of landslide activity and rockglaciers movement in the Swiss Alps with TerraSAR-X},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2009},
  volume = {3},
  pages = {III53-III56},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77950937998&doi=10.1109%2fIGARSS.2009.5418175&partnerID=40&md5=5ab1ff90f01c3cf92f5a8e8a0da10215},
  doi = {10.1109/IGARSS.2009.5418175}
}
Strozzi T, Wegmüller U, Werner C, Wiesmann A, Santoro M, Delaloye R, Raetzo H and Ambrosi C (2009), "Survey of landslide activity in the swiss alps with ALOS PALSAR", In European Space Agency, (Special Publication) ESA SP. Vol. 664 SP
Abstract: PALSAR data acquired over the Swiss Alps since the summer of 2006 have been interferometrically analyzed for the survey of the activity of unstable slopes. Differential interferometric analysis has been performed by use of a high precision external Digital Elevation Model (DEM). The differential interferograms are employed for a large-scale motion survey, determining the position, extent, contour, and approximate velocity of unstable slopes. Acquisition time intervals from one cycle (46 days) up to one year are useful depending on data availability, displacement velocities, landcover and season. Selected results in the Swiss Cantons of Valais and Ticino are discussed and compared with in-situ information and displacement maps derived from ERS- 1/2 SAR, ENVISAT ASAR and TERRASAR-X SAR data.
BibTeX:
@conference{Strozzi2009a,
  author = {Strozzi, T. and Wegmüller, U. and Werner, C. and Wiesmann, A. and Santoro, M. and Delaloye, R. and Raetzo, H. and Ambrosi, C.},
  title = {Survey of landslide activity in the swiss alps with ALOS PALSAR},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2009},
  volume = {664 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955175478&partnerID=40&md5=2974ef13d89d548097ea59d2190cf7fd}
}
Tanase M, Le Toan T, De La Riva J and Santoro M (2009), "An estimation of change in forest area in Central Siberia using multi temporal SAR data", In European Space Agency, (Special Publication) ESA SP. Vol. 664 SP
Abstract: The objective of this study is forest cover change quantification in Central Siberia, using ALOS-PALSAR data and forest/biomass map product of SIBERIA project. Two sites (Irkutsk and Krasnoyarsk), covering around 50,000 km2 each are studied. The classification algorithm is developed in the Irkutsk site and applied without further modification to the Krasnoyarsk site. Classification accuracy is assessed for the Krasnoyarsk site using as reference data from the Russian forest inventory. Over the studied period, a net forest cover loss of 9 to 11.5 % is estimated, depending on the site. Deforestation affects 12.2% to 16% of the area while forest regrowth is registered for only 3.2 to 4.5% of the studied area. Among the different causes that could explain forest area loss (e.g. natural disasters, clear cuts etc.) the geometric shape of the detected forest cover changes suggests an active deforestation process.
BibTeX:
@conference{Tanase2009b,
  author = {Tanase, M. and Le Toan, T. and De La Riva, J. and Santoro, M.},
  title = {An estimation of change in forest area in Central Siberia using multi temporal SAR data},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2009},
  volume = {664 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955172288&partnerID=40&md5=ddd8856cc8025efe34919e188c094998}
}
Tanase M, Santoro M, De La Riva J and Pérez-Cabello F (2009), "Backscatter properties of multitemporal TerraSAR-X data and the effects of influencing factors on burn severity evaluation, in a mediterranean pine forest", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. III593-III596.
Abstract: TerraSAR-X dual-polarized (HH and HV polarization) backscatter data have been investigated to assess the temporal backscatter stability of a burn scar in Spain. Analysis of the main factors influencing burn severity evaluation has been also carried out. The temporal stability of the backscatter was strong, unburned areas showing differences of less than 0.6 dB. For increasing burn severity the backscatter varied by up to 2 dB in highly burned areas located on slopes tilted towards the sensor. Heavy rainfall or moist vegetation increased the backscatter up to 1 dB. Steeper look angles resulted in significantly higher backscatter coefficients for HH polarization, while for HV polarization only marginal increase was observed. Association strength between backscatter and burn severity estimates improved with the size of the multi-look window, at the expenses however of spatial resolution. Even better results could be achieved at higher spatial resolution by applying a multi-temporal speckle filtering algorithm. 2009 IEEE.
BibTeX:
@conference{Tanase2009a,
  author = {Tanase, M. and Santoro, M. and De La Riva, J. and Pérez-Cabello, F.},
  title = {Backscatter properties of multitemporal TerraSAR-X data and the effects of influencing factors on burn severity evaluation, in a mediterranean pine forest},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2009},
  volume = {3},
  pages = {III593-III596},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77950952138&doi=10.1109%2fIGARSS.2009.5417827&partnerID=40&md5=fddc6ad34da8685dcdf10fd849cbabab},
  doi = {10.1109/IGARSS.2009.5417827}
}
Thiel C, Cartus O, Eckardt R, Richter N, Thiel C and Schmullius C (2009), "Analysis of multi-temporal land observation at C-band", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 318-321.
Abstract: The availability of reliable land cover information is crucial for a wide range of applications, like for example monitoring of land use change and land degradation as well as administrative matters in global, regional and local scales. In this paper the potential of SENTINEL-1 C-band SAR data for land cover applications, e.g. generating level-2 land cover classification products has been investigated. Therefore, the planned short revisit and dual polarization concept of SENTINEL-1 has been simulated using multitemporal ERS-2 and ENVISAT ASAR AP C-band backscatter intensity data. For classification, several multitemporal metrics and the minimum amount of SAR data acquired during one growing season have been analyzed to derive five basic land cover classes with accuracies greater than 85%.
BibTeX:
@conference{Thiel2009a,
  author = {Thiel, C. and Cartus, O. and Eckardt, R. and Richter, N. and Thiel, C. and Schmullius, C.},
  title = {Analysis of multi-temporal land observation at C-band},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2009},
  volume = {3},
  pages = {318-321},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77950933004&doi=10.1109%2fIGARSS.2009.5417764&partnerID=40&md5=f41f8a86d65ae02e91305459d1d8738b},
  doi = {10.1109/IGARSS.2009.5417764}
}
Thiel C, Thiel C, Santoro M and Schmullius C (2009), "ALOS PALSAR winter coherence and summer intensities for large scale forest monitoring in Siberia", In European Space Agency, (Special Publication) ESA SP. Vol. 664 SP
Abstract: In this paper summer intensity and winter coherence images are used for large scale forest monitoring. The intensities (FBD HH/HV) have been acquired during summer 2007 and feature the K&C intensity stripes [1]. The processing consisted of radiometric calibration, orthorectification, and topographic normalisation. The coherence has been estimated from interferometric pairs with 46-days repeat-pass intervals. The pairs have been acquired during the winters 2006/2007 and 2007/2008. During both winters suited weather conditions have been reported. Interferometric processing consisted of SLC co-registration at subpixel level, common-band filtering in range and azimuth and generation of a differential interferogram, which was used in the coherence estimation procedure based on adaptive estimation. All images were geocoded using SRTM data. The pixel size of the final SAR products is 50 m x 50 m. It could already be demonstrated, that by using PALSAR intensities and winter coherence forest and nonforest can be clearly separated [2]. By combining both data types hardly any overlap of the class signatures was detected, even though the analysis was conducted on pixel level and no speckle filter has been applied. Thus, the delineation of a forest cover mask could be executed operationally. The major hitch is the definition of a biomass threshold for regrowing forest to be distinguished as forest.
BibTeX:
@conference{Thiel2009b,
  author = {Thiel, C. and Thiel, C. and Santoro, M. and Schmullius, C.},
  title = {ALOS PALSAR winter coherence and summer intensities for large scale forest monitoring in Siberia},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2009},
  volume = {664 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955171762&partnerID=40&md5=ec53cfd1135d1d1e530ce402a807e58f}
}
Walter D, Wegmüller U, Spreckels V and Busch W (2009), "Application and evaluation of ALOS PALSAR data for monitoring of mining induced surface deformations using interferometric techniques", In European Space Agency, (Special Publication) ESA SP. Vol. 664 SP
Abstract: The main objective of the projects "Determination of ground motions in mining areas by interferometric analyses of ALOS data" (ALOS ADEN 3576, ESA) and "Monitoring of mining induced surface deformation" (ALOS-RA-094, JAXA) is to evaluate PALSAR data for surface deformation monitoring, using interferometric techniques. We present monitoring results of surface movements for an active hard coal colliery of the German hard coal mining company RAG Deutsche Steinkohle (RAG). Underground mining activities lead to ground movements at the surface with maximum subsidence rates of about 10cm per month for the test site. In these projects the L-band sensor clearly demonstrates the good potential for deformation monitoring in active mining areas, especially in rural areas. In comparison to C-band sensors we clearly observe advantages in resolving the high deformation gradients that are present in this area and we achieve a more complete spatial coverage than with C-band. Extensive validation data based on levelling data and GPS measurements are available within RAG's GIS based database "GeoMon" and thus enable an adequate analysis of the quality of the interferometric results. Previous analyses confirm the good accuracy of PALSAR data for deformation monitoring in mining areas. Furthermore, we present results of special investigations like precision geocoding of PALSAR data and corner reflector analysis. At present only DInSAR results are obtained due to the currently available number of PALSAR scenes. For the future we plan to also apply Persistent Scatterer Interferometry (PSI) using longer series of PALSAR data.
BibTeX:
@conference{Walter2009,
  author = {Walter, D. and Wegmüller, U. and Spreckels, V. and Busch, W.},
  title = {Application and evaluation of ALOS PALSAR data for monitoring of mining induced surface deformations using interferometric techniques},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2009},
  volume = {664 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955175818&partnerID=40&md5=629c4ca6cf8d13b684e5beb49fe24942}
}
Wegmüller U, Petrat L, Zimmermann K and Al Quseimi I (2009), "The potential of high resolution satellite interferometry", In 15th European Symposium on Improved Oil Recovery 2009. , pp. 94-103.
Abstract: Introduction: Rising importance of using Enhanced Oil Recovery (EOR) in oil production also increased the demand for monitoring related effects like surface movements. Over the last years land surface movement monitoring using satellite Synthetic Aperture Radar (SAR) interferometry became operational. In the last year a new generation of SAR satellites with high resolution modes and short revisit times was launched and interferometric data series are available. This development reveals the potential for monitoring small-scale and highly dynamic surface movements related to EOR more accurate than by using conventional systems. Application: A series of TerraSAR-X high resolution SAR data sets was acquired over an oilfield in Oman and interferometricalfy processed. Resulting surface displacements maps and time-series of surface displacements have been integrated with results from in-situ GPS measurements processed by using high precision satellite orbits. Achievements have been related to information about oil production parameters available from the field. Results: The arid character of the site proved to be ideal concerning the applicability of SAR interferometry for surface movement monitoring. Different types of deformation were observed ranging from uniform subsidence to highly dynamic and small-scale surface displacements. The short TerraSAR-X revisit time of 11-days and resulting availability of many observations was very useful to reduce atmospheric distortions and thus to reliably determine uniform subsidence related to conventional production. The short revisit time also allowed a temporally dense sampling of highly dynamic surface movements. High spatial data resolution yielded a very good spatial sampling of displacement patterns permitting to resolve high spatial deformation gradients, which is particularly relevant in the monitoring of responses of reservoirs on EOR measures. Comparison of the interferometric results with existing DGPS data of the same observation period confirmed the compliance of the two techniques. Conclusion: In the context of oil field related monitoring the results clearly indicate a good potential of High Resolution interferometry for "conventional" oil production with large-scale temporally relatively uniform subsidence as well as for oil production supported by Enhanced Oil Recovery.
BibTeX:
@conference{Wegmuller200994,
  author = {Wegmüller, U. and Petrat, L. and Zimmermann, K. and Al Quseimi, I.},
  title = {The potential of high resolution satellite interferometry},
  booktitle = {15th European Symposium on Improved Oil Recovery 2009},
  year = {2009},
  pages = {94-103},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878002030&partnerID=40&md5=1f13b275116db10ea034c6517167f11e}
}
Wegmüller U, Santoro M, Werner C, Strozzi T and Wiesmann A (2009), "ERS-envisat tandem cross - Interferometry coherence estimation", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. I128-I131.
Abstract: ERS-ENVISAT cross-interferometry is a unique tool for a number of applications since it combines a short repeat-pass interval (28 minutes) with a long perpendicular baseline (2 km). Temporal decorrelation effects are limited and the sensitivity to topographic features is strongly enhanced. In this contribution the focus is on problems encountered during the coherence estimation in ERS-ENVISAT crossinterferometry. Because of the ERS-2 Doppler Centroid variations the azimuth common band available is often only a relatively small fraction of the PRF. Similarly, in the case of not ideal baselines, the common range bandwidth is often much smaller than the chirp bandwidth. Furthermore, high phase gradients in the cross-interferograms can significantly affect the coherence estimates. In our contribution we propose methodologies to reduce these problems in the coherence estimation. 2009 IEEE.
BibTeX:
@conference{Wegmuller2009,
  author = {Wegmüller, U. and Santoro, M. and Werner, C. and Strozzi, T. and Wiesmann, A.},
  title = {ERS-envisat tandem cross - Interferometry coherence estimation},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2009},
  volume = {1},
  pages = {I128-I131},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-77950922570&doi=10.1109%2fIGARSS.2009.5416902&partnerID=40&md5=99b8052701903f46397ad6ec91c473ab},
  doi = {10.1109/IGARSS.2009.5416902}
}
Wegmüller U, Santoro M, Werner C, Strozzi T, Wiesmann A and Lengert W (2009), "DEM generation using ERS-ENVISAT interferometry", Journal of Applied Geophysics. Vol. 69(1), pp. 51-58.
Abstract: Space-borne SAR interferometry is one possible method for the generation of digital elevation models (DEMs). The sensitivity of this technique depends strongly on system parameters as the time interval between the observations used and the spatial baseline. Longer time intervals are less suited because of temporal decorrelation of the signal. Longer spatial baselines result in an increased height sensitivity. ERS-2 and ENVISAT ASAR operate in identical orbits at slightly different sensor frequencies with ASAR preceding ERS-2 by 28 min. This configuration offers a unique opportunity to study and apply ERS-ENVISAT interferometry. ERS-2-ENVISAT ASAR IS2 VV-polarization interferograms are characterized by a short 28 min repeat-pass interval and a long 1.5-2.5 km baseline. Given the long baseline and short time interval ERS-ENVISAT interferometry has a good potential for the generation of precise DEMs in relatively flat areas. The idea to use ERS-ENVISAT interferometry for DEM generation is not new, nevertheless, very few adequate data sets were identified and analyzed in the past. Now, thanks to a recent dedicated ERS-2-ENVISAT Tandem mission of ESA many well suited data sets became available. In this paper the ERS-ENVISAT interferometry methodology is described, its feasibility is demonstrated by presenting ERS-ENVISAT interferometry DEMs over several sites, and its potential is assessed. 2009 Elsevier B.V. All rights reserved.
BibTeX:
@article{Wegmuller200951,
  author = {Wegmüller, U. and Santoro, M. and Werner, C. and Strozzi, T. and Wiesmann, A. and Lengert, W.},
  title = {DEM generation using ERS-ENVISAT interferometry},
  journal = {Journal of Applied Geophysics},
  year = {2009},
  volume = {69},
  number = {1},
  pages = {51-58},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70149110203&doi=10.1016%2fj.jappgeo.2009.04.002&partnerID=40&md5=f3ece14d196a462290e7f6f83679ba06},
  doi = {10.1016/j.jappgeo.2009.04.002}
}
Werner C, Strozzi T, Wiesmann A and Wegmüller U (2009), "A ground-based real-aperture radar instrument for differential interferometry", In IEEE National Radar Conference - Proceedings.
Abstract: Radar differential interferometry was initially developed using satellite SAR sensors due to the requirements for precise control and knowledge of the interferometric baseline. The development of ground-based radar imaging systems extends this technology to obtain essentially continuous deformation measurements at high spatial resolution. Applications requiring near real-time deformation measurements such as monitoring of landslides, glaciers, and mining can benefit from this technology. We describe a real-aperture ground-based radar system operating at 17.2 GHz developed by Gamma Remote Sensing. Results for observations of landslides, glaciers and a dam in the Alps are presented. Sources of positional and deformation error including decorrelation and atmospheric phase delay along with strategies for reduction of these errors are discussed. 2009 IEEE.
BibTeX:
@conference{Werner2009,
  author = {Werner, C. and Strozzi, T. and Wiesmann, A. and Wegmüller, U.},
  title = {A ground-based real-aperture radar instrument for differential interferometry},
  booktitle = {IEEE National Radar Conference - Proceedings},
  year = {2009},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-69949102028&doi=10.1109%2fRADAR.2009.4977136&partnerID=40&md5=fd7371173b47963aceedc79c501d0fdc},
  doi = {10.1109/RADAR.2009.4977136}
}
d'Ozouville N, Deffontaines B, Benveniste J, Wegmüller U, Violette S and de Marsily G (2008), "DEM generation using ASAR (ENVISAT) for addressing the lack of freshwater ecosystems management, Santa Cruz Island, Galapagos", Remote Sensing of Environment. Vol. 112(11), pp. 4131-4147. Elsevier Inc..
Abstract: Low relief oceanic islands often suffer from scarcity of freshwater resources. Remote sensing has proved to be an effective tool to generate valuable data for hydrological analysis and has improved the management of ecosystems and water. However, remotely sensed data are often tested over areas with existing validation databases and not always where the need is greatest. In this paper we address the need for topographical data to understand the hydrological system of Santa Cruz Island (Galapagos archipelago) so that management of freshwater ecosystems and resources can take place. No high resolution, high accuracy topographical data exist for Santa Cruz Island, and its growing population has created an urgent need for water resource management and protection of unique and pristine ecosystems. Inaccessible National Park land covers more than 97% of Galapagos territory, which makes the use of remote sensing methods indispensable. SRTM data was insufficient in terms of grid size (90 m) to carry out the needed data analysis. We used ASAR data (ENVISAT) in VV polarization image mode for Digital Elevation Model (DEM) generation, in order to extract drainage network, watersheds, and flow characteristics from a morpho-structural analysis. Results show the high potential of these data for both interferometric and radargrammetric generation methods. Although interferometry suffered from low coherence over highly vegetated areas, it showed high precision over the rest of the island. Radargrammetry gave consistent results over the entire island, and details were enhanced by integrating the 90 m SRTM data as an external DEM. Accuracy of the SRTM and the combined radargrammetric/SRTM DEM was similar, with the radargrammetric having a finer pixel-based resolution (20 m). Validation of the extracted drainage networks and watersheds was carried out using ground-based field observations and comparison to mapped river networks visually extracted from aerial photographs and high resolution (1 m) satellite imagery available on GoogleEarth . For the first time, watershed characteristics and flow paths were made available for an island of the Galapagos archipelago. Furthermore, the drainage network is shown to be strongly influenced by observed and extracted structural discontinuities. Having characterized freshwater flow, water balance calculations were carried out for Pelican Bay watershed, where urban areas, agricultural land and Galapagos National Park land are concomitant. 2008 Elsevier Inc. All rights reserved.
BibTeX:
@article{dOzouville20084131,
  author = {d'Ozouville, N. and Deffontaines, B. and Benveniste, J. and Wegmüller, U. and Violette, S. and de Marsily, G.},
  title = {DEM generation using ASAR (ENVISAT) for addressing the lack of freshwater ecosystems management, Santa Cruz Island, Galapagos},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2008},
  volume = {112},
  number = {11},
  pages = {4131-4147},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-53149091020&doi=10.1016%2fj.rse.2008.02.017&partnerID=40&md5=a67010ecebb53bfa44c1a2af311fa6c5},
  doi = {10.1016/j.rse.2008.02.017}
}
Cartus O, Santoro M, Schmullius C, Pang Y, Chen E and Li Z (2008), "Creation of large area forest biomass maps for northeast China using ERS-1/2 tandem coherence", In European Space Agency, (Special Publication) ESA SP. (655 SP)
Abstract: One of the objectives of the Forest DRAGON project is the generation of a forest biomass map for Northeast China based on ERS-1/2 tandem coherence. The ERS-1/2 tandem dataset consisted of 223 image pairs acquired in all seasons between 1995 and 1998. ERS-1/2 tandem coherence has been shown to provide accurate estimates of forest biomass but is also known to depend strongly on the meteorological and environmental conditions at image acquisition. For large-area mapping existing algorithms have not been able so far to classify forest biomass based on a multi-seasonal dataset. In this study a new classification approach, based on synergy between the optical remote sensing product MODIS Vegetation Continuous Field and ERS-1/2 tandem coherence, has been developed for automatic and seasonal-adaptive retrieval of forest biomass. The procedure integrates the semi-empirical Interferometric Water Cloud Model. With this procedure a forest biomass map of Northeast China (∼ 7.5 Million km2) discriminating between four stem volume classes (0-20, 20-50, 50-80 and > 80 m3/ha) has been generated.
BibTeX:
@conference{Cartus2008,
  author = {Cartus, O. and Santoro, M. and Schmullius, C. and Pang, Y. and Chen, E. and Li, Z.},
  title = {Creation of large area forest biomass maps for northeast China using ERS-1/2 tandem coherence},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2008},
  number = {655 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-45749105105&partnerID=40&md5=7139007acefb25b733ca49cc89939c67}
}
Czarnogorska M, Graniczny M, Kowalski Z and Wegmüller U (2008), "Dynamics of surface changes in Upper Silesia in the period 10.07-25.08.2007 on the basis of ALOS satellite interferometric data [Dynamika zmian powierzchni terenu na Górnym Ślasku w okresie 10.07-25.08.2007 r. na podstawie danych interferometrycznych z satelity ALOS]", Przeglad Geologiczny. Vol. 56(7), pp. 524-527.
BibTeX:
@article{Czarnogorska2008524,
  author = {Czarnogorska, M. and Graniczny, M. and Kowalski, Z. and Wegmüller, U.},
  title = {Dynamics of surface changes in Upper Silesia in the period 10.07-25.08.2007 on the basis of ALOS satellite interferometric data [Dynamika zmian powierzchni terenu na Górnym Ślasku w okresie 10.07-25.08.2007 r. na podstawie danych interferometrycznych z satelity ALOS]},
  journal = {Przeglad Geologiczny},
  year = {2008},
  volume = {56},
  number = {7},
  pages = {524-527},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-55049117263&partnerID=40&md5=c50ed4b187438ba2a6224a86fb95238c}
}
Delaloye R, Strozzi T, Lambiel C, Perruchoud E and Raetzo H (2008), "Landslide-like development of rockglaciers detected with ERS-1/2 SAR interferometry", In European Space Agency, (Special Publication) ESA SP. (649 SP)
Abstract: Rockglaciers are permanently frozen sediments supersaturated with ice deforming steadily and slowly on periglacial mountain slopes. The frequency of alpine rockglaciers affected by "surge" (landslide-like) processes has increased during the last two decades probably in connexion with a signficant acceleration of rockglaciers deformation rate consecutive to permafrost warming. Flow velocities up to several metres per year can be observed. The analysis of 1-day ERS-1/2 differential SAR interferograms available for the period 1995-1999 has proved to be an adequate tool for detecting such very rapidly moving rockglaciers.
BibTeX:
@conference{Delaloye2008,
  author = {Delaloye, R. and Strozzi, T. and Lambiel, C. and Perruchoud, E. and Raetzo, H.},
  title = {Landslide-like development of rockglaciers detected with ERS-1/2 SAR interferometry},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2008},
  number = {649 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-47249104194&partnerID=40&md5=dc6dae4b033bc97980dcc4896fb16fb4}
}
Della Vecchia A, Ferrazzoli P, Guerriero L, Ninivaggi L, Strozzi T and Wegmüller U (2008), "Observing and modeling multifrequency scattering of maize during the whole growth cycle", IEEE Transactions on Geoscience and Remote Sensing. Vol. 46(11), pp. 3709-3718.
Abstract: The objective of this paper is to carry out a systematic investigation about the sensitivity of radar to maize crop growth and soil moisture by considering a wide range of frequencies and angles and all linear polarizations. We show the results of a correlation study carried out on the data collected on a maize field at Suberg, in the Swiss region named Central Plain, by the multifrequency RAdio ScAtteroMeter (RASAM). This agricultural field was monitored over a long period of time at a wide range of frequencies and observation angles so that the correlation between the backscattering and crop height and the biomass and soil moisture was studied under several plant and observation conditions. Moreover, we describe some recent refinements applied to the vegetation scattering model developed at Tor Vergata University, Rome, Italy, and we evaluate the accuracy of extended comparisons between model outputs and RASAM signatures. The Tor Vergata model is finally applied to give a theoretical basis to the experimental correlation findings. 2008 IEEE.
BibTeX:
@article{DellaVecchia20083709,
  author = {Della Vecchia, A. and Ferrazzoli, P. and Guerriero, L. and Ninivaggi, L. and Strozzi, T. and Wegmüller, U.},
  title = {Observing and modeling multifrequency scattering of maize during the whole growth cycle},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2008},
  volume = {46},
  number = {11},
  pages = {3709-3718},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-56849102149&doi=10.1109%2fTGRS.2008.2001885&partnerID=40&md5=cd7c3a83c89f8ad6fad7302ee882a9e7},
  doi = {10.1109/TGRS.2008.2001885}
}
Dowdeswell J, Benham T, Strozzi T and Hagen J (2008), "Iceberg calving flux and mass balance of the Austfonna ice cap on Nordaustlandet, Svalbard", Journal of Geophysical Research: Earth Surface. Vol. 113(3) Blackwell Publishing Ltd.
Abstract: Satellite radar interferometry, 60 MHz airborne ice-penetrating radar data, and visible band satellite imagery were used to calculate the velocity structure, ice thickness, and the changing ice-marginal extent of Austfonna (8000 km2 and 2500 km3), the largest ice cap in the Eurasian Arctic. Ice cap motion is generally less than about 10 m a-1, except where faster flowing curvilinear features with velocities of several tens to over 200 m a-1 are present. Most drainage basins of Austfonna have undergone ice-marginal retreat over the past few decades at an average of a few tens of meters per year. Integrating margin change around the whole ice cap gives a total area loss of about 10 km2 a-1. Iceberg flux from the marine margins of Austfonna is about 2.5 ± 0.5 km3 a-1 (water equivalent), about 45% of the total calving flux from the whole Svalbard archipelago. When mass loss by iceberg production is taken into account, the total mass balance of Austfonna is negative by between about 2.5 and 4.5 km3 a-1. This iceberg flux represents about 33 ± 5% of total annual mass loss from Austfonna, with the remainder lost through surface ablation. Iceberg flux should be included in calculations of the total mass balance of the many large Arctic ice caps, including those located in the Russian and Canadian Arctic that end in tidewater. The neglect of this term has led to underestimates of mass loss from these ice caps and, thus, to underestimates of the contribution of Arctic ice caps to global sea level rise. Copyright 2008 by the American Geophysical Union.
BibTeX:
@article{Dowdeswell2008,
  author = {Dowdeswell, J.A. and Benham, T.J. and Strozzi, T. and Hagen, J.O.},
  title = {Iceberg calving flux and mass balance of the Austfonna ice cap on Nordaustlandet, Svalbard},
  journal = {Journal of Geophysical Research: Earth Surface},
  publisher = {Blackwell Publishing Ltd},
  year = {2008},
  volume = {113},
  number = {3},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-56649106425&doi=10.1029%2f2007JF000905&partnerID=40&md5=9b38a1ddf901a327dbb0136f323d0bbb},
  doi = {10.1029/2007JF000905}
}
Eriksson L, Santoro M and Fransson J (2008), "Temporal decorrelation for forested areas observed in spaceborne lband sar interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. V283-V285.
Abstract: Interferometric coherence from nine image pairs acquired by the Japanese satellite ALOS over a forest area in northern Sweden have been analyzed. Coherence levels for sparse and dense forest are compared. The results are in line with previous studies for JERS-1 and confirm that in most cases the temporal decorrelation is a severe problem for Lband SAR with repeat cycles on the order of six weeks. However, frozen conditions can give relatively highcoherence for sparse forest and thereby allow good separation between dense and sparse forest. 2008 IEEE.
BibTeX:
@conference{Eriksson2008,
  author = {Eriksson, L.E.B. and Santoro, M. and Fransson, J.E.S.},
  title = {Temporal decorrelation for forested areas observed in spaceborne lband sar interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2008},
  volume = {5},
  pages = {V283-V285},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67649807945&doi=10.1109%2fIGARSS.2008.4780083&partnerID=40&md5=ede813cbc8c9b0b4edae7c774a63b239},
  doi = {10.1109/IGARSS.2008.4780083}
}
Frey O, Magnard C, Ruegg M and Meier E (2008), "Focusing sar data acquired from non-linear sensor trajectories", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 115-418.
Abstract: Standard focusing of SAR data assumes a straight recording track of the sensor platform. Small non-linearities of airborne platform tracks are corrected for during a motion compensation step while keeping the assumption of a linear flight path. In the following, the processing of SAR data from nonlinear tracks is discussed as may originate from small aircraft or drones flying at low altitude. They fly not a straight track but one dependent on topography, influences of weather and wind, or dependent on the shape of dedicated areas of interest such as rivers or traffic routes. A time-domain backprojection based technique, is proposed and evaluated with the help of experimental data featuring a drop in height, a double bend, a 90-degree curve and a linear flight track. In order to assess the quality of the focused data, close-ups of amplitude images are compared and the coherence is evaluated. The experimental data was acquired by the German Aerospace Center's E-SAR L-band system. 2008 IEEE.
BibTeX:
@conference{Frey2008b,
  author = {Frey, O. and Magnard, C. and Ruegg, M. and Meier, E.},
  title = {Focusing sar data acquired from non-linear sensor trajectories},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2008},
  volume = {4},
  pages = {115-418},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67649793219&doi=10.1109%2fIGARSS.2008.4779746&partnerID=40&md5=29b9b4ae1226cb40d52287cfb987c244},
  doi = {10.1109/IGARSS.2008.4779746}
}
Frey O, Magnard C, Rüegg M and Meier E (2008), "Non-Linear SAR Data Processing By Time-Domain Back-Projection", In Proc. EUSAR 2008 - 7th European Conference on Synthetic Aperture Radar. , pp. 165-168.
Abstract: Focusing of conventional stripmap SAR data assumes a straight recording track of the sensor platform. Small deviations from that linear trajectory are corrected by motion compensation steps while keeping the assumption of a linear acquisition path. In the following, the processing of SAR data from non-linear tracks is discussed as may originate from small aircraft or drones flying at low altitude. They fly not a straight track but one dependent on topography, influences of weather and wind, or dependent on the shape of dedicated areas of interest such as rivers or traffic routes. Experimental data featuring a drop in height, a double bend and a 90-degree curve have been processed using a time-domain back-projection approach. The data was acquired by the German Aerospace Center's E-SAR L-band system.
BibTeX:
@inproceedings{freyMagnardRueeggMeier08Eusar:Tracks,
  author = {Othmar Frey and Christophe Magnard and Maurice Rüegg and Erich Meier},
  title = {Non-Linear SAR Data Processing By Time-Domain Back-Projection},
  booktitle = {Proc. EUSAR 2008 - 7th European Conference on Synthetic Aperture Radar},
  year = {2008},
  pages = {165-168}
}
Frey O and Meier E (2008), "Combining time-domain back-projection and capon beamforming for tomographic SAR processing", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 445-448.
Abstract: Various tomographic processing methods have been investigated in recent years. The quality of the focused tomographic image is usually limited by several, factors. In particular, Fourier-based focusing methods are susceptible to irregular and sparse sampling, two problems that are unavoidable in case of multi-pass, multi-baseline SAR data acquired by an airborne system. Neither time-domain back-projection (TDBP) processing, although providing a very accurate processing framework, is able to overcome the problem of ambiguous target detection in the tomographic image. In this paper, a possible extension of the TDBP approach to multilooking based tomographic focusing methods like standard beamforming and Capon beamforming is discussed. Preliminary results obtained with a simulated and a real airborne tomographic P-band data set are shown. 2008 IEEE.
BibTeX:
@conference{Frey2008a,
  author = {Frey, O. and Meier, E.},
  title = {Combining time-domain back-projection and capon beamforming for tomographic SAR processing},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2008},
  volume = {2},
  pages = {445-448},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-66549111913&doi=10.1109%2fIGARSS.2008.4779024&partnerID=40&md5=3e06cddd0b47194ecf24128563b5d31e},
  doi = {10.1109/IGARSS.2008.4779024}
}
Frey O and Meier E (2008), "Tomographic Focusing by Combining Time-Domain Back-Projection and Multi-Looking Based Focusing Techniques", In Proc. EUSAR 2008 - 7th European Conference on Synthetic Aperture Radar. , pp. 73-76.
Abstract: Various tomographic processing methods have been investigated in recent years. The quality of the focused tomographic image is usually limited by several factors. In particular, Fourier-based focusing methods are susceptible to irregular and sparse sampling, two problems that are unavoidable in case of multi-pass, multi-baseline SAR data acquired by an airborne system. Neither time-domain back-projection (TDBP) processing, although providing a very accurate processing framework, is able to overcome the problem of ambiguous target detection in the tomographic image. In this paper, a possible extension of the TDBP approach to multi-looking based tomographic focusing methods like standard beamforming and Capon beamforming is discussed.
BibTeX:
@inproceedings{freyMeier08Eusar:Tomo,
  author = {Othmar Frey and Erich Meier},
  title = {Tomographic Focusing by Combining Time-Domain Back-Projection and Multi-Looking Based Focusing Techniques},
  booktitle = {Proc. EUSAR 2008 - 7th European Conference on Synthetic Aperture Radar},
  year = {2008},
  pages = {73-76}
}
Frey O, Morsdorf F and Meier E (2008), "Tomographic imaging of a forested area by airborne multi-baseline P-band SAR", Sensors. Vol. 8(9), pp. 5884-5896.
Abstract: In recent years, various attempts have been undertaken to obtain information about the structure of forested areas from multi-baseline synthetic aperture radar data. Tomographic processing of such data has been demonstrated for airborne L-band data but the quality of the focused tomographic images is limited by several factors. In particular, the common Fourierbased focusing methods are susceptible to irregular and sparse sampling, two problems, that are unavoidable in case of multi-pass, multi-baseline SAR data acquired by an airborne system. In this paper, a tomographic focusing method based on the time-domain back-projection algorithm is proposed, which maintains the geometric relationship between the original sensor positions and the imaged target and is therefore able to cope with irregular sampling without introducing any approximations with respect to the geometry. The tomographic focusing quality is assessed by analysing the impulse response of simulated point targets and an in-scene corner reflector. And, in particular, several tomographic slices of a volume representing a forested area are given. The respective P-band tomographic data set consisting of eleven flight tracks has been acquired by the airborne E-SAR sensor of the German Aerospace Center (DLR).
BibTeX:
@article{Frey20085884,
  author = {Frey, O. and Morsdorf, F. and Meier, E.},
  title = {Tomographic imaging of a forested area by airborne multi-baseline P-band SAR},
  journal = {Sensors},
  year = {2008},
  volume = {8},
  number = {9},
  pages = {5884-5896},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-53349166032&doi=10.3390%2fs8095884&partnerID=40&md5=dda857442c0924a87507764611288af8},
  doi = {10.3390/s8095884}
}
Graham E, Sarazin M, Kurlandczyk H, Neun M and Matzler C (2008), "Site selection for extremely large telescopes using the FriOWL software and global re-analysis climate data", In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 7012
Abstract: FriOWL is a site selection tool for large or extremely large telescope projects. It consists of a graphical user interface and a large global climatic and geophysical database, and is directly accessible on the world wide web. A new version (version 3.1) of the software has recently been developed by scientists at the University of Bern (Switzerland) and European Southern Observatory (Germany). The main feature of the new FriOWL database is the inclusion of ERA40 re-analysis data, giving access to over 40 years of long-term climate data. New software tools, programmed in the style of a Geographical Information System, include the capability of resampling layers and time series extraction. A new global seismic hazard layer has been introduced, as well as very high resolution (1km) topographic tiles. Reclassification and overlaying of layers is also possible. Although FriOWL is primarily designed for site selection projects, it can equally be used in other climate studies. It is especially important in the determination of the climatic stability of a potential site, and in the analysis of climatic anomalies and trends. The long-term astroclimatological seeing and photometric statistics for the Paranal and La Silla observatories can be used to validate FriOWL. A case study of ESO Paranal using FriOWL reveals that the deterioration in seeing conditions since 1998 is co-incident with a strong increase in 1000 hPa geopotential height to the south-east of the observatory; there may be a link with the Interdecadal Pacific Oscillation.
BibTeX:
@conference{Graham2008,
  author = {Graham, E. and Sarazin, M. and Kurlandczyk, H. and Neun, M. and Matzler, C.},
  title = {Site selection for extremely large telescopes using the FriOWL software and global re-analysis climate data},
  booktitle = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2008},
  volume = {7012},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-66749108745&doi=10.1117%2f12.787847&partnerID=40&md5=2f4a18d6491bbf073f7f66f71a51b5dd},
  doi = {10.1117/12.787847}
}
Grant J, Saleh-Contell K, Wigneron J-P, Guglielmetti M, Kerr Y, Schwank M, Skou N and Van De Griend A (2008), "Calibration of the L-MEB model over a coniferous and a deciduous forest", IEEE Transactions on Geoscience and Remote Sensing. Vol. 46(3), pp. 808-818.
Abstract: In this paper, the L-band Microwave Emission of the Biosphere (L-MEB) model used in the Soil Moisture and Ocean Salinity (SMOS) Level 2 Soil Moisture algorithm is calibrated using L-band (1.4 GHz) microwave measurements over a coniferous (Pine) and a deciduous (mixed/Beech) forest. This resulted in working values of the main canopy parameters optical depth (τ), single scattering albedo (ω), and structural parameters ii(H) and tt (V), besides the soil roughness parameters HR and NR. Using these calibrated values in the forward model resulted in a root mean-square error in brightness temperatures from 2.8 to 3.8 K, depending on data set and polarization. Furthermore, the relationship between canopy optical depth and leaf area index is investigated for the deciduous site. Finally, a sensitivity study is conducted for the focus parameters, temperature, soil moisture, and precipitation. The results found in this paper will be integrated in the operational SMOS Level 2 Soil Moisture algorithm and used in future inversions of the L-MEB model, for soil moisture retrievals over heterogeneous, partly forested areas. 2008 IEEE.
BibTeX:
@article{Grant2008808,
  author = {Grant, J.P. and Saleh-Contell, K. and Wigneron, J.-P. and Guglielmetti, M. and Kerr, Y.H. and Schwank, M. and Skou, N. and Van De Griend, A.A.},
  title = {Calibration of the L-MEB model over a coniferous and a deciduous forest},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2008},
  volume = {46},
  number = {3},
  pages = {808-818},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-40149105133&doi=10.1109%2fTGRS.2007.914801&partnerID=40&md5=189b32c36ff51e641e9a06f3c765a4ef},
  doi = {10.1109/TGRS.2007.914801}
}
Guglielmetti M, Schwank M, Matzler C, Oberdorster C, Vanderborght J and Fluhler H (2008), "FOSMEX: Forest soil moisture experiments with microwave radiometry", IEEE Transactions on Geoscience and Remote Sensing. Vol. 46(3), pp. 727-735.
Abstract: The microwave Forest Soil Moisture Experiment (FOSMEX) was performed at a deciduous forest site at the Research Centre Julich (Germany). An L- and an X-band radiometer were mounted 100 m above ground and directed to the canopy. The measurements consist of dual- and single-polarized L- and X-band data and simultaneously recorded ground moisture, temperature, and meteorological data. The canopy L-band transmissivity was estimated from a subset of the FOSMEX data, where the ground was masked with a metalized foil. For the foliage-free canopy, the reflecting foil diminished the L-band brightness by ≈24 K, whereas brightness increased by ≈14 K when the foil was removed from below the foliated canopy. Depending on the assumption made on the scattering albedo of the canopy, the transmissivities were between 0.2 and 0.51. Furthermore, the contribution of the foliage was quantified. Although, the evaluation revealed the semitransparency of the canopy for L-band frequencies, the brightness sensitivity with respect to ground moisture was substantially reduced for all foliation states. The effect of ground surface moisture was explored in an irrigation experiment. The L-band measurements were only affected for a few hours until the water drained through the litter layer. This emphasizes the significance of the presence of litter for soil moisture retrieval from remotely sensed L-band brightness data. The FOSMEX database serves for further testing and improving radiative transfer models used for interpreting microwave data received from future spaceborne L-band radiometers flying over areas comprising a considerable fraction of deciduous forests. 2008 IEEE.
BibTeX:
@article{Guglielmetti2008727,
  author = {Guglielmetti, M. and Schwank, M. and Matzler, C. and Oberdorster, C. and Vanderborght, J. and Fluhler, H.},
  title = {FOSMEX: Forest soil moisture experiments with microwave radiometry},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2008},
  volume = {46},
  number = {3},
  pages = {727-735},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-40149101901&doi=10.1109%2fTGRS.2007.914797&partnerID=40&md5=5bde857da5949ea32e8615b805b77d57},
  doi = {10.1109/TGRS.2007.914797}
}
Magnard C, Frey O, Rüegg M and Meier E (2008), "Improved Airborne SAR Data Processing by Blockwise Focusing, Mosaicking and Geocoding", In Proc. EUSAR 2008 - 7th European Conference on Synthetic Aperture Radar. , pp. 375-378.
Abstract: Standard focusing of SAR data assumes a straight recording track of the sensor platform. Small non-linearities of airborne platform are corrected for during a motion compensation step while keeping the assumption of a stripmap geometry. In the case of high resolution and high frequency SAR systems, the navigation data may not be accurate enough to perform such a motion compensation; SAR systems mounted on small aircrafts or drones flying at low altitude do not follow a straight track but one dependent on topography and atmospheric conditions. We present a blockwise focusing, mosaicking and geocoding method which allows processing such data. For the experiments, MEMPHIS and E-SAR data were used.
BibTeX:
@inproceedings{magnardFreyRueeggMeier08Eusar:Tracks,
  author = {Christophe Magnard and Othmar Frey and Maurice Rüegg and Erich Meier},
  title = {Improved Airborne SAR Data Processing by Blockwise Focusing, Mosaicking and Geocoding},
  booktitle = {Proc. EUSAR 2008 - 7th European Conference on Synthetic Aperture Radar},
  year = {2008},
  pages = {375-378}
}
Morsdorf F, Frey O, Meier E, Itten K and Allgower B (2008), "Assessment of the influence of flying altitude and scan angle on biophysical vegetation products derived from airborne laser scanning", International Journal of Remote Sensing. Vol. 29(5), pp. 1387-1406. Taylor and Francis Ltd..
Abstract: Airborne Laser Scanning (ALS) has been established as a valuable tool for the estimation of biophysical vegetation properties such as tree height, crown width, fractional cover and leaf area index (LAI). It is expected that the conditions of data acquisition, such as viewing geometry and sensor configuration influence the value of these parameters. In order to gain knowledge about these different conditions, we test for the sensitivity of vegetation products for viewing geometry, namely flying altitude and scanning (incidence) angle. Based on two methodologies for single tree extraction and derivation of fractional cover and LAI previously developed and published by our group, we evaluate how these variables change with either flying altitude or scanning angle. These are the two parameters which often need to be optimized towards the best compromise between point density and area covered with a single flight line, in order to reduce acquisition costs. Our test-site in the Swiss National Park was sampled with two nominal flying altitudes, 500 and 900 m above ground. Incidence angle and local incidence angle were computed based on the digital terrain model using a simple backward geocoding procedure. We divided the raw laser returns into several different incident angle classes based on the flight path data; the TopoSys Falcon II system used in this study has a maximum scan angle of +/- 7.15deg. We compared the derived biophysical properties from each of these classes with field measurements based on tachymeter measurements and hemispherical photographs, which were geolocated using differential GPS. It was found that with increasing flying height the well-known underestimation of tree height increases. A similar behaviour can be observed for fractional cover; its respective values decrease with higher flying height. The minimum distance between first and last echo increases from 1.2 metres for 500 m AGL to more than 3 metres for 900 m AGL, which does alter return statistics. The behaviour for incidence angles is not so evident, probably due to the small scanning angle of the system used. fCover seems to be most affected by incidence angles, with significantly higher differences for locations further away from nadir. As expected, incidence angle appears to be of higher importance for vegetation density parameters than local incidence angle.
BibTeX:
@article{Morsdorf20081387,
  author = {Morsdorf, F. and Frey, O. and Meier, E. and Itten, K.I. and Allgower, B.},
  title = {Assessment of the influence of flying altitude and scan angle on biophysical vegetation products derived from airborne laser scanning},
  journal = {International Journal of Remote Sensing},
  publisher = {Taylor and Francis Ltd.},
  year = {2008},
  volume = {29},
  number = {5},
  pages = {1387-1406},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-40049094519&doi=10.1080%2f01431160701736349&partnerID=40&md5=08662fe8540a15a1ab0af1788b7a961e},
  doi = {10.1080/01431160701736349}
}
Parcharidis I, Foumelis M, Kourkouli P, Wegmüller U, Lagios E and Sakkas V (2008), "Continuous risk assessment of structures in areas of ground deformation susceptibility by persistent scatterers InSAR: Preliminary result of the Rio-Antirio bridge (Greece)", In European Space Agency, (Special Publication) ESA SP. (649 SP)
Abstract: From hazard monitoring to risk assessment by monitoring both ground deformation and human structures stability (e.g. dams, specific buildings etc) is of great importance contributing to prevention and management of these risks. An analysis of the ground deformation in the area of Rio-Antirio (western Greece), where the longest cable stayed bridge in the world, was performed using ERS-1/2 SAR data. In this study preliminary results are presented for the preconstruction period. An interferometric point target analysis was performed with images covering the period between 1992 and 2000.
BibTeX:
@conference{Parcharidis2008,
  author = {Parcharidis, I. and Foumelis, M. and Kourkouli, P. and Wegmüller, U. and Lagios, E. and Sakkas, V.},
  title = {Continuous risk assessment of structures in areas of ground deformation susceptibility by persistent scatterers InSAR: Preliminary result of the Rio-Antirio bridge (Greece)},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2008},
  number = {649 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-47249109762&partnerID=40&md5=a41e7cd6902622c3234f957c0359fd12}
}
Rosenkranz P and Matzler C (2008), "Dependence of AMSU-A brightness temperatures on scattering from antarctic firn and correlation with polarization of SSM/I data", IEEE Geoscience and Remote Sensing Letters. Vol. 5(4), pp. 769-773.
Abstract: A function of Advanced Microwave Sounding Unit-A (AMSU-A) measurements at 50.3 and 52.8 GHz is denned, which has the property of being sensitive to the angular distribution of surface-scattered atmospheric thermal emission but insensitive to the surface reflectivity, assuming reflectivity to be equal at the two frequencies. A scattering model consisting of a linear combination of specular reflection and Lambertian scattering is fitted to observed values of the function over Antarctica. The Lambertian fraction typically lies in the range of 0.7-1.0 with a mean of 0.84, and it is negatively correlated with polarization of the surface reflectivity, as determined from Special Sensor Microwave/Imager data. Dual-polarized 37-GHz measurements, combined with a separate measurement of the surface temperature, could be used as a predictor of the diffuseness of surface scattering when the atmospheric temperature profile is retrieved from measurements made by AMSU-A or a similar instrument, or when the radiances are assimilated for numerical weather prediction. 2008 IEEE.
BibTeX:
@article{Rosenkranz2008769,
  author = {Rosenkranz, P.W. and Matzler, C.},
  title = {Dependence of AMSU-A brightness temperatures on scattering from antarctic firn and correlation with polarization of SSM/I data},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  year = {2008},
  volume = {5},
  number = {4},
  pages = {769-773},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-55649091234&doi=10.1109%2fLGRS.2008.2005428&partnerID=40&md5=533f1fb9788ce6918151c0d6164a8576},
  doi = {10.1109/LGRS.2008.2005428}
}
Ruckstuhl C, Philipona R, Behrens K, Coen M, Durr B, Heimo A, Matzler C, Nyeki S, Ohmura A, Vuilleumier L, Weller M, Wehrli C and Zelenka A (2008), "Aerosol and cloud effects on solar brightening and the recent rapid warming", Geophysical Research Letters. Vol. 35(12) American Geophysical Union.
Abstract: The rapid temperature increase of 1°C over mainland Europe since 1980 is considerably larger than the temperature rise expected from anthropogenic greenhouse gas increases. Here we present aerosol optical depth measurements from six specific locations and surface irradiance measurements from a large number of radiation sites in Northern Germany and Switzerland. The measurements show a decline in aerosol concentration of up to 60%, which have led to a statistically significant increase of solar irradiance under cloud-free skies since the 1980s. The measurements confirm solar brightening and show that the direct aerosol effect had an approximately five times larger impact on climate forcing than the indirect aerosol and other cloud effects. The overall aerosol and cloud induced surface climate forcing is ∼+1 W M-2 dec-1 and has most probably strongly contributed to the recent rapid warming in Europe. Copyright 2008 by the American Geophysical Union.
BibTeX:
@article{Ruckstuhl2008,
  author = {Ruckstuhl, C. and Philipona, R. and Behrens, K. and Coen, M.C. and Durr, B. and Heimo, A. and Matzler, C. and Nyeki, S. and Ohmura, A. and Vuilleumier, L. and Weller, M. and Wehrli, C. and Zelenka, A.},
  title = {Aerosol and cloud effects on solar brightening and the recent rapid warming},
  journal = {Geophysical Research Letters},
  publisher = {American Geophysical Union},
  year = {2008},
  volume = {35},
  number = {12},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-50849136519&doi=10.1029%2f2008GL034228&partnerID=40&md5=49a4975c06e943856271fc5016ce58d3},
  doi = {10.1029/2008GL034228}
}
Santoro M, Askne J, Beer C, Cartus O, Schmullius C, Wegmüller U and Wiesmann A (2008), "Automatic model inversion of multi-temporal C-band coherence and backscatter measurements for forest stem volume retrieval", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 124-127.
Abstract: Retrieval of forest stem volume from synthetic aperture (SAR) backscatter and interferometric SAR (InSAR) coherence is generally performed using a model-based approach, where in situ measurements are necessary to estimate the unknown model parameters. Problems arise when in situ data are either not available or of low quality or the observables present spatial variations. In this work we present three approaches for automatic modeling and inversion of forest backscatter and coherence to retrieve forest stem volume. The three approaches exploit statistical distributions of the observables to obtain estimates for the unknowns in the model. Results shows remarkable agreement with those obtained by means of traditional modeling approaches based on in situ data. 2008 IEEE.
BibTeX:
@conference{Santoro2008a,
  author = {Santoro, M. and Askne, J. and Beer, C. and Cartus, O. and Schmullius, C. and Wegmüller, U. and Wiesmann, A.},
  title = {Automatic model inversion of multi-temporal C-band coherence and backscatter measurements for forest stem volume retrieval},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2008},
  volume = {5},
  pages = {124-127},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67649827883&doi=10.1109%2fIGARSS.2008.4780043&partnerID=40&md5=a72fddd996f605f0298ea5bfabd8b37a},
  doi = {10.1109/IGARSS.2008.4780043}
}
Santoro M, Wegmüller U, Strozzi T, Werner C, Wiesmann A and Lengert W (2008), "Thematic applications of ers-envisat cross-interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 1225-1228.
Abstract: ERS-ENVISAT cross-interferometry is a unique tool for a number of applications since it combines a short repeat-pass interval (28 minutes) with a long perpendicular baseline (2 km). Temporal decorrelation effects are limited and the sensitivity to topographic features is strongly enhanced. The short repeat-pass also allows monitoring of fast-moving displacements. In this paper we show a number of examples on Digital Elevation Map (DEM) generation in flat areas, crop height retrieval and displacement monitoring using data from the recent tandem mission dedicated to ERSENVISAT interferometric acquisitions. The examples demonstrate the feasibility of the applications, highlighting at the same time some limitations, which are due primarily to the very specific configuration of the interferometric system. 2008 IEEE.
BibTeX:
@conference{Santoro2008b,
  author = {Santoro, M. and Wegmüller, U. and Strozzi, T. and Werner, C. and Wiesmann, A. and Lengert, W.},
  title = {Thematic applications of ers-envisat cross-interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2008},
  volume = {4},
  pages = {1225-1228},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67649813199&doi=10.1109%2fIGARSS.2008.4779950&partnerID=40&md5=e92ad8d69cc76d994eaefa973e02436a},
  doi = {10.1109/IGARSS.2008.4779950}
}
Schneebeli M, Matzler C, Wolf S and Eugster W (2008), "X-band opacity of a tropical tree canopy and its relation to intercepted rain, eddy fluxes and other meteorological variables", In 2008 Microwave Radiometry and Remote Sensing of the Environment - 10th Specialist Meeting, Proceedings, MICRORAD.
Abstract: During Summer and Autumn 2007, we deployed a 11 GHz microwave radiometer in an experimental tree plantation in Sardinilla, Panama, in the vicinity of the Panama Canal. With this instrument, we determined the opacity of the tree canopy. A collocated eddy-covariance flux tower measured water vapor and carbon dioxide fluxes as well as other meteorological variables such as photosynthetically active radiation (PAR), vapor pressure deficit (VPD) and rain. We observed a pronounced diurnal cycle of the opacity during dry periods and a close relation of the opacity to canopy intercepted rain during rainy periods. The diurnal opacity cycle shows a strong correlation with PAR, VPD and the water vapor flux. 2008 IEEE.
BibTeX:
@conference{Schneebeli2008,
  author = {Schneebeli, M. and Matzler, C. and Wolf, S. and Eugster, W.},
  title = {X-band opacity of a tropical tree canopy and its relation to intercepted rain, eddy fluxes and other meteorological variables},
  booktitle = {2008 Microwave Radiometry and Remote Sensing of the Environment - 10th Specialist Meeting, Proceedings, MICRORAD},
  year = {2008},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-51849085616&doi=10.1109%2fMICRAD.2008.4579514&partnerID=40&md5=00c68682da9c1e52570c3b37608a89e6},
  doi = {10.1109/MICRAD.2008.4579514}
}
Schwank M, Guglielmetti M, Malzler C and Fluhler H (2008), "Testing a new model for the L-band radiation of moist leaf litter", IEEE Transactions on Geoscience and Remote Sensing. Vol. 46(7), pp. 1982-1994.
Abstract: The crown vegetation of a deciduous forest is known to be semitransparent at low microwave frequencies, and leaf litter covering the forest soil has been recognized to have a significant impact on ground emission. The proposed approach for modeling the L-band radiative transfer through leaf litter consists of an isotropic effective medium approach for the litter permittivities, a coherent radiative transfer model for computing the coherent reflectivities from dielectric depth profiles, and an averaging procedure for computing the reflectivities determining the field-scale brightness temperatures. Evaluations were performed for the case of leaf litter on top of a conducting wire grid (litter-grid formation) and for litter on underlying soil (litter-soil formation). A model sensitivity analysis was performed with respect to parameters characterizing litter thickness variations and boundary roughness. For the litter-soil formation, the model was rather sensitive to local irregularities at the air-to-litter boundary. Modeled microwave signatures reproduced the major features of the measurements performed on a site comprising a litter-grid formation. Under dry conditions, the investigated litter layer was nearly "invisible." When the same litter layer was wetted, it acted as an important radiation source to be taken into account for the quantitative remote soil moisture detection of forested areas. Under certain conditions, the simulations revealed an increasing brightness when the litter is wetted prior to the underlying soil. Further wetting of the litter-soil system then resulted in a decreasing brightness as expected for increased moisture. Such effects are important to know to avoid misleading interpretations of L-band signatures. 2008 IEEE.
BibTeX:
@article{Schwank20081982,
  author = {Schwank, M. and Guglielmetti, M. and Malzler, C. and Fluhler, H.},
  title = {Testing a new model for the L-band radiation of moist leaf litter},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2008},
  volume = {46},
  number = {7},
  pages = {1982-1994},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-45849107271&doi=10.1109%2fTGRS.2008.916983&partnerID=40&md5=0b1643e6a02e1d2cd304f5fd95a3ecae},
  doi = {10.1109/TGRS.2008.916983}
}
Stramondo S, Bozzano F, Marra F, Wegmüller U, Cinti F, Moro M and Saroli M (2008), "Subsidence induced by urbanisation in the city of Rome detected by advanced InSAR technique and geotechnical investigations", Remote Sensing of Environment. Vol. 112(6), pp. 3160-3172.
Abstract: We applied the Interferometric Point Target Analysis (IPTA) technique to study the city of Rome (Italy) aiming to detect and measure the surface movements of buildings and urban structures. The available SAR dataset has been delivered by ESA CAT1 3258 and ranges the period 1992-2005. In particular ERS1-ERS2 data processed covers 1995-2000, while Envisat ASAR 2002-2005. The Point Target velocity map shows a general stability except for some very local areas affected by subsidence rate larger than 10 mm/year. The analysis of the time series, compared to a detailed geological and geotechnical investigation of the lithostratigraphy of the alluvial sediments of the Tiber River, and combined with a temporal reconstruction of the expansion of the city over the alluvial valleys, allowed us to depict the main factors controlling the observed subsidence. These are: the in situ effective stress conditions, the related compressibility and viscous characteristics of the loaded soils, the thickness of the compressible stratum, the time since loading instant, and the entity of loading. Furthermore the observed subsidence is time-dependent, even at a long time-scale, with respect to the age of the buildings being most of the buildings constructed since the '50s still affected by slow subsidence. We mainly focused on the Grottaperfetta stream valley that is characterized by an anomalous high and time-lasting subsidence. Original data on the lithostratigraphic setting of this alluvial valley indicate that the high subsidence rate measured up to 2005 is caused by a still active primary consolidation process. 2008 Elsevier Inc. All rights reserved.
BibTeX:
@article{Stramondo20083160,
  author = {Stramondo, S. and Bozzano, F. and Marra, F. and Wegmüller, U. and Cinti, F.R. and Moro, M. and Saroli, M.},
  title = {Subsidence induced by urbanisation in the city of Rome detected by advanced InSAR technique and geotechnical investigations},
  journal = {Remote Sensing of Environment},
  year = {2008},
  volume = {112},
  number = {6},
  pages = {3160-3172},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-43949130710&doi=10.1016%2fj.rse.2008.03.008&partnerID=40&md5=f1d99697dc6e45b61bb536d3a97897be},
  doi = {10.1016/j.rse.2008.03.008}
}
Strozzi T, Kouraev A, Wiesmann A, Wegmüller U, Sharov A and Werner C (2008), "Estimation of Arctic glacier motion with satellite L-band SAR data", Remote Sensing of Environment. Vol. 112(3), pp. 636-645.
Abstract: Offset fields between pairs of JERS-1 satellite SAR data acquired in winter with 44 days time interval were employed for the estimation of Arctic glacier motion over Svalbard, Novaya Zemlya and Franz-Josef Land. The displacement maps show that the ice caps are divided into a number of clearly defined fast-flowing units with displacement larger than about 6 m in 44 days (i.e. 50 m/year). The estimated error of the JERS-1 offset tracking derived displacement is on the order of 20 m/year. Occasionally, azimuth streaks related to auroral zone ionospheric disturbances were detected and dedicated processing steps were applied to minimize their influence on the estimated motion pattern. Our analysis demonstrated that offset tracking of L-band SAR images is a robust and direct estimation technique of glacier motion. The method is particularly useful when differential SAR interferometry is limited by loss of coherence, i.e. for rapid and incoherent flow and large acquisition time intervals between the two SAR images. The JERS-1 results, obtained using SAR data acquired by a satellite operated until 1998, raise expectations of L-band SAR data from the ALOS satellite launched in early 2006. 2007 Elsevier Inc. All rights reserved.
BibTeX:
@article{Strozzi2008636,
  author = {Strozzi, T. and Kouraev, A. and Wiesmann, A. and Wegmüller, U. and Sharov, A. and Werner, C.},
  title = {Estimation of Arctic glacier motion with satellite L-band SAR data},
  journal = {Remote Sensing of Environment},
  year = {2008},
  volume = {112},
  number = {3},
  pages = {636-645},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-39749175144&doi=10.1016%2fj.rse.2007.06.007&partnerID=40&md5=01e297da0639f9b7a8ee0ab1f5f592f7},
  doi = {10.1016/j.rse.2007.06.007}
}
Strozzi T, Wegmüller U, Perruchoud E, Delaloye R, Kaab A and Ambrosi C (2008), "Evolution of a deep-seated rock mass movement observed with satellite SAR interferometry", In European Space Agency, (Special Publication) ESA SP. (649 SP)
Abstract: The displacement of an unstable slope in the Aletschwald region (Canton of Valais, Switzerland) has been observed between 1992 and 2007 with satellite SAR interferometry. Analysis of ERS-1, JERS, ERS-2, ENVISAT and ALOS differential SAR interferograms revealed an acceleration of the movement. The ERS-1 / ENVISAT-IS2 line-of-sight displacement rate increased from about 3 cm/year at the beginning of the observation period to more than 15 cm/year in the summer of 2007 in the centre of the unstable slope. These values correspond to about 5 cm/year and 30 cm/year, respectively, when projected on the direction of maximum slope derived from a digital elevation model, and are consistent with the rates detected with JERS and ALOS differential SAR interferograms.
BibTeX:
@conference{Strozzi2008,
  author = {Strozzi, T. and Wegmüller, U. and Perruchoud, E. and Delaloye, R. and Kaab, A. and Ambrosi, C.},
  title = {Evolution of a deep-seated rock mass movement observed with satellite SAR interferometry},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2008},
  number = {649 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-47249090831&partnerID=40&md5=a6a210555d4adb570143b5e2bb802ee3}
}
Tian X, Li Z, Chen E, Pang Y, Yang Y, Schmullius C, Cartus O, Santoro M and Le Toan T (2008), "Large-scale forest mapping in northeast China and map updating by using ERS-1/2 tandem and ENVISAT ASAR data", In European Space Agency, (Special Publication) ESA SP. (655 SP)
Abstract: Forest mapping in China and map update at large scale is the objective of Forest DRAGON Project. This paper aims at assessing the classification performance of ENVISAT ASAR Alternating Polarization (AP) data and detecting forest changes during the last decade by comparing the forest maps from ERS-1/2 tandem and ENVISAT ASAR AP data in Northeast (NE) China. About 960 scenes of ENVISAT ASAR AP data acquired during 2004-2005 on 3-5 ENVISAT cycles covering almost the entire Northeast China have been processed to generate an up-to-date forest/non-forest map. An unsupervised classifier has been used to generate the large-scale forest map. Using as reference a land use map derived from Landsat TM images acquired in 2000, the accuracy of the forest/non-forest map from multi-temporal ASAR AP data has been found to meet the requirements of mapping the Chinese boreal forests at large scale. For the past decade, several forest changes have been detected, which have been confirmed by the forest fire database.
BibTeX:
@conference{Tian2008,
  author = {Tian, X. and Li, Z. and Chen, E. and Pang, Y. and Yang, Y. and Schmullius, C. and Cartus, O. and Santoro, M. and Le Toan, T.},
  title = {Large-scale forest mapping in northeast China and map updating by using ERS-1/2 tandem and ENVISAT ASAR data},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2008},
  number = {655 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-45749152128&partnerID=40&md5=c8edac5393690480af2af413ea16ed51}
}
Tosi L, Carbognin L, Gasparetto-Stori G, Rizzetto F, Strozzi T and Teatpni P (2008), "Processes of land subsidence and salt water intrusion in Venice: Potential for soil desertification [Processi di subsidenza ed intrusione sali na nell'area veneziana: Potenziali cause di desertificazione]", Rendiconti Online Societa Geologica Italiana. Vol. 3(2), pp. 758-759.
Abstract: The catchment south of the Venice Lagoon is threatened by shallow aquifer salinization and land subsidence. Although the area is not experiencing everywhere saline contamination and high sinking rates, a very serious situation has been brought to light in a large portion of the coastal farmland. The salt water contamination extends up to 20 km inland from the coast. The depth of the fresh/salt-water interface varies from 1 to 30 m below the ground level and exhibits a significant, mainly seasonal, time variation. The dynamics of the soil salinization process is especially sensitive to changes in river (Brenta, Bacchiglione, Adige, Gorzone) discharges, in groundwater and channel levels, regulated by a number of pumping stations of the reclamation network, and in climate conditions. At the same time an ongoing land subsidence, with rates varying from few mm/yr to cm/yr, affects the southern lagoon margin and the nearby watershed. The settlement of these territories is mainly due to natural consolidation and geochemical subsidence, i.e. peat oxidation promoted by farming activities. Salt water intrusion and land subsidence combined with significant dry seasons expose this area to the potential soil desertification. The combined effect of both processes is producing an alarming social and environmental impact on the south Venice coastland, also in relation to the expected global climate change.
BibTeX:
@article{Tosi2008758,
  author = {Tosi, L. and Carbognin, L. and Gasparetto-Stori, G. and Rizzetto, F. and Strozzi, T. and Teatpni, P.},
  title = {Processes of land subsidence and salt water intrusion in Venice: Potential for soil desertification [Processi di subsidenza ed intrusione sali na nell'area veneziana: Potenziali cause di desertificazione]},
  journal = {Rendiconti Online Societa Geologica Italiana},
  year = {2008},
  volume = {3},
  number = {2},
  pages = {758-759},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84863463136&partnerID=40&md5=656ac2855566cf8c9aa3314ec0c66dcf}
}
Toure A, Goïta K, Royer A, Matzler C and Schneebeli M (2008), "Near-infrared digital photography to estimate snow correlation length for microwave emission modeling", Applied Optics. Vol. 47(36), pp. 6723-6733. OSA - The Optical Society.
Abstract: The study is based on experimental work conducted in alpine snow. We made microwave radiometric and near-infrared reflectance measurements of snow slabs under different experimental conditions. We used an empirical relation to link near-infrared reflectance of snow to the specific surface area (SSA), and converted the SSA into the correlation length. From the measurements of snow radiances at 21 and 35GHz, we derived the microwave scattering coefficient by inverting two coupled radiative transfer models (the sandwich and six-flux model). The correlation lengths found are in the same range as those determined in the literature using cold laboratory work. The technique shows great potential in the determination of the snow correlation length under field conditions. 2008 Optical Society of America.
BibTeX:
@article{Toure20086723,
  author = {Toure, A.M. and Goïta, K. and Royer, A. and Matzler, C. and Schneebeli, M.},
  title = {Near-infrared digital photography to estimate snow correlation length for microwave emission modeling},
  journal = {Applied Optics},
  publisher = {OSA - The Optical Society},
  year = {2008},
  volume = {47},
  number = {36},
  pages = {6723-6733},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-60949111236&doi=10.1364%2fAO.47.006723&partnerID=40&md5=55d75ef1f597578b6d0ca7268822519d},
  doi = {10.1364/AO.47.006723}
}
Wegmüller U, Santoro M, Werner C, Strozzi T, Wiesmann A, Lengert W and Miranda N (2008), "ERS-2 zero-gyro-mode data application showcases", In European Space Agency, (Special Publication) ESA SP. (649 SP)
Abstract: Since 2001 ERS-2 operates in Zero-Gyro Mode (ZGM), which does not guarantee the very high stability of the satellite's orbital attitude as defined in the mission requirements. In spite of this degradation ERS2 SAR is operational and both the ERS-2 ZGM archive and new acquisitions are still very useful for a wide range of applications. The scope of this contribution is to demonstrate with a number of examples that ERS-2 ZGM data still allow InSAR applications. Archived ERS-2 data of the period 2001-2004 are of particular interest for surface deformation monitoring as only few ENVISAT ASAR interferometric observations exist for this period over many sites. Another unique opportunity offered by ERS-2 ZGM data is ERS-2 - ASAR cross-interferometry. ERS-2 - ASAR IS2 VV-polarization interferograms are characterized by a short 28 minutes repeat-pass interval and a long 1.5km to 2.5km baseline. Given the large baseline and short time interval ERS-ENVISAT cross-interferometry has a good potential for the generation of precise DEMs in relatively flat areas.
BibTeX:
@conference{Wegmuller2008b,
  author = {Wegmüller, U. and Santoro, M. and Werner, C. and Strozzi, T. and Wiesmann, A. and Lengert, W. and Miranda, N.},
  title = {ERS-2 zero-gyro-mode data application showcases},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2008},
  number = {649 SP},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-47249096992&partnerID=40&md5=b4060c873df413c16c77c98e087e7cc3}
}
Wegmüller U, Werner C, Wiesmann A, Strozzi T and Santoro M (2008), "Initial assessment of the applicability of terrasar-x for repeat-track interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 529-532.
Abstract: In our contribution we present an initial assessment of the applicability of TerraSAR-X for repeat-track interferometry. A series of TerraSAR-X repeat observation in stripmap mode over an test site that includes different landuse classes as well as fast and slow deformation phenomena was selected for our investigation. From our investigation we conclude that longterm interferograms can mainly be interpreted over urban areas. For forested areas and for denser agricultural vegetation such as fully grown crops the coherence levels are very low even for 11 day intervals. For sparse vegetation as present in late winter the coherence is high, over many fields even over several 11-day cycles. The high spatial resolution is ideal to measure localized deformation patterns. For slow deformation at larger scale confusion with atmospheric effects is strong. Multi-temporal approaches can be used to resolve the deformation and atmospheric phase components if sufficient numbers of observations are available. 2008 IEEE.
BibTeX:
@conference{Wegmuller2008a,
  author = {Wegmüller, U. and Werner, C. and Wiesmann, A. and Strozzi, T. and Santoro, M.},
  title = {Initial assessment of the applicability of terrasar-x for repeat-track interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2008},
  volume = {2},
  pages = {529-532},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-66549083859&doi=10.1109%2fIGARSS.2008.4779045&partnerID=40&md5=c34ec078f7452aca9077a0edaf33f3d5},
  doi = {10.1109/IGARSS.2008.4779045}
}
Werner C, Strozzi T, Wiesmann A and Wegmüller U (2008), "A real-aperture radar for ground-based differential interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 210-213.
Abstract: Satellite interferometry has been used extensively for ground-motion monitoring with good success. In the case of landslides, for example, space-borne SAR interferometry has a good potential to get an overview on the slope stability. The role of a space-borne INSAR as an element in a landslide or rock fall warning system is constrained by the specific space-borne SAR imaging geometry, the typical multiple-week repeat-interval, and uncertainties in the data availability. Most of these limitations can be overcome with an in-situ radar imaging system. GAMMA has developed a portable radar interferometer that utilizes real-aperture antennas to obtain high azimuth resolution. Images are acquired line by line while rotating the transmitting and receiving antennas about a vertical axis. Phase differences between successive images acquired from the same location are used to determine line-of-sight displacements. The instrument operates at 17.2 GHz and has measurement sensitivity better than 1 mm. The instrument uses two receiving antennas with a short baseline to form an interferometer. Phase differences between simultaneous acquisitions by these antennas are used to calculate the precise look angle relative to the baseline, permitting derivation of the surface topography. Expected statistical noise in the height measurements is on the order of 1 meter. In this contribution the design, measurement principles and characteristics of GAMMA's Portable Radar Interferometer (GPRI) are presented. 2008 IEEE.
BibTeX:
@conference{Werner2008,
  author = {Werner, C. and Strozzi, T. and Wiesmann, A. and Wegmüller, U.},
  title = {A real-aperture radar for ground-based differential interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2008},
  volume = {3},
  pages = {210-213},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67649793585&doi=10.1109%2fIGARSS.2008.4779320&partnerID=40&md5=d2a72e7a7e5b0016e8358001b95f531a},
  doi = {10.1109/IGARSS.2008.4779320}
}
Wiesmann A, Werner C, Matzler C, Schneebeli M, Strozzi T and Wegmüller U (2008), "Mobile X- to ku-band scatterometer in support of the core-H2O mission", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 244-247.
Abstract: Information on snow coverage, structure, and liquid water content are important for many applications including avalanche warning, numerical weather prognosis (NWP), and snow pack water storage estimate. Active microwave remote sensing from space has an excellent potential to address these needs. However, the current generation of Cband SAR satellite systems are not well suited for snow related applications because of the small impact of the dry snow cover on the backscattering signal at 5.3 GHz.. In order to be more sensitive to snow properties the envisaged ESA CoReH20 mission proposes a dual-frequency radar operating at 9 and 18 GHz (X- and Ku-band). In support of this mission, a ground based 9 to 18 GHz scatterometer is being developed to help to address the lack of simultaneous backscatter information of snow in this frequency range. We are also preparing a dedicated field campaign in the Swiss Alps to evaluate the performance of the system and acquire first data. 2008 IEEE.
BibTeX:
@conference{Wiesmann2008a,
  author = {Wiesmann, A. and Werner, C. and Matzler, C. and Schneebeli, M. and Strozzi, T. and Wegmüller, U.},
  title = {Mobile X- to ku-band scatterometer in support of the core-H2O mission},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2008},
  volume = {5},
  pages = {244-247},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67649831868&doi=10.1109%2fIGARSS.2008.4780073&partnerID=40&md5=a00c5650b48dae9b95b3571e786c7cab},
  doi = {10.1109/IGARSS.2008.4780073}
}
Wiesmann A, Werner C, Schwank M, Matzler C, Elsasser B and Wegmüller U (2008), "ELBARAII, L-band radiometer system", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 653-656.
Abstract: L-band (1-2 GHz) microwave radiometry is an important remote sensing technique to monitor soil moisture over land surfaces at the global scale. The ESA L-Band SMOS radiometer mission aims at providing asglobal maps of soil moisture, with accuracy better than 0.04 m3m-3 every 3 days, with a spatial resolution better than 50 km. To improve the models used and for specifying the accuracy of the aimed global soil moisture data product, ground based radiometer campaigns before launch, during the commissioning phase and during the operative SMOS mission are important. Furthermore, the availability of ground-based L-band data measured simultaneously with the over-flying SMOS satellite are required for calibration and validation purposes. To address these needs three ELBARA II radiometers are being constructed for ESA. They rely on the proven architecture of the ELBARA radiometer [1] with improvements on the user interface, the mechanics, and the microwave electronics. Especially the development of an Active Cold Load (ACL) [2] as cold reference is expected to improve the radiometric accuracy. 2008 IEEE.
BibTeX:
@conference{Wiesmann2008b,
  author = {Wiesmann, A. and Werner, C. and Schwank, M. and Matzler, C. and Elsasser, B. and Wegmüller, U.},
  title = {ELBARAII, L-band radiometer system},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2008},
  volume = {2},
  pages = {653-656},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-66549091992&doi=10.1109%2fIGARSS.2008.4779077&partnerID=40&md5=bfc8de8291ad7d5c03487577601d52ff},
  doi = {10.1109/IGARSS.2008.4779077}
}
Askne J and Santoro M (2007), "Boreal forest stem volume estimation from multitemporal C-band InSAR observations", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: Ten ERS image pairs from the tandem period have been analyzed for two test sites in Sweden and the results have been compared with results based on 24 image pairs from two previously studied test sites. All four test sites represent boreal forests and include 338 forest stands with stem volumes up to 539 m3/ha. With optimal environmental conditions (sub zero temperature, dry snow layer, moderate breeze) and large and homogeneous forest stands the relative RMSE is of the order of 20% while for less optimal environmental conditions the relative RMSE is of the order of 30%. The relative RMSEr is increasing with increasing number of small stands or stands with low stem volume. No saturation with stem volume is found. The consistency of coherence observations for a certain stand can be used to identify the potential of giving accurate estimates of stem volume. A baseline of the order of 200-250 m is favorable.
BibTeX:
@conference{Askne2007,
  author = {Askne, J. and Santoro, M.},
  title = {Boreal forest stem volume estimation from multitemporal C-band InSAR observations},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36448942192&partnerID=40&md5=9c9591734c7d2f25526777787061f764}
}
Askne J and Santoro M (2007), "Selection of forest stands for stem volume retrieval from stable ERS tandem InSAR observations", IEEE Geoscience and Remote Sensing Letters. Vol. 4(1), pp. 46-50.
Abstract: Environmental factors influence the accuracy in stem volume retrieval using European Remote Sensing Satellite (ERS) tandem synthetic aperture radar (SAR) interferometry. Some forest stands are more sensitive than others to heterogeneity of environmental properties, forest properties, and noise. It is shown that the consistency of coherence observations between different image pairs or the consistency of the estimated stem volume can be used to sort forest stands according to increasing errors in stem volume estimates associated with varying forest properties. Fifteen ERS tandem pairs were used to determine the relative root mean square error (RMSE) of stem volume estimated from C-band SAR interferometry. The test site, Tuusula in Finland, contains 210 forest stands with stem volumes up to 539 m3/ha. RMSE varies between 17% and 63% depending on number and type of stands included in the retrieval accuracy analysis. The more homogeneous forest stands with larger area and higher stem volumes of spruce and pine are those with highest retrieval accuracy. 2006 IEEE.
BibTeX:
@article{Askne200746,
  author = {Askne, J. and Santoro, M.},
  title = {Selection of forest stands for stem volume retrieval from stable ERS tandem InSAR observations},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  year = {2007},
  volume = {4},
  number = {1},
  pages = {46-50},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33846630436&doi=10.1109%2fLGRS.2006.883525&partnerID=40&md5=ea3a5a756001f92818cbdf3f531d22c3},
  doi = {10.1109/LGRS.2006.883525}
}
Benecke N, Kuchenbecker R, Knospe S and Wegmüller U (2007), "Radarinterferometry for monitoring of surface movements caused by mining - State-of-the-art and future expectations [Ueberwachung bergbaubedingter Bodenbewegungen mit Radarinterferometrie - Heute und morgen]", Geotechnik. Vol. 30(1), pp. 35-41.
Abstract: The civil and commercial use of radar-data for earth observation commenced with the launch of European ERS satellites (European Remote Sensing 1 and 2) some fifteen years ago. Since then radar data, covering several regions of Earth, have been acquired and archived by ESA (European Space Agency). The coherent processing of this data enables the application of Interferometric evaluation methods, which provides information about wery small surface movements. Beside others, radarinterferometric techniques for mapping large scaled surface movements have been established. This contribution first gives an overview over the latest results in radarinterferometric research. Second, a description about the conversion from research to operational application is given by using an example form practice. Some general remarks concerning the terms precision, accuracy and reliability of radarinterferometric results are given, because of their strong influence on acceptance of the technique in industry, state authority and public. Finally, a general over view concerning the perspectives of the technique for practical use is presented.
BibTeX:
@article{Benecke200735,
  author = {Benecke, N. and Kuchenbecker, R. and Knospe, S. and Wegmüller, U.},
  title = {Radarinterferometry for monitoring of surface movements caused by mining - State-of-the-art and future expectations [Ueberwachung bergbaubedingter Bodenbewegungen mit Radarinterferometrie - Heute und morgen]},
  journal = {Geotechnik},
  year = {2007},
  volume = {30},
  number = {1},
  pages = {35-41},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33947533364&partnerID=40&md5=41dcfb8b3c13c0467e3881117a3e7667}
}
Brooks B, Merrifield M, Foster J, Werner C, Gomez F, Bevis M and Gill S (2007), "Space geodetic determination of spatial variability in relative sea level change, Los Angeles basin", Geophysical Research Letters. Vol. 34(1)
Abstract: We combine Synthetic Aperture Radar Interferometry (InSAR), tide gauge, and continuous GPS measurements to determine the spatial variation in vertical land motion (VLM) along the coast of the Los Angeles basin over the past decade, and to examine the impact of spatially variable VLM on relative sea level trends. By identifying radar scattering targets with long-term coherence we make height corrections which allow interferogram creation for nearly the entire ERS-1 catalog and permit estimation of average deformation rates with minimal temporal aliasing. Between Los Angeles Harbor and Newport Beach, mean VLM trends range from ∼3.4 to ∼4.3 mm/yr, reflecting the high level of ground water and oil extraction activity in the region. West of Los Angeles Harbor, VLM rates and spatial variability are roughly half as large. The 8-year VLM trends exceed the long-term sea level trend (0.8 mm/yr) determined from the 80 year Los Angeles Harbor tide gauge. The high degree of observed VLM variability emphasizes the need for the spatially continuous measurements provided by InSAR; a single tide gauge assessment of regional RSL would otherwise have limited applicability. Copyright 2007 by the American Geophysical Union.
BibTeX:
@article{Brooks2007,
  author = {Brooks, B.A. and Merrifield, M.A. and Foster, J. and Werner, C.L. and Gomez, F. and Bevis, M. and Gill, S.},
  title = {Space geodetic determination of spatial variability in relative sea level change, Los Angeles basin},
  journal = {Geophysical Research Letters},
  year = {2007},
  volume = {34},
  number = {1},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548048775&doi=10.1029%2f2006GL028171&partnerID=40&md5=fe8f660e4677fb2cdb8f78d03dc58bfc},
  doi = {10.1029/2006GL028171}
}
Cartus O, Santoro M, Schmullius C, Yong P and Zengyuan L (2007), "Creation of large area forest biomass maps for NE China using ERS-1/2 tandem coherence", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: ERS-1/2 tandem coherence is known to allow forest stem volume mapping with reasonable accuracy. Largescale forest mapping, however, is hindered by the variability of coherence with meteorological, environmental and orbital acquisition conditions. The traditional way of stem volume retrieval is based on the training of models, relating coherence to stem volume, using forest inventory which is generally available for a few small test sites but not for large areas. In this paper a new approach is presented that allows the training of a semi-empirical model on a frame-by-frame basis using the MODIS Vegetation Continuous Field product without further need of ground data. A comparison of the new approach with the traditional regression-based and ground-data dependent model training procedure and the application of the new approach to a multiseasonal and multi-baseline ERS-1/2 tandem coherence dataset covering Northeast China are presented.
BibTeX:
@conference{Cartus2007,
  author = {Cartus, O. and Santoro, M. and Schmullius, C. and Yong, P. and Zengyuan, L.},
  title = {Creation of large area forest biomass maps for NE China using ERS-1/2 tandem coherence},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36448945518&partnerID=40&md5=effffed8febfccde9f8896b5d7faada4}
}
Delaloye R, Lambiel C, Lugon R, Raetzo H and Strozzi T (2007), "Typical ERS InSAR signature of slope movements in a periglacial mountain environment (Swiss Alps)", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: ERS InSAR has been used for mapping and assessing slope movements in an alpine periglacial test region. A large number of areas have thus been recognized as affected by mass wasting related to permafrost or not. Glaciers and most of the active geomorphic landforms display in fact typical ERS InSAR signals. A typology has been established. It can be seen as a useful tool to interpret ERS InSAR data in such a mountain environment.
BibTeX:
@conference{Delaloye2007,
  author = {Delaloye, R. and Lambiel, C. and Lugon, R. and Raetzo, H. and Strozzi, T.},
  title = {Typical ERS InSAR signature of slope movements in a periglacial mountain environment (Swiss Alps)},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36549024014&partnerID=40&md5=dfa28356be13ad989d8fbffd3ece44cc}
}
Della Vecchia A, Ferrazzoli P, Guerriero L, Strozzi T and Wegmüller U (2007), "A statistical and theoretical study about radar sensitivity to crop growth from S to X band", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1424-1427.
Abstract: In this work, we show the correlation study carried out on the data collected on a maize field in the Swiss region named Central Plain, by the multifrequency RASAM scatterometer. This agricultural field was monitored over long periods, at a wide range of frequencies and observation angles, so that the correlation between backscattering and crop height, biomass and soil moisture could have been studied under several plant and observation conditions. Moreover, we describe some recent refinements applied to the vegetation scattering model developed at Tor Vergata University, and we evaluate the accuracy of extended comparisons between model outputs and RASAM signatures. The Tor Vergata model is finally applied to give a theoretical basis to the experimental correlation findings. 2007 IEEE.
BibTeX:
@conference{DellaVecchia20071424,
  author = {Della Vecchia, A. and Ferrazzoli, P. and Guerriero, L. and Strozzi, T. and Wegmüller, U.},
  title = {A statistical and theoretical study about radar sensitivity to crop growth from S to X band},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2007},
  pages = {1424-1427},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-82355164278&doi=10.1109%2fIGARSS.2007.4423074&partnerID=40&md5=1e845584a377817e9cab7b3d390bebab},
  doi = {10.1109/IGARSS.2007.4423074}
}
Duric A, Hitz B, Murk A and Matzler C (2007), "Correction of the off-axis reflector beam squint in passive images of the fourth stokes parameter at 91 GHz", In IET Seminar Digest. (11961)
Abstract: In this paper we analyze effects of the antenna beam squint on the fourth Stokes parameter V images taken by the fully polarimetric imager SPIRA and suggest methods to correct them. The first images of complex scenery, containing man- made and natural objects, showed unexpected features in the y-parameter with amplitudes of up to 30 K, depending on the contrast in the total intensity images. They have pronounced variation in elevation direction, whereas in azimuth (horizontal) only small changes are observed. A simple relation can be established between the measured fourth Stokes parameter and the scene brightness distributions in V and the total intensity I. It allows correction of the beam-squint effects in the V Stokes parameter image using image processing methods. Another, less general method, could be more easily applied to SPIRA images, achieving a comparable enhancement. In this way, the beam-squint effects were reduced down to the uncertainty of the instrumental polarimetric calibration.
BibTeX:
@conference{Duric2007,
  author = {Duric, A. and Hitz, B. and Murk, A. and Matzler, C.},
  title = {Correction of the off-axis reflector beam squint in passive images of the fourth stokes parameter at 91 GHz},
  booktitle = {IET Seminar Digest},
  year = {2007},
  number = {11961},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349762909&doi=10.1049%2fic.2007.1159&partnerID=40&md5=7e1cb127aaf128e774e453f65fbc2701},
  doi = {10.1049/ic.2007.1159}
}
Frey O, Morsdorf F and Meier E (2007), "Tomographic processing of multi-baseline P-band SAR data for imaging of a forested area", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 156-159.
Abstract: Recently, various attempts have been undertaken to obtain information about the structure of forested areas from multi-baseline synthetic aperture radar data. Tomographic processing of such data has been demonstrated but the quality of the focused tomographic image is limited by several factors. In particular Fourier-based focusing methods are susceptible to irregular and sparse sampling, two problems, that are unavoidable in case of multi-pass, multi-baseline SAR data acquired by an airborne system. We propose a tomographic focusing method based on the time-domain back-projection algorithm, which maintains the geometric relationship between the original sensor positions and the imaged target and is therefore able to cope with irregular sampling without introducing any approximations with respect to the geometry. We assess the tomographic focusing quality with the help of the impulse response of simulated point targets and an in-scene corner reflector. And, in particular, preliminary results obtained with the newly acquired P-band tomographic data set consisting of eleven flight tracks are presented. 2007 IEEE.
BibTeX:
@conference{Frey2007156,
  author = {Frey, O. and Morsdorf, F. and Meier, E.},
  title = {Tomographic processing of multi-baseline P-band SAR data for imaging of a forested area},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2007},
  pages = {156-159},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-58149530700&doi=10.1109%2fIGARSS.2007.4422753&partnerID=40&md5=699458be262d3e533cbe2bb8b3d2efa4},
  doi = {10.1109/IGARSS.2007.4422753}
}
Frey O, Morsdorf F and Meier E (2007), "Tomographic SAR imaging of a forested area by time-domain back-projection", In International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives. Vol. 36 International Society for Photogrammetry and Remote Sensing.
Abstract: Recently, various attempts have been undertaken to retrieve information about the three-dimensional structure of vegetation from multi-baseline synthetic aperture radar data. Although tomographic processing of such data has been demonstrated, yet, there are still several problems that limit the focusing quality. In particular, the frequency-domain based focusing methods are susceptible to irregular and sparse sampling, two problems, which are unavoidable in case of multi-pass, multi-baseline radar data acquired by an airborne system. We propose a time-domain back-projection algorithm, which maintains the original geometric relationship between the original sensor positions and the imaged target and is therefore able to cope with irregular and sparse sampling without introducing any geometric approximations. Preliminary results obtained with a newly acquired P-band tomographic data set consisting of eleven flight tracks are shown and discussed. 2007 International Society for Photogrammetry and Remote Sensing. All rights reserved.
BibTeX:
@conference{Frey2007,
  author = {Frey, O. and Morsdorf, F. and Meier, E.},
  title = {Tomographic SAR imaging of a forested area by time-domain back-projection},
  booktitle = {International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives},
  publisher = {International Society for Photogrammetry and Remote Sensing},
  year = {2007},
  volume = {36},
  note = {7/C50},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85069737446&partnerID=40&md5=9b9392e6b1ab144149ceed01438f4f70}
}
Grant J, Wigneron J-P, Van De Griend A, Guglielmetti M, Saleh K and Schwank M (2007), "Calibration of L-MEB for soil moisture retrieval over forests", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 2248-2251.
Abstract: Soil moisture retrieval from passive microwave remote sensing over densely vegetated areas, such as forests, has become a pertinent subject in the light of ESA's upcoming Soil Moisture and Ocean Salinity (SMOS) mission. Even though it is probably not possible to retrieve soil moisture over forested areas with the accuracy required by SMOS, understanding forest radiative transfer properties at L-band (1.1-1.7 GHz) is still important for soil moisture retrieval in partly forested pixels. The forward model to be used by the SMOS Level 2 Soil Moisture algorithm is 'L-MEB', from 'L-band Microwave Emission of the Biosphere'. This paper shows the results of L-MEB model calibration over two forest types in terms of various soil and vegetation parameters, together with an assessment of model performance in both forward and inverse mode. While, as expected, the retrieval of soil moisture over forest areas does not give results up to the standard required by SMOS, the forward model does result in an acceptable root mean square error in terms of 'reconstructed' brightness temperatures. 2007 IEEE.
BibTeX:
@conference{Grant20072248,
  author = {Grant, J.P. and Wigneron, J.-P. and Van De Griend, A.A. and Guglielmetti, M. and Saleh, K. and Schwank, M.},
  title = {Calibration of L-MEB for soil moisture retrieval over forests},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2007},
  pages = {2248-2251},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051762244&doi=10.1109%2fIGARSS.2007.4423287&partnerID=40&md5=c7c244b8dfbf1d5f7306d7ca14a589f3},
  doi = {10.1109/IGARSS.2007.4423287}
}
Guglielmetti M, Schwank M, Matzler C, Oberdorster C, Vanderborght J and Fluhler H (2007), "Measured microwave radiative transfer properties of a deciduous forest canopy", Remote Sensing of Environment. Vol. 109(4), pp. 523-532.
Abstract: A field experiment was performed with an L- and X-band radiometer operating at 1.4 GHz and 11.4 GHz in a deciduous forest in Julich (Germany) from September to November 2004. The radiometers were installed on the ground being directed upwards through the canopy. In this position downwelling microwave radiation was measured during the defoliation of the forest with a time resolution of 4 h. Simultaneously we measured the air and soil temperatures. Based on these data, the transmissivities of the forest canopy were estimated at different foliation states. Typical L-band transmissivities determined for the foliated and the defoliated states were 0.41 and 0.46, confirming the semi-transparency of the canopy at low microwave frequencies. Due to the anisotropic crown structure the L-band brightness temperatures were slightly horizontally polarized to the same degree for any state of the vegetation. From this we conclude that branches are the prevailing emitters of the canopy whereas leaves and trunks are less relevant for L-band observations. In the X-band, the canopy was opaque in the foliated state and became semi-transparent in the course of defoliation indicating that leaves are an important radiation source at this wavelength. Our results provide the experimental evidence to quantify the radiation properties of a deciduous forest canopy. This is crucial for interpreting the microwave radiation emitted from forested areas measured from space-borne microwave sensing platforms. 2007 Elsevier Inc. All rights reserved.
BibTeX:
@article{Guglielmetti2007523,
  author = {Guglielmetti, M. and Schwank, M. and Matzler, C. and Oberdorster, C. and Vanderborght, J. and Fluhler, H.},
  title = {Measured microwave radiative transfer properties of a deciduous forest canopy},
  journal = {Remote Sensing of Environment},
  year = {2007},
  volume = {109},
  number = {4},
  pages = {523-532},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34347389708&doi=10.1016%2fj.rse.2007.02.003&partnerID=40&md5=6ca690f62410fd83df9877222891e8af},
  doi = {10.1016/j.rse.2007.02.003}
}
Magnard C, Meier E, Ruegg M, Brehm T and Essen H (2007), "High resolution millimeter wave SAR interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 5061-5064.
Abstract: High resolution millimeter wave synthetic aperture radar (SAR) interferometry is presented using the MEMPHIS multi-baseline InSAR system. A complete processing chain is used to generate digital elevation models starting from the radar raw data. A deeper focus is laid on the phase unwrapping step, which is achieved using the multi-baseline properties of the system. In November 2006, an experiment was realized including two test sites in Switzerland; the actual results are presented and discussed.
BibTeX:
@conference{Magnard20075061,
  author = {Magnard, C. and Meier, E. and Ruegg, M. and Brehm, T. and Essen, H.},
  title = {High resolution millimeter wave SAR interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2007},
  pages = {5061-5064},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79957631664&doi=10.1109%2fIGARSS.2007.4423999&partnerID=40&md5=d1160fcdd80f352374ed4dc63cd6e149},
  doi = {10.1109/IGARSS.2007.4423999}
}
Manconi A, Walter T and Amelung F (2007), "Effects of mechanical layering on volcano deformation", Geophysical Journal International. Vol. 170(2), pp. 952-958.
Abstract: The migration and accumulation of magma beneath volcanoes often causes surface displacements that can be measured by geodetic techniques. Usually, deformation signals are explained using models with uniform mechanical properties. In this paper, we study surface displacements due to magma chamber inflation, using heterogeneous finite element models. We first present a systematic analysis of the influence of mechanical layering, showing that the stiffness contrast significantly affects the entity and the pattern of vertical and radial displacements. Second, as an example we apply the models to interpret ground displacements at Darwin volcano (Galápagos Islands) as revealed by InSAR data in the period 1992-1998. The considered models suggest that geodetic data interpreted using homogeneous models leads to underestimation of the source depth and volume change. Thus, we propose correction factors for the source parameters estimated by homogeneous models, in order to consider a range of variation due to mechanical layering as analysed in this study. The effect of the mechanical heterogeneities affects the correct understanding of geodetic data and also influences the evaluation of a volcanic hazard potential. 2007 The Authors Journal Compilation 2007 RAS.
BibTeX:
@article{Manconi2007952,
  author = {Manconi, A. and Walter, T.R. and Amelung, F.},
  title = {Effects of mechanical layering on volcano deformation},
  journal = {Geophysical Journal International},
  year = {2007},
  volume = {170},
  number = {2},
  pages = {952-958},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547171155&doi=10.1111%2fj.1365-246X.2007.03449.x&partnerID=40&md5=c73a484ee4b15dab42dd2b19703cb2a8},
  doi = {10.1111/j.1365-246X.2007.03449.x}
}
Matzler C and Rosenkranz P (2007), "Dependence of microwave brightness temperature on bistatic surface scattering: Model functions and application to AMSU-A", IEEE Transactions on Geoscience and Remote Sensing. Vol. 45(7), pp. 2130-2138.
Abstract: For significant surface reflection, the brightness temperature above planetary surfaces depends not only on surface temperature, emissivity, and atmospheric emission, but also on the type of bistatic scattering. For a plane-parallel atmosphere, this dependence can be specified by an effective incidence angle θeff from zenith of downwelling radiation. We obtained analytic expressions for the reflectivity and θeff for typical scattering functions such as Lambert, Lommel-Seeliger, multiple isotropic scattering (Chandrasekhar), and Peake's grass model. In all cases, θeff decreases with increasing zenith opacity (considered range: 0 to 1), and in most cases, the dependence on observation direction is small. These results are in contrast to specular reflection, where the effective incidence angle is given by the observation angle, which is, of course, independent of opacity. The dependence of terrestrial polar-region brightness temperatures on the type of bistatic scattering was studied for the Advanced Microwave Sounding Unit-A (AMSU-A). The difference between upwelling brightness temperatures calculated with diffuse and specular surface scattering is greatest for the zenith direction and for zenith opacities in the range of 0.3 to 0.6, and it decreases with increasing emissivity. A potential exists to infer a parameter AL describing the relative contributions of Lambertian (AL =1) and specular (AL = 0) scattering. Some non-Lambertian scattering functions give values of AL > 1. For example, Lommel-Seeliger surfaces that are observed near vertical give A L values of about 1.2, and still larger values (∼1.6) are obtained with the model of Peake. The angle dependence of AMSU-A measurements from the vicinity of Dome C, Antarctica, agrees with the Lambert model. 2007 IEEE.
BibTeX:
@article{Matzler20072130,
  author = {Matzler, C. and Rosenkranz, P.W.},
  title = {Dependence of microwave brightness temperature on bistatic surface scattering: Model functions and application to AMSU-A},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2007},
  volume = {45},
  number = {7},
  pages = {2130-2138},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34347222816&doi=10.1109%2fTGRS.2007.898089&partnerID=40&md5=f2ef4278b3f10d52fa98834e800e8178},
  doi = {10.1109/TGRS.2007.898089}
}
Morland J and Matzler C (2007), "Spatial interpolation of GPS integrated water vapour measurements made in the Swiss Alps", Meteorological Applications. Vol. 14(1), pp. 15-26.
Abstract: The 31 stations in the Swiss GPS network are located at altitudes between 330 and 3584 m and have provided hourly Integrated Water Vapour (IWV) measurements since November 2000. A correction based on an exponential relationship is proposed for the decrease in IWV with altitude. The scale height depends on the ratio of IWV measured at Jungfraujoch (3584 m) to that measured at Payerne (498 m). An additional coefficient, dependent on the east-west and north-south spatial differences in the IWV, improves the fit to the data. The IWV at heights between 750 and 3500 m was estimated from GPS measurements at Payerne and compared with the Payerne radiosounding. The altitude correction introduced an additional bias of 0.2 to 0.4 mm between GPS and radiosonde. The IWV was normalized to 500 m and the increases and decreases due to the passage of a series of frontal systems between 11 and 14 January 2004 were mapped. A four-year climatology of IWV normalized to 500 m showed that the Alpine stations are more moist in spring, summer and autumn than the stations in the Swiss plains to the north of the Alps. This was attributed to more moist Mediterranean air being blocked by the Alps. Copyright 2007 Royal Meteorological Society.
BibTeX:
@article{Morland200715,
  author = {Morland, J. and Matzler, C.},
  title = {Spatial interpolation of GPS integrated water vapour measurements made in the Swiss Alps},
  journal = {Meteorological Applications},
  year = {2007},
  volume = {14},
  number = {1},
  pages = {15-26},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33947362943&doi=10.1002%2fmet.2&partnerID=40&md5=0184feb141ab577348e2c4776a2411be},
  doi = {10.1002/met.2}
}
Raetzo H, Wegmüller U, Strozzi T, Marks F and Farina P (2007), "Monitoring of lumnez landslide with ERS and envisat SAR data", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: As part of the ESA Terrafirma Project an interferometric point target analysis (IPTA) was conducted to monitor the LUMNEZ landslide. The main interferometric result consists of the average line-of-sight deformation rates and the deformation histories for the selected points. The observed deformation rates reach values up to several centimeters per year. The interferometric result was delivered to the Swiss Federal Office for Environment and to the University of Florence where it was further interpreted. Combining IPTA results with the use of digital terrain data, aerial imagery and in-situ data a geomorphologic and geological interpretation of the Lumnez landslide was carried out. DTM data and aerial imagery allowed a geomorphologic zonation of the unstable slope taking into account derivates of the DTM as shaded relief, slope and aspect map. A field survey enabled the assessment of findings from the satellite monitoring, with the identification of damaged buildings and morphologic evidences connected to the slope movements.
BibTeX:
@conference{Raetzo2007,
  author = {Raetzo, H. and Wegmüller, U. and Strozzi, T. and Marks, F. and Farina, P.},
  title = {Monitoring of lumnez landslide with ERS and envisat SAR data},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36448937472&partnerID=40&md5=363c8b205f109d409474fefecec76370}
}
Saleh K, Wigneron J-P, De Rosnay P, Escorihuela M, Kerr Y, Calvet J-C, Schwank M and Waldteufel P (2007), "Estimates of surface soil moisture in prairies using L-band passive microwaves", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1200-1203.
Abstract: This paper compares L-band measurements from three different experiments in areas covered by grass. The main objective is to assess soil moisture retrievals based on the L-band Microwave Emission of the Biosphere model (L-MEB) used by the Soil Moisture and Ocean Salinity mission (SMOS). Results indicate that over grass the vegetation is isotropic to the microwave propagation at horizontal polarisation, while at vertical polarisation non-zero scattering is observed for all the grass data sets. Surface soil moisture is retrieved with enough accuracy for all data sets as long as the soil roughness and litter emission are calibrated beforehand. The study also highlights the importance of detecting strong attenuation by wet vegetation and litter due to rainfall interception. We show that strong rainfall interception can be flagged using a microwave polarisation index. 2007 IEEE.
BibTeX:
@conference{Saleh20071200,
  author = {Saleh, K. and Wigneron, J.-P. and De Rosnay, P. and Escorihuela, M.J. and Kerr, Y. and Calvet, J.-C. and Schwank, M. and Waldteufel, P.},
  title = {Estimates of surface soil moisture in prairies using L-band passive microwaves},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2007},
  pages = {1200-1203},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-73249116058&doi=10.1109%2fIGARSS.2007.4423020&partnerID=40&md5=79fd93609e35218979c490c5ec61b4c2},
  doi = {10.1109/IGARSS.2007.4423020}
}
Saleh K, Wigneron J-P, Waldteufel P, de Rosnay P, Schwank M, Calvet J-C and Kerr Y (2007), "Estimates of surface soil moisture under grass covers using L-band radiometry", Remote Sensing of Environment. Vol. 109(1), pp. 42-53.
Abstract: The scope of this study is to establish the parameters of the L-band (1.4 GHz) Microwave Emission of the Biosphere model (L-MEB) for grass covers, and to assess surface soil moisture retrievals in areas covered by grass. L-MEB parameters are key ancillary information for the Soil Moisture and Ocean Salinity mission (SMOS) retrieval algorithm that produces estimates of the surface soil moisture from measurements of the surface brightness temperature at L-band. L-band data sets from three ground-based experiments over grass are analysed in this paper: BARC (orchard grass and alfalfa), ELBARA-ETH (clover grass), and SMOSREX (grass and litter from a field left fallow). Modelling of the brightness temperature using the zero-th order radiative transfer model in L-MEB indicates that the vegetation appears isotropic to microwaves propagating with horizontal polarisation, and that the single scattering albedo can be neglected. At vertical polarisation, non-zero scattering is observed for all the grass data sets. Surface soil moisture is retrieved with enough accuracy for all data sets as long as the soil and litter emission are calibrated beforehand. Then surface soil moisture and vegetation optical depth can be left as free parameters in the retrieval process. Finally, the study highlights the importance of detecting strong emission and attenuation by wet vegetation and litter due to rainfall interception in order to obtain accurate estimates of the surface soil moisture. The study illustrates how strong rainfall interception can be flagged straightforwardly using a microwave polarisation index. 2006 Elsevier Inc. All rights reserved.
BibTeX:
@article{Saleh200742,
  author = {Saleh, K. and Wigneron, J.-P. and Waldteufel, P. and de Rosnay, P. and Schwank, M. and Calvet, J.-C. and Kerr, Y.H.},
  title = {Estimates of surface soil moisture under grass covers using L-band radiometry},
  journal = {Remote Sensing of Environment},
  year = {2007},
  volume = {109},
  number = {1},
  pages = {42-53},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34248680726&doi=10.1016%2fj.rse.2006.12.002&partnerID=40&md5=fddc2f14cfbaeca7621bf234ae870674},
  doi = {10.1016/j.rse.2006.12.002}
}
Santoro M, Askne J, Wegmüller U and Werner C (2007), "Observations, modeling, and applications of ERS-ENVISAT coherence over land surfaces", IEEE Transactions on Geoscience and Remote Sensing. Vol. 45(8), pp. 2600-2611.
Abstract: European Remote Sensing satellite (ERS) ENVISAT coherence is a new repeat-pass interferometric synthetic aperture radar product characterized by a very short repeat-pass interval between acquisitions (28 min). In this paper, we investigate the properties of two 28-mins coherence images acquired over the regions of Paris, France, and Prague, Czech Republic, as well as a 35-day coherence image from Prague. Bare soils showed higher coherence compared to forests and urban areas. The range of coherence was larger for 28-min pairs, perpendicular baseline closer to 2 km, and stable weather conditions between acquisitions. Coherence modeling shows that because of the long baseline: 1) significant surface decorrelation occurs when slopes are not accounted for in the common-band filtering and for variation of topography in the resolution cell and 2) volume decorrelation is significant. Temporal decorrelation seems to be relevant for vegetation even at the 28-min interval time scale. Observations and modeled coherence were found to be in good agreement. Land cover classification using coherence and backscatter has been tested for the Paris scene for mapping the four major classes. The classification accuracy was 86% when an edge-eroded version of the reference land cover map was used. It decreases to 68% when the full land cover map was used as reference because of local mismatches between the coherence image and the land cover map, and the reduced common band in range. The high coherence difference between forests and bare fields suggests the possibility to use the ERS-ENVISAT coherence for forest/nonforest mapping and estimation of biophysical properties of short vegetation. 2007 IEEE.
BibTeX:
@article{Santoro20072600,
  author = {Santoro, M. and Askne, J.I.H. and Wegmüller, U. and Werner, C.L.},
  title = {Observations, modeling, and applications of ERS-ENVISAT coherence over land surfaces},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2007},
  volume = {45},
  number = {8},
  pages = {2600-2611},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547426807&doi=10.1109%2fTGRS.2007.897420&partnerID=40&md5=7fe085aaa88cc25c083f84fa18073db3},
  doi = {10.1109/TGRS.2007.897420}
}
Santoro M, Beer C, Shvidenko A, McCallum I, Wegmüller U, Wiesmann A and Schmullius C (2007), "Comparison of forest biomass estimates in Siberia using spaceborne SAR, inventory-based information and the LPJ dynamic global vegetation model", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: Estimation of forest biomass using spaceborne SAR data is an active field of investigation. C-band backscatter is known to provide little information on biomass because of the weak sensitivity to forest biophysical properties. However, if a large multitemporal dataset is used, it should be possible to improve the estimation. This assumption has been tested with ENVISAT ASAR Wide Swath (WS) data over a 400.000 km2 large region in Central Siberia. Forest biomass, expressed as growing stock volume, has been retrieved using an approach based on a Water-Cloud like model and a multi-temporal combination of estimates. To avoid any dependence of the modelling procedure upon in situ training data, a novel training approach based on the information content of the MODIS Vegetation Continuous Fields tree canopy cover product has been developed. Biomass has been estimated at 1 km resolution to be comparable both to the inventory data and the coarse-scale biomass simulations by the LPJ Dynamic Vegetation Model. The patterns of biomass estimated from ASAR WS and from the inventory compare well. This result is far beyond initial expectations. Compared to LPJ-based simulated biomass, the WS-based biomass presents a much higher degree of detail making comparison difficult. ENVISAT ASAR WS data appear as a potential candidate for estimation of large-scale forest biomass for a wide range of applications.
BibTeX:
@conference{Santoro2007,
  author = {Santoro, M. and Beer, C. and Shvidenko, A. and McCallum, I. and Wegmüller, U. and Wiesmann, A. and Schmullius, C.},
  title = {Comparison of forest biomass estimates in Siberia using spaceborne SAR, inventory-based information and the LPJ dynamic global vegetation model},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36448982552&partnerID=40&md5=f033d8048efa3931500ced080032058c}
}
Santoro M, Shvidenko A, McCallum I, Askne J and Schmullius C (2007), "Properties of ERS-1/2 coherence in the Siberian boreal forest and implications for stem volume retrieval", Remote Sensing of Environment. Vol. 106(2), pp. 154-172.
Abstract: Properties of multi-temporal ERS-1/2 tandem coherence in boreal forests and retrieval accuracy of forest stem volume have been investigated mostly for small, managed forest areas. The clear seasonal trends and the high accuracy of the retrieval are therefore valid for specific types of forest and question is if these findings extend to large areas with different forest types in a similar manner. Using multi-temporal ERS-1/2 coherence data and extensive sets of inventory data at stand level at seven forest compartments in Central Siberia we confirm that the trend of coherence as a function of stem volume is mainly driven by the environmental conditions at acquisition. In addition, we have now found that the variability of the coherence for a given stem volume are due to spatial variations of the environmental conditions, strong topography (slope > 10°), small stand size (< 3-4 ha) and low relative stocking (< 50%). Further deviations can be related to errors in the ground data. Stem volume retrieval behaves consistently under stable winter frozen conditions. For stands larger than 3-4 ha and relative stocking of at least 50%, a relative RMSE of 20-25% can be considered the effective retrieval error achievable in Siberian boreal forest. Combined with previous experience from managed test forests in Sweden and Finland, C-band ERS-1/2 tandem coherence observations acquired under stable winter conditions with a snow cover and an at least moderate breeze can be considered so far the most suitable spaceborne remote sensing observable for the estimation of forest stem volume in homogeneous forest stands throughout the boreal zone. 2006 Elsevier Inc. All rights reserved.
BibTeX:
@article{Santoro2007154,
  author = {Santoro, M. and Shvidenko, A. and McCallum, I. and Askne, J. and Schmullius, C.},
  title = {Properties of ERS-1/2 coherence in the Siberian boreal forest and implications for stem volume retrieval},
  journal = {Remote Sensing of Environment},
  year = {2007},
  volume = {106},
  number = {2},
  pages = {154-172},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845976718&doi=10.1016%2fj.rse.2006.08.004&partnerID=40&md5=8d0315784891f087ce740602f173e07e},
  doi = {10.1016/j.rse.2006.08.004}
}
Santoro M, Werner C, Wegmüller U and Cartus O (2007), "Improvement of interferometric SAR coherence estimates by slope-adaptive range common-band filtering", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 129-132.
Abstract: The accuracy of SAR interferometric coherence estimates depends on the precision of several processing steps. In particular decorrelation can occur if range common-band filtering does not perform optimally. Typically a planar surface is adopted which introduces additional decorrelation in case of sloped terrain. To take into account topographic variations a slope-adaptive range common-band filtering method has been developed. A DEM is used to simulate an unwrapped interferogram and the fringe rate is used as driver for the filter size in the range common-band filtering step. Tests with several spaceborne interferometric SAR datasets confirmed the robustness of the method. The improvement of the coherence increased for increasing perpendicular baseline. As a consequence, the fringe visibility also greatly improved. To quantify the improvement of the coherence estimates with the slope-adaptive range common-band filtering, we considered the variation of classification in forest mapping, i.e. an application in which accurate coherence estimates are needed. With improved coherence the classified forest stem volume agreed better with forest maps derived from other remote sensing datasets. 2007 IEEE.
BibTeX:
@conference{Santoro2007129,
  author = {Santoro, M. and Werner, C. and Wegmüller, U. and Cartus, O.},
  title = {Improvement of interferometric SAR coherence estimates by slope-adaptive range common-band filtering},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2007},
  pages = {129-132},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-82355170951&doi=10.1109%2fIGARSS.2007.4422746&partnerID=40&md5=fb01b45a7b0f7782df996a80902e405f},
  doi = {10.1109/IGARSS.2007.4422746}
}
Schwank M and Green T (2007), "Simulated effects of soil temperature and salinity on capacitance sensor measurements", Sensors. Vol. 7(4), pp. 548-577. MDPI AG.
Abstract: Dielectric measurement techniques are used widely for estimation of water content in environmental media. However, factors such as temperature and salinity affecting the readings require further quantitative investigation and explanation. Theoretical sensitivities of capacitance sensors to liquid salinity and temperature of porous media were derived and computed using a revised electrical circuit analogue model in conjunction with a dielectric mixing model and a finite element model of Maxwell's equation to compute electrical field distributions. The mixing model estimates the bulk effective complex permittivities of solidwater-air media. The real part of the permittivity values were used in electric field simulations, from which different components of capacitance were calculated via numerical integration for input to the electrical circuit analogue. Circuit resistances representing the dielectric losses were calculated from the complex permittivity of the bulk soil and from the modeled fields. Resonant frequencies from the circuit analogue were used to update frequency-dependent variables in an iterative manner. Simulated resonant frequencies of the capacitance sensor display sensitivities to both temperature and salinity. The gradients in normalized frequency with temperature ranged from negative to positive values as salinity increased from 0 to 10 g L -1. The model development and analyses improved our understanding of processes affecting the temperature and salinity sensitivities of capacitance sensors in general. This study provides a foundation for further work on inference of soil water content under field conditions. 2007 by MDPI.
BibTeX:
@article{Schwank2007548,
  author = {Schwank, M. and Green, T.R.},
  title = {Simulated effects of soil temperature and salinity on capacitance sensor measurements},
  journal = {Sensors},
  publisher = {MDPI AG},
  year = {2007},
  volume = {7},
  number = {4},
  pages = {548-577},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34248174485&doi=10.3390%2fs7040548&partnerID=40&md5=b8dc1f3aab01fcc4a8503a8caf35c2ab},
  doi = {10.3390/s7040548}
}
Strozzi T and Ambrosi C (2007), "SAR interferometric point target analysis and interpretation of aerial photographs for landslides investigations in Ticino, Southern Switzerland", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: Information on landslide displacement from SAR Interferometric Point Target Analysis (IPTA) and sketch maps from aerial photography interpretation are combined for the study of landslides in Ticino, Southern Switzerland. Numerous unstable phenomena are considered in this mountainous region, with an elevation range from approximately 200 m a.s.l. to more than 3000 m a.s.l. The results achieved with IPTA are attractive to complement aerial photographs interpretation for the evaluation of the state of activity of landslides over villages and in sparsely vegetated areas with numerous exposed rocks. On the other hand, over vegetated areas (forests and meadows) IPTA failed to retrieve displacement information.
BibTeX:
@conference{Strozzi2007a,
  author = {Strozzi, T. and Ambrosi, C.},
  title = {SAR interferometric point target analysis and interpretation of aerial photographs for landslides investigations in Ticino, Southern Switzerland},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36448932364&partnerID=40&md5=2625fde23a2d9029a87cb8c3a6c52fc1}
}
Strozzi T, Wegmüller U, Werner C and Wiesmann A (2007), "Surface velocity of Swiss alpine glaciers from ERS SAR interferometry", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: Differential SAR interferograms were computed over the Swiss Alps with ERS-1/2 Tandem data acquired between 1995 and 2000 from ascending and descending orbits and use of an external Digital Elevation Model (DEM). Comparison with the Swiss glacier inventory 2000 shows that winter interferograms with one day time interval have a generally high degree of coherence and are straightforward to identify the line-of-sight movement of major and minor glaciers visible in the satellite SAR acquisitions (excluding therefore layover and shadow). Signal decorrelation is mainly observed for areas with high crevasses and displacement larger than some tens of centimeters. For areas with sufficient coherence to allow reliable phase unwrapping maps of the satellite line-of-sight displacement were computed and transformed, in certain cases, to surface velocity maps by assuming flowing along the terrain gradient.
BibTeX:
@conference{Strozzi2007b,
  author = {Strozzi, T. and Wegmüller, U. and Werner, C. and Wiesmann, A.},
  title = {Surface velocity of Swiss alpine glaciers from ERS SAR interferometry},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36448936785&partnerID=40&md5=386967f713d4a2a4814c5c09e6c423cb}
}
Strozzi T, Wegmüller U, Werner C, Wiesmann A and Santoro M (2007), "Potential of a C-band SAR mission with 12-day repeat cycle to derive ice surface velocity with interferometry and offset tracking", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 4229-4232.
Abstract: The goal of this contribution is the assessment of the potential of a C-band SAR mission with repeat-pass interval of 12 days - as the intended European satellite system Sentinel-1 - to derive ice surface velocity using SAR interferometry (InSAR) and offset-tracking. For this purpose we investigated ERS-1 SAR data acquired during the ice missions in 1992 and 1994 in 3-day repeat-orbits at Nordaustlandet in the northeast Svalbard archipelago. In 12-days winter InSAR pairs phase decorrellation is mainly observed in areas of high strain rates and, in certain cases, because of snow melting or redistribution through snowfall or wind. Velocity maps derived from these image pairs were found useful to enhance in regions of slow glacier flow the mapping of the surface ice-flow divides previously determined from optical imagery and topographic information. Range-azimuth offset-tracking investigations suggest that the expected error of this method is on the order of 50 m/year and that spatial coverage is generally satisfactory. Application of dual-azimuth offset-tracking, use of HH polarization and enhanced spatial resolution, feasible with Sentinel-1, could enhance the expected error. 2007 IEEE.
BibTeX:
@conference{Strozzi20074229,
  author = {Strozzi, T. and Wegmüller, U. and Werner, C. and Wiesmann, A. and Santoro, M.},
  title = {Potential of a C-band SAR mission with 12-day repeat cycle to derive ice surface velocity with interferometry and offset tracking},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2007},
  pages = {4229-4232},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-82355186618&doi=10.1109%2fIGARSS.2007.4423784&partnerID=40&md5=042c78995999f83791916b7280ef5dd0},
  doi = {10.1109/IGARSS.2007.4423784}
}
Tampellini L, Ober G, Vescovi F, Power D, Strozzi T, Vincent P, Eikvil L, Malnes E, Nagler T and Rott H (2007), "EO-Hydro: An earth observation service for hydropower plant management", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: EO-Hydro Service has been developed in the frame of the ESA EOMD Programme, with the aim of providing Hydropower Companies with innovative products based on the processing of Earth Observation data. These are derived from both SAR and optical satellite sensors. The service results from the integration of different technologies available in research institutes and industries based in the Alpine area, Canada and Norway. Its main focus is the water management and the security of the dams. The provided services are snow cover monitoring service, snow water equivalent service, water runoff forecast service and land displacement service. Different products (maps, plots, reports, etc.) are provided at different scales and frequencies. In this paper some study cases of practical applications are presented and discussed.
BibTeX:
@conference{Tampellini2007,
  author = {Tampellini, L. and Ober, G. and Vescovi, F.D. and Power, D. and Strozzi, T. and Vincent, P. and Eikvil, L. and Malnes, E. and Nagler, T. and Rott, H.},
  title = {EO-Hydro: An earth observation service for hydropower plant management},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85069092250&partnerID=40&md5=18c7813db94b1e31640695911a4f3022}
}
Teatini P, Strozzi T, Tosi L, Wegmüller U, Werner C and Carbognin L (2007), "Assesing short- and long-time displacements in the Venice coastland by synthetic aperture radar interferometric point target analysis", Journal of Geophysical Research: Earth Surface. Vol. 112(1) Blackwell Publishing Ltd.
Abstract: The Venice Lagoon in Italy is a unique environment vulnerable to loss in surface elevation relative to the mean sea level. We present detailed synthetic aperture radar (SAR) interferometric analyses on persistent point targets for the historical center of Venice, the tourist area of Sottomarina, and the Zennare farmland close to the southern lagoon edge. The selected areas are characterized by different degrees of development and our analyses show the remarkable capability of SAR Interferometric Point Target Analysis (IPTA) to map land displacement rates in densely urbanized zones and to detect movement information on isolated structures with a mm/year accuracy. A detailed analysis of the time series from 1992 to 2000 provided by IPTA shows that the vertical component of the measured displacements are the superposition of a short timescale, generally seasonal, movement on the order of 1 cm that is likely related to the fluctuation of environmental variables (temperature, piezometric head in the aquifer system underlying the lagoon, sea/lagoon water level) and a long-term ground deformation associated with building construction, the geomorphology of the area, and the human development of natural resources. If Venice is confirmed to be generally stable, significant long-term subsidence on the order of 4 mm/year is detected at the Sottomarina coastland. The highest displacement rates, of up to 8-10 mm/year, are recorded in the farmland bounding the lagoon margin where the movements are found to be highly site-specific. Copyright 2007 by the American Geophysical Union.
BibTeX:
@article{Teatini2007b,
  author = {Teatini, P. and Strozzi, T. and Tosi, L. and Wegmüller, U. and Werner, C. and Carbognin, L.},
  title = {Assesing short- and long-time displacements in the Venice coastland by synthetic aperture radar interferometric point target analysis},
  journal = {Journal of Geophysical Research: Earth Surface},
  publisher = {Blackwell Publishing Ltd},
  year = {2007},
  volume = {112},
  number = {1},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34249660554&doi=10.1029%2f2006JF000656&partnerID=40&md5=22d5d6d5958e126fb21b884b42e324b1},
  doi = {10.1029/2006JF000656}
}
Teatini P, Strozzi T, Tosi L, Wegmüller U, Werner C, Carbognin L, Rosselli R, Cecconi G and Giada M (2007), "ERS and envisat SAR interferometry to measure land subsidence in the venice lagoon on natural and artificial point targets", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: The Venice Lagoon, Italy, is a unique worldwide environment which is presently vulnerable due to loss in surface elevation as a result of land subsidence referred to the mean sea level. Land displacements in the Venice coastland have been determined over time by traditional monitoring techniques (i.e., spirit leveling and GPS). Recently, SAR-based analyses have been used to complement the ground-based methods. Interferometric analysis on persistent point targets has been proved to be very effective in detecting land displacement in the coastal environment. ERS SAR and ENVISAT ASAR images spanning the time period 1992-2005 and 2003-2006, respectively, have been processed at regional and local scale and on "natural" as well as "artificial" reflectors.
BibTeX:
@conference{Teatini2007a,
  author = {Teatini, P. and Strozzi, T. and Tosi, L. and Wegmüller, U. and Werner, C. and Carbognin, L. and Rosselli, R. and Cecconi, G. and Giada, M.},
  title = {ERS and envisat SAR interferometry to measure land subsidence in the venice lagoon on natural and artificial point targets},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36448970517&partnerID=40&md5=f466f99c2b5bb81b92996772d4203764}
}
Tian X, Li Z, Chen E, Pang Y, Schmullius C, Cartus O, Santoro M and Le Toan T (2007), "Assessment and update of forest classification using multi-parameter satellite SAR data for NE China", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: The objective of this paper is to improve as well as to assess the performance of mapping forest by ENVISAT ASAR data and update forest map from ERS SAR images. The preliminary results of there test sites show it is very potential to use HH/HV ASAR AP data for forest map update. Tuqiang site have been undergoing dramatic changes during the last several decades due to the regeneration after forest fire. The Multi-temporal Stand Deviation feature extraction can improve the discrimination ability among some land cover types, especially for summer-winter multi-temporal compositions of ASAR data. Totally, about 900 scenes, covering North-East China, have been acquired since August 2004, and most of them are HH/HV polarization composition. Based on this processing method, the forest/non-forest map of whole North-East China have been generating. Assessed on basis of the land use map from 2001 ETM+ image, the accuracy of the maps from multi-temporal ASAR AP data can meet the request of mapping the boreal forests at large scale.
BibTeX:
@conference{Tian2007,
  author = {Tian, X. and Li, Z. and Chen, E. and Pang, Y. and Schmullius, C. and Cartus, O. and Santoro, M. and Le Toan, T.},
  title = {Assessment and update of forest classification using multi-parameter satellite SAR data for NE China},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36448954732&partnerID=40&md5=9779f84338e4478a2e951e8df05a49b3}
}
Wegmüller U, Santoro M and Wiesmann A (2007), "A novel methodology for parameter retrieval from multi-temporal data demonstrated for forest biomass retrieval from C-band SAR backscatter", In Proceedings of MultiTemp 2007 - 2007 International Workshop on the Analysis of Multi-Temporal Remote Sensing Images.
Abstract: A methodology for parameter retrieval from multi-temporal Earth observation data is proposed and applied to forest biomass retrieval from C-band SAR backscatter. The potential of single observation C-band SAR data to map forest biomass is limited mainly due to a low sensitivity and the dependence of C-band scattering on many other parameters. In this contribution a methodology to retrieve forest biomass from multi-temporal C-band SAR observations is presented. The method was applied to map forest biomass over a large area in Central Siberia using significant stacks of ENVISAT ASAR Wide-Swath data. The resulting forest biomass map is assessed by comparison with available inventory data. The quality achieved appears very promising. 2007 IEEE.
BibTeX:
@conference{Wegmuller2007a,
  author = {Wegmüller, U. and Santoro, M. and Wiesmann, A.},
  title = {A novel methodology for parameter retrieval from multi-temporal data demonstrated for forest biomass retrieval from C-band SAR backscatter},
  booktitle = {Proceedings of MultiTemp 2007 - 2007 International Workshop on the Analysis of Multi-Temporal Remote Sensing Images},
  year = {2007},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-47249084775&doi=10.1109%2fMULTITEMP.2007.4293067&partnerID=40&md5=7ea12a2e8f3a7b747bcb0dcf3a52d63e},
  doi = {10.1109/MULTITEMP.2007.4293067}
}
Wegmüller U, Strozzi T, Benecke N, Petrat L, Schlautmann M, Kuchenbecker R, Deutschmann J, Spreckels V, Schafer M, Busch W, Schade M, Paar W, Maly R, Staisch H, Hoffmann F and Al-Enezf A (2007), "Monitoring mining induced ground-movements using SAR interferometric techniques", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: This paper introduces the project EOMD Mining. High-level objectives of the project included the definition and implementation of a marketable integrated service for the mining market which includes satellite SAR based land surface deformation monitoring as a key element and to achieve market awareness and acceptance for this EO based integrated service. After a short introduction of the service offer the main focus of this paper is on the presentation and evaluation of the pre-commercial projects conducted as par of the EOMD Mining project.
BibTeX:
@conference{Wegmuller2007c,
  author = {Wegmüller, U. and Strozzi, T. and Benecke, N. and Petrat, L. and Schlautmann, M. and Kuchenbecker, R. and Deutschmann, J. and Spreckels, V. and Schafer, M. and Busch, W. and Schade, M. and Paar, W. and Maly, R. and Staisch, H. and Hoffmann, F. and Al-Enezf, A.},
  title = {Monitoring mining induced ground-movements using SAR interferometric techniques},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36448979206&partnerID=40&md5=757dc56acd5b5744d9cd48f9626b0bea}
}
Wiesmann A, Strozzi T, Werner C, Wegmüller U and Santoro M (2007), "Microwave remote sensing of alpine snow", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 1223-1227.
Abstract: In the alpine zone snow is a dominant factor for more than half of the year and has strong influence on the ecosystem and economy. The knowledge of snow coverage, structure, liquid water content etc. is important and useful for many applications ranging from flood management to avalanche warning. Remote sensing from space has good potential to address these needs. Within ASSIST, Alpine Safety, Security and Information services and Technologies, these topics are also of interest. Two snow related products were identified that can be produced on an operational base with the available satellite systems to be ingested into the ASSIST service. Avalanche maps, mapping the contours of avalanches, and snow cover maps, mapping the snow covered area. The produced products are in good agreement with validation data. Unfortunately the current available satellite systems (mainly c-band SAR that is applicable) are not very well suited for snow related applications due to the small influence of the dry snow on the microwave signal at C-band. To overcome this limitation the CoReH2O mission was designed. With its X- and Ku-band system and repeat rates of 3 and 15 days it has high potential for alpine snow applications. Additional microwave signature measurements at these frequencies with standardized and reproducible snow characterization information will be needed for model development and validation. Recent developments allow a more quantitative snow characterizations and will be considered in the SnowScat project in combination with traditional snow characterization methods. 2007 IEEE.
BibTeX:
@conference{Wiesmann20071223,
  author = {Wiesmann, A. and Strozzi, T. and Werner, C. and Wegmüller, U. and Santoro, M.},
  title = {Microwave remote sensing of alpine snow},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2007},
  pages = {1223-1227},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-82355195019&doi=10.1109%2fIGARSS.2007.4423026&partnerID=40&md5=39c837ea4757692eba25ed043b4923d7},
  doi = {10.1109/IGARSS.2007.4423026}
}
Wiesmann A, Wegmüller U, Strozzi T, Meister R, Rhyner J, Klingler C and Werner C (2007), "Alpine landslide survey and monitoring with interferometric SAR techniques in the frame of the EC framework 6 GMES project assist", In European Space Agency, (Special Publication) ESA SP. (SP-636)
Abstract: In the frame of ASSIST, an EC FP6 Strep project, landslide survey maps and landslide monitoring was performed over the border area of Switzerland, Austria and Italy using differential SAR techniques. Results are in good agreement with large scale geodetic measurements, a detailed quality analysis and dissemination are ongoing.
BibTeX:
@conference{Wiesmann2007,
  author = {Wiesmann, A. and Wegmüller, U. and Strozzi, T. and Meister, R. and Rhyner, J. and Klingler, C. and Werner, C.},
  title = {Alpine landslide survey and monitoring with interferometric SAR techniques in the frame of the EC framework 6 GMES project assist},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2007},
  number = {SP-636},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-36448980286&partnerID=40&md5=d9fedd514b268c5c8f8f5677a890ce86}
}
Wigneron J-P, Kerr Y, Waldteufel P, Saleh K, Escorihuela M-J, Richaume P, Ferrazzoli P, de Rosnay P, Gurney R, Calvet J-C, Grant J, Guglielmetti M, Hornbuckle B, Matzler C, Pellarin T and Schwank M (2007), "L-band Microwave Emission of the Biosphere (L-MEB) Model: Description and calibration against experimental data sets over crop fields", Remote Sensing of Environment. Vol. 107(4), pp. 639-655.
Abstract: In the near future, the SMOS (Soil Moisture and Ocean Salinity) mission will provide global maps of surface soil moisture (SM). The SMOS baseline payload is an L-band (1.4 GHz) two dimensional interferometric microwave radiometer which will provide multi-angular and dual-polarization observations. In the framework of the ground segment activities for the SMOS mission an operational SMOS Level 2 Soil Moisture algorithm was developed. The principle of the algorithm is to exploit multi-angular data in order to retrieve simultaneously several surface parameters including soil moisture and vegetation characteristics. The algorithm uses an iterative approach, minimizing a cost function computed from the differences between measured and modelled brightness temperature (TB) data, for all available incidence angles. In the algorithm, the selected forward model is the so-called L-MEB (L-band Microwave Emission of the Biosphere) model which was the result of an extensive review of the current knowledge of the microwave emission of various land covers. This model is a key element in the SMOS L2 algorithm and could be used in future assimilation studies. There is thus a strong need for a reference study, describing the model and its implementation. In order to address these needs a detailed description of soil and vegetation modelling in L-MEB is given in this study. In a second step, the use of L-MEB in soil moisture retrievals is evaluated for several experimental data sets over agricultural crops. Calibrations of the soil and vegetation L-MEB parameters are investigated for corn, soybean and wheat. Over the different experiments, very consistent results are obtained for each vegetation type in terms of calibration and soil moisture retrievals. 2006 Elsevier Inc. All rights reserved.
BibTeX:
@article{Wigneron2007639,
  author = {Wigneron, J.-P. and Kerr, Y. and Waldteufel, P. and Saleh, K. and Escorihuela, M.-J. and Richaume, P. and Ferrazzoli, P. and de Rosnay, P. and Gurney, R. and Calvet, J.-C. and Grant, J.P. and Guglielmetti, M. and Hornbuckle, B. and Matzler, C. and Pellarin, T. and Schwank, M.},
  title = {L-band Microwave Emission of the Biosphere (L-MEB) Model: Description and calibration against experimental data sets over crop fields},
  journal = {Remote Sensing of Environment},
  year = {2007},
  volume = {107},
  number = {4},
  pages = {639-655},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34047178358&doi=10.1016%2fj.rse.2006.10.014&partnerID=40&md5=2a5d3e82f2651e8fbedd6d030ab222ac},
  doi = {10.1016/j.rse.2006.10.014}
}
Blaes X, Defourny P, Wegmüller U, Vecchia A, Guerriero L and Ferrazzoli P (2006), "C-band polarimetric indexes for maize monitoring based on a validated radiative transfer model", IEEE Transactions on Geoscience and Remote Sensing. Vol. 44(4), pp. 791-799.
Abstract: This paper assess the possibilities of the synthetic aperture radar (SAR) sensors currently in orbit for the maize monitoring defining the configurations (polarization and incidence angles at C-band) maximizing the sensitivity to plant growth and reducing the impact of the soil moisture on the signal. Temporal evolution of the signal was simulated in all the possible configurations using the radiative transfer model developed by the University of Rome "Tor Vergata." The input parameters came from an intensive field campaign providing a detailed description of maize crop over the Belgian Loamy site all along the 2003 growing season. The model was validated for vertical (VV) and horizontal (HH) polarization using ERS, ENVISAT, and RADARSAT observations. The C-band SAR signal in single polarization was found to be sensitive to crop growth till the leaf area index (LAI) reached 4.6 m 2 / m2, while the soil moisture influenced the signal for sparsely vegetated fields (LAI < 2.7 m2 / m2). Dual-polarizations indexes were found sensitive to maize growth and less sensitive to soil moisture variations. The VV/VH polarization ratios computed from signal recorded at high incidence angle (35° to 45°) could be considered to assess the crop growth till LAI reached 4.9 m2 / m 2 with low sensitivity to soil moisture. At the beginning of growth, the emergence of maize plants could be detected using the copolarized ratio (VV/HH) computed at low incidence angle. These indexes allow discriminating various crop conditions at a given date between fields of a same region. 2006 IEEE.
BibTeX:
@article{Blaes2006791,
  author = {Blaes, X. and Defourny, P. and Wegmüller, U. and Vecchia, A.D. and Guerriero, L. and Ferrazzoli, P.},
  title = {C-band polarimetric indexes for maize monitoring based on a validated radiative transfer model},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2006},
  volume = {44},
  number = {4},
  pages = {791-799},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645698989&doi=10.1109%2fTGRS.2005.860969&partnerID=40&md5=b7647e247d07538501648acfb9d5d807},
  doi = {10.1109/TGRS.2005.860969}
}
Delia Vecchia A, Ferrazzoli P, Giorgio F, Guerriero L, Guglielmetti M and Schwank M (2006), "A parametric study about soil emission and vegetation effects for forests at L-band", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 440-443.
Abstract: This paper describes a model which simulates the emission of forests at L band. In particular, the problem of soil emission attenuated by vegetation is considered. Results of comparisons with experimental data collected by the upward looking ELBARA radiometer are presented and discussed.
BibTeX:
@conference{DeliaVecchia2006440,
  author = {Delia Vecchia, A. and Ferrazzoli, P. and Giorgio, F. and Guerriero, L. and Guglielmetti, M. and Schwank, M.},
  title = {A parametric study about soil emission and vegetation effects for forests at L-band},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2006},
  pages = {440-443},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34948892574&doi=10.1109%2fIGARSS.2006.117&partnerID=40&md5=f283009bf0433e7891449a385b7d51d4},
  doi = {10.1109/IGARSS.2006.117}
}
Della Vecchia A, Ferrazzoli P, Guerriero L, Blaes X, Defourny P, Dente L, Mattia F, Satalino G, Strozzi T and Wegmüller U (2006), "Influence of geometrical factors on crop backscattering at C-band", IEEE Transactions on Geoscience and Remote Sensing. Vol. 44(4), pp. 778-789.
Abstract: Several efforts, aimed at developing and refining crop backscattering models, have been done during the last years. Although important advances have been achieved, it is recognized that further work is required, both in the electromagnetic characterization of single scatterers and in the combination of contributions. This work is focused on the description of leaf geometry and of the internal structure of stems. Recently developed routines, able to model the scattering cross sections of curved sheets and hollow cylinders, are adopted for this purpose and run within the multiple-scattering model developed at the University of Rome "Tor Vergata." Input parameters are taken from experimental campaigns. In particular, ground data collected over a maize field at the Central Plain site in 1988, over wheat and maize fields at the Loamy site in 2003, and over wheat fields at the Matera site in 2001 and 2003 are considered. The multitemporal backscattering coefficients at C-band are simulated. The results obtained under different assumptions are compared to each other, and with C-band radar signatures collected over the same fields. The influence of some critical factors, affecting crop backscattering, is discussed. It is demonstrated that a more detailed scatterer characterization may improve the model accuracy, especially in the case of hollow stems. 2006 IEEE.
BibTeX:
@article{DellaVecchia2006778,
  author = {Della Vecchia, A. and Ferrazzoli, P. and Guerriero, L. and Blaes, X. and Defourny, P. and Dente, L. and Mattia, F. and Satalino, G. and Strozzi, T. and Wegmüller, U.},
  title = {Influence of geometrical factors on crop backscattering at C-band},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2006},
  volume = {44},
  number = {4},
  pages = {778-789},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645688856&doi=10.1109%2fTGRS.2005.860489&partnerID=40&md5=3381838f4d024a078caf23e253685a55},
  doi = {10.1109/TGRS.2005.860489}
}
Eriksson L, Askne J, Santoro M and Wiesmann A (2006), "Forest parameter estimation using JERS-1 repeat-pass interferometry: Stem volume retrieval in Siberia and Sweden", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 2212-2215.
Abstract: This paper presents results from estimation of stem volume in boreal forest using backscatter and interferometric coherence from the L-band SAR on the Japanese Earth Resources Satellite (JERS-1). Five test areas in Siberia and one in Sweden have been included in the study. Data from 14 JERS-1 44-day pairs from Siberia and 12 pairs covering the Swedish test area have been evaluated. The best multitemporal combinations of the measurements give relative RMSE values ranging from 33% to 48%. When considering one of the two observables only, the lowest retrieval errors are obtained under frozen conditions when inverting the coherence and under unfrozen conditions when inverting the backscatter.
BibTeX:
@conference{Eriksson20062212,
  author = {Eriksson, L.E.B. and Askne, J. and Santoro, M. and Wiesmann, A.},
  title = {Forest parameter estimation using JERS-1 repeat-pass interferometry: Stem volume retrieval in Siberia and Sweden},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2006},
  pages = {2212-2215},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34948826324&doi=10.1109%2fIGARSS.2006.572&partnerID=40&md5=a7f330b2b903cbb8638b86bda879bbfe},
  doi = {10.1109/IGARSS.2006.572}
}
Foster J, Brooks B, Cherubini T, Shacat C, Businger S and Werner C (2006), "Mitigating atmospheric noise for InSAR using a high resolution weather model", Geophysical Research Letters. Vol. 33(16) American Geophysical Union.
Abstract: A high resolution weather model is used to predict atmospheric delays for the acquisition times of synthetic aperture radar images over Hawaii. Refraction of the radar by water vapor in the atmosphere in Hawaii leads to apparent ground-motions with wavelengths and magnitudes similar to the actual ground motions generated by tectonic and volcanic processes. We examine the potential for a weather model to help characterize the atmospheric component in InSAR scenes and find that in the best cases it models the observed delays well, reducing the variance at wavelengths of 30 km and greater by ∼60%, while even in the worst cases it provides an independent means of quantifying the expected variance in the image due to the atmosphere. Copyright 2006 by the American Geophysical Union.
BibTeX:
@article{Foster2006,
  author = {Foster, J. and Brooks, B. and Cherubini, T. and Shacat, C. and Businger, S. and Werner, C.L.},
  title = {Mitigating atmospheric noise for InSAR using a high resolution weather model},
  journal = {Geophysical Research Letters},
  publisher = {American Geophysical Union},
  year = {2006},
  volume = {33},
  number = {16},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845633708&doi=10.1029%2f2006GL026781&partnerID=40&md5=0cabc6dd7cdea81f6bba044e509e81a6},
  doi = {10.1029/2006GL026781}
}
Frey O, Meier E and Nüesch D (2006), "An Integrated Focusing and Calibration Procedure for Airborne SAR Data", In Proc. EUSAR 2006 - 6th European Conference on Synthetic Aperture Radar.
Abstract: Topography-induced variation of radar brightness still poses a problem in terms of radiometric calibration of SAR data, which is undoubtedly an indispensable step in order to deduce bio- or geophysical parameters from amplitude images. We propose an integrated focusing and calibration procedure for airborne SAR data based on the time-domain backprojection technique. With the help of sensor position and attitude data as well as a digital elevation model (DEM) the true acquisition geometry is maintained throughout the combined focusing and calibration step. The effectiveness of the method is evaluated by means of an E-SAR L-band data set acquired over undulating terrain.
BibTeX:
@inproceedings{freyMeierNueschEusar2006:TDBP,
  author = {Othmar Frey and Erich Meier and Daniel Nüesch},
  title = {An Integrated Focusing and Calibration Procedure for Airborne SAR Data},
  booktitle = {Proc. EUSAR 2006 - 6th European Conference on Synthetic Aperture Radar},
  year = {2006}
}
Guerova G, Bettems J-M, Brockmann E and Matzler C (2006), "Assimilation of COST 716 Near-Real Time GPS data in the nonhydrostatic limited area model used at MeteoSwiss", Meteorology and Atmospheric Physics. Vol. 91(1-4), pp. 149-164.
Abstract: Application of the GPS derived water vapor into Numerical Weather Prediction (NWP) models is one of the focuses of the COST Action 716 "Exploitation of Ground based GPS for climate and numerical weather prediction applications". For this purpose the GPS data covering Europe have been collected within the Near-Real Time (NRT) demonstration project and provided for Observing System Experiments (OSE). For the experiments presented in this manuscript the operational NWP system of MeteoSwiss is used. The limited area nonhydrostatic aLpine Model (aLMo) of MeteoSwiss covers most of western Europe, has a horizontal resolution of 7km, 45 layers in the vertical, and uses a data assimilation scheme based on the Newtonian relaxation (nudging) method. In total 17 days analyses and two 30 hours daily forecasts have been computed, with 100 GPS sites assimilated for three selected periods in autumn 2001, winter and summer 2002. It is to be noted that only in the last period data from 10 french sites, i.e. west of Switzerland are assimilated. The GPS NRT data quality has been compared with the Post-Processed data. Agreement within 3mm level Zenith Total Delay bias and 8mm standard deviation was found, corresponding to an Integrated Water Vapor (IWV) bias below 0.5kg/m2. Most of the NRT data over aLMo domain are available within a prescribed time window of 1h 45min. In the nudging process the NRT data are successfully used by the model to correct the IWV deficiencies present in the reference analysis; stronger forcing with a shorter time scale could be however recommended. Comparing the GPS derived IWV with radiosonde observations, a dry radiosonde bias has been found over northern Italy. Through GPS data assimilation the aLMo analysis bias and standard deviation in the diurnal cycle has been reduced. The negative bias of -0.64kg/m2 in the reference analysis has been reduced to 0.34kg/m2 in GPS analysis. However, the diurnal cycle statistic from the forecast does show the characteristic negative bias only slightly reduced starting with the GPS analysis. The GPS IWV impact on aLMo is large in June 2002 and moderate in September 2001 OSE. January OSE is inconclusive due to inconsistent use of humidity data below the freezing point. In June 2002 OSE, a substantial IWV impact is seen up to the end of the forecast. Over Switzerland the dry bias in the reference analysis has been successfully corrected and the 2m temperature and dew point have been slightly improved over the whole aLMo domain. The subjective verification of precipitation against radar data in autumn 2001 and summer 2002 gives mixed results. In the forecast the impact is limited to the first six hours and to strong precipitation events. A missing precipitation pattern has been recovered via GPS assimilation in June 20 2002 forecast. A negative impact on precipitation analysis on June 23 has been observed. The future operational use of GPS will depend on data availability; European GPS networks belong mainly to the geodetic community. A further increase of GPS network density in southern Europe is welcome. The GPS derived gradient and Slant Path estimates could possibly improve efficiency of IWV assimilation via the nudging technique. Springer-Verlag/Wien 2006.
BibTeX:
@article{Guerova2006149,
  author = {Guerova, G. and Bettems, J.-M. and Brockmann, E. and Matzler, Ch.},
  title = {Assimilation of COST 716 Near-Real Time GPS data in the nonhydrostatic limited area model used at MeteoSwiss},
  journal = {Meteorology and Atmospheric Physics},
  year = {2006},
  volume = {91},
  number = {1-4},
  pages = {149-164},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-31044440006&doi=10.1007%2fs00703-005-0110-6&partnerID=40&md5=4def0b5f11cd99b0cd1e8ac1a1dd3231},
  doi = {10.1007/s00703-005-0110-6}
}
Martin L, Matzler C, Hewison T and Ruffieux D (2006), "Intercomparison of integrated water vapour measurements", Meteorologische Zeitschrift. Vol. 15(1), pp. 57-64.
Abstract: Measurements of tropospheric integrated water vapour (IWV) made with two microwave radiometers (ASMUWARA, TP/WVP-3000), GPS, and radiosondes (SRS 400) during the Temperature, hUmidity, and Cloud (TUC) profiling campaign under mid-latitude conditions in Payerne, Switzerland, in winter 2003/2004 are compared. All methods provide robust IWV retrievals in clear sky and cloudy situations. The mean difference between radiometric and radiosonde IWV is less than 0,15 kgm-2 being not significant with respect to the standard deviation and to the theoretical accuracy. The GPS IWV measurements have a persistent significant dry bias of approx. 0,5 kgm-2 with respect to radiometers and radiosondes. The different temporal and spatial resolutions of the instruments were found to have a strong influence on the standard deviation. A characteristic diurnal cycle of the GPS and radiometric IWV was observed. Gebruder Borntraeger, Berlin, Stuttgart 2006.
BibTeX:
@article{Martin200657,
  author = {Martin, L. and Matzler, C. and Hewison, T.J. and Ruffieux, D.},
  title = {Intercomparison of integrated water vapour measurements},
  journal = {Meteorologische Zeitschrift},
  year = {2006},
  volume = {15},
  number = {1},
  pages = {57-64},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646021306&doi=10.1127%2f0941-2948%2f2006%2f0098&partnerID=40&md5=c9970de24821e9bd9fe86eecd10790c6},
  doi = {10.1127/0941-2948/2006/0098}
}
Martin L, Schneebeli M and Matzler C (2006), "ASMUWARA, a ground-based radiometer system for tropospheric monitoring", Meteorologische Zeitschrift. Vol. 15(1), pp. 11-17.
Abstract: ASMUWARA, the All-Sky MUlti WAvelength RAdiometer, is a new ground-based and automatically operating radiometer system designed for tropospheric monitoring. ASMUWARA has ten channels in the microwave and infrared range and is able to observe the sky in all directions with an angular resolution of 9°. No radome is used to allow an optimum view quality at all wavelengths. The purpose of ASMUWARA is to retrieve temperature and humidity profiles, maps of integrated water vapour and liquid water, and additional cloud properties. The construction and characteritics of ASMUWARA are described. Special emphasis is put on the calibration loads, the calibration method, and the correction of antenna beamwidth effects. Gebruder Borntraeger, Berlin, Stuttgart 2006.
BibTeX:
@article{Martin200611,
  author = {Martin, L. and Schneebeli, M. and Matzler, C.},
  title = {ASMUWARA, a ground-based radiometer system for tropospheric monitoring},
  journal = {Meteorologische Zeitschrift},
  year = {2006},
  volume = {15},
  number = {1},
  pages = {11-17},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646040990&doi=10.1127%2f0941-2948%2f2006%2f0092&partnerID=40&md5=52be2424cc777eae3165dcb5d64b6dfa},
  doi = {10.1127/0941-2948/2006/0092}
}
Martin L, Schneebeli M and Matzler C (2006), "Tropospheric water and temperature retrieval for ASMUWARA", Meteorologische Zeitschrift. Vol. 15(1), pp. 37-44.
Abstract: The retrieval of tropospheric water and temperature with the ground-based and automatically operating radiometer system ASMUWARA (All-Sky MUlti WAvelength RAdiometer) is described. This instrument operates simultaneously at microwave and IR channels. Integrated water vapour (IWV) and integrated liquid water (ILW) are retrieved with a newly developed linear algorithm to an accuracy of 0.014 kgm-2 (ILW) and 0.41 kgm-2 (IWV), thanks to the inclusion of a channel at 151 GHz. These measurements are made for the whole hemisphere and therefore provide information about the spatial distribution of water in the troposphere. With an optimal estimation algorithm, tropospheric temperature and humidity profiles are retrieved. The results are quasi bias free with a mean error of less than 2.5 K for the temperature (less than 1 K in the lowest km above ground), and less than 1 gm-3 for the humidity. Examples of all measurements are shown. Gebruder Borntraeger, Berlin, Stuttgart 2006.
BibTeX:
@article{Martin200637,
  author = {Martin, L. and Schneebeli, M. and Matzler, C.},
  title = {Tropospheric water and temperature retrieval for ASMUWARA},
  journal = {Meteorologische Zeitschrift},
  year = {2006},
  volume = {15},
  number = {1},
  pages = {37-44},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646070279&doi=10.1127%2f0941-2948%2f2006%2f0093&partnerID=40&md5=b1f191e85c7b25a05fd6b7f77cf18527},
  doi = {10.1127/0941-2948/2006/0093}
}
Matzler C (2006), "Thermal microwave radiation: Applications for remote sensing", Thermal Microwave Radiation: Applications for Remote Sensing. , pp. 1-556. Institution of Engineering and Technology.
Abstract: This book combines theoretical concepts with experimental results on thermal microwave radiation to increase the understanding of the complex nature of terrestrial media. With the emphasis on radiative transfer models, this book covers the urgent needs for the transition from the experimental phase of microwave remote sensing to operational applications. 2006: The Institution of Engineering and Technology.
BibTeX:
@book{Matzler20061,
  author = {Matzler, C.},
  title = {Thermal microwave radiation: Applications for remote sensing},
  journal = {Thermal Microwave Radiation: Applications for Remote Sensing},
  publisher = {Institution of Engineering and Technology},
  year = {2006},
  pages = {1-556},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013472559&doi=10.1049%2fPBEW052E&partnerID=40&md5=d8a91a09c29d2d2c0411679147d54082},
  doi = {10.1049/PBEW052E}
}
Matzler C, Ellison W, Thomas B, Sihvola A and Schwank M (2006), "Dielectric properties of natural media", Thermal Microwave Radiation: Applications for Remote Sensing. , pp. 427. Institution of Engineering and Technology.
Abstract: Dielectric, refractive and possibly magnetic properties of the media to be studied with microwave radiometry are important in several ways. First, the absorption coefficient follows from the imaginary part of the refractive index. The refractive index is a simple function of the dielectric constant and of the magnetic permeability. Second, the wave impedance and the scattering properties are related to the dielectric and magnetic properties. And finally, the ray path of the radiation depends on the refractive index in the propagating medium. Uncertainties of radiative transfer computations have often been limited by the insufficient accuracy of dielectric properties. The purpose of this chapter is to review the present knowledge in this field. A simplification to be made is the assumption that the magnetic permeability can be approximated by the value found in vacuum. It means that the small diamagnetic and paramagnetic effects can be ignored, and that ferromagneticity is not relevant to remote sensing. As an example water is slightly diamagnetic with a relative magnetic permeability of µ = 0.999991. In our approximation, this quantity is set to 1. The remaining electromagnetic key parameter is the complex dielectric constant. The dielectric constant of a substance depends both upon the electromagnetic field which interacts with the matter and upon the physical properties of the substance itself. For the fields considered in this book, e depends only upon the frequency, v, of the field. As for its dependence upon the matter, it will be a function of bulk properties such as temperature, pressure etc., a function of the physical constituents and of the molecular and atomic structure of the substance. 2006: The Institution of Engineering and Technology.
BibTeX:
@book{Matzler2006427,
  author = {Matzler, C. and Ellison, W. and Thomas, B. and Sihvola, A. and Schwank, M.},
  title = {Dielectric properties of natural media},
  journal = {Thermal Microwave Radiation: Applications for Remote Sensing},
  publisher = {Institution of Engineering and Technology},
  year = {2006},
  pages = {427},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013380398&doi=10.1049%2fPBEW052E_ch5&partnerID=40&md5=0d1098496ef649cf653f188116ad243f},
  doi = {10.1049/PBEW052E_ch5}
}
Matzler C and Melsheimer C (2006), "Radiative transfer and microwave radiometry", Thermal Microwave Radiation: Applications for Remote Sensing. , pp. 1-23. Institution of Engineering and Technology.
Abstract: This book chapter gives an introduction to radiative transfer with focus on microwave radiometry. The topics discussed include: Kirchhoff's law of thermal radiation; the radiative transfer equation; and polarisation and Stokes parameters. 2006: The Institution of Engineering and Technology.
BibTeX:
@book{Matzler2006a,
  author = {Matzler, C. and Melsheimer, C.},
  title = {Radiative transfer and microwave radiometry},
  journal = {Thermal Microwave Radiation: Applications for Remote Sensing},
  publisher = {Institution of Engineering and Technology},
  year = {2006},
  pages = {1-23},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013481666&doi=10.1049%2fPBEW052E_ch1&partnerID=40&md5=b95c687fbf9fa47e222d7c08ccd835ab},
  doi = {10.1049/PBEW052E_ch1}
}
Morland J, Deuber B, Feist D, Martin L, Nyeki S, Kampfer N, Matzler C, Jeannet P and Vuilleumier L (2006), "The STARTWAVE atmospheric water database", Atmospheric Chemistry and Physics. Vol. 6(8), pp. 2039-2056. European Geosciences Union.
Abstract: The STARTWAVE (STudies in Atmospheric Radiative Transfer and Water Vapour Effects) project aims to investigate the role which water vapour plays in the climate system, and in particular its interaction with radiation. Within this framework, an ongoing water vapour database project was set up which comprises integrated water vapour (IWV) measurements made over the last ten years by ground-based microwave radiometers, Global Positioning System (GPS) receivers and sun photometers located throughout Switzerland at altitudes between 330 and 3584 m. At Bern (46.95° N, 7.44° E) tropospheric and stratospheric water vapour profiles are obtained on a regular basis and integrated liquid water, which is important for cloud characterisation, is also measured. Additional stratospheric water vapour profiles are obtained by an airborne microwave radiometer which observes large parts of the northern hemisphere during yearly flight campaigns. The database allows us to validate the various water vapour measurement techniques. Comparisons between IWV measured by the Payerne radiosonde with that measured at Bern by two microwave radiometers, GPS and sun photometer showed instrument biases within ±0.5 mm. The bias in GPS relative to sun photometer over the 2001 to 2004 period was -0.8mm at Payerne (46.81° N, 6.94° E, 490m), which lies in the Swiss plains north of the Alps, and +0.6 mm at Davos (46.81° N, 9.84° E, 1598m), which is located within the Alps in the eastern part of Switzerland. At Locarno (46.18° N, 8.78° E, 366 m), which is located on the south side of the Alps, the bias is +1.9 mm. The sun photometer at Locarno was found to have a bias of -2.2mm (13% of the mean annual IWV) relative to the data from the closest radiosonde station at Milano. This result led to a yearly rotation of the sun photometer instruments between low and high altitude stations to improve the calibrations. In order to demonstrate the capabilites of the database for studying water vapour variations, we investigated a front which crossed Switzerland between 18 November 2004 and 19 November 2004. During the frontal passage, the GPS and microwave radiometers at Bern and Payerne showed an increase in IWV of between 7 and 9 mm. The GPS IWV measurements were corrected to a standard height of 500 m, using an empirically derived exponential relationship between IWV and altitude. A qualitative comparison was made between plots of the IWV distribution measured by the GPS and the 6.2μm water vapour channel on the Meteosat Second Generation (MSG) satellite. Both showed that the moist air moved in from a northerly direction, although the MSG showed an increase in water vapour several hours before increases in IWV were detected by GPS or microwave radiometer. This is probably due to the fact that the satellite instrument is sensitive to an atmospheric layer at around 320 hPa, which makes a contribution of one percent or less to the IWV.
BibTeX:
@article{Morland20062039,
  author = {Morland, J. and Deuber, B. and Feist, D.G. and Martin, L. and Nyeki, S. and Kampfer, N. and Matzler, C. and Jeannet, P. and Vuilleumier, L.},
  title = {The STARTWAVE atmospheric water database},
  journal = {Atmospheric Chemistry and Physics},
  publisher = {European Geosciences Union},
  year = {2006},
  volume = {6},
  number = {8},
  pages = {2039-2056},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745552507&doi=10.5194%2facp-6-2039-2006&partnerID=40&md5=6bf98435116f57e6393c8544b887d362},
  doi = {10.5194/acp-6-2039-2006}
}
Morland J, Liniger M, Kunz H, Balin I, Nyeki S, Matzler C and Kampfer N (2006), "Comparison of GPS and ERA40 IWV in the Alpine region, including correction of GPS observations at Jungfraujoch (3584 m)", Journal of Geophysical Research Atmospheres. Vol. 111(4) Blackwell Publishing Ltd.
Abstract: The 31 stations in the Global Positioning System (GPS) network of Switzerland span an altitude range of 330 to 3584 m. The highest station in the network, Jungfraujoch, suffers from a constant negative bias in the Integrated Water Vapor (IWV) due to a protective radome. We compared Jungfraujoch GPS IWV measurements with coincident Precision Filter Radiometer (PFR) observations and showed that the bias in the GPS is fairly constant with respect to the time of year and to the PFR IWV value. A correction was developed for the GPS data and validated by comparison with coincident Raman lidar observations. The IWV observations from nine GPS stations, including Jungfraujoch, were then compared with the IWV field of the ECMWF 40 year reanalysis (ERA40) data. Altitude differences between the ERA40 surface level and the GPS stations resulted, as expected, in a positive bias in the ERA40 IWV. A fairly linear relationship, with an intercept of -0.3 mm, was found between this bias and the difference between the ERA40 surface pressure and the surface pressure at the GPS station. The ERA40 reanalysis captured water vapor variations on timescales of several days very well, as evidenced by an r2 correlation greater than 0.9 where the altitude difference between ERA40 and the GPS station was less than 1000 m. A comparison between ERA40 and GPS at Davos showed that the reanalysis underestimates IWV during winter temperature inversions. Copyright 2006 by the American Geophysical Union.
BibTeX:
@article{Morland2006,
  author = {Morland, J. and Liniger, M.A. and Kunz, H. and Balin, I. and Nyeki, S. and Matzler, C. and Kampfer, N.},
  title = {Comparison of GPS and ERA40 IWV in the Alpine region, including correction of GPS observations at Jungfraujoch (3584 m)},
  journal = {Journal of Geophysical Research Atmospheres},
  publisher = {Blackwell Publishing Ltd},
  year = {2006},
  volume = {111},
  number = {4},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645501368&doi=10.1029%2f2005JD006043&partnerID=40&md5=f64f79ae0a8a6f3197591228dc15553e},
  doi = {10.1029/2005JD006043}
}
Santoro M and Askne J (2006), "Accuracy assessment of stem volume retrieval from ERS-1/2 multitemporal coherence in eurasian boreal forests", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 2208-2211.
Abstract: The sensitivity of the ERS-1/2 tandem coherence to forest biophysical properties is recognized to be sufficient for achieving accurate estimation of stem volume in boreal forest. Nonetheless, depending on environmental conditions and forest stand properties (e.g. size, structure) the retrieval accuracy can change significantly. For this reason methods are required for the identification of forest stands for which high retrieval accuracy can be obtained. From an analysis of multi-temporal coherence datasets at several test sites in Scandinavia and Siberia, we can conclude that optimal conditions for the retrieval are represented by stable winter frozen conditions with an at least moderate breeze. For such conditions, the retrieval accuracy increases if only stands larger than a few hectares and with a certain degree of homogeneity are considered. For such stands, the effective stem volume retrieval error that can be obtained in boreal forests ranges between 15 and 25%.To overcome the necessity of falling back on inventory data to identify such stands, multi-temporal consistency of coherence, of stem volume estimates and stand size can be used as stand selection criteria.
BibTeX:
@conference{Santoro20062208,
  author = {Santoro, M. and Askne, J.},
  title = {Accuracy assessment of stem volume retrieval from ERS-1/2 multitemporal coherence in eurasian boreal forests},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2006},
  pages = {2208-2211},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34948820557&doi=10.1109%2fIGARSS.2006.571&partnerID=40&md5=6db98c3f6023e6dccf0ab6c44294c54b},
  doi = {10.1109/IGARSS.2006.571}
}
Santoro M, Cartus O, Schmullius C, Wegmüller U, Werner C, Wiesmann A, Pang Y and Li Z (2006), "On the generation of a forest biomass map for Northeast China: SAR interferometric processing and development of classification algorithm", In European Space Agency, (Special Publication) ESA SP. (610)
Abstract: The experience gained in more than a decade of investigations based on ERS-1/2 coherence images for forest applications is currently exploited to map forest biomass of a 1.5 Million km2 large region in Northeast China. For the generation of the biomass map more than 250 ERS-1/2 tandem image pairs are used. The dataset consists of multi-temporal and multi-baseline image frames acquired between 1995 and 1998. For 223 image pairs the geocoded coherence, backscatter and terrain information images with 50 × 50 m pixel size have been obtained. Data quality and geolocational accuracies are very high and coherence contrast is in most cases at an optimal level for forestry applications. For biomass classification, the SIBERIA coherence model and the Interferometric Water Cloud Model (IWCM) were evaluated at test sites in China and, for reference, in Siberia. The original SIBERIA coherence model did not always follow the trend in the measurements. For the IWCM, the use of the MODIS Vegetation Continuous Fields (VCF) tree cover product as training input resulted in model parameters estimates in line with results obtained by using forest inventory data. These results suggest that (i) the SIBERIA coherence model must be improved to represent multitemporal coherence and different forest conditions, and (ii) the IWCM with VCF as input information should be further tested.
BibTeX:
@conference{Santoro2006,
  author = {Santoro, M. and Cartus, O. and Schmullius, C. and Wegmüller, U. and Werner, C. and Wiesmann, A. and Pang, Y. and Li, Z.},
  title = {On the generation of a forest biomass map for Northeast China: SAR interferometric processing and development of classification algorithm},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2006},
  number = {610},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33746597064&partnerID=40&md5=bb42785ff700e53ae45cdd8c0ec9dbeb}
}
Santoro M, Eriksson L, Askne J and Schmullius C (2006), "Assessment of stand-wise stem volume retrieval in boreal forest from JERS-1 L-band SAR backscatter", International Journal of Remote Sensing. Vol. 27(16), pp. 3425-3454. Taylor and Francis Ltd..
Abstract: JERS-1 L-band SAR backscatter from test sites in Sweden, Finland and Siberia has been investigated to determine the accuracy level achievable in the boreal zone for stand-wise forest stem volume retrieval using a model-based approach. The extensive ground-data and SAR imagery datasets available allowed analysis of the backscatter temporal dynamics. In dense forests the backscatter primarily depended on the frozen/unfrozen state of the canopy, showing a ∼4 dB difference. In sparse forests, the backscatter depended primarily on the dielectric properties of the forest floor, showing smaller differences throughout the year. Backscatter modelling as a function of stem volume was carried out by means of a simple L-band Water Cloud related scattering model. At each test site, the model fitted the measurements used for training irrespective of the weather conditions. Of the three a priori unknown model parameters, the forest transmissivity coefficient was most affected by seasonal conditions and test site specific features (stand structure, forest management, etc.). Several factors determined the coefficient's estimate, namely weather conditions at acquisition, structural heterogeneities of the forest stands within a test site, forest management practice and ground data accuracy. Stem volume retrieval was strongly influenced by these factors. It performed best under unfrozen conditions and results were temporally consistent. Multi-temporal combination of single-image estimates eliminated outliers and slightly decreased the estimation error. Retrieved and measured stem volumes were in good agreement up to maximum levels in Sweden and Finland. For the intensively managed test site in Sweden a 25% relative rms error was obtained. Higher errors were achieved in the larger and more heterogeneous forest test sites in Siberia. Hence, L-band backscatter can be considered a good candidate for stand-wise stem volume retrieval in boreal forest, although the forest site conditions play a fundamental role for the final accuracy.
BibTeX:
@article{Santoro20063425,
  author = {Santoro, M. and Eriksson, L. and Askne, J. and Schmullius, C.},
  title = {Assessment of stand-wise stem volume retrieval in boreal forest from JERS-1 L-band SAR backscatter},
  journal = {International Journal of Remote Sensing},
  publisher = {Taylor and Francis Ltd.},
  year = {2006},
  volume = {27},
  number = {16},
  pages = {3425-3454},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33746946131&doi=10.1080%2f01431160600646037&partnerID=40&md5=1fa3df1ff7b23b57781b71c964b40082},
  doi = {10.1080/01431160600646037}
}
Santoro M, Wegmüller U, Werner C and Askne J (2006), "ERS-ENVISAT coherence properties of land cover", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 2561-2564.
Abstract: ERS-ENVISAT coherence is a new SAR interferometric product with interesting properties due to the very short repeat-pass interval between acquisitions. When the requirements set by ERS-ENVISAT interferometry on baseline length and Doppler centroids are fulfilled, the ERS-ENVISAT coherence can present a large span of values. For an ERS-2/ENVISAT image pair acquired over the region surrounding the city of Paris, bare soils have much higher coherence compared to forests and urban areas. As a consequence the use of the ERS-ENVISAT coherence for detecting forest cover changes and estimation of biophysical properties of regrowing forest / crops seems feasible. An analysis of the decorrelation phenomena for the ERS-ENVISAT coherence shows that (i) decorrelation can increase from near to far range if the common band filtering is not perfect, (ii) volume decorrelation is relevant because of the long baseline, and (iii) temporal decorrelation seems to be relevant for vegetation even at the 30 minutes interval time scale.
BibTeX:
@conference{Santoro20062561,
  author = {Santoro, M. and Wegmüller, U. and Werner, C. and Askne, J.},
  title = {ERS-ENVISAT coherence properties of land cover},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2006},
  pages = {2561-2564},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34948840805&doi=10.1109%2fIGARSS.2006.662&partnerID=40&md5=702cc4e2dadb34efb8bbaa47f03f6502},
  doi = {10.1109/IGARSS.2006.662}
}
Schmullius C, Li Z, Bouvet A, Cartus O, Chen E, Jeannin N, Le Toan T, L'Hermitte J, Pang Y, Santoro M, Tian X, Wegmüller U, Wiesmann A, Werner C and Zhu H (2006), "Mid-term status of the forest DRAGON project", In European Space Agency, (Special Publication) ESA SP. (611), pp. 271-280.
Abstract: The objective of the Forest DRAGON Project is the development of algorithms for classification of synthetic aperture radar, SAR, data and interferometric SAR (InSAR) data, and the generation of forest maps at regional level for the main forested regions of China. For this purpose ERS-1/2 tandem coherence and ENVISAT ASAR data in Alternating Polarisation (AP) and Wide Swath (WS) mode are considered. ERS-1/2 tandem coherence has been chosen as primary candidate for the estimation of forest stem volume because of its strong sensitivity to forest biophysical parameters. Interferometric processing is carried out by means of a well-established chain at the end of which geocoded coherence, backscatter and local topography products are obtained. Forest base-maps are obtained for the mid-1990s making use of the SIBERIA Project algorithm. First investigations in Northeast China show the need of an improvement of the algorithm to take into account the availability of multi-seasonal data and misclassifications in areas with strong topography. To update the maps multi-temporal ENVISAT ASAR AP images in HH/HV mode are considered. A data processing chain, which includes data import, calibration, geocoding and mosaicing, has been set to process the ASAR data automatically. Preliminary results in Northeast China show that forest/non-forest types can be discriminated well using one date ASAR AP HH/HV images. ScanSAR or Wide Swath mode represent an important source of data for updating global and continental maps, yet to be explored. In this study, ENVISAT ASAR WS data over Northeast China are analysed for forest/non-forest mapping at regional scale. The results are compared with existing land cover maps, in particular the Vegetation Continuous Field (VCF) from MODIS.
BibTeX:
@conference{Schmullius2006271,
  author = {Schmullius, C. and Li, Z. and Bouvet, A. and Cartus, O. and Chen, E. and Jeannin, N. and Le Toan, T. and L'Hermitte, J. and Pang, Y. and Santoro, M. and Tian, X. and Wegmüller, U. and Wiesmann, A. and Werner, C. and Zhu, H.},
  title = {Mid-term status of the forest DRAGON project},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2006},
  number = {611},
  pages = {271-280},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745609295&partnerID=40&md5=edc5bae8227b9988d414edf3b6119483}
}
Schwank M, Green T, Matzler C, Benedickter H and Fluhler H (2006), "Laboratory characterization of a commercial capacitance sensor for estimating permittivity and inferring soil water content", Vadose Zone Journal. Vol. 5(3), pp. 1048-1064.
Abstract: Ring-capacitor sensors are used widely for real-time estimation of volumetric soil water content θ from measured resonant frequency f r, which is directly affected by the bulk soil permittivity ε. However, the relationship fr(ε) requires improved quantification. We conducted laboratory experiments to characterize the response of the Sentek EnviroSMART sensor system for a full range of e values from air to water and a range of temperatures. Water-dioxane mixtureswere placed into a solvent-resistant container equipped with custom tools for heating and mixing the fluid, removing air bubbles from sensitive surfaces, measuring permittivity in situ, and creating an axisymmetric metal disturbance to the electric field. Total capacitance C was measured using a vector network analyzer (VNA) connected to one sensor, while four other sensors provided replicated fr readings. The measured temperature response of free water permittivity was linear with a negative slope, which is qualitatively consistent with theory. A precise nonlinear relationship between ε and normalized fr was derived. The instrumental error in ε was RMSEε 5 0.226 (for 3 < ε < 43), which corresponds to a measurement precision in θ(ε) derived from Topp's equation of RMSEθ = 0.0034 m3 m-3. Axisymmetric numerical simulations of the electric field supplemented the experimental results. The characteristic length scale for the distance measured radially from the access tube is 12.5 mm, meaning that 80 and 95% of the signal are sensed within approximately 20 and 37 mm of the access tube, respectively. The results are crucial for scientific applications of the investigated sensor type to environmental media. Soil Science Society of America.
BibTeX:
@article{Schwank20061048,
  author = {Schwank, M. and Green, T.R. and Matzler, C. and Benedickter, H. and Fluhler, H.},
  title = {Laboratory characterization of a commercial capacitance sensor for estimating permittivity and inferring soil water content},
  journal = {Vadose Zone Journal},
  year = {2006},
  volume = {5},
  number = {3},
  pages = {1048-1064},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34248185689&doi=10.2136%2fvzj2006.0009&partnerID=40&md5=cbba3f4f0a20cd9c744a965c6bcebf53},
  doi = {10.2136/vzj2006.0009}
}
Strozzi T, Wegmüller U, Keusen H, Graf K and Wiesmann A (2006), "Analysis of the terrain displacement along a funicular by SAR interferometry", IEEE Geoscience and Remote Sensing Letters. Vol. 3(1), pp. 15-18.
Abstract: An analysis of the terrain displacement along a funicular in Switzerland was performed by satellite synthetic aperture radar interferometry using ERS-1/ 2 data. An initial interferometric point target analysis was performed with images acquired before 1999 and excluding all winter acquisitions with snow cover. The line-of-sight profile of the displacement rate along the funicular shows maximum values of about 1.5 cm/year, with negligible displacements near the lower and upper stations. After the spring of 1999, when displacements of several decimeters occurred because of heavy rainfall, the analysis was continued with single interferograms on the previously identified point targets. With a series of interferograms with large baselines the displacement could be analyzed in 1999 and 2000 along parts of the funicular. 2006 IEEE.
BibTeX:
@article{Strozzi200615,
  author = {Strozzi, T. and Wegmüller, U. and Keusen, H.R. and Graf, K. and Wiesmann, A.},
  title = {Analysis of the terrain displacement along a funicular by SAR interferometry},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  year = {2006},
  volume = {3},
  number = {1},
  pages = {15-18},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-31144432411&doi=10.1109%2fLGRS.2005.855072&partnerID=40&md5=a3f4aa4c49246fa1751177f127c82158},
  doi = {10.1109/LGRS.2005.855072}
}
Strozzi T, Wiesmann A, Sharov A, Kouraev A, Wegmüller U and Werner C (2006), "Capabilities of L-band SAR data for arctic glacier motion estimation", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3816-3819.
Abstract: L-band SAR interferometry and offset tracking were applied for the estimation of arctic glacier motion over Franz Josef Land, Novaya Zemlya and Svalbard using SAR data acquired by the JERS-1 satellite with 44 days time interval. Our SAR interferometric results indicate a generally good coherence with well preserved fringes over the slow moving glaciers. Decorrelation is mainly observed along outlet glacier margins with excessive strain rates. On the other hand, the effects on the interferometric coherence of snow and ice melting, snow accumulation or wind drift, and volume decorrelation because of microwave penetration in the dry snow cover and ice are limited. Offset tracking applied to pairs of SLC images highlights the displacement of the fastest moving glaciers around the ice caps. However, azimuth streaks, possibly related to auroral zone ionospheric disturbances, were detected.
BibTeX:
@conference{Strozzi20063816,
  author = {Strozzi, T. and Wiesmann, A. and Sharov, A. and Kouraev, A. and Wegmüller, U. and Werner, C.},
  title = {Capabilities of L-band SAR data for arctic glacier motion estimation},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2006},
  pages = {3816-3819},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34948875336&doi=10.1109%2fIGARSS.2006.978&partnerID=40&md5=7a4c59b49a5b4cd056ed1cde72650609},
  doi = {10.1109/IGARSS.2006.978}
}
Wegmüller U, Cordey R, Werner C and Meadows P (2006), ""Flashing fields" in nearly simultaneous ENVISAT and ERS-2 C-Band SAR images", IEEE Transactions on Geoscience and Remote Sensing. Vol. 44(4), pp. 801-805.
Abstract: Large differences are observed between radar backscatter measurements made by the ENVISAT and ERS-2 satellite synthetic aperture radars, within 30 min of each other over certain agricultural fields in Flevoland, The Netherlands. The differences appear to be caused by the presence of highly directive scattering combined with very small variations in the azimuth illumination angle of the two sensors at the degree or subdegree level. There is relatively little awareness of such sensitivity to illumination direction, and it is not predicted by models for microwave interaction usually applied to soils and vegetation. It is, however, to be expected if there are significant contributions from coherent scattering extending over patches of the agricultural fields in question. We present analysis that supports such a conclusion. 2006 IEEE.
BibTeX:
@article{Wegmuller2006801,
  author = {Wegmüller, U. and Cordey, R.A. and Werner, C. and Meadows, P.J.},
  title = {"Flashing fields" in nearly simultaneous ENVISAT and ERS-2 C-Band SAR images},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2006},
  volume = {44},
  number = {4},
  pages = {801-805},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645675267&doi=10.1109%2fTGRS.2005.861479&partnerID=40&md5=57811f06190debb3e2c6b48b9e552484},
  doi = {10.1109/TGRS.2005.861479}
}
Wegmüller U, Werner C, Strozzi T and Wiesmann A (2006), "ERS - ASAR integration in the interferometric point target analysis", In European Space Agency, (Special Publication) ESA SP. (610)
Abstract: The possibility to continue deformation monitoring between the rich archive of SAR data acquired by the ERS satellites and ENVISAT ASAR is essential for related applications and services. In many cases the current time monitoring is in the center of the interest, but the existence of the ERS archive is relevant as a record of the deformation history. Another important factor is that the reliability and accuracy of current time monitoring with ASAR is improved by the availability of the historic ERS observations, this particularly in cases where only few ASAR images were acquired. In this contribution, an approach for the integration of ERS and ASAR data in the Interferometric Point Target Analysis (IPTA) is presented. An important advantage of the use of targets with point like scatter characteristics in a SAR interferometric analysis is that coherence is maintained for many scatterers across series including both ERS and ENVISAT data - this in spite of the slightly different sensor carrier frequencies. The main steps of the integration are the transformation of the ASAR scenes to the ERS reference geometry, the consideration of the different carrier frequencies in the phase interpretation, and the estimation of a point-wise ERS - ASAR phase offset. Based on examples mainly from the mining subsidence application the steps done and the results achieved are discussed.
BibTeX:
@conference{Wegmuller2006,
  author = {Wegmüller, U. and Werner, C. and Strozzi, T. and Wiesmann, A.},
  title = {ERS - ASAR integration in the interferometric point target analysis},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2006},
  number = {610},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33746620524&partnerID=40&md5=a57c332a2a17518174770d74ed77c435}
}
Wegmüller U, Werner C, Strozzi T and Wiesmann A (2006), "Ionospheric electron concentration effects on SAR and INSAR", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3731-3734.
Abstract: The launch of ALOS and the high potential expected for the L-band PALSAR motivated us to investigate ionospheric electron concentration effects using JERS L-band SAR data acquired at high latitudes. An important focus of our work was on the identification of ionospheric effects and resulted in methodologies to detect ionospheric effects in single SAR acquisitions as well as in repeat-orbit pairs. For cases where significant ionospheric anomalies are present, procedures to improve SAR offset tracking and interferometric results are proposed and the retrieval of free electron density maps is discussed.
BibTeX:
@conference{Wegmuller20063731,
  author = {Wegmüller, U. and Werner, C. and Strozzi, T. and Wiesmann, A.},
  title = {Ionospheric electron concentration effects on SAR and INSAR},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2006},
  pages = {3731-3734},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34948855975&doi=10.1109%2fIGARSS.2006.956&partnerID=40&md5=70d1699a68b1c29f2bb7e287863b2cb3},
  doi = {10.1109/IGARSS.2006.956}
}
Wiesmann A, Werner C, Santoro M, Wegmüller U and Strozzi T (2006), "ScanSAR interferometry for land use applications and terrain deformation", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 3103-3106.
Abstract: ScanSAR interferometry is an attractive technology thanks to its wide swath imaging capabilities. It allows efficient interferometric mapping for various applications such as deformation or landuse monitoring. The motivation for this work is the availability of the new Envisat ASAR Wide Swath Mode Single Look Complex Product (WSS) produced by ESA. Furthermore, other sensors as Radarsat, Radarsat 2, and ALOS PALSAR can be operated in ScanSAR mode resulting in an increased relevance of repeat-pass ScanSAR interferometry and related applications. With the launch of the new Envisat product, a large archive of historical wide swath Envisat ASAR data is now available for ScanSAR interferometry. First applications include deformation mapping, topographic mapping, large-scale athmosphere monitoring, and landuse mapping.
BibTeX:
@conference{Wiesmann20063103,
  author = {Wiesmann, A. and Werner, C. and Santoro, M. and Wegmüller, U. and Strozzi, T.},
  title = {ScanSAR interferometry for land use applications and terrain deformation},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2006},
  pages = {3103-3106},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34948890610&doi=10.1109%2fIGARSS.2006.796&partnerID=40&md5=34294951b652562f8eedf0ddf9298f8f},
  doi = {10.1109/IGARSS.2006.796}
}
Wigneron J-P, Andersen S, Boutin J, Calvet J-C, Chen K-S, de Rosnay P, Dinnat E, English S, Escorihuela M, Ferrazzoli P, Guerriero L, Hallikainen M, Heygster G, Holmes T, Hornbuckle B, Jupp A, Kerr Y, Matzler C, Pellarin T, Prigent C, Pulliainen J, Contell K, Schwank M, Shi J, Tonboe R, Pedersen L, van de Griend A, Waldteufel P and Wiesmann A (2006), "Surface emission", Thermal Microwave Radiation: Applications for Remote Sensing. , pp. 225-425. Institution of Engineering and Technology.
Abstract: The purpose of this chapter is to use analytical expressions for the comparison of thermal microwave radiation as functions of temperature, layer thickness, absorption and scattering coefficient. For an observer from above, a growing cover is an increased screening of the underlying surface by scattering, absorption and emission. Here the discussion is limited to soft covers by which is meant that the transition from the atmosphere to the canopy is gentle enough to avoid reflections. Reflection is accounted for at the bottom surface, and volume interactions are allowed inside the cover. For simplicity polarisation effects have been neglected, and the angular dependence has been treated in a simplified way. The models can be extended to include better angular dependence, polarisation, hard covers and multi-layer systems. 2006: The Institution of Engineering and Technology.
BibTeX:
@book{Wigneron2006225,
  author = {Wigneron, J.-P. and Andersen, S. and Boutin, J. and Calvet, J.-C. and Chen, K.-S. and de Rosnay, P. and Dinnat, E.P. and English, S.J. and Escorihuela, M.J. and Ferrazzoli, P. and Guerriero, L. and Hallikainen, M. and Heygster, G. and Holmes, T.R.H. and Hornbuckle, B.K. and Jupp, A. and Kerr, Y.H. and Matzler, C. and Pellarin, T. and Prigent, C. and Pulliainen, J. and Contell, K.S. and Schwank, M. and Shi, J. and Tonboe, R.T. and Pedersen, L.T. and van de Griend, A. and Waldteufel, P. and Wiesmann, A.},
  title = {Surface emission},
  journal = {Thermal Microwave Radiation: Applications for Remote Sensing},
  publisher = {Institution of Engineering and Technology},
  year = {2006},
  pages = {225-425},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013477724&doi=10.1049%2fPBEW052E_ch4&partnerID=40&md5=8bbbc82dc6c6327945a61e6c740dc294},
  doi = {10.1049/PBEW052E_ch4}
}
Askne J and Santoro M (2005), "Multitemporal repeat pass SAR interferometry of boreal forests", IEEE Transactions on Geoscience and Remote Sensing. Vol. 43(6), pp. 1219-1228.
Abstract: Multitemporal interferometric European Remote Sensing 1 and 2 satellite tandem pairs from a forest test site in Finland are examined in order to determine the stem volume retrieval accuracy. A form of multitemporal filtering is introduced to investigate what forest stands show a multitemporal consistency in coherence. It is found that a large stand size is a major factor to obtain accurate retrievals. The effect of heterogeneity of forest stands is also discussed. Based on the stands showing highest multitemporal consistency different models for scattering and coherence are compared. The interferometric water cloud model is chosen for stem volume retrieval. The variation of the model parameters with meteorological parameters is investigated and the results illustrate that the best imaging conditions are obtained for subzero temperatures and windy conditions. It is shown that for the 20 stands showing highest multitemporal consistency the stem volume can be retrieved with a relative error of 21%, deteriorating when the number of testing stands is increased, e.g., for 80 stands the error is 48%. For 37 large forest stands representing 48% of the investigated area the relative stem volume error is 26%. With experience from another site in Sweden we may conclude that the error level for a multitemporal interferometric synthetic aperture radar evaluation of stem volume for large forest stands (>2 ha) in a well managed and homogeneous boreal forest may be expected to be in the 15% to 25% range, deteriorating for small and heterogeneous stands and for images acquired under nonwinter conditions. 2005 IEEE.
BibTeX:
@article{Askne20051219,
  author = {Askne, J. and Santoro, M.},
  title = {Multitemporal repeat pass SAR interferometry of boreal forests},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2005},
  volume = {43},
  number = {6},
  pages = {1219-1228},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-20444488441&doi=10.1109%2fTGRS.2005.846878&partnerID=40&md5=5aa148ea4669dcbe112bbd58604812e1},
  doi = {10.1109/TGRS.2005.846878}
}
Catani F, Farina P, Moretti S, Nico G and Strozzi T (2005), "On the application of SAR interferometry to geomorphological studies: Estimation of landform attributes and mass movements", Geomorphology. Vol. 66(1-4 SPEC. ISS.), pp. 119-131.
Abstract: This paper presents two examples of application of Synthetic Aperture Radar (SAR) interferometry (InSAR) to typical geomorphological problems. The principles of InSAR are introduced, taking care to clarify the limits and the potential of this technique for geomorphological studies. The application of InSAR to the quantification of landform attributes such as the slope and to the estimation of landform variations is investigated. Two case studies are presented. A first case study focuses on the problem of measuring landform attributes by interferometric SAR data. The interferometric result is compared with the corresponding one obtained by a Digital Elevation Model (DEM). In the second case study, the use of InSAR for the estimation of landform variations caused by a landslide is detailed. 2004 Elsevier B.V. All rights reserved.
BibTeX:
@article{Catani2005119,
  author = {Catani, F. and Farina, P. and Moretti, S. and Nico, G. and Strozzi, T.},
  title = {On the application of SAR interferometry to geomorphological studies: Estimation of landform attributes and mass movements},
  journal = {Geomorphology},
  year = {2005},
  volume = {66},
  number = {1-4 SPEC. ISS.},
  pages = {119-131},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-14844287012&doi=10.1016%2fj.geomorph.2004.08.012&partnerID=40&md5=4e310b242d02659ee9a3eef4b302b87c},
  doi = {10.1016/j.geomorph.2004.08.012}
}
Eriksson L, Askne J, Santoro M, Schmullius C and Wiesmann A (2005), "Stem volume retrieval with spaceborne L-band repeat-pass coherence: Multi-temporal combination for boreal forest", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 3591-3594.
Abstract: In this paper retrieval of stem volume from JERS-1 repeat-pass interferometric coherence is demonstrated for five large forest areas in central Siberia. A method for multi-temporal combination of the retrieved stem volumes from several coherence images is applied. Compared to the best results from single coherence images the retrieval accuracy is in most cases significantly improved by the multi-temporal combination. The obtained multi-temporal relative retrieval accuracy is in the range 35 - 39% for four of five areas. The best RMSE is 54 m3/ha. 2005 IEEE.
BibTeX:
@conference{Eriksson20053591,
  author = {Eriksson, L.E.B. and Askne, J. and Santoro, M. and Schmullius, C. and Wiesmann, A.},
  title = {Stem volume retrieval with spaceborne L-band repeat-pass coherence: Multi-temporal combination for boreal forest},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2005},
  volume = {5},
  pages = {3591-3594},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745726406&doi=10.1109%2fIGARSS.2005.1526624&partnerID=40&md5=3cdc955c37e0236403b9e594660193c9},
  doi = {10.1109/IGARSS.2005.1526624}
}
Frey O, Meier E and Nuesch D (2005), "A study on integrated SAR processing and geocoding by means of time-domain backprojection", In Proceedings International Radar Symposium. Vol. 2005-January IEEE Computer Society.
Abstract: Geocoded products of synthetic aperture radar data are of great interest for many applications. The conventional processing chain, which leads to geographically referenced synthetic aperture data consists of two main steps: first, the raw data are focused and, in a second step, the resulting single look complex image is geocoded to the favoured coordinate system. We investigate a time-domain backprojection approach that replaces the two steps, focusing and geocoding, by one algorithm leading directly to terrain-geocoded images. The technique is evaluated with ENVISAT/ASAR image mode data. We assess the geolocation accuracy and the radiometric performance of dedicated point targets such as transponders and a corner reflector. In addition, we compare our findings with results from corresponding level 1 products processed at the European Space Agency (ESA), which were validated within the scope of ENVISAT/ASAR Cal/Val activities.
BibTeX:
@conference{Frey2005b,
  author = {Frey, O. and Meier, E. and Nuesch, D.},
  title = {A study on integrated SAR processing and geocoding by means of time-domain backprojection},
  booktitle = {Proceedings International Radar Symposium},
  publisher = {IEEE Computer Society},
  year = {2005},
  volume = {2005-January},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961615513&partnerID=40&md5=9d1e89d22cad8f2ffa4d3531457b148c}
}
Frey O, Meier E and Nüesch D (2005), "A Study on Integrated SAR Processing and Geocoding by Means of Time-Domain Backprojection", In Proc. Int. Radar Symp..
Abstract: Geocoded products of synthetic aperture radar data are of great interest for many applications. The conventional processing chain, which leads to geographically referenced synthetic aperture data consists of two main steps: first, the raw data are focused and, in a second step, the resulting single look complex image is geocoded to the favoured coordinate system. We investigate a time-domain backprojection approach that replaces the two steps, focusing and geocoding, by one algorithm leading directly to terrain-geocoded images. The technique is evaluated with ENVISAT/ASAR image mode data. We assess the geolocation accuracy and the radiometric performance of dedicated point targets such as transponders and a corner reflector. In addition, we compare our findings with results from corresponding level 1 products processed at the European Space Agency (ESA), which were validated within the scope of ENVISAT/ASAR Cal/Val activities.
BibTeX:
@inproceedings{freyMeierNueschIRS05:StudyIntegratedBackproj,
  author = {Othmar Frey and Erich Meier and Daniel Nüesch},
  title = {A Study on Integrated SAR Processing and Geocoding by Means of Time-Domain Backprojection},
  booktitle = {Proc. Int. Radar Symp.},
  year = {2005}
}
Frey O, Meier EH and Nüesch DR (2005), "Processing SAR data of rugged terrain by time-domain back-projection", In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 5980
Abstract: Processing of SAR imagos of rugged terrain deserves special care because the topography affects the focused image in a number of ways. In order to obtain geometrically and radiometrically corrected SAR, images of mountainous areas additional knowledge about the topography and the sensor's trajectory and attitude has to be included in the processing or post-processing steps. Various well-known focusing techniques are available to transform SAR, raw data into a single look complex image such as the range-Doppler. the chirp scaling or the ω-k algorithm. While these algorithms perform the azimuth focusing step in the frequency domain the time-domain back-projection processing technique focuses the data geometrically, i.e., in the time domain. In contrast to the frequency-domain techniques, time-domain back-projection maintains the entire geometric relationship between the sensor and the illuminated area. This implies a couple of advantages: a stringent, terrain-based correction for the elevation antenna gain pattern may be implemented and topography-induced variation of radar brightness can be eliminated in a single step. Further, the SAR image is focused directly onto an arbitrary reconstruction grid and in the desired geodetic reference frame without requiring any additional processing steps. We discuss the influence of rugged terrain on the radiometric properties of focused SAR, data and demonstrate how the time-domain bock-projection approach accounts for these effects within one integrated processing frame-work by incorporating both a correction for terrain slope induced variation of radar brightness and a stringent correction for the elevation antenna gain pattern. The algorithm is evaluated for ENVISAT/ASAR, image mode data of a mountainous area.
BibTeX:
@conference{Frey2005a,
  author = {Frey, Othmar and Meier, Erich H. and Nüesch, Daniel R.},
  editor = {Posa F.},
  title = {Processing SAR data of rugged terrain by time-domain back-projection},
  booktitle = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2005},
  volume = {5980},
  url = {https://www.gamma-rs.ch/uploads/media/FreyMeierNueesch_SPIE2005.pdf},
  doi = {10.1117/12.627647}
}
Guerova G, Brockmann E, Schubiger F, Morland J and Matzler C (2005), "An integrated assessment of measured and modeled integrated water vapor in Switzerland for the period 2001-03", Journal of Applied Meteorology. Vol. 44(7), pp. 1033-1044.
Abstract: In this paper an integrated assessment of the vertically integrated water vapor (IWV) measured by radiosonde, microwave radiometer (MWR), and GPS and modeled by the limited-area mesoscale model of MeteoSwiss is presented. The different IWV measurement techniques are evaluated through intercomparisons of GPS to radiosonde in Payerne, Switzerland, and to the MWR operated at the Institute of Applied Physics at the University of Bern in Switzerland. The validation of the IWV field of the nonhydrostatic mesoscale Alpine Model (aLMo) of MeteoSwiss is performed against 14 GPS sites from the Automated GPS Network of Switzerland (AGNES) in the period of 2001-03. The model forecast and the nudging analysis are evaluated, with special attention paid to the diurnal cycle. The results from the GPS-radiosonde intercomparison are in agreement, but with a bimodal distribution of the day-to-night basis. At 0000 UTC, the bias is negative (-0.4 kg m-2); at 1200 UTC, it is positive (0.9 kg m-2) and the variability increases. The intercomparison of GPS to MWR shows better agreement (0.4 kg m-2), with a small increase of the daytime bias with 0.3 kg m-2. The intercomparison of MWR to the radiosonde gives a bimodal distribution of the bias, with an increase in the standard deviation at the daytime measurement. The relative bias is negative (-3%) at 0000 UTC and is positive (3%) at 1200 UTC. Based on this cross correlation, it can be concluded that the bimodal distribution is a result of radiosonde humidity measurements. Possible reasons are the solar-heating correction or sensor errors. The monthly bias and standard deviation of aLMo exhibit a strong seasonal dependence with a pronounced dry bias during the warm months of May-October 2002. The diurnal IWV cycle in 2001 shows good model performance between 0000 and 0900 UTC but IWV underestimation by up to 1.5 kg m-2 for the rest of the day. In 2002 the diurnal cycle shows a systematic dry bias in both the analysis and forecast that is more pronounced in the analysis. This substantial underestimation of IWV was found to correlate with overestimation of aLMo precipitation, especially light precipitation up to 0.1 mm (6 h)-1 in 2002. There is strong evidence that this underestimation can be related to the dry radiosonde bias in midday summer observations. The aLMo dry bias is about 1.0-1.5 kg m-2 greater in the nudging analysis as compared with the forecast initialized at 0000 UTC. 2005 American Meteorological Society.
BibTeX:
@article{Guerova20051033,
  author = {Guerova, G. and Brockmann, E. and Schubiger, F. and Morland, J. and Matzler, C.},
  title = {An integrated assessment of measured and modeled integrated water vapor in Switzerland for the period 2001-03},
  journal = {Journal of Applied Meteorology},
  year = {2005},
  volume = {44},
  number = {7},
  pages = {1033-1044},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-24644433135&doi=10.1175%2fJAM2255.1&partnerID=40&md5=78724d24c9ff53002295010a3c0f8619},
  doi = {10.1175/JAM2255.1}
}
Kaab A, Huggel C, Fischer L, Guex S, Paul F, Roer I, Salzmann N, Schlaefli S, Schmutz K, Schneider D, Strozzi T and Weidmann Y (2005), "Remote sensing of glacier- and permafrost-related hazards in high mountains: An overview", Natural Hazards and Earth System Science. Vol. 5(4), pp. 527-554.
Abstract: Process interactions and chain reactions, the present shift of cryospheric hazard zones due to atmospheric warming, and the potential far reach of glacier disasters make it necessary to apply modern remote sensing techniques for the assessment of glacier and permafrost hazards in high-mountains. Typically, related hazard source areas are situated in remote regions, often difficult to access for physical and/or political reasons. In this contribution we provide an overview of air- and spaceborne remote sensing methods suitable for glacier and permafrost hazard assessment and disaster management. A number of image classification and change detection techniques support high-mountain hazard studies. Digital terrain models (DTMs), derived from optical stereo data, synthetic aperture radar or laserscanning, represent one of the most important data sets for investigating high-mountain processes. Fusion of satellite stereo-derived DTMs with the DTM from the Shuttle Radar Topography Mission (SRTM) is a promising way to combine the advantages of both technologies. Large changes in terrain volume such as from avalanche deposits can indeed be measured even by repeat satellite DTMs. Multitemporal data can be used to derive surface displacements on glaciers, permafrost and landslides. Combining DTMs, results from spectral image classification, and multitemporal data from change detection and displacement measurements significantly improves the detection of hazard potentials. Modelling of hazardous processes based on geographic information systems (GIS) complements the remote sensing analyses towards an integrated assessment of glacier and permafrost hazards in mountains. Major present limitations in the application of remote sensing to glacier and permafrost hazards in mountains are, on the one hand, of technical nature (e.g. combination and fusion of different methods and data; improved understanding of microwave backscatter). On the other hand, better dissemination of remote sensing expertise towards institutions involved in high-mountain hazard assessment and management is needed in order to exploit the large potential of remote sensing in this field. European Geosciences Union 2005 Author(s). This work is licensed under a Creative Commons License.
BibTeX:
@article{Kaab2005527,
  author = {Kaab, A. and Huggel, C. and Fischer, L. and Guex, S. and Paul, F. and Roer, I. and Salzmann, N. and Schlaefli, S. and Schmutz, K. and Schneider, D. and Strozzi, T. and Weidmann, Y.},
  title = {Remote sensing of glacier- and permafrost-related hazards in high mountains: An overview},
  journal = {Natural Hazards and Earth System Science},
  year = {2005},
  volume = {5},
  number = {4},
  pages = {527-554},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-24344506011&partnerID=40&md5=18a85dd986505ef165de8924f4d925cb}
}
Li Z, Pang Y, Chen E, Schmullius C and Santoro M (2005), "Forest mapping using ENVISAT and ERS SAR data in Northeast of China", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 8, pp. 5670-5673.
Abstract: The need to monitor forest is dramatically increasing in China, particularly after the introduction of new laws against deforestation. The well known ERS-1/2 tandem mission provides a large mount of SAR for interferometric processing. As forests have special volume decorrelation mechanism, the Interferometric Land-Use (ILU) images were used to generate forest map in Northeast of China. The striped ILU images processed by ESRIN Interferometric Quick-Look (IQL) processor have been used to generate forest/nonforest map. The algorithms of long strip ILU data geo-reference and mosaic have been developed. Decision tree classifier was used to map forest/nonforest on a pixel basis. The algorithm depends primarily on interferometric coherence. The threshold levels are adapted to the radiometry of individual strips. The gaps among ERS are filled by Landsat TM data of the same phase. The limited quality of the ILU from IQL system and the partial coverage of China limited the generation of forest base maps for larger areas of China. Under the Dragon Forest project between China MOST and ESA, the ERS SLC SAR data will be processed and the SIBERIA-I methods will be adapted to generate a forest volume density base map of 1995-1996 in this region. The Envisat ASAR Alternating Polarisation (AP) data will be used to update the base map to 2004-2005. Several hundred scenes ASAR AP data have been received during the summer and winter of 2004. Three test sites have been used to develop methodologies, which located in Daxinganling, Xiaoxinganling and Changbaishan separately. The digitalized forest map and field plots are used as reference data. The results from test sites show: i) It is very potential and feasible to generate forest volume density map using winter ERS tandem data, ii) Forest can be well discriminated from non-forest with ASAR AP (HH/HV) data, iii) ASAR HV backscattering signals increase with forest canopy density. 2005 IEEE.
BibTeX:
@conference{Li20055670,
  author = {Li, Z. and Pang, Y. and Chen, E. and Schmullius, C. and Santoro, M.},
  title = {Forest mapping using ENVISAT and ERS SAR data in Northeast of China},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2005},
  volume = {8},
  pages = {5670-5673},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745699717&doi=10.1109%2fIGARSS.2005.1526063&partnerID=40&md5=beb948b21a50a1800d2e5111a318a37c},
  doi = {10.1109/IGARSS.2005.1526063}
}
Ludi A, Beyrich F and Matzler C (2005), "Determination of the Turbulent Temperature - Humidity Correlation from Scintillometric Measurements", Boundary-Layer Meteorology. Vol. 117(3), pp. 525-550.
Abstract: We report on the investigation and successful application of the bichromatic correlation of optical and microwave signals for determining the area-averaged correlation of temperature-humidity fluctuations. The additional technical effort is marginal compared to the common 'two-wavelength method,' which has (in contrast) the restriction that only two of the three relevant meteorological structure parameters can be deduced. Therefore, in the past, it was often assumed that the turbulent humidity and temperature fluctuations are perfectly positively or negatively correlated. However, as shown in this study, over non-homogeneous terrain when the flow conditions are not ideal, this assumption is questionable. The measurements were analysed statistically, and were compared to in situ measurements of the Bowen ratio Bo and the correlation of temperature-humidity fluctuations using eddy-covariance techniques. The latter is in good agreement to that derived by scintillometry. We found that the correlation is not ±1 but as low as -0.6 for Bo smaller than -2, and up to 0.8 for Bo larger than 1. Springer 2005.
BibTeX:
@article{Ludi2005525,
  author = {Ludi, A. and Beyrich, F. and Matzler, C.},
  title = {Determination of the Turbulent Temperature - Humidity Correlation from Scintillometric Measurements},
  journal = {Boundary-Layer Meteorology},
  year = {2005},
  volume = {117},
  number = {3},
  pages = {525-550},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-32044447895&doi=10.1007%2fs10546-005-1751-1&partnerID=40&md5=0cd943ff8db42edb0837115076a8a502},
  doi = {10.1007/s10546-005-1751-1}
}
Luthi T and Matzler C (2005), "Stereoscopic passive millimeter-wave imaging and ranging", IEEE Transactions on Microwave Theory and Techniques. Vol. 53(8), pp. 2594-2599.
Abstract: This paper presents the first stereoscopic range measurements at a wavelength of 3.3 mm and discusses the accuracy of this new method. The synthesis of passive millimeter-wave imaging and stereoscopy combines the advantages of both principles, naturally looking high-contrast images and superior poor-weather performance (compared to visible and infrared wavelengths), as well as the passive ranging capability. Our setup using two antennas with a half-power beamwidth (HPBW) of 0.9° and a stereoscopic baseline of 1.15 m allows ranging with an accuracy of ≈10 % up to a distance of ≈300 m. The range resolution improves with increasing stereoscopic baseline, lower radiometer noise, narrower antenna beams, and higher scene contrast. For scenes with sufficient contrast, the directional resolution is considerably better than the antenna HPBW. Thus, massive oversampling of the scene in the plane of the stereoscopic baseline is required. For our setup, an oversampling factor of 36 is optimal. Since additional ranging errors result from nonstationary scenes, fast scanning imagers should be applied. 2005 IEEE.
BibTeX:
@article{Luthi20052594,
  author = {Luthi, T. and Matzler, C.},
  title = {Stereoscopic passive millimeter-wave imaging and ranging},
  journal = {IEEE Transactions on Microwave Theory and Techniques},
  year = {2005},
  volume = {53},
  number = {8},
  pages = {2594-2599},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-24344440877&doi=10.1109%2fTMTT.2005.852757&partnerID=40&md5=4389a6217fb25b507ab70e2154a646ca},
  doi = {10.1109/TMTT.2005.852757}
}
Matzler C (2005), "On the determination of surface emissivity from satellite observations", IEEE Geoscience and Remote Sensing Letters. Vol. 2(2), pp. 160-163.
Abstract: Terrestrial brightness temperatures measured from satellites have been used to determine the surface emissivity. The results not only depend on surface temperature and on atmospheric properties, but also on the type of surface scattering. For otherwise identical conditions (same emissivity, same nonscattering atmosphere), the radiation above the Lambertian surface is larger than for a specular surface if the incidence angle is smaller than about 55°. The opposite is true for larger angles. The effect leads to overestimates of emissivity for observations especially near nadir with the use of algorithms assuming specular reflection. The problem may be solved by the introduction of a specularity parameter to characterize realistic surfaces by a combination of specular and Lambert scattering. A simple solution lies in the use of conically scanning radiometers at a constant incidence angle near 55°. Although the topic applies to all ranges of thermal radiation, the present discussion concentrates on the microwave spectrum in the Rayleigh-Jeans approximation. 2005 IEEE.
BibTeX:
@article{Matzler2005160,
  author = {Matzler, C.},
  title = {On the determination of surface emissivity from satellite observations},
  journal = {IEEE Geoscience and Remote Sensing Letters},
  year = {2005},
  volume = {2},
  number = {2},
  pages = {160-163},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18844434439&doi=10.1109%2fLGRS.2004.842448&partnerID=40&md5=4a6b797fbed625bcf27c2a457a74a7cc},
  doi = {10.1109/LGRS.2004.842448}
}
Nyeki S, Vuilleumier L, Morland J, Bokoye A, Viatte P, Matzler C and Kampfer N (2005), "A 10-year integrated atmospheric water vapor record using precision filter radiometers at two high-alpine sites", Geophysical Research Letters. Vol. 32(23), pp. 1-4.
Abstract: Measurements of integrated water vapor (IWV) density using precision filter radiometers (PFRs) at two high-alpine, mid-latitude stations in the Swiss Alps are reported. Both sites, Davos (1590 m asl) and Jungfraujoch (JFJ; 3580 m asl), exhibited a maximum IWV in summer and minimum in winter. Annual mean IWV was 6.7 (±3.9; 1 std) kg m-2 from 1995 to 2005 and 2.2 (±1.5) kg m-2 from 1999 to 2005, respectively. Co-located GPS measurements exhibited a small positive IWV bias (GPS - PFR) at Davos (0.4 kg m-2) and a large negative bias at JFJ (-1.5 kg m-2). Microwave radiometer IWV at JFJ agreed well with PFR IWV suggesting that GPS IWV suffers from unmodeled effects. Linear IWV trend analysis indicated no significant trend at either Davos or JFJ for clear-sky periods. The GPS-IWV time series is at present too short to determine the trend for all-weather conditions. Copyright 2005 by the American Geophysical Union.
BibTeX:
@article{Nyeki20051,
  author = {Nyeki, S. and Vuilleumier, L. and Morland, J. and Bokoye, A. and Viatte, P. and Matzler, C. and Kampfer, N.},
  title = {A 10-year integrated atmospheric water vapor record using precision filter radiometers at two high-alpine sites},
  journal = {Geophysical Research Letters},
  year = {2005},
  volume = {32},
  number = {23},
  pages = {1-4},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-31544452073&doi=10.1029%2f2005GL024079&partnerID=40&md5=d00b876349b4ab206dfca02cf7aeb560},
  doi = {10.1029/2005GL024079}
}
Pritchard H, Murray T, Luckman A, Strozzi T and Barr S (2005), "Glacier surge dynamics of Sortebræ, east Greenland, from synthetic aperture radar feature tracking", Journal of Geophysical Research: Earth Surface. Vol. 110(3) Blackwell Publishing Ltd.
Abstract: We have measured the surface flow rate of the large east Greenland glacier, Sortebrœ, through both the initiation and termination of a major surge using synthetic aperture radar (SAR) feature tracking, optimized to minimize error. The Sortebrœ surge began between November and January 1992-1993, after at least 6 weeks of subfreezing temperatures over the whole glacier, and propagated rapidly up-glacier from a central nucleus. Sortebræ reached sustained fast flow rates of up to 24 m d-1, and the active phase lasted for 28-32 months before terminating in June 1995. Termination was abrupt, coinciding with the arrival of the spring thaw and the apparent release of a large volume of stored water from a single outlet at the front. The surge mechanism is interpreted as a switch from channelized to distributed drainage, which at present is best explained by Kamb's linked cavity sliding model. Copyright 2005 by the American Geophysical Union.
BibTeX:
@article{Pritchard2005,
  author = {Pritchard, H. and Murray, T. and Luckman, A. and Strozzi, T. and Barr, S.},
  title = {Glacier surge dynamics of Sortebræ, east Greenland, from synthetic aperture radar feature tracking},
  journal = {Journal of Geophysical Research: Earth Surface},
  publisher = {Blackwell Publishing Ltd},
  year = {2005},
  volume = {110},
  number = {3},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750345182&doi=10.1029%2f2004JF000233&partnerID=40&md5=c01285c8d30a655890a07c4c5189ab73},
  doi = {10.1029/2004JF000233}
}
Santoro M, Askne J and Dammert P (2005), "Tree height influence on ERS interferometric phase in boreal forest", IEEE Transactions on Geoscience and Remote Sensing. Vol. 43(2), pp. 207-216.
Abstract: The European Remote Sensing 1/2 (ERS-1/2) "tandem" coherence has been shown to provide estimates of stem volume in boreal forest in agreement with in situ data. Tree height estimation from ERS interferometric phase represents a further step in the investigations concerning the retrieval of biophysical parameters using repeat-pass synthetic aperture radar (SAR) interferometry. At two test sites located in Sweden and Finland, sets of respectively nine and eight ERS "tandem" interferograms were available. Images acquired under stable winter weather conditions and during nighttime were found to be less affected by atmospheric artifacts. Reduction of atmospheric artifacts in interferograms was performed with a phase screen estimated over a dense grid of open areas. Nonetheless, at each test site, only a limited set of pairs was useful for tree height investigations. Under stable winter conditions, the interferometric tree height obtained from an inversion of the differential interferometric phase at stand level was found to be much lower than the true tree height. Spread and uncertainty in the interferometric tree height measurements were caused by phase noise and residual atmospheric artifacts. Using the semiempirical interferometric water cloud model (IWCM), the modeled interferometric tree height was generally in reasonable agreement with the measurements, showing the need of a phase term in interferometric modeling of forests. The inversion of the IWCM for tree height retrieval showed the strong effect of phase noise and atmospheric artifacts on the estimates. Hence, tree height retrieval from ERS repeat-pass SAR interferometry seems to have limited forestry applications. The results also indicate under what conditions the forest influence is small on digital elevation models derived from repeat-pass interferometry.
BibTeX:
@article{Santoro2005207,
  author = {Santoro, M. and Askne, J. and Dammert, P.B.G.},
  title = {Tree height influence on ERS interferometric phase in boreal forest},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2005},
  volume = {43},
  number = {2},
  pages = {207-216},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-13144294080&doi=10.1109%2fTGRS.2004.841250&partnerID=40&md5=b1a86af8fee49d2cdac115f0d882e8c7},
  doi = {10.1109/TGRS.2004.841250}
}
Santoro M, Askne J, Eriksson L and Schmullius C (2005), "Comparison of stem volume retrieval accuracy in boreal forest using multi-temporal ERS coherence images", In European Space Agency, (Special Publication) ESA SP. (572), pp. 1289-1298.
Abstract: The availability of multi-temporal ERS one-day coherence images and extensive in situ data from test sites located in Sweden, Finland and Siberia has allowed a first assessment on the consistency of stem volume retrieval at stand level within the boreal zone. The test sites are characterised by different forest structure and ground properties. The coherence data had baselines up to 374 m. The relationship between coherence and stem volume measurements and the spread of the coherence measurements depended on the environmental conditions at and between image acquisitions, specific features of the test site (e.g. forest homogeneity, ground dielectric properties) and ground data accuracy. To retrieve stem volume the semiempirical Interferometric Water Cloud Model, IWCM, was used and it was compared to a simple empirical model. The IWCM could describe the trend in the observations under all environmental and baseline conditions. The accuracy of stem volume retrieval depended on environmental conditions and forest stand structure as well as ground data. Frozen and stable weather conditions were most suitable for retrieval. Smaller errors were obtained at managed test sites. For natural forests the spread of the measurements affected the retrieval negatively. Multi-temporal combination of estimates from individual images could yield results comparable to in situ measurements for managed homogeneous forest stands.
BibTeX:
@conference{Santoro20051289,
  author = {Santoro, M. and Askne, J. and Eriksson, L. and Schmullius, C.},
  title = {Comparison of stem volume retrieval accuracy in boreal forest using multi-temporal ERS coherence images},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2005},
  number = {572},
  pages = {1289-1298},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-23844474419&partnerID=40&md5=58f2da21b5aee3da41d360f1d2c84a61}
}
Santoro M, Balzter H, George C, Gerard F, Hese S, Roscher M, Rowland C and Schmullius C (2005), "Siberia-II: Monitoring forest cover changes in Siberia by means of spaceborne data", In European Space Agency, (Special Publication) ESA SP. (572), pp. 2279-2287.
Abstract: Within the SIBERIA-II project the identification of areas subject to forest cover change due to disturbances has an important role in the project's objective, i.e. full greenhouse gas account. Fire scars were mapped using data from SPOT-VEGETATION and MODIS acquired in 1999, 2002 and 2003, using various vegetation indices. The fire scars were then dated with thermal anomaly 'hotspot' data to provide yearly burnt area statistics. A preliminary cross-comparison of the fire scar map with ASAR Wide Swath data shows a good agreement. Pollution effects on vegetation have been investigated in the area of Noril'sk where enormous sulphur dioxide and heavy metal emissions from copper and nickel plants have occurred. A temporal sequence of ASAR Wide Swath images from 2003 was used to map pollution damage and the results were compared to maps obtained from Landsat TM data from 1995 and 2002. ASAR can detect pollution damage, the extent of the damage having not changed significantly since 1995. Afforestation, Reforestation, Deforestation (ARD) activities are detected using multi-temporal classification of high resolution Landsat TM 5 and ETM data at four test territories comparing the 1989 Kyoto Protocol baseline with the 2000 status. With an object oriented change detection approach based on a primary segmentation it has been possible to detect forest cover changes, differentiating between human induced clear cuts from old fire scars. For ARD monitoring, ERS and ENVISAT SAR backscatter data have also been investigated showing the possibility to detect deforestation whereas for reforestation a longer time interval of data than the 8-years data available so far is needed.
BibTeX:
@conference{Santoro20052279,
  author = {Santoro, M. and Balzter, H. and George, C.T. and Gerard, F. and Hese, S. and Roscher, M. and Rowland, C. and Schmullius, C.},
  title = {Siberia-II: Monitoring forest cover changes in Siberia by means of spaceborne data},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2005},
  number = {572},
  pages = {2279-2287},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-23844505009&partnerID=40&md5=ba6edeed6cb856cb945a5f438d68f612}
}
Schafer D, Manconi A, Grandel S and Dahmke A (2005), "Consequences of different kinetic approaches for simulation of microbial degradation on contaminant plume development", Reactive Transport in Soil and Groundwater: Processes and Models. , pp. 127-139. Springer Berlin Heidelberg.
Abstract: This study investigates the consequences of assuming different kinetic approaches for calculation of microbial degradation on plume development in a simple case of natural attenuation on field scale. If the required parameters are properly chosen, all approaches can simulate similar plumes for a particular given time step. The differences of contaminant concentrations in the plumes are small and would not attract attention in a natural aquifer. On long term prognoses the kinetics result in very different plumes: A complex Monod approach considering microbial growth prognoses a further spreading of the plume, compared to a first order rate law, which results in a short and early stationary plume. Other approaches show plumes between these two extremes. On the other hand, the forecasts for plumes assuming Monod kinetics are similar, even if different values for parameterization are chosen. The reason for this insensibility is, that degradation is not limited by microbial kinetics in the simulation, but by dispersive mixing. Simplifying approaches may have few and well determinable parameters, but they are not suited for proper prognoses if they neglect the prerequisite, that contaminant and electron acceptor have to be present for a reaction. 2005 Springer-Verlag Berlin Heidelberg.
BibTeX:
@book{Schafer2005127,
  author = {Schafer, D. and Manconi, A. and Grandel, S. and Dahmke, A.},
  title = {Consequences of different kinetic approaches for simulation of microbial degradation on contaminant plume development},
  journal = {Reactive Transport in Soil and Groundwater: Processes and Models},
  publisher = {Springer Berlin Heidelberg},
  year = {2005},
  pages = {127-139},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33947385245&doi=10.1007%2f3-540-26746-8_9&partnerID=40&md5=cf90aafbbb3532750772a952b47ca7f3},
  doi = {10.1007/3-540-26746-8_9}
}
Schwank M, Matzler C, Guglielmetti M and Fluhler H (2005), "L-band radiometer measurements of soil water under growing clover grass", IEEE Transactions on Geoscience and Remote Sensing. Vol. 43(10), pp. 2225-2236.
Abstract: A field experiment with an L-band radiometer at 1.4 GHz was performed from May-July 2004 at an experimental site near Zurich, Switzerland. Before the experiment started, clover grass was seeded. Thermal infrared, in situ temperature, and time-domain reflectometer (TDR) measurements were taken simultaneously with hourly radiometer measurements. This setup allowed for investigation of the microwave optical depths and mode opacities (parallel and perpendicular to the soil surface) of the clover grass canopy. Optical depths and opacities were determined by in situ analysis and remotely sensed measurements using a nonscattering radiative transfer model. Due to the canopy structure, optical depth and opacity depend on the polarization and radiometer direction, respectively. A linear relation between vegetation water-mass equivalent and polarization-averaged optical depth was observed. Furthermore, measured and modeled radiative transfer properties of the canopy were compared. The model is based on an effective-medium approach considering the vegetation components as ellipsoidal inclusions. The effect of the canopy structure on the opacities was simulated by assuming an anisotropic orientation of the vegetation components. The observed effect of modified canopy structure due to a hail event was successfully reproduced by the model. It is demonstrated that anisotropic vegetation models should be used to represent the emission properties of vegetation. The sensitivity of radiometer measurements to soil water content was investigated in terms of the fractional contribution of radiation emitted from the soil to total radiation. The fraction of soil-emitted radiation was reduced to approximately 0.3 at the most developed vegetation state. The results presented contribute toward a better understanding of the interaction between L-band radiation and vegetation canopies. Such knowledge is important for evaluating data generated from future satellite measurements. 2005 IEEE.
BibTeX:
@article{Schwank20052225,
  author = {Schwank, M. and Matzler, C. and Guglielmetti, M. and Fluhler, H.},
  title = {L-band radiometer measurements of soil water under growing clover grass},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2005},
  volume = {43},
  number = {10},
  pages = {2225-2236},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844481037&doi=10.1109%2fTGRS.2005.855135&partnerID=40&md5=a4be71d6203bfaba3c25ce2751af9604},
  doi = {10.1109/TGRS.2005.855135}
}
Strozzi T, Farina P, Corsini A, Ambrosi C, Thuring M, Zilger J, Wiesmann A, Wegmüller U and Werner C (2005), "Survey and monitoring of landslide displacements by means of L-band satellite SAR interferometry", Landslides. Vol. 2(3), pp. 193-201.
Abstract: This paper illustrates the capabilities of L-band satellite SAR interferometry for the investigation of landslide displacements. SAR data acquired by the L-band JERS satellite over the Italian and Swiss Alps have been analyzed together with C-band ERS-1/2 SAR data and in situ information. The use of L-band SAR data with a wavelength larger than the usual C-band, generally considered for ground motion measurements, reduces some of the limitations of differential SAR interferometry, in particular, signal decorrelation induced by vegetation cover and rapid displacements. The sites of the Alta Val Badia region in South Tyrol (Italy), Ruinon in Lombardia (Italy), Saas Grund in Valais (Switzerland) and Campo Vallemaggia in Ticino (Switzerland), representing a comprehensive set of different mass wasting phenomena in various environments, are considered. The landslides in the Alta Val Badia region are good examples for presenting the improved performance of L-band in comparison to C-band for vegetated areas, in particular concerning open forest. The landslides of Ruinon, Saas Grund, and Campo Vallemaggia demonstrate the strength of L-band in observing moderately fast displacements in comparison to C-band. This work, performed with historical SAR data from a satellite which operated until 1998, demonstrates the capabilities of future planned L-band SAR missions, like ALOS and TerraSAR-L, for landslide studies.
BibTeX:
@article{Strozzi2005193,
  author = {Strozzi, T. and Farina, P. and Corsini, A. and Ambrosi, C. and Thuring, M. and Zilger, J. and Wiesmann, A. and Wegmüller, U. and Werner, C.},
  title = {Survey and monitoring of landslide displacements by means of L-band satellite SAR interferometry},
  journal = {Landslides},
  year = {2005},
  volume = {2},
  number = {3},
  pages = {193-201},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-30744441163&doi=10.1007%2fs10346-005-0003-2&partnerID=40&md5=58b32ebd4d9178d93e2281bc569df825},
  doi = {10.1007/s10346-005-0003-2}
}
Strozzi T, Keusen H, Graf K, Wiesmann A, Wegmüller U and Werner C (2005), "Analysis of the displacement along a funicular with large baseline interferograms on point targets", In European Space Agency, (Special Publication) ESA SP. (572), pp. 743-748.
Abstract: An analysis of the displacement along a funicular in Switzerland was performed using ERS-1/2 SAR data. An initial interferometric point target analysis was performed with images acquired before the spring of 1999 and excluding all winter acquisitions with snow cover. The profile of the displacement rate along the funicular shows maximum values of about 1.5 cm/year in the satellite line-of-sight direction, with negligible displacements near the lower and upper stations. After the spring of 1999, when displacements of several dm's occurred because of heavy rainfall, the analysis was continued on single interferograms on the previously identified point targets. With a series of interferograms with large baselines we could analyze the displacements along parts of the funicular during 1999 and 2000.
BibTeX:
@conference{Strozzi2005743,
  author = {Strozzi, T. and Keusen, H.R. and Graf, K. and Wiesmann, A. and Wegmüller, U. and Werner, C.},
  title = {Analysis of the displacement along a funicular with large baseline interferograms on point targets},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2005},
  number = {572},
  pages = {743-748},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-23844446441&partnerID=40&md5=08668b8561af24c6cae7021fa14328e2}
}
Strozzi T, Werner C, Wegmüller U and Wiesmann A (2005), "Monitoring land subsidence in Mexico city with ENVISAT ASAR interferometry", In European Space Agency, (Special Publication) ESA SP. (572), pp. 935-939.
Abstract: Mexico City is built on highly compressible clays and because of strong groundwater extraction a total subsidence of more than nine meters has been observed over the last century. Previous studies using ERS and JERS SAR differential interferometry between 1994 and 1996 showed a maximum subsidence rate larger than 40 cm/year over part of the city. Between November 2002 and January 2004 ENVISAT ASAR acquired 10 scenes in IS2 mode over Mexico City. These regular interferometric ASAR acquisitions were used to assess recent subsidence rates at Mexico City. The results demonstrate that ENVISAT ASAR interferograms are of excellent quality for land subsidence studies and that land subsidence in Mexico City is continuing at an impressive rate of several decimeters per year.
BibTeX:
@conference{Strozzi2005935,
  author = {Strozzi, T. and Werner, C. and Wegmüller, U. and Wiesmann, A.},
  title = {Monitoring land subsidence in Mexico city with ENVISAT ASAR interferometry},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2005},
  number = {572},
  pages = {935-939},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-23844483857&partnerID=40&md5=2bc2c1ffac417e990021dcf9194ef9a8}
}
Tampellim L, Eikvil L, Maines E, Ober G, Power D, Strozzi T, Vescovi F and Vincent P (2005), "EO-HYDRO: Earth Observation data for the hydropower plant management", In Proceedings, 31st International Symposium on Remote Sensing of Environment, ISRSE 2005: Global Monitoring for Sustainability and Security.
Abstract: The results presented in this paper were obtained in the framework of EO-HYDRO, a user oriented service which provides hydro power companies with Earth Observation products. Its main focus is the water management and the security of the dams. The results here presented are derived from the application of image processing methods aiming at mapping the snow cover and the snow water equivalent (SWE). The snow cover maps are generated for Norway and the Alps. The used algorithms integrate data from different optical (MODIS, AATSR, MERIS, DXONOS) and radar (ASAR) sensors. Information derived from DEM, vegetation cover and a cloud mask are also added. The SWE maps are generated from RADARSAT and ENVISAT ASAR data. Snow density and land cover data are needed in input as well. A software has been developed (EQeau) for the purpose. Methods and results are accurately discussed.
BibTeX:
@conference{Tampellim2005,
  author = {Tampellim, L. and Eikvil, L. and Maines, E. and Ober, G. and Power, D. and Strozzi, T. and Vescovi, F.D. and Vincent, P.},
  title = {EO-HYDRO: Earth Observation data for the hydropower plant management},
  booktitle = {Proceedings, 31st International Symposium on Remote Sensing of Environment, ISRSE 2005: Global Monitoring for Sustainability and Security},
  year = {2005},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85081785344&partnerID=40&md5=b2cfabd76cfe8cdc818a63b07e2a6d70}
}
Teatini P, Tosi L, Strozzi T, Carbognin L, Wegmüller U and Rizzetto F (2005), "Mapping regional land displacements in the Venice coastland by an integrated monitoring system", Remote Sensing of Environment. Vol. 98(4), pp. 403-413.
Abstract: An original integrated monitoring method is designed to infer an accurate and reliable figure of regional land displacements in coastal areas where the presence of internal waters, wetlands, farmlands, urban and industrial centers usually reduces the efficiency of single ground-based and satellite-based measuring techniques. Five different methods, i.e. spirit leveling, Differential Global Positioning System (DGPS), Continuous GPS (CGPS), Interferometric Synthetic Aperture Radar (InSAR), and Interferometric Point Target Analysis (IPTA), are integrated into a Subsidence Integrated Monitoring System (SIMS) to overcome the limits characterizing each technique. The SIMS has been used over the past decade to provide a new image of the land displacements in the Venice region. The result exhibits a resolution never obtained before. The central lagoon, including the city of Venice, shows a general stability while the northern and southern lagoon extremities and their related catchment sectors sink with serious rates averaging 3 to 5 mm/year. The sinking rates increase up to 10-15 mm/year in the coastland south of the lagoon. Relatively small uplifts (less than 1 mm/year) are observed at the Alpine foothills and in a wide area comprised between the Euganean Hills and the lagoon. The observed land displacements have been associated to the geological features of the study region, i.e. tectonics, seismicity, differential consolidation of the middle-upper Pleistocene and Holocene deposits, and to anthropogenic activities, such as land reclamation and groundwater withdrawal. 2005 Elsevier Inc. All rights reserved.
BibTeX:
@article{Teatini2005403,
  author = {Teatini, P. and Tosi, L. and Strozzi, T. and Carbognin, L. and Wegmüller, U. and Rizzetto, F.},
  title = {Mapping regional land displacements in the Venice coastland by an integrated monitoring system},
  journal = {Remote Sensing of Environment},
  year = {2005},
  volume = {98},
  number = {4},
  pages = {403-413},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-26944496047&doi=10.1016%2fj.rse.2005.08.002&partnerID=40&md5=8fdc7f45d05ce8979b3e8d7a24cfed63},
  doi = {10.1016/j.rse.2005.08.002}
}
Wegmüller U, Spreckels V, Werner C, Strozzi T and Wiesmann A (2005), "Monitoring of mining induced surface deformation using L-band SAR interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 2165-2168.
Abstract: In the mining context there is a specific interest in monitoring temporally non-uniform high deformation rates with high spatial gradients. In recent years land surface deformation monitoring with SAR data reached some maturity. Mainly C-band SAR data were used. Nevertheless, there remain important limitations to the availability of the interferometry based deformation information. Reasons include incomplete spatial coverage with information gaps for low coherence areas, problems in resolving high deformation gradients, and problems in resolving temporally non-uniform deformation. The objective of our contribution is to demonstrate that these limitations are significantly reduced at L-band. In vegetated areas and for fast deformations a good applicability of L-band INSAR was found. 2005 IEEE.
BibTeX:
@conference{Wegmuller20052165,
  author = {Wegmüller, U. and Spreckels, V. and Werner, C. and Strozzi, T. and Wiesmann, A.},
  title = {Monitoring of mining induced surface deformation using L-band SAR interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2005},
  volume = {3},
  pages = {2165-2168},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745698944&doi=10.1109%2fIGARSS.2005.1526447&partnerID=40&md5=40ae161a23f2a8c26abc81756941885a},
  doi = {10.1109/IGARSS.2005.1526447}
}
Wegmüller U, Werner C and Cordey R (2005), "Flashing fields! a preliminary investigation", In European Space Agency, (Special Publication) ESA SP. (572), pp. 301-306.
Abstract: Large localized discrepancies are observed between measurements made by ASAR and by the ERS-2 AMI, within 30 minutes of each other over Flevoland, NL. The discrepancies appear to be related to fine details of the observing geometries of the two instruments, specifically the relative Doppler centroids of the two instruments. There is little awareness of such sensitivity and it is not predicted by the models for microwave interaction usually applied to soils and vegetation. The objective of the present investigation is to improve understanding of the phenomenon and examine strategies to mitigate its effects.
BibTeX:
@conference{Wegmuller2005301,
  author = {Wegmüller, U. and Werner, C. and Cordey, R.},
  title = {Flashing fields! a preliminary investigation},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2005},
  number = {572},
  pages = {301-306},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-23844529913&partnerID=40&md5=83619fb09b50165fb4cb1b2a1bf625f7}
}
Wegmüller U, Werner C, Petrat L, Strozzi T, Wiesmann A and Benecke N (2005), ""EOMD Mining project - Improvements to the EO service part"", In European Space Agency, (Special Publication) ESA SP. (572), pp. 705-710.
Abstract: This paper introduces the project "EOMD Mining: EO Services Market Development for the Mining Sector", an Earth Observation Market Development (EOMD) activity within the framework of the ESA EOEP Market Development Element. High-level objectives of the project include the definition and implementation of a marketable integrated service for the mining market which includes satellite SAR based land surface deformation monitoring as a key element and to achieve market awareness and acceptance for this EO based integrated service. The main focus of this paper is on the EO service side where recent developments are addressed to improve the availability of the INSAR based deformation information.
BibTeX:
@conference{Wegmuller2005705,
  author = {Wegmüller, U. and Werner, C. and Petrat, L. and Strozzi, T. and Wiesmann, A. and Benecke, N.},
  title = {"EOMD Mining project - Improvements to the EO service part"},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2005},
  number = {572},
  pages = {705-710},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-23844478567&partnerID=40&md5=0aaf59a62390299a2b9a5291799eeefb}
}
Werner C, Wegmüller U, Strozzi T and Wiesmann A (2005), "Precision estimation of local offsets between pairs of SAR SLCs and detected SAR images", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 7, pp. 4803-4805.
Abstract: Measurement of the offsets between SAR images is required for SAR applications including multi-temporal studies, change detection, radargrammetry (stereo), interferometry, and surface deformation. Offsets between SAR images are measured in slant range and azimuth (along-track) directions. Applications requiring offset information can be classed into those that require only a global offset function and those, such as radar stereo and deformation mapping that require localized individual measurements. This paper describes our investigation to improve the accuracy of single measurements. The offset estimation algorithm is described. Over-sampling of the Single-Look Complex (SLC) data prior to estimating the offsets improves accuracy substantially. Estimates of the offset errors including offset dependent bias are evaluated using data from ERS. 2005 IEEE.
BibTeX:
@conference{Werner20054803,
  author = {Werner, C. and Wegmüller, U. and Strozzi, T. and Wiesmann, A.},
  title = {Precision estimation of local offsets between pairs of SAR SLCs and detected SAR images},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2005},
  volume = {7},
  pages = {4803-4805},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745700223&doi=10.1109%2fIGARSS.2005.1526747&partnerID=40&md5=d9e7a4fe6e84e07ecadcc4c0336e910f},
  doi = {10.1109/IGARSS.2005.1526747}
}
Wiesmann A, Wegmüller U, Toan T, Santoro M, Werner C and Strozzi T (2005), "Use of ENVISAT ASAR wide-swath mode data over Siberia for large area land cover mapping, parameter retrieval, and change detection", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 3595-3598.
Abstract: Multi-temporal, multi-incidence ASAR WSM data over Siberia were used to derive land cover information. In an initial step several hundred ASAR WSM scenes were integrated into a database. Then the backscattering characteristics (signatures) of different land cover types were investigated. Based on the results, methodologies to retrieve land cover classes, including different forest biomass classes, were developed and applied. Parameters considered include a temporal backscattering variability parameter and an incidence angle dependence parameter. 2005 IEEE.
BibTeX:
@conference{Wiesmann20053595,
  author = {Wiesmann, A. and Wegmüller, U. and Toan, T.L. and Santoro, M. and Werner, C. and Strozzi, T.},
  title = {Use of ENVISAT ASAR wide-swath mode data over Siberia for large area land cover mapping, parameter retrieval, and change detection},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2005},
  volume = {5},
  pages = {3595-3598},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745712401&doi=10.1109%2fIGARSS.2005.1526625&partnerID=40&md5=d8ed24eefdf83c7c974b14ca545b666e},
  doi = {10.1109/IGARSS.2005.1526625}
}
Belitz K, Corsini A, Mair V, Strozzi T, Wegmüller U and Zilger J (2004), "Support of satellite radar to hazard zone mapping in the Italian Alps", In European Space Agency, (Special Publication) ESA SP. (550), pp. 29-34.
Abstract: Living in areas of highly active natural processes as the alpine environment demands the careful assessment of natural hazards and their provision in regional and local development planning processes, providing the chance to substantially reduce damage and loss of property and lives. Consequently techniques for the corresponding tasks of mapping and monitoring natural hazards are subject of ongoing challenging research in this region. Earth observation data and methodology have proven to be able to provide mapping of the spatial distribution of different environmental parameters but are still rarely included in operational administrative and planning processes of hazard management. The presented study focussed on the potential integration of Differential SAR Interferometry techniques into current tasks of landslide hazard management in the Italian Alps including test-cases in the Province of Bolzano-South Tyrol. A close cooperation with the responsible Geologic Service was established for detailed regarding of the specific user requirements. Limitations and obstacles of the potential support from earth observation techniques were considered carefully and the path of integration of products and services into the users processing chain was analysed in detail under operational aspects and demonstrated.
BibTeX:
@conference{Belitz200429,
  author = {Belitz, K. and Corsini, A. and Mair, V. and Strozzi, T. and Wegmüller, U. and Zilger, J.},
  editor = {Lacoste H.},
  title = {Support of satellite radar to hazard zone mapping in the Italian Alps},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2004},
  number = {550},
  pages = {29-34},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18644366965&partnerID=40&md5=8d0109c5d378c44c6903c1b5e3b503ee}
}
Bruzzone L, Marconcini M, Wegmüller U and Wiesmann A (2004), "An advanced system for the automatic classification of multitemporal SAR images", IEEE Transactions on Geoscience and Remote Sensing. Vol. 42(6), pp. 1321-1334.
Abstract: A novel system for the classification of multitemporal synthetic aperture radar (SAR) images is presented. It has been developed by integrating an analysis of the niultitemporal SAR signal physics with a pattern recognition approach. The system is made up of a feature-extraction module and a neural-network classifier, as well as a set of standard preprocessing procedures. The feature-extraction module derives a set of features from a series of multitemporal SAR images. These features are based on the concepts of long-term coherence and backscattering temporal variability and have been defined according to an analysis of the multitemporal SAR signal behavior in the presence of different land-cover classes. The neural-network classifier (which is based on a radial basis function neural architecture) properly exploits the multitemporal features for producing accurate land-cover maps. Thanks to the effectiveness of the extracted features, the number of measures that can be provided as input to the classifier is significantly smaller than the number of available niultitemporal images. This reduces the complexity of the neural architecture (and consequently increases the generalization capabilities of the classifier) and relaxes the requirements relating to the number of training patterns to be used for classifier learning. Experimental results (obtained on a multitemporal series of European Remote Sensing 1 satellite SAR images) confirm the effectiveness of the proposed system, which exhibits both high classification accuracy and good stability versus parameter settings. These results also point out that properly integrating a pattern recognition procedure (based on machine learning) with an accurate feature extraction phase (based on the SAR sensor physics understanding) represents an effective approach to SAR data analysis.
BibTeX:
@article{Bruzzone20041321,
  author = {Bruzzone, L. and Marconcini, M. and Wegmüller, U. and Wiesmann, A.},
  title = {An advanced system for the automatic classification of multitemporal SAR images},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2004},
  volume = {42},
  number = {6},
  pages = {1321-1334},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-3042559631&doi=10.1109%2fTGRS.2004.826821&partnerID=40&md5=9139460038bd17f83b7131ca594ae7eb},
  doi = {10.1109/TGRS.2004.826821}
}
Del Frate F, Ferrazzoli P, Guerriero L, Strozzi T, Wegmüller U, Cookmartin G and Quegan S (2004), "Wheat cycle monitoring using radar data and a neural network trained by a model", IEEE Transactions on Geoscience and Remote Sensing. Vol. 42(1), pp. 35-44.
Abstract: This paper describes an algorithm aimed at monitoring the soil moisture and the growth cycle of wheat fields using radar data. The algorithm is based on neural networks trained by model simulations and multitemporal ground data measured on fields taken as a reference. The backscatter of wheat canopies is modeled by a discrete approach, based on the radiative transfer theory and including multiple scattering effects. European Remote Sensing satellite synthetic aperture radar signatures and detailed ground truth, collected over wheat fields at the Great Driffield (U.K.) site, are used to test the model and train the networks. Multitemporal, multifrequency data collected by the Radiometer-Scatterometer (RASAM) instrument at the Central Plain site are used to test the retrieval algorithm.
BibTeX:
@article{DelFrate200435,
  author = {Del Frate, F. and Ferrazzoli, P. and Guerriero, L. and Strozzi, T. and Wegmüller, U. and Cookmartin, G. and Quegan, S.},
  title = {Wheat cycle monitoring using radar data and a neural network trained by a model},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2004},
  volume = {42},
  number = {1},
  pages = {35-44},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-1242286443&doi=10.1109%2fTGRS.2003.817200&partnerID=40&md5=82193bc6e83fb4f57268d29b113f7708},
  doi = {10.1109/TGRS.2003.817200}
}
Eriksson L, Toan T, Wiesmann A, Grippa M, Wegmüller U and Schmullius C (2004), "SAR repeat-pass coherence in winter for boreal forest applications. A first comparison between ASAR and JERS-1 SAR", In European Space Agency, (Special Publication) ESA SP. (550), pp. 205-210.
Abstract: This paper presents the first comparison between repeat-pass coherence from AS AR and JERS-1 SAR. To reduce the influence of temporal decorrelation, repeat-pass pairs acquired during the winter season have been selected. ASAR 35-day coherence and JERS-1 44-day coherence from six different test areas in Siberia and northern Europe have been evaluated. The results indicate that the decorrelation is more severe for ASAR coherence than for coherence from JERS-1. Only one of the five studied ASAR pairs shows coherence levels that are high enough to contain information that can be useful for forest applications. More ASAR pairs will be acquired during the current winter season. For most of the included JERS-1 pairs, the coherence is high enough to provide useful forest information. An example of growing stock volume estimation from one of the test areas shows a potential application.
BibTeX:
@conference{Eriksson2004205,
  author = {Eriksson, L. and Toan, T.L. and Wiesmann, A. and Grippa, M. and Wegmüller, U. and Schmullius, C.},
  editor = {Lacoste H.},
  title = {SAR repeat-pass coherence in winter for boreal forest applications. A first comparison between ASAR and JERS-1 SAR},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2004},
  number = {550},
  pages = {205-210},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18644372262&partnerID=40&md5=8c14f39020697d14fe3117f4d5d33f4c}
}
Frey O, Meier E, Nüesch D and Roth A (2004), "Geometric Error Budget Analysis for TerraSAR-X", In Proc. EUSAR 2004 - 5th European Conference on Synthetic Aperture Radar. Ulm, Germany, May, 2004. , pp. 513-516.
Abstract: The impact of potential error sources on geocoded products has been investigated with respect to the high resolution capabilities of the TerraSAR-X sensor. Datum shift parameters, maps, digital terrain and surface models have been identified as external error sources. The accuracy of the geocoded products depends heavily on the quality and availability of this information, which underlies regional variations. Error sources closely related to the sensor are its position, sampling window start time and Doppler centroid frequency. Another error source is given by atmospheric refraction. Ionospheric and atmospheric path delays have a considerable impact. Appropriate modeling can mitigate this effect. Further, high requirements on radiometric accuracy ask for an improved antenna gain pattern correction, which depends on the actual elevation angle and the terrain height.
BibTeX:
@inproceedings{freyMeierNueeschRoth04:ErrorBudget,
  author = {Othmar Frey and Erich Meier and Daniel Nüesch and Achim Roth},
  title = {Geometric Error Budget Analysis for TerraSAR-X},
  booktitle = {Proc. EUSAR 2004 - 5th European Conference on Synthetic Aperture Radar},
  year = {2004},
  pages = {513-516}
}
Guerova G, Bettems J-M, Brockmann E and Matzler C (2004), "Assimilation of the GPS-derived integrated water vapour (IWV) in the MeteoSwiss numerical weather prediction model-a first experiment", Physics and Chemistry of the Earth. Vol. 29(2-3), pp. 177-186.
Abstract: A high resolution (7 km) limited area model called aLpine model (aLMo) is used for operational numerical weather prediction (NWP) at MeteoSwiss. A continuous data assimilation scheme based on the nudging technique produces the initial conditions for the forecast. Since November 2001 all standard meteorological observations have been routinely assimilated. The goal of this study is to evaluate the benefit of introducing GPS-derived integrated water vapour (IWV) in this scheme. In this first observing system experiment, data provided for COST action 716 "Exploitation of ground based GPS for climate and numerical weather prediction application" are used. A two week period in mid September 2001 was selected, characterized by an advective weather regime and intense precipitation events. On average observations from 80 European GPS sites are assimilated by the model. Results presented here are based on the aLMo assimilation cycle only, the impact on the forecast has not been evaluated. This experiment shows a tendency for GPS data to increase the model IWV amounts in the day-time, and shows a substantial impact of GPS in the southern part of the model domain. The negative bias of the model IWV daily cycle is mainly corrected by assimilating GPS data. An improvement of the daily precipitation cycle over Switzerland for the grid points below 800 m is also observed in the GPS run. The bias precipitation score confirms the better model performance when the GPS data are assimilated. This experiment has also revealed a weakness in the way the IWV is assimilated. In presence of highly inhomogeneous humidity fields an isotropic influence of the IWV increments can be detrimental. The first GPS assimilation results are considered encouraging but need to be consolidated. New assimilation experiments will be performed to investigate the GPS data impact for different weather regimes. 2004 Elsevier Ltd. All rights reserved.
BibTeX:
@article{Guerova2004177,
  author = {Guerova, G. and Bettems, J.-M. and Brockmann, E. and Matzler, Ch.},
  title = {Assimilation of the GPS-derived integrated water vapour (IWV) in the MeteoSwiss numerical weather prediction model-a first experiment},
  journal = {Physics and Chemistry of the Earth},
  year = {2004},
  volume = {29},
  number = {2-3},
  pages = {177-186},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-1842784704&doi=10.1016%2fj.pce.2004.01.009&partnerID=40&md5=67834ef818715457641fdad17e3d7860},
  doi = {10.1016/j.pce.2004.01.009}
}
Haefele P, Martin L, Becker M, Brockmann E, Morland J, Nyeki S, Matzler C and Kirchner M (2004), "Impact of radiometrie water vapor measurements on troposphere and height estimates by GPS", In Proceedings of the 17th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS 2004. , pp. 2289-2302.
Abstract: The Measurement of Alpine Tropospheric Delay by Radiometers And GPS (MATRAG) project was designed to study the limits of precise GPS height determination and to answer the question of how radiometric water vapor measurements can contribute to this and to the GPS estimation of tropospheric delays. The measurements with Water Vapor Radiometers (WVR) and GPS were conducted at dedicated stations in Central Switzerland in September 2003. In this paper we will first concentrate on the technique of radiometry itself with the goal of assessing the calibration and stability of different types of WVRs. Results of simultaneous measurements of several instruments were used to determine the accuracy of state-of-the-art devices. They are consistent at the 1.2 kg/m 2 level with an uncertainty of ± 0.5 kg/m 2. The validation of GPS-derived tropospheric estimates -namely the zenith total delays - by WVR is presented in the second part of this paper, where we find a mean difference between GPS and WVR results of about 4.5 ± 5.3 mm. The last part of the paper focuses on the analysis of two particular baselines within the triangle Zimmerwald, Bern and Jungfraujoch. This triangle with height differences of about 3,000 m and short baselines of 10 and 50 km was observed simultaneously by WVR and GPS. The analysis of these baselines was accomplished with various strategies and different levels of a-priori information for the GPS estimation, i.e. introduction of meteorological observations and / or WVR wet delays. Resulting biases in estimated station heights of up to 2 cm are studied as well as station height repeatabilities of 3 to 5 mm and estimated tropospheric delays. The observed biases are mainly introduced by the WVRs, whereas the elevation cut-off dependent height offsets are caused by commonly known GPS error sources such as Multipath and antenna phase center variations.
BibTeX:
@conference{Haefele20042289,
  author = {Haefele, P. and Martin, L. and Becker, M. and Brockmann, E. and Morland, J. and Nyeki, S. and Matzler, C. and Kirchner, M.},
  title = {Impact of radiometrie water vapor measurements on troposphere and height estimates by GPS},
  booktitle = {Proceedings of the 17th International Technical Meeting of the Satellite Division of the Institute of Navigation, ION GNSS 2004},
  year = {2004},
  pages = {2289-2302},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-22144491924&partnerID=40&md5=d43b4f43597a1afffe3023e79d87c852}
}
Jehle M, Frey O, Small D, Meier E and Nüesch D (2004), "Improved Knowledge of SAR Geometry through Atmospheric Modelling", In Proc. EUSAR 2004 - 5th European Conference on Synthetic Aperture Radar. Ulm, Germany, May, 2004. , pp. 909-911.
Abstract: Satellites observing and measuring the Earth s surface with electromagnetic waves are subject to atmospheric path delays. These atmospheric effects on radar signal propagation modify the signal velocity and direction and can be considered by simple modeling. In order to increase the geolocation accuracy of spaceborne SAR applications we developed a software tool that accounts for atmospheric path delays. Well-calibrated spaceborne ENVISAT-ASAR data are used to investigate improvements to knowledge of the geometry of the scene.
BibTeX:
@inproceedings{jehleFreySmallMeierNueesch04:Atmosphere,
  author = {Michael Jehle and Othmar Frey and David Small and Erich Meier and Daniel Nüesch},
  title = {Improved Knowledge of SAR Geometry through Atmospheric Modelling},
  booktitle = {Proc. EUSAR 2004 - 5th European Conference on Synthetic Aperture Radar},
  year = {2004},
  pages = {909-911}
}
Manunta P, Brugioni M, Casagli N, Colombo D, Deflorio A, Farina P, Ferretti A, Gontier E, Graf K, Haeberle J, Lateltin O, Meloni E, Mayoraz R, Montini G, Moretti S, Paganini M, Palazzo F, Spina D, Sulli L and Strozzi T (2004), "SLAM, a service for landslide monitoring based on EO-data", In European Space Agency, (Special Publication) ESA SP. (550), pp. 451-456.
Abstract: Every year slope instabilities cause large socio-economic losses on life and property worldwide. Indeed, the casualties caused by mass movements are among the highest in the industrialized world. In this contest the SLAM project is aimed to the implementation of landslides mapping and monitoring service that can be integrated into the current landslide management procedures. The innovative aspect of the SLAM project is the integration of the SAR techniques and EO data with the in situ documentation currently in use for the landslide monitoring. In particular, SLAM is designed to realise three types of products: Landslide Motion Survey, Landslide Displacement Monitoring and Landslide Susceptibility Mapping. The realization of SLAM project, entirely funded by ESA, is carried out by an international Consortium led by Planetek Italia (I) and formed by other five partners: Tele-Rilevamento Europa (I), Gamma Remote Sensing (CH), Spacebel (B), Geotest (CH) and Earth Science Department of the University of Firenze (I). For the Italian service cases the interferometric analysis is based on the PS technique, developed and patented by the Politecnico di Milano (Italy) and improved by Tele-Rilevamento Europa. For the Swiss service cases, multi-pass SAR interferometry, including the Interferometric Point Target Analysis (IPTA), is applied by Gamma Remote Sensing.
BibTeX:
@conference{Manunta2004451,
  author = {Manunta, P. and Brugioni, M. and Casagli, N. and Colombo, D. and Deflorio, A.M. and Farina, P. and Ferretti, A. and Gontier, E. and Graf, K. and Haeberle, J. and Lateltin, O. and Meloni, E. and Mayoraz, R. and Montini, G. and Moretti, S. and Paganini, M. and Palazzo, F. and Spina, D. and Sulli, L. and Strozzi, T.},
  editor = {Lacoste H.},
  title = {SLAM, a service for landslide monitoring based on EO-data},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2004},
  number = {550},
  pages = {451-456},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-20844452225&partnerID=40&md5=2cbc2c10bf922dee250cf0594ffb332c}
}
Rabus B, Werner C, Wegmüller U and McCardle A (2004), "Interferometric point target analysis of RADARSAT-1 data for deformation monitoring at the Belridge/Lost Hills oil fields", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 2611-2613.
Abstract: Interferometric Point Target Analysis using Gamma Remote Sensing's IPTA module has been applied to two interferometric stacks of RADARSAT-1 FINE mode data over the Belridge/Lost Hills oil fields in California. The stacks (∼30 images each) are both from descending orbits and span the same 2 year time period (2002/02 - 2004/02) but incidence angles are different (F1 vs. F3F). An IPTA analysis is carried out on each stack separately and results are then compared in terms of achieved density of the scatterers and residual errors of the motion analysis. We verify the accuracy of our methods indirectly by studying the subtle difference in line-of-sight motion caused by the different incidence angles of the data stacks (38.4 vs. 43.1 degrees at the study site).
BibTeX:
@conference{Rabus20042611,
  author = {Rabus, B. and Werner, C. and Wegmüller, U. and McCardle, A.},
  title = {Interferometric point target analysis of RADARSAT-1 data for deformation monitoring at the Belridge/Lost Hills oil fields},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2004},
  volume = {4},
  pages = {2611-2613},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-15944364394&partnerID=40&md5=ace41ce69d62c991912a15096479808e}
}
Santoro M, Askne J and Dammert P (2004), "Tree height estimation from multi-temporal ERS SAR interferometric phase", In European Space Agency, (Special Publication) ESA SP. (550), pp. 193-198.
Abstract: Multi-temporal sets of ERS-1/2 SAR interferometric (InSAR) phase have been evaluated at several test sites in Europe for tree height estimation. Atmospheric artefacts affected a large number of image pairs. These were generally well compensated in case of large-scale artefacts over small forests, whereas for large forests their effect could only be assessed. Hence, the amount of pairs utilizable for further investigation considerably decreased. The interferometric tree height, i.e. the forest "topography" seen by an InSAR system, did not show temporal consistency because of the target phase noise, ranging from slightly below the ground level to slightly above the true tree height. With a multi-temporal combination, the estimates were below the true tree height, depending on the canopy closure. To retrieve the total true height from InSAR tree height measurements, the Interferometric Water Cloud Model was used. Modelled InSAR tree heights resulted generally in reasonable agreement with observations. Nevertheless, because of the strong noise components and the weak contrast between ground and vegetation coherence, the compensated tree height showed an almost constant value, independent of the true height. Hence, the several sources of error and uncertainty strongly limit the usefulness of C-band repeat-pass SAR interferometry for tree height estimation.
BibTeX:
@conference{Santoro2004193,
  author = {Santoro, M. and Askne, J. and Dammert, P.B.G.},
  editor = {Lacoste H.},
  title = {Tree height estimation from multi-temporal ERS SAR interferometric phase},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2004},
  number = {550},
  pages = {193-198},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18644386299&partnerID=40&md5=9ca3d71387d0ccec20a30cd63cd441fa}
}
Santoro M and Schmullius C (2004), "Investigations on ARD monitoring in Siberian forest using spaceborne SAR", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 1029-1032.
Abstract: Nation-wide monitoring of afforestation, reforestation and deforestation (ARD) activities is explicitly addressed in the Kyoto Protocol. This paper investigates the feasibility of ARD mapping using spaceborne synthetic aperture radar (SAR) and interferometric SAR (InSAR) data from the European Remote Sensing (ERS) satellite, the ENVISAT satellite and the Japanese Earth Resources Satellite (JERS). As test site the forest enterprise of Bolshe-Murtinsky, Central Siberia, was chosen since relatively long time series of ERS-ENVISAT and JERS SAR data were available spanning 1996-2004 and 1994-1997 respectively. The ERS-2 SAR and ASAR Image Mode (IM) backscatter acquired during winter under frozen conditions decreased by 1-2 dB following stand-wise logging, whereas reforestation in young stands could not be detected. The JERS SAR backscatter commonly showed stronger forest/non-forest contrast, between 2 and 4 dB depending on the weather conditions at image acquisition, whereas the repeat-pass JERS coherence was characterized by a 0.3-0.4 difference before and after deforestation activities. None of these two signatures was found to provide information on reforestation, mainly because of the too short time series with respect to the forest growth rate. To assess the possibility of using ERS-ENVISAT- and JERS-type of data for reforestation, a first-order approach has been developed. Preliminary results show that young stands can be distinguished from non-forested areas not earlier than approximately 25 years using JERS repeat-pass coherence and 30 years using ERS-ENVISAT SAR backscatter.
BibTeX:
@conference{Santoro20041029,
  author = {Santoro, M. and Schmullius, C.},
  title = {Investigations on ARD monitoring in Siberian forest using spaceborne SAR},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2004},
  volume = {2},
  pages = {1029-1032},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-15944385685&partnerID=40&md5=52c807c5c50e5822fb5d1159c1132ff0}
}
Santoro M, Schmullius C, Askne J and Eriksson L (2004), "Evaluation of JERS-1 L-band SAR backscatter for stem volume retrieval in boreal forest", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. 515-518.
Abstract: To assess the possibility of using L-band synthetic aperture radar (SAR) backscatter for forest stem volume mapping in the boreal zone, a comparative analysis was carried out at test sites located in Sweden, Finland and Central Siberia from which an extensive set of Japanese Earth Resources Satellite (JERS-1) images and ground data was available. The backscatter showed clear seasonal dynamics, increasing by 3-4 dB in dense forests and 1-2 dB in sparse forests when going from frozen to unfrozen conditions. To retrieve stem volume a simple L-band Water Cloud-related scattering model was used. Model training performed well in all cases, the model parameters estimates being affected by weather conditions at acquisition and test site-specific forest stand structure. At each test site the retrieval performed best under unfrozen conditions and worst under frozen conditions. The highest retrieval accuracy was achieved at the small and intensively managed test site of Kattbole in Sweden with a 25% relative RMS error. For the other test sites the much larger retrieval error could be explained as a consequence of heterogeneities in the forest stand structure, as well as differences in the ground dielectric properties and inaccuracy in the ground data.
BibTeX:
@conference{Santoro2004515,
  author = {Santoro, M. and Schmullius, C. and Askne, J. and Eriksson, L.},
  title = {Evaluation of JERS-1 L-band SAR backscatter for stem volume retrieval in boreal forest},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2004},
  volume = {1},
  pages = {515-518},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-15944376235&partnerID=40&md5=608ce878d1744ccf5fc53c9aad82d4fe}
}
Schneeberger K, Schwank M, Stamm C, de Rosnay P, Matzler C and Fluhler H (2004), "Topsoil structure influencing soil water retrieval by microwave radiometry", Vadose Zone Journal. Vol. 3(4), pp. 1169-1179. Soil Science Society of America.
Abstract: Many remote sensing applications, including those of future space missions, require accurate knowledge of the influence of topsoil structure on the water content as measured using L-band radiometry. We report on field-measured L-band (1.4 GHz) microwave emission from a bare soil. Of special interest in this work is the procedure used to transform remotely sensed data to soil water content and its comparability with time domain reflectometer (TDR) in situ measurements. Surface roughness of the soil was characterized on a millimeter scale using an optical measurement technique. Different models for interpreting the microwave signals in terms of the water content were investigated. The agreement between in situ water contents and surface water contents estimated with radiometry data using the Fresnel equation was found to be poor. A coherent layer model, with and without considering roughness effects, was tested to compare radiometrically measured and modeled soil reflectivities. The correspondence remained unsatisfactory, even when we considered a dielectric gradient fitted to the TDR profiles and surface roughness represented by a scattering model. We developed a new air-to-soil transition model, which includes dielectric mixing effects due to small-scale surface structures. This model considerably improved agreement between measured and modeled results. We conclude that small-scale structures of the topsoil cannot be neglected in interpreting L-band measurements. Soil Science Society of America.
BibTeX:
@article{Schneeberger20041169,
  author = {Schneeberger, K. and Schwank, M. and Stamm, C. and de Rosnay, P. and Matzler, C. and Fluhler, H.},
  title = {Topsoil structure influencing soil water retrieval by microwave radiometry},
  journal = {Vadose Zone Journal},
  publisher = {Soil Science Society of America},
  year = {2004},
  volume = {3},
  number = {4},
  pages = {1169-1179},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18844392970&doi=10.2113%2f3.4.1169&partnerID=40&md5=4b20b341ed1576b690c7343e8e0a7d2f},
  doi = {10.2113/3.4.1169}
}
Schneeberger K, Stamm C, Matzler C and Fluhler H (2004), "Ground-based dual-frequency radiometry of bare soil at high temporal resolution", IEEE Transactions on Geoscience and Remote Sensing. Vol. 42(3), pp. 588-595.
Abstract: We report on an experiment linking microwave brightness temperatures and emissivities to the dynamics of in situ measured water content. The bare plot of 14 × 20 m was instrumented with two ground-based radiometers (1.4 and 11.4 GHz, respectively) and in situ time domain reflectometer (TDR) and temperature probes installed at five depths in three soil profiles. All data were recorded every 30 min from May to July 2002. The measured brightness temperature dynamics is a superposition of three patterns. The largest variations were caused by the changes in water content due to precipitation and the subsequent drying process. During dry periods, we observed daily oscillations of brightness temperature. Calculating effective soil temperatures based on the in situ measured temperature profiles revealed that these oscillations were partially due to changes in water content in the very topsoil. This effect was especially pronounced for the 11.4-GHz measurements, indicating that the very surface experienced the strongest changes in water content. At 1.4 GHz and horizontal polarization, the brightness temperature measurements turned out to be very sensitive to sun reflection at the ground. This reflection was visible through exceptionally high brightness temperature values at distinct times of the day. We observed pronounced hysteresis loops when comparing the emissivities of the two radiometers or the radiometric signals with the water content measured in situ at 2-cm depth. Such loops could be seen for the daily wetting and drying cycles as well as in the longer term drying and wetting behavior. This demonstrates that the gradient of the water content in the topsoil is a dynamic property depending on various time scales. These gradients affected the measurements of radiometers and TDR probes to different degrees and at different times. Despite an almost smooth surface, slight changes in the surface structure during the experiment caused a substantial variability with respect to the relationships between water content and emissivity for both radiometers. This is an indication that surface structures smaller than the wavelength may exert important effects on the emissivity of a bare soil.
BibTeX:
@article{Schneeberger2004588,
  author = {Schneeberger, K. and Stamm, C. and Matzler, C. and Fluhler, H.},
  title = {Ground-based dual-frequency radiometry of bare soil at high temporal resolution},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2004},
  volume = {42},
  number = {3},
  pages = {588-595},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-1842586107&doi=10.1109%2fTGRS.2003.821058&partnerID=40&md5=aec51e9414d12d9ee76f2e13bdbaa471},
  doi = {10.1109/TGRS.2003.821058}
}
Schwank M, Stahli M, Wydler H, Leuenberger J, Matzler C and Fluhler H (2004), "Microwave L-band emission of freezing soil", IEEE Transactions on Geoscience and Remote Sensing. Vol. 42(6), pp. 1252-1261.
Abstract: We report on field-measured microwave emission in a period of frost penetration into a grassland soil. The measurements were recorded with a high temporal resolution using an L-band radiometer mounted on a 7-m high tower. The observation period (December 2002 to March 2003) included two cycles of soil freezing and thawing with maximum frost depth of 25 cm. In situ soil temperature and liquid water content were measured at five depths down to 45 cm. Soil moisture profiles were calculated using the COUP numerical soil water and heat model in combination with measured soil properties and meteorological data monitored at the site. The L-band radiation data clearly showed the penetration and thawing of seasonal soil frost. We calculated soil reflectivities based on in situ measured and modeled soil moisture profiles by applying a coherent radiative transfer model. The calculated reflectivities were compared with the radiometrically determined soil reflectivities. It was demonstrated that the quantitative consistency between these reflectivities was significantly improved by applying an impedance matching approach accounting for surface effects. In this particular case, the dielectric structure of the uppermost soil horizon was largely influenced by soil roughness, vegetation, and show cover. The radiometrically measured soil reflectivities were fitted using a radiative transfer model in combination with a roughness model assuming a soil surface roughness of 25 mm. The analysis during a period of frost penetration shows coherent behavior of the soil reflectivity. Temporal oscillation of the measured L-band radiation appears to be a coherent effect. This effect has the potential to be used for estimating the frost penetration velocity.
BibTeX:
@article{Schwank20041252,
  author = {Schwank, M. and Stahli, M. and Wydler, H. and Leuenberger, J. and Matzler, C. and Fluhler, H.},
  title = {Microwave L-band emission of freezing soil},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2004},
  volume = {42},
  number = {6},
  pages = {1252-1261},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-3042652924&doi=10.1109%2fTGRS.2004.825592&partnerID=40&md5=b79c578235524fd9d63ccb3618f5190a},
  doi = {10.1109/TGRS.2004.825592}
}
Strozzi T, Kaab A and Frauenfelder R (2004), "Detecting and quantifying mountain permafrost creep from in situ inventory, space-borne radar interferometry and airborne digital photogrammetry", International Journal of Remote Sensing. Vol. 25(15), pp. 2919-2931. Taylor and Francis Ltd..
Abstract: In this paper three different techniques for detecting and quantifying mountain permafrost creep are compared: (1) rock glacier inventory and characterization from in situ indicators, (2) space-borne radar interferometry, and (3) digital processing of repeated airborne imagery. The specific characteristics of the three methods and their complementarity are investigated for the Fletschhorn mountain range in the Simplon/Saas valley region, Swiss Alps. We found that radar interferometry is suitable to quantify the degree of activity and the order of surface velocity of rock glaciers over large areas in one process, with the possibility to also detect very small movements of inactive and relict rock glaciers. On the other hand, aero-photogrammetry represents a valuable base for additional interpretation of the three-dimensional surface flow field (including speed, direction and change in thickness) of the most active rock glaciers. Results from radar interferometry can also form the basis for further detailed in situ investigations. 2004 Taylor and Francis Ltd.
BibTeX:
@article{Strozzi20042919,
  author = {Strozzi, T. and Kaab, A. and Frauenfelder, R.},
  title = {Detecting and quantifying mountain permafrost creep from in situ inventory, space-borne radar interferometry and airborne digital photogrammetry},
  journal = {International Journal of Remote Sensing},
  publisher = {Taylor and Francis Ltd.},
  year = {2004},
  volume = {25},
  number = {15},
  pages = {2919-2931},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-3242746711&doi=10.1080%2f0143116042000192330&partnerID=40&md5=7d1b273de08e8a5c07307d313988c09f},
  doi = {10.1080/0143116042000192330}
}
Strozzi T, Wegmüller U, Wiesmann A, Kaab A, Frauenfelder R, Werner C, Graf K, Ratzo H and Lateltin O (2004), "Differential interferometric applications in alpine regions", In European Space Agency, (Special Publication) ESA SP. (550), pp. 133-138.
Abstract: The potential and limitations of differential SAR interferometry for the detection and monitoring of unstable high-mountain slopes was investigated. It was observed that the scattering behavior of snow changes significantly with snow moisture and also with the presence of density heterogeneities. A series of differential interferograms, with the topographic related phase removed by use of an external DEM with posting of 25 m, for the Grubengletscher region, Switzerland, was found to illustrate the coherence and viewing geometry issues on a typical alpine area. It was found that summer JERS interferograms with acquisition time intervals of 88 and 1144 days are useful for the identification of displacements in alpine areas.
BibTeX:
@conference{Strozzi2004133,
  author = {Strozzi, T. and Wegmüller, U. and Wiesmann, A. and Kaab, A. and Frauenfelder, R. and Werner, C. and Graf, K. and Ratzo, H. and Lateltin, O.},
  editor = {Lacoste H.},
  title = {Differential interferometric applications in alpine regions},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2004},
  number = {550},
  pages = {133-138},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-18644382870&partnerID=40&md5=86ce563a3e55a7dc5ed8df2e7ae41186}
}
Tampellini M, Brivio P, Carrara P, Fantoni D, Gnocchi S, Ober G, Pepe M, Rampini A, Ratti R, Nodari F and Strozzi T (2004), "Monitoring snow cover in alpine regions through the integration of meris and aatsr envisat satellite observations", In European Space Agency, (Special Publication) ESA SP. (549), pp. 145-150.
Abstract: The ENVISAT mission with a suite of high performance sensors offers some opportunities for mapping snow cover at regional and catchment scale. The geometric resolution of MERIS data and the spectral resolution of AATSR data are suitable for these purposes. A new approach, developed in the framework of the GLASNOWMAP project (ESA-DUP2) for monitoring snow cover in Alpine regions, based on the combined use of MERIS and AATSR observations, and topographic information, is proposed. As MERIS spectral bands are not completely proper for the discrimination of snow from clouds - due to the lack of short wave infrared channels - a multisource classification scheme has been developed to combine the results obtained by the classification of MERIS data with the information on cloud distribution as derived from AATSR data; the integration is performed with the aid of snow elevation distribution as derived from the Digital Elevation Model. A supervised fuzzy statistical classifier (Wang 1990) has been chosen to perform classification of MERIS images, being particularly suited for the representation of land cover class mixture. The classifier bases estimates of the distribution of pixels in multispectral space on the concept of the probability measure of fuzzy events to produce an output of the proportions of individual components. A cloud normalized index has been defined to extract clouds from AATSR images previously registered and resampled on MERIS images. The results of MERIS and AATSR processing are integrated to produce a snow cover map masked over the cloud covered areas, taking into account also the elevation. The Alpine region is selected as test area to demonstrate the potential and limitations of the novel approach. In particular, the attention is focused on three regions of Northern Italy (Valle d'Aosta, Piemonte, Lombardia). The first results obtained by the application of this new method to Earth Observation data will be presented and analysed.
BibTeX:
@conference{Tampellini2004145,
  author = {Tampellini, M.L. and Brivio, P.A. and Carrara, P. and Fantoni, D. and Gnocchi, S. and Ober, G. and Pepe, M. and Rampini, A. and Ratti, R. and Nodari, F.R. and Strozzi, T.},
  title = {Monitoring snow cover in alpine regions through the integration of meris and aatsr envisat satellite observations},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2004},
  number = {549},
  pages = {145-150},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-22144454251&partnerID=40&md5=06057d21d6dc0aa56a56091c71c3fa30}
}
Tansey K, Luckman A, Skinner L, Balzter H, Strozzi T and Wagner W (2004), "Classification of forest volume resources using ERS tandem coherence and JERS backscatter data", International Journal of Remote Sensing. Vol. 25(4), pp. 751-768.
Abstract: Considering recent progress in the development of techniques and methods to achieve biomass estimates and full carbon accounting, remote sensing research of forested ecosystems needs to be aimed towards the retrieval of information at global scales. In this paper, an algorithm for the estimation of growing stock volume, an important parameter for the commercial forest community and a proxy for woody biomass density, from ERS and JERS synthetic aperture radar (SAR) data is described. The algorithm is based on the information content of both ERS tandem coherence and JERS backscatter images and was developed using ground data, made available by the Russian Forestry Services. It is tested on SAR datasets of boreal forests in Siberia, a managed, temperate forest plantation in the United Kingdom and a semi-natural boreal forest at Siggefora in Sweden. Comparisons of the classified products, comprising three growing stock interval classes and one non-forest class are made with ground data. The results of this accuracy assessment exercise show that the algorithm yields, in all cases, overall classification accuracies of greater than 70%. A visual comparison is made of the algorithm performance over a tropical forest region of Brazil. The results indicate that the algorithm has the potential to retrieve growing stock volume estimates in forest ecosystems throughout the globe. 2004 Taylor & Francis Ltd.
BibTeX:
@article{Tansey2004751,
  author = {Tansey, K.J. and Luckman, A.J. and Skinner, L. and Balzter, H. and Strozzi, T. and Wagner, W.},
  title = {Classification of forest volume resources using ERS tandem coherence and JERS backscatter data},
  journal = {International Journal of Remote Sensing},
  year = {2004},
  volume = {25},
  number = {4},
  pages = {751-768},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-1542645976&doi=10.1080%2f0143116031000149970&partnerID=40&md5=52356c0758f7276b13b3ec9f8228bb1f},
  doi = {10.1080/0143116031000149970}
}
Wegmüller U, Werner C, Strozzi T and Wiesmann A (2004), "Monitoring mining induced surface deformation", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1933-1935.
Abstract: There exists a significant demand for the monitoring of mining induced surface deformation for legal obligation, safety, and environmental reasons. In recent years land surface deformation monitoring with SAR data reached some maturity. Nevertheless, there remain important limitations to the availability of the EO based information. Reasons include incomplete spatial coverage with information gaps for low coherence areas, problems in resolving high phase gradients, and unavailability of the required SAR data. The objective of our contribution is to show that important improvements to these limitations are still possible. In vegetated areas and for fast deformations L-band INSAR was found to be more robust with a wider applicability than C-band INSAR. In some low coherence areas point-like scatterers can be identified which permit to fill important information gaps. Furthermore, pairs with long baselines can be included in the interferometric analysis, supporting a more complete use of the available SAR acquisitions and to improve the temporal sampling.
BibTeX:
@conference{Wegmuller20041933,
  author = {Wegmüller, U. and Werner, C. and Strozzi, T. and Wiesmann, A.},
  title = {Monitoring mining induced surface deformation},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2004},
  volume = {3},
  pages = {1933-1935},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-15944407729&partnerID=40&md5=1299e137861cee31da85b6f2b164f55e}
}
Westwater E, Crewell S and Matzler C (2004), "Frontiers in surface-based microwave and millimeter wavelength radiometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 1268-1272.
Abstract: Surface-based radiometric sensing of atmospheric parameters has a long history of providing useful measurements of temperature, water vapor, and cloud liquid. In this Special Tributary Session to Professor Calvin Swift, several contemporary instruments are discussed and representative results are presented. Recent and promising developments include new absorption models, improved retrieval techniques, multi-frequency radiometers, scanning observations of clouds, and combined active-passive remote sensing.
BibTeX:
@conference{Westwater20041268,
  author = {Westwater, Ed.R. and Crewell, S. and Matzler, C.},
  title = {Frontiers in surface-based microwave and millimeter wavelength radiometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2004},
  volume = {2},
  pages = {1268-1272},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-15944374821&partnerID=40&md5=f6a8bd13bc8dd94281a4ad760bab6e0c}
}
Wiesmann A, Wegmüller U, Haeberlin Y, Retiere A, Senegas O, Strozzi T and Werner C (2004), "SAR based products for the implementation of humanitarian aid and development assistance projects within the UNOSAT project", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 7, pp. 4803-4806.
Abstract: The UNOSAT service is an ESA Earth Observation Market Development initiative whose objective is to encourage, facilitate, accelerate and expand the use of accurate geo-information derived from EO satellite imagery by professionals involved in the implementation of humanitarian aid and development assistance projects. In this paper we will focus on the role of SAR within this context. Space-borne SAR has a particularly good potential to support disaster management and humanitarian relief projects thanks to its all-weather capability, its capabilities for change detection, the large existing data archives, and, of course, the geometric and thematic information content of the images. Basic processing techniques, including precision image co-registration, multi-temporal analysis, terrain corrected geocoding, interferometry, and radargrammetry are well developed and operational. Advanced techniques like differential interferometry and interferometric point target analysis (IPTA) became more and more operational during the last years and provide unique information about terrain stability and deformation.
BibTeX:
@conference{Wiesmann20044803,
  author = {Wiesmann, A. and Wegmüller, U. and Haeberlin, Y. and Retiere, A. and Senegas, O. and Strozzi, T. and Werner, C.},
  title = {SAR based products for the implementation of humanitarian aid and development assistance projects within the UNOSAT project},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2004},
  volume = {7},
  pages = {4803-4806},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-15944421246&partnerID=40&md5=7421b71d494e5ba1dc36f289eb731533}
}
Wiesmann A, Werner C, Strozzi T and Wegmüller U (2004), "Combination of point and extended target based interferometric techniques", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 989-991.
Abstract: The objective of this paper is to present an approach that combines the interferoemetric point target analysis (IPTA) and the extended target based interferometric techniques (InSAR). The improvements achieved are most obvious in cases where the individual techniques result in complementary coverage in the information retrieved.
BibTeX:
@conference{Wiesmann2004989,
  author = {Wiesmann, A. and Werner, C. and Strozzi, T. and Wegmüller, U.},
  title = {Combination of point and extended target based interferometric techniques},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2004},
  volume = {2},
  pages = {989-991},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-15944418638&partnerID=40&md5=1569db6828e6daa59d5fc3425a718eea}
}
Askne J, Santoro M, Smith G and Fransson J (2003), "Multitemporal repeat-pass SAR interferometry of boreal forests", IEEE Transactions on Geoscience and Remote Sensing. Vol. 41(7 PART I), pp. 1540-1550.
Abstract: Multitemporal European Remote Sensing satellites 1 and 2 (ERS-1/2) and the Japanese Earth Resources Satellite 1 (JERS-1) interferometric synthetic aperture radar (InSAR) data from a boreal forest test site in Sweden (stem volumes up to 335 m3/ha, equivalent to above-ground dry biomass of ∼200 tons/ha) are studied in order to estimate stem volume using coherence and backscatter. The changes of JERS-1 backscatter and ERS-1/2 tandem coherence between images are consistent over the area studied, in contrast to ERS-1/2 backscatter. A model-based regression analysis has been performed, and the use of the model for inversion is discussed and compared with other approaches found in the literature. The model parameters are discussed in terms of their relation to wind speed and temperature. Results from the different acquisitions are combined to improve the stem volume estimation. The accuracy in terms of rms error (RMSE) for standwise estimated stem volume is ≈10 m3/ha using ERS-1/2 coherence. Using backscatter and coherence from JERS-1 we obtain an RMSE of ≈30-35 m3/ha. Finally, conditions for accurate retrieval of stem volume using multitemporal InSAR observations are discussed. We conclude that C- and L-band repeat-pass InSAR can provide stem volume estimates in boreal forests with accuracies similar to those of standard in situ measurements.
BibTeX:
@article{Askne20031540,
  author = {Askne, J. and Santoro, M. and Smith, G. and Fransson, J.E.S.},
  title = {Multitemporal repeat-pass SAR interferometry of boreal forests},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2003},
  volume = {41},
  number = {7 PART I},
  pages = {1540-1550},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0042429071&doi=10.1109%2fTGRS.2003.813397&partnerID=40&md5=37503b73d2d2fdbf87877ca05d136585},
  doi = {10.1109/TGRS.2003.813397}
}
Del Frate F, Ferrazzoli P, Guerriero L, Strozzi T, Wegmüller U, Cookmartin G and Quegan S (2003), "Investigating the performance of radar configurations in crop monitoring", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 2860-2862.
Abstract: This paper describes an algorithm aimed at monitoring the soil moisture and the growth cycle of wheat fields using radar data. The algorithm is based on neural networks trained by an electromagnetic model and multitemporal ground data measured on fields taken as a reference. The retrieval procedure is tested using mutitemporal signatures collected at a test site.
BibTeX:
@conference{DelFrate20032860,
  author = {Del Frate, F. and Ferrazzoli, P. and Guerriero, L. and Strozzi, T. and Wegmüller, U. and Cookmartin, G. and Quegan, S.},
  title = {Investigating the performance of radar configurations in crop monitoring},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {4},
  pages = {2860-2862},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242541228&partnerID=40&md5=2b98e54a4231c586d96cf64d60c8987f}
}
Eriksson L, Santoro M, Schmullius C and Wiesmann A (2003), "The Potential of ALOS Single Polarization InSAR for Estimation of Growing Stock Volume in Boreal Forest", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1939-1941.
Abstract: This paper present the main results from an investigation of the potential of L-band coherence from ALOS PALSAR for estimation of growing stock volume. The work has been limited to the boreal biome zone where two forest territories in central Siberia have been selected as test regions. 18 coherence images from repeat-pass acquisitions with ALOS predecessor JERS have been used for the analysis. The results indicate that growing stock volume estimation should be possible with PALSAR repeat pass coherence using only the HH polarization. Seasonal limitations have been identified and show that repeat-pass acquisitions should be avoided during periods of freeze and thaw. The most promising results are obtained from the winter season.
BibTeX:
@conference{Eriksson20031939,
  author = {Eriksson, L.E.B. and Santoro, M. and Schmullius, C. and Wiesmann, A.},
  title = {The Potential of ALOS Single Polarization InSAR for Estimation of Growing Stock Volume in Boreal Forest},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {3},
  pages = {1939-1941},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242458410&partnerID=40&md5=92bcc90141931386baaf66dd8e53db1f}
}
Eriksson L, Santoro M, Wiesmann A and Schmullius C (2003), "Multitemporal JERS repeat-pass coherence for growing-stock volume estimation of Siberian forest", IEEE Transactions on Geoscience and Remote Sensing. Vol. 41(7 PART I), pp. 1561-1570.
Abstract: Multitemporal radar data from the Japanese Earth Resources Satellite (JERS) satellite from the period 1993 to 1998 have been used to investigate if L-band interferometric coherence with a 44-day temporal baseline is suitable for estimations of growing-stock volume in boreal forest. Two forest regions north of Krasnoyarsk in Siberia have been used as test areas. Seasonal variations in the repeat-pass coherence have been studied, and a comparison with C-band coherence from the European Remote sensing Satellite 1 and 2 (ERS-1/2) tandem missions in 1997 and 1998 has been done. JERS coherence from the winter shows a clear correlation with the forest growing-stock volume. For the summer scenes, the spread in the values is too large to give reliable results. Acquisitions from the spring and fall show large problems with decorrelation caused by temporal changes. The results indicate potential of repeat-pass interferometric L-band coherence in winter, as will be provided by the forthcoming Advanced Land Observing Satellite/Phased Array type L-band Synthetic Aperture Radar (ALOS/PALSAR) to map growing-stock volume in Siberia and boreal forests.
BibTeX:
@article{Eriksson20031561,
  author = {Eriksson, L.E.B. and Santoro, M. and Wiesmann, A. and Schmullius, C.C.},
  title = {Multitemporal JERS repeat-pass coherence for growing-stock volume estimation of Siberian forest},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2003},
  volume = {41},
  number = {7 PART I},
  pages = {1561-1570},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0042929771&doi=10.1109%2fTGRS.2003.814131&partnerID=40&md5=7c29a5d70012e00db86828b6c7ed0046},
  doi = {10.1109/TGRS.2003.814131}
}
Guerova G, Brockmann E, Quiby J, Schubiger F and Matzler C (2003), "Validation of NWP mesoscale models with Swiss GPS network AGNES", Journal of Applied Meteorology. Vol. 42(1), pp. 141-150. American Meteorological Society.
Abstract: The importance of water vapor for the hydrological cycle of the earth and the atmosphere is well known but difficult to study and sample. In this respect, the vertically integrated water vapor (IWV) derived from global positioning system (GPS) delay is a potential source of valuable weather information. Because of the relatively dense station distribution, both the temporal and horizontal variability of water vapor are well captured by the GPS. This makes GPS data well suited for numerical weather prediction (NWP) models. In this paper the automated GPS network of Switzerland (AGNES) is used for calculation of IWV and for comparison with radiosonde data and two NWP mesoscale models from MeteoSwiss named Local Model (LM) and Swiss Model (SM). Reasonably good agreement between GPS and radiosonde data is reported. It has been identified that in some particular weather situations with low stratus clouds and temperature inversion, the radiosonde significantly overestimates the water vapor amount. The LM and SM verification with GPS data indicates good agreement during the winter period (November 2000-March 2001) and high variability and bias in the summer period (August 2000). The monthly mean IWV values from GPS and LM show a systematic deviation over the Swiss plateau region and a very good agreement for the high-altitude alpine station, Andermatt. The capability of GPS in monitoring the atmospheric phenomena has been demonstrated. Unrealistic IWV at Jungfraujoch (∼3600 m MSL) caused by GPS antenna problems is reported.
BibTeX:
@article{Guerova2003141,
  author = {Guerova, G. and Brockmann, E. and Quiby, J. and Schubiger, F. and Matzler, C.},
  title = {Validation of NWP mesoscale models with Swiss GPS network AGNES},
  journal = {Journal of Applied Meteorology},
  publisher = {American Meteorological Society},
  year = {2003},
  volume = {42},
  number = {1},
  pages = {141-150},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0141650503&doi=10.1175%2f1520-0450%282003%29042%3c0141%3aVONMMW%3e2.0.CO%3b2&partnerID=40&md5=3bb88e68cd628eaa2bb5359b61f66550},
  doi = {10.1175/1520-0450(2003)042<0141:VONMMW>2.0.CO;2}
}
Hame T, Sirro L, Rauste Y, Ahola H, Wegmüller U, Wiesmann A, Van Brusselen J, Schuck A, Hippi I and Volden E (2003), "Treaty Enforcement Services Using Earth Observation (TESEO) Theme Carbon - Main Results", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1480-1482.
Abstract: Earth observation techniques using optical and SAR data were developed to help the implementation of the Kyoto Protocol. Forest area and major tree species were mapped in study sites in Italy and Finland. Forest biomass was estimated in a plantation in Borneo using very high-resolution data. Results showed that instruments similar to Landsat Thematic Mapper are effective to provide required forest area information. C-band SAR can also be used in pure forest and non-forest mapping. A major challenge is to obtain reliable ground training and validation data as well as adequate and high-quality imagery for the reference year 1990 of the Protocol.
BibTeX:
@conference{Hame20031480,
  author = {Hame, T. and Sirro, L. and Rauste, Y. and Ahola, H. and Wegmüller, U. and Wiesmann, A. and Van Brusselen, J. and Schuck, A. and Hippi, I. and Volden, E.},
  title = {Treaty Enforcement Services Using Earth Observation (TESEO) Theme Carbon - Main Results},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {3},
  pages = {1480-1482},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242542378&partnerID=40&md5=e45986a70341a9cc62874243eb30338c}
}
Kampfer N, Deuber B, Feist D, Gerber D, Matzler C, Martin L, Morland J and Vasic V (2003), "Microwave remote sensing of water vapor in the atmosphere [La sensibilite a distance de la radiometrie micro-ondes a la vapeur d'eau dans l'atmosphere] [Mikrowellen-Fernerkundung von Wasserdampf in der Atmosphäre]", Geographica Helvetica. Vol. 58(2), pp. 81-89.
Abstract: Microwave Remote Sensing of Water Vapor in the Atmosphere Water vapor in the atmosphere plays a crucial role in climate and in atmospheric processes. Due to its long Chemical lifetime it can be used as a tracer for inves-tigations of dynamical processes in the middle atmosphere. Microwave radiometry is one of the few remote sensing methods which is capable of inferring information on the water vapor content of the troposphere to the mesosphere, however with a different altitude resolution. Different microwave radiometers that can be operated from the ground and from an airborne plat-form have been built at the Institute of Applied Phys-ics, University of Berne. The paper presents the method of microwave remote sensing and gives an overview of recently achieved results with regard to water vapor distribution as a function of altitude and latitude. First results of an imaging radiometer for the two dimensional distribution of liquid water is presented. Author(s) 2003. This work is distributed.
BibTeX:
@article{Kampfer200381,
  author = {Kampfer, N. and Deuber, B. and Feist, D. and Gerber, D. and Matzler, C. and Martin, L. and Morland, J. and Vasic, V.},
  title = {Microwave remote sensing of water vapor in the atmosphere [La sensibilite a distance de la radiometrie micro-ondes a la vapeur d'eau dans l'atmosphere] [Mikrowellen-Fernerkundung von Wasserdampf in der Atmosphäre]},
  journal = {Geographica Helvetica},
  year = {2003},
  volume = {58},
  number = {2},
  pages = {81-89},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84984414372&doi=10.5194%2fgh-58-81-2003&partnerID=40&md5=dd12bd22065161f14f66a9118ea6d407},
  doi = {10.5194/gh-58-81-2003}
}
Luckman A, Murray T, Jiskoot H, Pritchard H and Strozzi T (2003), "ERS SAR feature-tracking measurement of outlet glacier velocities on a regional scale in East Greenland", Annals of Glaciology. Vol. 36, pp. 129-134.
Abstract: Feature tracking, or patch intensity cross-correlation, is used to derive two-dimensional ice-surface velocity fields from 1 day and 35 day repeat-pass European Remote-sensing Satellite (ERS) synthetic aperture radar (SAR) data covering a 500 km by 500 km area of central East Greenland. Over regions of fast ice flow, 35 day tracking yields only a slightly lower density of velocity measurements than 1 day tracking, and both are broadly in agreement about the spatial pattern of ice velocity except at the glacier termini where tidal effects may dominate. This study suggests that SAR feature tracking may be used to routinely monitor ice-discharge velocities on a regional basis and thereby inform studies of regional mass balance.
BibTeX:
@article{Luckman2003129,
  author = {Luckman, A. and Murray, T. and Jiskoot, H. and Pritchard, H. and Strozzi, T.},
  title = {ERS SAR feature-tracking measurement of outlet glacier velocities on a regional scale in East Greenland},
  journal = {Annals of Glaciology},
  year = {2003},
  volume = {36},
  pages = {129-134},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0041352831&partnerID=40&md5=1e45cabc7105713cc9a5c61a988ce038}
}
Matzler C, Weber D, Wuthrich M, Schneeberger K, Stamm C, Wydler H and Fluhler H (2003), "ELBARA, the ETH L-Band Radiometer for Soil-Moisture Research", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 3058-3060.
Abstract: A 1.4 GHz radiometer, ELBARA, was constructed in 2001 at the Institute of Applied Physics, University of Bern, in collaboration with and for studies at ETH in soil-moisture research, especially to infer soil-hydraulic properties from the dynamics of the water content in the top soil. ELBARA is used together with MORA, an older, but equivalent system at 11.4 GHz and with a set of time-domain reflectometer (TDR) sensors. In the normal setup, the radiometers are operated from a tower at incidence angles between nadir and zenith. Here we report on the realization and on features of ELBARA. Results from first measurements in 2002 were presented elsewhere.
BibTeX:
@conference{Matzler20033058,
  author = {Matzler, C. and Weber, D. and Wuthrich, M. and Schneeberger, K. and Stamm, C. and Wydler, H. and Fluhler, H.},
  title = {ELBARA, the ETH L-Band Radiometer for Soil-Moisture Research},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {5},
  pages = {3058-3060},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-17344378327&partnerID=40&md5=ecd9cb79254d04ce70103d3990d3695b}
}
Murray T, Luckman A, Strozzi T and Nuttall A-M (2003), "The initiation of glacier surging at Fridtjovbreen, Svalbard", Annals of Glaciology. Vol. 36, pp. 110-116.
Abstract: Glacier surges in Svalbard have long durations and multi-year terminations, but much less is known regarding surge initiation in the archipelago. Fridtjovbreen, a 12 km long glacier in central Spitsbergen, advanced ∼2.8 km during a surge in the 1990s at a maximum rate of ∼1.2 md 1. Differential dual-azimuth satellite radar interferometry SRI is used to produce ten snapshots of three-dimensional surface dynamics and four digital elevation models covering the period October 1991 October 1997. The glacier velocity rose slowly and uniformly until June 1995. It then increased dramatically to a measured maximum of ∼2.5 md 1 during February and May 1996, and by October 1997 it had dropped. We attempt to evaluate errors in the calculated velocities. Systematic errors are evaluated using the apparent displacement of bedrock, ∼0.03 md 1. Errors arise from assumptions during processing, for example that ice-flow direction does not change during the surge. Two independent measurements using dual-azimuth processing show the mean absolute change in flow direction was ∼1.2. This study covers fast-flow initiation and peak flow, but not the deceleration phase. The SRI observations show a progressive acceleration phase to the surge, with no evidence of a surge front propagating down-glacier.
BibTeX:
@article{Murray2003110,
  author = {Murray, T. and Luckman, A. and Strozzi, T. and Nuttall, A.-M.},
  title = {The initiation of glacier surging at Fridtjovbreen, Svalbard},
  journal = {Annals of Glaciology},
  year = {2003},
  volume = {36},
  pages = {110-116},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0042404124&partnerID=40&md5=00b0f33dde2bebf6b171de2384538ae8}
}
Murray T, Strozzi T, Luckman A, Jiskoot H and Christakos P (2003), "Is there a single surge mechanism? Contrasts in dynamics between glacier surges in Svalbard and other regions", Journal of Geophysical Research: Solid Earth. Vol. 108(5), pp. EPM 3-1 - 3-15. Blackwell Publishing Ltd.
Abstract: During the 1990s, Monacobreen, a 40-km-long tidewater glacier in Svalbard, underwent a major surge. We mapped the surge dynamics using ERS synthetic aperture radar images, differential dual-azimuth interferometry and intensity correlation tracking. A series of 11 three-dimensional (3-D) velocity maps covering the period 1991-1997 show a months-long initiation and years-long termination to the surge, with no indication of a surge front travelling downglacier. During the surge, the front of the glacier advanced ∼2 km, the velocity and derived strain rate increased by more than an order of magnitude, and maximum ice flow rates measured during 1994 were ∼5 m d 1. The spatial pattern of both velocity and strain rate was remarkably consistent and must therefore be controlled by spatially fixed processes operating at the glacier bed. We combine these results with those published in the literature to construct a typical Svalbard glacier surge cycle and compare this to surge dynamics of glaciers from other cluster regions, especially those of Variegated Glacier in Alaska. The strong contrast in dynamics suggests that there exist at least two distinct surge mechanisms.
BibTeX:
@article{Murray2003,
  author = {Murray, T. and Strozzi, T. and Luckman, A. and Jiskoot, H. and Christakos, P.},
  title = {Is there a single surge mechanism? Contrasts in dynamics between glacier surges in Svalbard and other regions},
  journal = {Journal of Geophysical Research: Solid Earth},
  publisher = {Blackwell Publishing Ltd},
  year = {2003},
  volume = {108},
  number = {5},
  pages = {EPM 3-1 - 3-15},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0042885837&partnerID=40&md5=9ffcf732d61c9c1a51e00e56744ede85}
}
Paganini M, Palazzo F, Arino O, Manunta P, Ferretti A, Gontier E, Wunderle S, Pasquali P, Strozzi T, Zilger J and Van Westen C (2003), "SLAM, the development of an EO Service to support the legal obligations of Swiss and Italian Geological Risk Services in landslide risk forecasting and prevention", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 2422-2424.
Abstract: The necessity to identify and monitor slope movement is of paramount importance to reduce the socio-economic toll that every year is paid in developing as well as in developed countries. From the late 80's Italian and Swiss legislations regarding hydro-geological risks, have identified landslide hazard maps as essential tools to mitigate the risk associated to landslides. Several projects funded by the European Space Agency within the framework of its Data User Program (DUP), have investigated the feasibility and the operational applicability of spaceborne imagery to respond to the needs of governmental institutions that have a mandate in landslide analysis and prevention. Techniques based on SAR interferometry and on the combination of state of the art Remote Sensing observations with GIS modeling have been analysed in order to assess the contribution of Satellite Remote Sensing information in support to the practices of the Geological Risk Services Agencies.
BibTeX:
@conference{Paganini20032422,
  author = {Paganini, M. and Palazzo, F. and Arino, O. and Manunta, P. and Ferretti, A. and Gontier, E. and Wunderle, S. and Pasquali, P. and Strozzi, T. and Zilger, J. and Van Westen, C.},
  title = {SLAM, the development of an EO Service to support the legal obligations of Swiss and Italian Geological Risk Services in landslide risk forecasting and prevention},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {4},
  pages = {2422-2424},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242710573&partnerID=40&md5=b116268346d6262b91f1a54de59fc05f}
}
Petrat L and Wegmüller U (2003), "Simulation of Abandoned Mining Induced Surface Movements for Estimating DInSAR Detection Limits", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 2936-2938.
Abstract: Underground mining activities very often cause changes to the surface. Beside the strong influences of active mining, former mining activities with still existing cavities in the underground do influence the surface as well, causing a risk for people and infrastructure. The main risk is induced by sudden falls of the surface. In contrast to surface deformations induced by active mining these deformations are difficult to predict. The risk justifies the monitoring of ground movements in historical mining areas. One technique evaluated is Differential Interferometric Synthetic Aperture Radar (DInSAR). The main difference to other applications of DInSAR is, that location, subsidence rate and spatial extent can just roughly be estimated using related historic information about former mining activities. In addition, the expected character of the subsidence complicates the separation between deformation signal and atmospherical artifacts. In order to get a first idea about the limits of the technique, circular shaped deformation models with different extents and maximum vertical displacements have been modeled and integrated into the DInSAR processing chain. The final results have been evaluated qualitatively and quantitatively in order to get an idea about the detection limits of DInSAR using ERS-1/2 data. The qualitative assessment shows that subsidence cones of circular shape with radii below 400 m cannot be reliably identified in a single interferogram in the investigated case. In the quantitative assessment the highest relative RMS errors between model and result were found for subsidence cones with small radii and small maximum vertical displacements. Furthermore it could be shown that the use of multiple interferograms by applying stacking techniques leads to a better detection limit of the DInSAR method.
BibTeX:
@conference{Petrat20032936,
  author = {Petrat, L. and Wegmüller, U.},
  title = {Simulation of Abandoned Mining Induced Surface Movements for Estimating DInSAR Detection Limits},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {4},
  pages = {2936-2938},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242457563&partnerID=40&md5=90a30e34ba080284f557d781ac0c5205}
}
Pritchard H, Murray T, Strozzi T, Barr S and Luckman A (2003), "Surge-related topographic change of the glacier Sortebræ, East Greenland, derived from synthetic aperture radar interferometry", Journal of Glaciology. Vol. 49(166), pp. 381-390.
Abstract: A major surge of the glacier complex of Sortebræ, East Greenland, occurred between 1992 and 1995. The impact of this surge on the topography of Sortebræ was examined through the production of a pre-surge (1981) digital elevation model (DEM) from interpolated digital map data, and a post-surge DEM from differential synthetic aperture radar interferometry using European Remote-sensing Satellite (ERS) imagery. The combined vertical error is typically 30-40 m; however, downdraw Of up to 270 m in the reservoir zone, and uplift of up to 145 in the receiving zone were measured. The upper glacier reservoir area discharged in excess of 24.3 ± 9.5 km3 volume over the surge, of which ∼12.5 km3 was stored in the advanced lower glacier, the balance being lost, predominantly to calving.
BibTeX:
@article{Pritchard2003381,
  author = {Pritchard, H. and Murray, T. and Strozzi, T. and Barr, S. and Luckman, A.},
  title = {Surge-related topographic change of the glacier Sortebræ, East Greenland, derived from synthetic aperture radar interferometry},
  journal = {Journal of Glaciology},
  year = {2003},
  volume = {49},
  number = {166},
  pages = {381-390},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-1842760586&partnerID=40&md5=1b95dcde177a6664d2b584f0016418b7}
}
Schneeberger K, Stamm C, Matzler C and Fluhler H (2003), "Estimating Soil Hydraulic Properties from Time Series of L-band Measured Water Contents", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 1175-1177.
Abstract: In this paper we present an approach to estimate the hydraulic properties based on time-series of water content measurements in the topsoil at the plot scale. The data base consists of series of ground-based remotely sensed water contents by using a 1.4 GHz (L-band) and 11.4 GHz radiometer as well as in-situ TDR measurements. A technical description of the new L-band radiometer will also be presented at this meeting (Matzler C. et al.). The measuring period contained several natural rainfall and dry-down cycles. In order to test the possibility to derive soil structural information from this approach we depend on a high temporal resolution of the measurements. The comparison of the in-situ and remotely sensed water contents by the microwave radiometers revealed a synchronous behavior. Although preferential flow was neglected in the modelling approach we were able to get a satisfying fit to the in-situ measured water contents. The comparison of the derived parameters to literature data revealed a structural influence, since the parameter combination lied outside the confidence interval. This indicates that the behavior of structured soils may be extractable from remotely sensed topsoil water dynamics.
BibTeX:
@conference{Schneeberger20031175,
  author = {Schneeberger, K. and Stamm, C. and Matzler, C. and Fluhler, H.},
  title = {Estimating Soil Hydraulic Properties from Time Series of L-band Measured Water Contents},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {2},
  pages = {1175-1177},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242711467&partnerID=40&md5=12499fd7a922a1de02da2a91ac2b5974}
}
Strozzi T, Kaab A, Frauenfelder R and Wegmüller U (2003), "Detection and Monitoring of Unstable High-Mountain Slopes with L-Band SAR Interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1852-1854.
Abstract: This contribution reports on the potential and limitations of L-band differential SAR interferometry for the detection and monitoring of unstable high-mountain slopes. SAR data of the JERS-1 satellite for the Swiss Alps have been analyzed together with ERS SAR data. Significant results for permafrost creep and rockslides after glacier retreat are presented.
BibTeX:
@conference{Strozzi20031852,
  author = {Strozzi, T. and Kaab, A. and Frauenfelder, R. and Wegmüller, U.},
  title = {Detection and Monitoring of Unstable High-Mountain Slopes with L-Band SAR Interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {3},
  pages = {1852-1854},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242626842&partnerID=40&md5=a13f0986c5a5e033362f6aa5b27b82b7}
}
Strozzi T, Tosi L, Wegmüller U, Werner C, Teatini P and Carbognin L (2003), "Land Subsidence Monitoring Service in the Lagoon of Venice", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. 212-214.
Abstract: A land subsidence monitoring service in the lagoon of Venice was implemented with the integration of INSAR and levelling surveys. INSAR was employed to complement the levelling and global positioning system (GPS) surveys. A time series of six interferometric radar images of the European Remote Sensing Satellites ERS-1 and ERS-2 from 1993 to 2000 was also described.
BibTeX:
@conference{Strozzi2003212,
  author = {Strozzi, T. and Tosi, L. and Wegmüller, U. and Werner, C. and Teatini, P. and Carbognin, L.},
  title = {Land Subsidence Monitoring Service in the Lagoon of Venice},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {1},
  pages = {212-214},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242628297&partnerID=40&md5=51cd3782ca8dceb0223abdb117074480}
}
Strozzi T, Wegmüller U, Werner C, Wiesmann A and Spreckels V (2003), "JERS SAR interferometry for land subsidence monitoring", IEEE Transactions on Geoscience and Remote Sensing. Vol. 41(7 PART I), pp. 1702-1708.
Abstract: In this paper, the potential of L-band repeat-pass differential synthetic aperture radar (SAR) interferometry for land subsidence monitoring is evaluated using Japanese Earth Resources Satellite (JERS) SAR data. Bologna, Mexico City, and the Ruhrgebiet are selected as application sites representing slow to fast deformation velocities. The investigation includes feasibility aspects such as data availability, the temporal decorrelation over different landcover classes and the range of useful spatial baselines, an analysis of the achieved deformation accuracy, and considerations on the complementarity to European Remote Sensing satellite (ERS) SAR interferometry and leveling surveys. In spite of the rather limited data availability, land subsidence maps could be generated for the three selected application sites. In contrast to ERS C-band SAR data, JERS L-band interferometry permitted the retrieval of subsidence values over vegetated areas and forest when using interferograms of less than one year acquisition time interval and short baseline. In addition, the longer L-band wavelength was found to be superior in the case of large deformation gradients that lead to phase-unwrapping problems in C-band interferometry.
BibTeX:
@article{Strozzi20031702,
  author = {Strozzi, T. and Wegmüller, U. and Werner, C.L. and Wiesmann, A. and Spreckels, V.},
  title = {JERS SAR interferometry for land subsidence monitoring},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2003},
  volume = {41},
  number = {7 PART I},
  pages = {1702-1708},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0042429055&doi=10.1109%2fTGRS.2003.813273&partnerID=40&md5=27a76c1835580fbf45f68bfc00d2efc7},
  doi = {10.1109/TGRS.2003.813273}
}
Strozzi T, Wegmüller U, Wiesmann A and Werner C (2003), "Validation of the X-SAR SRTM DEM for ERS and JERS SAR geocoding and 2-pass differential interferometry in alpine regions", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. 109-111.
Abstract: The X-SAR SRTM DEM of an alpine region in Switzerland was validated for SAR geocoding and 2-pass differential interferometry using ERS and JERS data. The absolute horizontal and vertical accuracies of the X-SAR SRTM DEM are in general in line with the nominal indications, but in very rugged areas we found horizontal offsets of up to 50 m in both northing and easting directions and some extreme absolute height errors up to even 1000 m. Also visible in the X-SAR SRTM DEM is an important noise for the slopes facing to the east, which correspond to the back slopes of SAR illumination. The ERS and JERS SAR images geocoded with the X-SAR SRTM DEM do not contain significant geometric artifacts, but, in parallel to what was discussed before, show in comparison to the map offsets in both easting and northing directions. The matching of geocoded products of descending and ascending modes is very good, i.e. on the order of 1 to 2 pixels. Considering that in our geocoding approach the geocoded SAR images are accurately co-registered to the DEM, the horizontal offsets have no influence for 2-pass differential interferometry. We found that the X-SAR SRTM DEM is well suited for ERS and JERS interferograms of the descending mode of baselines up to 100 m. For the differential interferometric analysis of ERS SAR data in ascending mode, however, attention has to be paid to the noise of the slopes facing away from the X-SAR.
BibTeX:
@conference{Strozzi2003109,
  author = {Strozzi, T. and Wegmüller, U. and Wiesmann, A. and Werner, C.},
  title = {Validation of the X-SAR SRTM DEM for ERS and JERS SAR geocoding and 2-pass differential interferometry in alpine regions},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {1},
  pages = {109-111},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242459904&partnerID=40&md5=e1e374e7a127d3fdc690a35a34d535da}
}
Tampellini M, Brivio P, Carrara P, Fantoni D, Gnocchi S, Ober G, Pepe M, Rampini A, Ratti R, Nodari F and Strozzi T (2003), "Monitoring of glacier and snow cover changes in alpine region using remote sensing data", In 54th International Astronautical Congress of the International Astronautical Federation (IAF), the International Academy of Astronautics and the International Institute of Space Law. Vol. 1, pp. 963-973.
Abstract: Subject of this paper is to propose a new approach for the monitoring of glacier and snow cover changes in Alpine regions, carried out using Synthetic Aperture Radar (SAR) data, optical satellite multiscale observations, ground collected data and geographical information. Moreover, a dynamic modeling of snow melt runoff for water resource management is discussed. The main purposes of this approach are: Provide a new method for glacier monitoring through the combined use of SAR observations, Landsat Thematic Mapper (TM) images and Digital Terrain Model. Provide a novel instrument for the preparation of snow-cover maps using both radar and optical data. Quantify the water availability setting up a snow melting runoff model. The proposed approach takes advantage from the variations of the spectral characteristics of snow in different states of metamorphism. It is possible to identify various snow types by the combined use of different bands of the satellite sensors in the visible, infrared and microwave wavelengths. These sensors provide reflected, emitted and backscattered measurements from which the snow covered area and snow water equivalence.
BibTeX:
@conference{Tampellini2003963,
  author = {Tampellini, M.L. and Brivio, P.A. and Carrara, P. and Fantoni, D. and Gnocchi, S. and Ober, G. and Pepe, M. and Rampini, A. and Ratti, R. and Nodari, F.R. and Strozzi, T.},
  title = {Monitoring of glacier and snow cover changes in alpine region using remote sensing data},
  booktitle = {54th International Astronautical Congress of the International Astronautical Federation (IAF), the International Academy of Astronautics and the International Institute of Space Law},
  year = {2003},
  volume = {1},
  pages = {963-973},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-22344442170&partnerID=40&md5=acd48b06b89be3f4059ad4afae754309}
}
Wagner W, Luckman A, Vietmeier J, Tansey K, Balzter H, Schmullius C, Davidson M, Gaveau D, Gluck M, Le Toan T, Quegan S, Shvidenko A, Wiesmann A and Yu J (2003), "Large-scale mapping of boreal forest in SIBERIA using ERS tandem coherence and JERS backscatter data", Remote Sensing of Environment. Vol. 85(2), pp. 125-144. Elsevier Inc..
Abstract: Siberia's boreal forests represent an economically and ecologically precious resource, a significant part of which is not monitored on a regular basis. Synthetic aperture radars (SARs), with their sensitivity to forest biomass, offer mapping capabilities that could provide valuable up-to-date information, for example about fire damage or logging activity. The European Commission SIBERIA project had the aim of mapping an area of approximately 1 million km2 in Siberia using SAR data from two satellite sources: the tandem mission of the European Remote Sensing Satellites ERS-1/2 and the Japanese Earth Resource Satellite JERS-1. Mosaics of ERS tandem interferometric coherence and JERS backscattering coefficient show the wealth of information contained in these data but they also show large differences in radar response between neighbouring images. To create one homogeneous forest map, adaptive methods which are able to account for brightness changes due to environmental effects were required. In this paper an adaptive empirical model to determine growing stock volume classes using the ERS tandem coherence and the JERS backscatter data is described. For growing stock volume classes up to 80 m3/ha, accuracies of over 80% are achieved for over a hundred ERS frames at a spatial resolution of 50 m. 2003 Elsevier Science Inc. All rights reserved.
BibTeX:
@article{Wagner2003125,
  author = {Wagner, W. and Luckman, A. and Vietmeier, J. and Tansey, K. and Balzter, H. and Schmullius, C. and Davidson, M. and Gaveau, D. and Gluck, M. and Le Toan, T. and Quegan, S. and Shvidenko, A. and Wiesmann, A. and Yu, J.J.},
  title = {Large-scale mapping of boreal forest in SIBERIA using ERS tandem coherence and JERS backscatter data},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Inc.},
  year = {2003},
  volume = {85},
  number = {2},
  pages = {125-144},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242432323&doi=10.1016%2fS0034-4257%2802%2900198-0&partnerID=40&md5=2506211fbee50b96028914aaff494223},
  doi = {10.1016/S0034-4257(02)00198-0}
}
Wegmüller U, Strozzi T, Wiesmann A and Werner C (2003), "ENVISAT ASAR for land cover information", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 2996-2998.
Abstract: In 2002 ENVISAT with the advanced SAR (ASAR) as one important instrument was launched. As compared to the preceding SARs on ERS-1 and ERS-2 the ASAR has additional functionality with many different modes. Important aspects of the ASAR include the alternating polarization modes for quasi simultaneous acquisition of data at two different polarizations, and beam-steering capability, which permits to acquire data at different incidence angles. In this paper the use of the ENVISAT ASAR for land cover information retrieval is discussed. For multi-incidence angle data a coefficient to characterize the incidence angle dependence is proposed.
BibTeX:
@conference{Wegmuller20032996,
  author = {Wegmüller, U. and Strozzi, T. and Wiesmann, A. and Werner, C.},
  title = {ENVISAT ASAR for land cover information},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {5},
  pages = {2996-2998},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-17344394591&partnerID=40&md5=1b2c342675c5525ba5f108731222d7fe}
}
Wegmüller U, Werner C, Wiesmann A and Strozzi T (2003), "Radargrammetry and space triangulation for DEM generation and image ortho-rectification", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. 179-181.
Abstract: In 2002 ENVISAT with the advanced SAR (ASAR) as one important instrument was launched. As compared to the preceding SAR sensors on ERS-1 and ERS-2 the ASAR has beam-steering capability permitting the acquisition of data over the same area under different incidence angles as required by radargrammetry. In this paper a concept for a combined use of radargrammetry and space triangulation to derive digital elevation models (DEMs) is presented. Space triangulation with opposite side acquisitions is used to determine a number of control points. Radargrammetry is then used to derive a DEM using these control points as reference. Preliminary tests on the different steps of the combined method are presented.
BibTeX:
@conference{Wegmuller2003179,
  author = {Wegmüller, U. and Werner, C. and Wiesmann, A. and Strozzi, T.},
  title = {Radargrammetry and space triangulation for DEM generation and image ortho-rectification},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {1},
  pages = {179-181},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242543388&partnerID=40&md5=a11ff348359aca5992fbfc6fd58f3cb6}
}
Werner C, Andreas Wiesmann U and Strozzi T (2003), "Interferometric Point Target Analysis with JERS-1 L-Band SAR Data", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 7, pp. 4359-4361.
Abstract: Interferometric Point Target Analysis (IPTA) is a method that exploits the temporal and spatial characteristics of interferometric signatures collected from point targets that exhibit long-term coherence to map surface deformation. This paper demonstrates the viability of this technique for L-Band data collected by the JERS-1 sensor during the time period 1992-1998. A data set covering Koga, Japan is used for demonstration and indicates regions of substantial subsidence.
BibTeX:
@conference{Werner20034359,
  author = {Werner, C. and Andreas Wiesmann, U.W. and Strozzi, T.},
  title = {Interferometric Point Target Analysis with JERS-1 L-Band SAR Data},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {7},
  pages = {4359-4361},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242625272&partnerID=40&md5=a3a1b3f208fee880892f90dd650874e9}
}
Werner C, Wegmüller U, Strozzi T and Wiesmann A (2003), "Interferometric Point Target Analysis for Deformation Mapping", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 7, pp. 4362-4364.
Abstract: Interferometric Point Target Analysis (IPTA) is a method to exploit the temporal and spatial characteristics of interferometric signatures collected from point targets to accurately map surface deformation histories, terrain heights, and relative atmospheric path delays. In this contribution the IPTA concept is introduced, including the point selection criteria, the phase model and the iterative improvement of the model parameters. Intermediate and final results of an IPTA example using a stack of ERS-1 and ERS-2 data, confirm the validity of the concept and indicate a high accuracy of the resulting products.
BibTeX:
@conference{Werner20034362,
  author = {Werner, C. and Wegmüller, U. and Strozzi, T. and Wiesmann, A.},
  title = {Interferometric Point Target Analysis for Deformation Mapping},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {7},
  pages = {4362-4364},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242456806&partnerID=40&md5=54ee3e770426110b7106cb99f31964b3}
}
Wiesmann A, Wegmüller U, Werner C and Strozzi T (2003), "ASAR multi-swath techniques", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 3114-3116.
Abstract: In 2002 ENVISAT with the advanced SAR (ASAR) as one important instrument was launched. As compared to the preceding SARs on ERS-1 and ERS-2 the ASAR has additional functionality with many different modes. Important aspects of the ASAR include the alternating polarization modes for quasi simultaneous acquisition of data at two different polarizations, and beam-steering capability, which permits to acquire data at different incidence angles. To optimize the use of the new functionality adequate processing techniques are required. This is particularly important for data acquired in different swaths, i.e. with different image geometries. In this paper ASAR multi-swath techniques are discussed, including image co-registration, multi-channel filtering, and multi-swath multi-temporal techniques.
BibTeX:
@conference{Wiesmann20033114,
  author = {Wiesmann, A. and Wegmüller, U. and Werner, C. and Strozzi, T.},
  title = {ASAR multi-swath techniques},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {5},
  pages = {3114-3116},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242541113&partnerID=40&md5=ae5447ac9db94c2e48394b9f3e831485}
}
Wiesmann A, Wegmüller U, Werner C and Strozzi T (2003), "Subsidence monitoring over oil fields with L-band SAR interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1546-1548.
Abstract: The objective of our investigation was to validate the potential of L-band SAR for the mapping of rapid subsidence and to demonstrate its monitoring capability for the specific case, Belridge in California USA. The results confirm the good potential of L-band repeat-pass interferometry to map and monitor subsidence. Subsidence rates of more than 46 cm per year were observed and mapped.
BibTeX:
@conference{Wiesmann20031546,
  author = {Wiesmann, A. and Wegmüller, U. and Werner, C. and Strozzi, T.},
  title = {Subsidence monitoring over oil fields with L-band SAR interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2003},
  volume = {3},
  pages = {1546-1548},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242711321&partnerID=40&md5=6b3948571390e6fad1eecad60d37cb2c}
}
Askne J, Santoro M, Smith G and Fransson J (2002), "Large area Boreal forest investigations using ERS InSAR", In European Space Agency, (Special Publication) ESA SP. (475), pp. 39-44.
Abstract: Multi-temporal InSAR data from a boreal forest area in Sweden is analyzed in order to estimate stem volume using coherence and backscatter. A model-based regression is performed using 21 forest stands and tested on another 21 forest stands, 2 to 14 ha in size, from an area with accurate in situ stem volume data varying from 8 to 335 m3/ha. The model approach is discussed and compared with other approaches found in the literature. Results from the different pairs are combined to give a best stem volume estimate. The accuracy in terms of RMSE for standwise estimated stem volume corrected for sampling errors is 10 m3/ha. Evaluation at plot level (20m diameter - 216 plots) showed an RMSE of 55 m3/ha. The best pairs are characterized by below zero temperature and snow on the ground. For the large area (4325 km2) 166 Swedish National Forest Inventory (NFI), plots were used as reference resulting in an RMSE of 71 m3/ha i.e. 30% worse than the reference are located up to 50 km away. The plot based accuracy estimates illustrate effects of the limited resolution of the coherence estimate and the variability of the forest and stresses the need for evaluations over forest stands. By averaging over larger areas we obtain an accuracy of ≤ 30 m3/ha for areas ≥ 150 km2. We conclude that InSAR can for areas above 2 ha provide forest stem volume estimates of similar order of accuracy as ground data.
BibTeX:
@conference{Askne200239,
  author = {Askne, J. and Santoro, M. and Smith, G. and Fransson, J.E.S.},
  title = {Large area Boreal forest investigations using ERS InSAR},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2002},
  number = {475},
  pages = {39-44},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036182748&partnerID=40&md5=4c3becf47957e08304f8fc91a7e75692}
}
Del Frate F, Ferrazzoli P, Guerriero L, Strozzi T, Wegmüller U, Cookmartin G and Quegan S (2002), "Monitoring crop cycles by SAR using a neural network trained by a model", In European Space Agency, (Special Publication) ESA SP. (475), pp. 239-244.
Abstract: An algorithm, based on an electromagnetic model and a neural network, aimed at monitoring the multitemporal evolution of wheat fields, is described. Three different sites are used to validate the model, provide reference ground data, and test the algorithm.
BibTeX:
@conference{DelFrate2002239,
  author = {Del Frate, F. and Ferrazzoli, P. and Guerriero, L. and Strozzi, T. and Wegmüller, U. and Cookmartin, G. and Quegan, S.},
  title = {Monitoring crop cycles by SAR using a neural network trained by a model},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2002},
  number = {475},
  pages = {239-244},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036180744&partnerID=40&md5=c0d3e3d36500a321ddce57e83ae9a417}
}
Del Frate F, Ferrazzoli P, Guerriero L, Strozzi T, Wegmüller U, Cookmartin G and Quegan S (2002), "Wheat cycle monitoring using radar data and a neural network trained by a model", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. 481-483.
Abstract: An algorithm, based on an electromagnetic model and a neural network, aimed at monitoring the multitemporal evolution of wheat fields, is described. Three different sites are used to validate the model, provide reference ground data, and test the algorithm.
BibTeX:
@conference{DelFrate2002481,
  author = {Del Frate, F. and Ferrazzoli, P. and Guerriero, L. and Strozzi, T. and Wegmüller, U. and Cookmartin, G. and Quegan, S.},
  title = {Wheat cycle monitoring using radar data and a neural network trained by a model},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2002},
  volume = {1},
  pages = {481-483},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036031415&partnerID=40&md5=8b3520314ca8351b95f65a5794d977ff}
}
Eriksson L, Schmullius C, Riedel T and Wiesmann A (2002), "Multi-temporal JERS coherence for observation of Siberian forest", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 2896-2898.
Abstract: This paper presents the first results from a study of multi-temporal JERS repeat pass coherence. Two test areas in a forest region north of Krasnoyarsk in Siberia have been used to investigate if L-band coherence with a 44-day temporal baseline can be used for estimations of growing stock volume in boreal forest. The available data show promising results for winter images, but for the summer scenes the standard deviations are too large to give reliable results. A comparison with ERS tandem coherence has also been done.
BibTeX:
@conference{Eriksson20022896,
  author = {Eriksson, L.E.B. and Schmullius, C. and Riedel, T. and Wiesmann, A.},
  title = {Multi-temporal JERS coherence for observation of Siberian forest},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2002},
  volume = {5},
  pages = {2896-2898},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036399029&partnerID=40&md5=5be6e876ca08c206407f6a1bf7ccf808}
}
Eriksson L, Wiesmann A and Schmullius C (2002), "JERS repeat pass coherence for observation of Siberian forest", In European Space Agency, (Special Publication) ESA SP. (475), pp. 33-38.
Abstract: This paper presents the first results from a study of JERS repeat pass coherence. The goal of the study is to find out if JERS repeat pass coherence can be used for observation of Siberian forests and to compare it with results for ERS tandem coherence. Two forest territories in Siberia are used as test sites. These two territories, Bolshe-Murtinsky and Chunsky, are chosen for their good availability of satellite and ground data. The rest sites were also studied in the EC-financed SIBERIA project (SAR Imaging for Boreal Ecology and Radar Interferometry Applications), but a detailed study of the JERS coherence has previously not been done for these regions. The data analysis show that JERS coherence in combination with JERS backscatter intensity can be used for forest/non-forest monitoring.
BibTeX:
@conference{Eriksson200233,
  author = {Eriksson, L. and Wiesmann, A. and Schmullius, C.},
  title = {JERS repeat pass coherence for observation of Siberian forest},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2002},
  number = {475},
  pages = {33-38},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036178328&partnerID=40&md5=069395d3ff4ca3963519a25ae1885d47}
}
Fanelli A and Santoro M (2002), "Characterization of urban areas using principal component analysis from multitemporal ERS coherence imagery", In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 4886, pp. 224-232.
Abstract: C-band SAR interferometry using ERS data has been shown to be potential for urban areas studies. This work illustrates the application of Principal Components Analysis (PCA) to a multi-temporal set of ERS coherence images to detect urban areas and their features. In particular Principal Component Transformation was applied on sets of one-day and long-term coherence images for urban mapping applications in the area of Naples, Italy. Two main classes, urban and non-urban, which then included two classes each, were considered in this study. Dense built-up areas and residential areas formed the urban class. Water bodies and vegetated areas (fields and woods) were grouped in the non-urban class. The first principal component was found to be more suitable than higher order components for detection of urban areas. Moreover, a simple algorithm based on distance between the first principal component of a pixel and the value representative for each class was tested for intra-urban mapping. Results showed that the first principal component could discriminate reasonably well between dense built-up and residential areas.
BibTeX:
@conference{Fanelli2002224,
  author = {Fanelli, A. and Santoro, M.},
  editor = {Ehlers M.},
  title = {Characterization of urban areas using principal component analysis from multitemporal ERS coherence imagery},
  booktitle = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2002},
  volume = {4886},
  pages = {224-232},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037951633&doi=10.1117%2f12.462360&partnerID=40&md5=6a734acbffac2c6d796c218f4585d8ca},
  doi = {10.1117/12.462360}
}
Luckman A, Murray T and Strozzi T (2002), "Surface flow evolution throughout a glacier surge measured by satellite radar interferometry", Geophysical Research Letters. Vol. 29(23), pp. 10-1-10-4. American Geophysical Union.
Abstract: The surface flow evolution over 6 years of a glacier surge in Svalbard is revealed by satellite radar interferometry from ERS-1 and ERS-2. Eleven surface velocity maps, generated by combining multi-temporal, differential interferograms utilising 36 ascending and descending-pass images, give an unprecedented overview of the spatio-temporal development of the surge. The surge is characterised by gradual initiation and termination phases, and flow resctrictions appear to remain spatially consistent despite the relatively large changes in surface velocity. Results from this type of study are expected to help constrain physically-based models of surge behaviour.
BibTeX:
@article{Luckman200210-1,
  author = {Luckman, A. and Murray, T. and Strozzi, T.},
  title = {Surface flow evolution throughout a glacier surge measured by satellite radar interferometry},
  journal = {Geophysical Research Letters},
  publisher = {American Geophysical Union},
  year = {2002},
  volume = {29},
  number = {23},
  pages = {10-1-10-4},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85081147485&partnerID=40&md5=7301451c008407a28064a6151c4fda0f}
}
Matzler C (2002), "Relation between grain-size and correlation length of snow", Journal of Glaciology. Vol. 48(162), pp. 461-466.
Abstract: In the past it has often been difficult to compare results of different types of snow-structural information. Grain-size and correlation length are such parameters of granular media, and there exist different definitions and different measurement methods for both of them. The relation between these parameters is analyzed from theoretical and from experimental points of view, considering optical and microwave properties. For spherical ice grains the connecting formulas are simple, but for other shapes the two parameters are not directly related. Care must be taken in the measurement procedure. Especially if grain-size is regarded as the maximum extent of connected ice particles, the results are likely to lead to extreme overestimates. Therefore it is concluded that grain-size should be complemented by an additional size parameter, namely, the surface-to-volume ratio of equivalent spheres, i.e. a measure of the correlation length. Methods to determine this quantity in the laboratory have been known for a long time. Methods to obtain such measurements in the field are described here.
BibTeX:
@article{Matzler2002461,
  author = {Matzler, C.},
  title = {Relation between grain-size and correlation length of snow},
  journal = {Journal of Glaciology},
  year = {2002},
  volume = {48},
  number = {162},
  pages = {461-466},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036939049&partnerID=40&md5=fb2ea4ad748c92561a6de90420514dd4}
}
Murray T, Strozzi T, Luckman A, Pritchard H and Jiskoot H (2002), "Ice dynamics during a surge of Sortebrae, East Greenland", Annals of Glaciology. Vol. 34, pp. 323-329.
Abstract: Sortebræ, a large tidewater-terminating glacier in East Greenland, underwent a major surge between 1992 and 1995 during which the glacier terminus advanced by nearly 10 km. In this paper, intensity tracking, interferometry and visual interpretation have been used to characterize the ice dynamics during the surge from satellite synthetic aperture radar images. The surge had a rapid initiation that saw velocities increase by 60-1500 times, and within 13 months the entire lower 53 km of the glacier was affected. Surge termination occurred very rapidly during summer, and ice velocity dropped from around 20 m d-1 to around 2 m d-1 in only 3 months. Uniquely, part of the upper glacier remained fast-flowing even after the main surge event had terminated. Ice dynamics together with observations of large turbid lakes at the glacier margins suggest that the surge resulted from a throttling of basal water by a switch in the hydrological system.
BibTeX:
@article{Murray2002323,
  author = {Murray, T. and Strozzi, T. and Luckman, A. and Pritchard, H. and Jiskoot, H.},
  title = {Ice dynamics during a surge of Sortebrae, East Greenland},
  journal = {Annals of Glaciology},
  year = {2002},
  volume = {34},
  pages = {323-329},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036336689&partnerID=40&md5=75840a82d9843d4cf5495fd82c3f2310}
}
Pellarin T, Calvet J-C, Wigneron J-P, Simmonds L, Lopez-Baeza E, Berger M, Camps A, Chanzy A, Ferrazzoli P, Hallikainen M, Kerr Y, Matzler C, Mauser W, Van De Griend A, Van Den Hurk B, Van Oevelen P, Viterbo P and Waldteufel P (2002), "Soil moisture retrieval by SMOS: A global feasibility study", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 3075-3077.
Abstract: The high potential of simple statistical methods to retrieve surface soil moisture using brightness temperatures was shown using two different methodologies. The first one (GRM) gives relatively good results provided densely forested pixels are excluded and water fraction is accounted for. The second one (LRM) seemed to provide an efficient way to retrieve surface soil moisture with an accuracy better than 0.04 m3m-3 over about 90% of the global continental areas.
BibTeX:
@conference{Pellarin20023075,
  author = {Pellarin, T. and Calvet, J.-C. and Wigneron, J.-P. and Simmonds, L.P. and Lopez-Baeza, E. and Berger, M. and Camps, A. and Chanzy, A. and Ferrazzoli, P. and Hallikainen, M.T. and Kerr, Y.H. and Matzler, C. and Mauser, W. and Van De Griend, A. and Van Den Hurk, B. and Van Oevelen, P.J. and Viterbo, P. and Waldteufel, P.},
  title = {Soil moisture retrieval by SMOS: A global feasibility study},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2002},
  volume = {5},
  pages = {3075-3077},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036398912&partnerID=40&md5=f92725539b8458d73048a057dbc96e9b}
}
Santoro M, Askne J, Eriksson L, Schmullius C, Wiesmann A and Fransson J (2002), "Seasonal dynamics and stem volume retrieval in boreal forests using JERS-1 backscatter", In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 4879, pp. 231-242.
Abstract: The paper analyses seasonal effects on L-band backscatter in boreal forests and the implications for stem volume retrieval (JERS-1 mission). As test sites, the estate of Kattbole, Sweden, and two compartments in Bolshe-Murtinsky, Siberia, were considered. The in-situ measured stem volumes ranged from 5 to 350 m3/ha in Kattbole and to 400 m3/ha in Bolshe-Murtinsky, at stand level. For each site nine SAR images were available. Forest backscatter strongly depended on seasonal conditions. With respect to other seasons, in frozen conditions the dynamic range was smaller and the forest backscatter at least 3 dB lower. When precipitation occurred, the backscatter showed saturation. In Kattbole, no saturation was found in images acquired at dry/unfrozen conditions. By means of a semi-empirical model, a regression between stem volume and backscatter was performed. Stem volume was then retrieved for an independent set of backscatter measurements. Images acquired at dry/unfrozen conditions showed a relative RMS error of around 30% for the images acquired over Kattbole. At both sites the retrieval error was higher for other weather conditions, around 50%. When dry/unfrozen conditions occurred, multi-temporal combination of stem volume estimates showed the smallest error (22%). Hence, for boreal forest monitoring L-band images acquired at dry/unfrozen conditions should be used.
BibTeX:
@conference{Santoro2002231,
  author = {Santoro, M. and Askne, J. and Eriksson, L. and Schmullius, C. and Wiesmann, A. and Fransson, J.E.S.},
  editor = {Owe M., D'Urso G., Toulios L.},
  title = {Seasonal dynamics and stem volume retrieval in boreal forests using JERS-1 backscatter},
  booktitle = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2002},
  volume = {4879},
  pages = {231-242},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038532566&doi=10.1117%2f12.462441&partnerID=40&md5=d706910980d982cdecab84324c47b03b},
  doi = {10.1117/12.462441}
}
Santoro M, Askne J, Smith G and Fransson J (2002), "Stem volume retrieval in boreal forests from ERS-1/2 interferometry", Remote Sensing of Environment. Vol. 81(1), pp. 19-35.
Abstract: C-band repeat-pass interferometry, in particular, the coherence, has been shown to be of great potential for stem volume retrieval. For boreal forests, we have investigated a stem volume retrieval method based on inversion of ERS-1/2 coherence measurements by means of a semiempirical model. A multitemporal combination of several stem volume estimates has been used in order to reduce errors in the estimation. The retrieval procedure was first applied in a forest estate located in Kattbole, Sweden, where accurate in situ measurements were taken. Stem volume was determined both at the stand level (between 2 and 14 ha) and at the pixel level (25 × 25 m). A multitemporal combination of coherence data acquired in stable winter-type conditions gave the most accurate results. Based on the results obtained in Kattbole, the retrieval procedure was extended to a large area of 4235 km2 around Kattbole. Retrieval was performed in all forested areas on a pixel basis (25 × 25 m), generating stem volume maps. In Kattbole, at the stand level, stem volume up to 350 m3/ha was estimated with an error comparable to the ground truth, i.e. 10 m3/ha. At the pixel level, the error reached the value of 55 and 71 m3/ha in the forest estate and in the large area, respectively. Compared to the results from the stand analysis, the higher error is believed to be mainly due to the higher uncertainty of coherence estimation at high stem volume and to geometric mismatch between field data and coherence data. Moreover, over large areas, spatial variation of the parameters in the model should be considered. 2002 Elsevier Science Inc. All rights reserved.
BibTeX:
@article{Santoro200219,
  author = {Santoro, M. and Askne, J. and Smith, G. and Fransson, J.E.S.},
  title = {Stem volume retrieval in boreal forests from ERS-1/2 interferometry},
  journal = {Remote Sensing of Environment},
  year = {2002},
  volume = {81},
  number = {1},
  pages = {19-35},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036262746&doi=10.1016%2fS0034-4257%2801%2900329-7&partnerID=40&md5=0e25dfdbda780169cc325df84b2ba31f},
  doi = {10.1016/S0034-4257(01)00329-7}
}
Santoro M, Schmullius C, Eriksson L and Hese S (2002), "The SIBERIA and SIBERIA-II projects: An overview", In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 4886, pp. 247-256.
Abstract: The international EU-funded SIBERIA project (1998-2000) aimed at the production of an extensive forest map using spaceborne SAR data acquired by the ERS and JERS satellites. For a large geographical region (900.000 km2) located in the Central Siberian Plateau, one-day ERS coherence and JERS backscatter were used to retrieve growing stock volume. A classification algorithm based on peaks in the coherence and backscatter histograms was used. Four volume classes, water and open land were considered. An independent test in 10 areas showed an accuracy above 80%. The produced forest map serves as a tool for the sustainable management of Siberian natural resources and for a better understanding of the role of boreal forests in climate change. The objective of the international EU-funded SIBERIA-EI project (2002-2005) is to demonstrate the viability of full carbon accounting, including all greenhouse gasses, with a multi-sensor approach over a 2 million-km2 area in Siberia. Having recently started, a general overview of the aims and the objectives of the project is given. Using several satellite observations available and the SIBERIA database, the first step consists in the generation of several Earth Observation (EO) products (such as biomass, phenological parameters, soil moisture, snow cover etc). Together with land-cover information from local institutions, these products will be input to two dynamic vegetation models for full regional carbon accounting. To increase knowledge, additional products such as Afforestation-Reforestation-Deforestation and fire scars maps are planned.
BibTeX:
@conference{Santoro2002247,
  author = {Santoro, M. and Schmullius, C. and Eriksson, L. and Hese, S.},
  editor = {Ehlers M.},
  title = {The SIBERIA and SIBERIA-II projects: An overview},
  booktitle = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2002},
  volume = {4886},
  pages = {247-256},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037613655&doi=10.1117%2f12.462357&partnerID=40&md5=6bc99a3c01405f02be78d6738aa7c6d3},
  doi = {10.1117/12.462357}
}
Schneeberger K, Stamm C, Matzler C, Fluhler H, Lehmann E and Willneff J (2002), "Multifrequency ground-based radiometer and in-situ measurements of soil moisture at high temporal resolution", In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 4879, pp. 174-183.
Abstract: A field experiment with two different ground-based radiometers centered at a 5m X 10m bare soil plot was reported. As such, the brightness temperature measured with passive microwave sensors contains information on surface water content that was already spatially averaged. Furthermore, the water content was measured in-situ with time domain reflectometry probe (TDR) assembled at five depths.
BibTeX:
@conference{Schneeberger2002174,
  author = {Schneeberger, K. and Stamm, C. and Matzler, C. and Fluhler, H. and Lehmann, E. and Willneff, J.},
  editor = {Owe M., D'Urso G., Toulios L.},
  title = {Multifrequency ground-based radiometer and in-situ measurements of soil moisture at high temporal resolution},
  booktitle = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2002},
  volume = {4879},
  pages = {174-183},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037518512&doi=10.1117%2f12.462376&partnerID=40&md5=ccc60c1fcc6db211bbc4e05f36091be5},
  doi = {10.1117/12.462376}
}
Schneeeberger K, Stamm C, Matzler C, Wydler H and Fluhler H (2002), "Influence of soil structure on topsoil water dynamics observed by a groundbased 11.4 GHz microwave radiometer - First results", In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 4542, pp. 122-129.
Abstract: For various applications in soil science, hydrology and climatology it is important to estimate soil hydraulic properties over large areas. The methods to quantify them have been of limited success so far. One of the main difficulties is the influence of soil structure on infiltration and drainage of soils. The classical soil physical methods cannot be applied because they yield local measurements of properties, which are spatially averaged over sampling volumes of soil columns but not over plots or entire fields. One way out of this dilemma may be the use of microwave radiometry to quantify the dynamics of surface water contents and use this information as a proxy variable to estimate the hydraulic properties of the underlying soil. This study reports on a field experiment conducted from April to July 2001. Beside measuring the dynamics of the water content in the topsoil by a ground-based 11.4 GHz microwave radiometer, we carried out in-situ measurements of water content, temperature and matric potential. The infiltration pattern, visualized with a blue dye tracer added to the infiltrating solution, showed that both soils were strongly susceptible to preferential flow. The changes in topsoil water content seemed to be well comparable to the changes in the measured reflectivities.
BibTeX:
@conference{Schneeeberger2002122,
  author = {Schneeeberger, K. and Stamm, C. and Matzler, C. and Wydler, H. and Fluhler, H.},
  title = {Influence of soil structure on topsoil water dynamics observed by a groundbased 11.4 GHz microwave radiometer - First results},
  booktitle = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2002},
  volume = {4542},
  pages = {122-129},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036398366&doi=10.1117%2f12.454204&partnerID=40&md5=3e6748a73e037d35eede1967ccecdacd},
  doi = {10.1117/12.454204}
}
Stamm C, Schneeberger K, Fluhler H and Matzler C (2002), "Estimating soil hydraulic properties from time-series of remotely sensed and in-situ measured topsoil water contents", In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 4879, pp. 211-220.
Abstract: Soil hydraulic properties are needed in many applications. One of the most difficult quantities to assess is the hydraulic conductivity function. One reason for this is the influence of soil structure on the infiltration capacity. In this paper we present an approach to estimate the hydraulic properties-based on time-series of water contents measured in the topsoil of an experimental field plot. Based on the van Genuchten-Mualem model for the soil hydraulic functions we investigate how these properties affect the dynamics of the topsoil water content. We postulate that the water retention curve can be estimated from the range of the top soil water contents observable in the field. The experimental evidence obtained in the plot experiment supports this theoretical conjection. With regard to the hydraulic conductivity function simulations of the drying process demonstrate that there is no straightforward, linear effect of the saturated conductivity Ks on the drying rate. Depending on the initial conditions and the water retention curve drying may be faster or slower with increasing values of Ks. Despite this non-linear behavior the simulation results indicate that for certain soils the influence of soil structure on the conductivity function may be observed by monitoring diurnal cycles of water content. The lack of these cycles in the measured data points to a small Ks-value for the soil matrix of the experimental plot. This is in agreement with the infiltration patterns observed on that plot. A further way to detect bimodal pore-size distributions consists in measuring during a number of drying periods that differ substantially in the initial water distribution in the profile. Simulations show larger effects on the drying rate caused by larger Ks-values.
BibTeX:
@conference{Stamm2002211,
  author = {Stamm, C. and Schneeberger, K. and Fluhler, H. and Matzler, C.},
  editor = {Owe M., D'Urso G., Toulios L.},
  title = {Estimating soil hydraulic properties from time-series of remotely sensed and in-situ measured topsoil water contents},
  booktitle = {Proceedings of SPIE - The International Society for Optical Engineering},
  year = {2002},
  volume = {4879},
  pages = {211-220},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038193903&doi=10.1117%2f12.462382&partnerID=40&md5=5597f45b3e364c7a5a55d412b9fe0320},
  doi = {10.1117/12.462382}
}
Strozzi T, Luckman A, Murray T, Wegmüller U and Werner C (2002), "Glacier motion estimation using SAR offset-tracking procedures", IEEE Transactions on Geoscience and Remote Sensing. Vol. 40(11), pp. 2384-2391.
Abstract: Two image-to-image patch offset techniques for estimating feature motion between satellite synthetic aperture radar (SAR) images are discussed. Intensity tracking, based on patch intensity cross-correlation optimization, and coherence tracking, based on patch coherence optimization, are used to estimate the movement of glacier surfaces between two SAR images in both slant-range and azimuth direction. The accuracy and application range of the two methods are examined in the case of the surge of Monacobreen in Northern Svalbard between 1992 and 1996. Offset-tracking procedures of SAR images are an alternative to differential SAR interferometry for the estimation of glacier motion when differential SAR interferometry is limited by loss of coherence, i.e., in the case of rapid and incoherent flow and of large acquisition time intervals between the two SAR images. In addition, an offset-tracking procedure in the azimuth direction may be combined with differential SAR interferometry in the slant-range direction in order to retrieve a two-dimensional displacement map when SAR data of only one orbit configuration are available.
BibTeX:
@article{Strozzi20022384,
  author = {Strozzi, T. and Luckman, A. and Murray, T. and Wegmüller, U. and Werner, C.L.},
  title = {Glacier motion estimation using SAR offset-tracking procedures},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {2002},
  volume = {40},
  number = {11},
  pages = {2384-2391},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036875613&doi=10.1109%2fTGRS.2002.805079&partnerID=40&md5=15050d6165eec5236529011d54f7a0a7},
  doi = {10.1109/TGRS.2002.805079}
}
Strozzi T, Wegmüller U, Werner C and Wiesmann A (2002), "Alpine landslide periodical survey", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 6, pp. 3629-3631.
Abstract: Potential and limitations of differential SAR interferometry for the periodical survey of alpine displacements are investigated. For the alpine territory, which is characterized by low vegetation, C-band differential SAR interferometry shows a relatively high coherence during the snow-free season permitting the detection and monitoring of unstable slopes on a regular basis. Limitations to the spatial coverage arise from decorrelation over forested and snow covered areas and from layover and shadowing caused by the very rugged topography. Significant results in the Swiss Alps using ERS-1/2 SAR data are used as support to our investigations.
BibTeX:
@conference{Strozzi20023629,
  author = {Strozzi, T. and Wegmüller, U. and Werner, C. and Wiesmann, A.},
  title = {Alpine landslide periodical survey},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2002},
  volume = {6},
  pages = {3629-3631},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036399339&partnerID=40&md5=4cd82f67b7070b6e8e66481b775392e3}
}
Strozzi T, Wegmüller U, Werner C and Wiesmann A (2002), "JERS SAR interferometry for land subsidence monitoring", In European Space Agency, (Special Publication) ESA SP. (475), pp. 145-150.
Abstract: In this paper the potential of L-Band repeat-pass differential SAR interferometry for land subsidence monitoring is evaluated using JERS SAR data. Bologna, Mexico City and the Ruhrgebiet were selected as application sites representing slow to fast deformation velocities. The investigation includes feasibility aspects as the data availability, the temporal decorrelation over different landcover classes and the range of useful spatial baselines, an analysis of the achieved deformation accuracy and considerations on the complementarity to ERS SAR interferometry and levelling surveys. In spite of the rather limited data availability, land subsidence maps could be generated for the three selected application sites. Unlike with ERS C-Band SAR data, JERS L-Band interferometry permitted to retrieve subsidence values also over vegetated areas and forest when using interferograms of less than one year acquisition time interval and short baseline. In addition, the longer L-Band wavelength was found to be superior in the case of large deformation gradients that lead to phase unwrapping problems in C-Band interferometry.
BibTeX:
@conference{Strozzi2002145,
  author = {Strozzi, T. and Wegmüller, U. and Werner, C. and Wiesmann, A.},
  title = {JERS SAR interferometry for land subsidence monitoring},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2002},
  number = {475},
  pages = {145-150},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036182575&partnerID=40&md5=77ff33b4e17c92cfa9c096799fdd4733}
}
Tosi L, Carbognin L, Teatini P, Strozzi T and Wegmüller U (2002), "Evidence of the present relative land stability of Venice, Italy, from land, sea, and space observations", Geophysical Research Letters. Vol. 29(12), pp. 3-1-3-4. American Geophysical Union.
Abstract: The city of Venice is very vulnerable to loss in surface elevation as a result of subsidence and eustacy because of its small elevation above sea level. The alarm of the scientific community related to this persistent problem is increasing because of the forecasts of sea level rise caused by global warming. In order to evaluate the present relative subsidence of Venice, a study has been performed by combining high precision leveling, Satellite Radar Interferometry (SRI) and tide gauge measurements. The analysis of the most recent data points out with an unprecedented detail the present ground stability of the city.
BibTeX:
@article{Tosi20023-1,
  author = {Tosi, L. and Carbognin, L. and Teatini, P. and Strozzi, T. and Wegmüller, U.},
  title = {Evidence of the present relative land stability of Venice, Italy, from land, sea, and space observations},
  journal = {Geophysical Research Letters},
  publisher = {American Geophysical Union},
  year = {2002},
  volume = {29},
  number = {12},
  pages = {3-1-3-4},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037098775&doi=10.1029%2f2001GL013211&partnerID=40&md5=f26de12e75695111421828b74fc8bbcc},
  doi = {10.1029/2001GL013211}
}
Wegmüller U, Wiesmann A, Honikel M, Strozzi T and Werner C (2002), "Potential roles for space-borne SAR in disaster management and humanitarian relief", In European Space Agency, (Special Publication) ESA SP. (475), pp. 307-311.
Abstract: This contribution is an assessment of possible roles of space-borne SAR in disaster management and humanitarian relief projects. Time constraints, data selection, and the selected approach depend strongly on the specific task requested. Different categories of tasks were identified, including rapid mapping (i.e. making cartographic information available for a poorly mapped area in a short period of time), hazard mapping (i.e. mapping the spatial extent and the degree of damage which occurred in a hazard event), thematic mapping for reconstruction planning, and risk assessment. The results of an evaluation of the methodology, potential, and limitations of SAR for rapid mapping and hazard mapping based on specific examples are presented.
BibTeX:
@conference{Wegmuller2002307,
  author = {Wegmüller, U. and Wiesmann, A. and Honikel, M. and Strozzi, T. and Werner, C.L.},
  title = {Potential roles for space-borne SAR in disaster management and humanitarian relief},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2002},
  number = {475},
  pages = {307-311},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036179467&partnerID=40&md5=adb25c6cb979fe515f6c0120b84684db}
}
Wegmüller U, Wiesmann A, Strozzi T and Werner C (2002), "ENVISAT ASAR in disaster management and humanitarian relief", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 2282-2284.
Abstract: Space-borne SAR has a good potential to support disaster management and humanitarian relief projects thanks to its all-weather capability, its capabilities for change detection, the large existing data archives, and, of course, the geometric and thematic information content of the images. Basic processing techniques, including precision image co-registration, multi-temporal analysis, terrain corrected geocoding, interferometry, and radargrammetry, are well developed and operational. This contribution is an assessment of possible roles of space-borne SAR and in particular ENVISAT ASAR in disaster management and humanitarian relief projects. Relevant additional functionality of ASAR as compared to ERS-1/2 comes from the beam-steering, multipolarization, larger angle, wide-angle, and scan-SAR capability.
BibTeX:
@conference{Wegmuller20022282,
  author = {Wegmüller, U. and Wiesmann, A. and Strozzi, T. and Werner, C.},
  title = {ENVISAT ASAR in disaster management and humanitarian relief},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2002},
  volume = {4},
  pages = {2282-2284},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036399021&partnerID=40&md5=ce345e2d0bf42013dede15ad2e10857f}
}
Werner C, Strozzi T, Wegmüller U and Wiesmann A (2002), "SAR geocoding and multi-sensor image registration", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 902-904.
Abstract: Quantitative analyses of remote sensing data acquired with variable geometries and different sensors are greatly facilitated by geocoding the data to a common geographical reference. Errors in geocoded SAR images are due to inaccuracies in the orbit data, errors in the processing parameters, and DEM errors. Automated terrain geocoding of SAR data is possible using only a single resampling of the native slant-range to the final map geometry after measurement and correction for residual geolocation errors. An accurate adaptive resampling algorithm for the interpolation from the SAR geometry to the map coordinate system is presented. This processing paradigm has been extended to permit combining data from different SAR instruments.
BibTeX:
@conference{Werner2002902,
  author = {Werner, C. and Strozzi, T. and Wegmüller, U. and Wiesmann, A.},
  title = {SAR geocoding and multi-sensor image registration},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2002},
  volume = {2},
  pages = {902-904},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036029369&partnerID=40&md5=782e2426af9eb5e3ee1e2ab170985a71}
}
Wiesmann A, Wegmüller U, Honikel M, Strozzi T and Werner C (2002), "Hazard mapping with multi-temporal SAR and InSAR", In European Space Agency, (Special Publication) ESA SP. (475), pp. 133-138.
Abstract: In our hazard mapping methodology multi-temporal SAR backscattering and multi-temporal coherence data are considered. Process models are used to characterize the targets before, during and/or after the hazard event. Forward models describe the effect on the backscatter and coherence data, allowing development of a strategy and to specify the classification algorithm used. Results presented for these different types of hazard events are forest storm damage, flood, and avalanche mapping. The temporal behavior of the backscattering coefficient and the temporal behavior of the coherence (determined from ERS tandem data) permitted detecting the change, leading to a damage map. For the investigated events, the presented methodology proved to be robust and reliable. Careful radiometric calibration, coregistration, geolocalisation, and estimation schemes were found to be important for the quality of the results.
BibTeX:
@conference{Wiesmann2002133,
  author = {Wiesmann, A. and Wegmüller, U. and Honikel, M. and Strozzi, T. and Werner, C.L.},
  title = {Hazard mapping with multi-temporal SAR and InSAR},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2002},
  number = {475},
  pages = {133-138},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036179532&partnerID=40&md5=a995b98ff6b4ca1b233912c4e865f611}
}
Fanelli A, Ferri M, Santoro M and Vitale A (2001), "Analysis of coherence images over urban areas in the extraction of buildings heights", In IEEE/ISPRS Joint Workshop on Remote Sensing and Data Fusion over Urban Areas, DFUA 2001. , pp. 69-73. Institute of Electrical and Electronics Engineers Inc..
Abstract: In this paper we show how ERS coherence imagery can be useful to extract information about building heights in urban areas. The first part analyses the causes of decorrelation over urban areas. Spatial decorrelation is partially offset by spectral shift filtering, while thermal and processor decorrelation can be neglected. In order to extract building heights, we use tandem coherence only, so that temporal coherence can be set equal to one. Hence, the estimated coherence over built-up areas coincides with volume scattering decorrelation. Using the Van Cittert Zernike theorem, we introduce a model for the backscatter coefficient of urban areas. This model links volume decorrelation to a height variable so that theoretical coherence values can be obtained for varying heights. At this stage, it is possible to compare theoretical and experimental values of tandem coherence and mean heights of buildings can be extracted. To test the procedure, four sites in Italy, have been considered. For one area, results show that in situ measurements are in agreement with values of building heights obtained from coherence comparison. For two areas, results seem to agree with local observations. For the fourth area, discrepancies occur, probably due to weather effects. Hence, the described procedure seems to be promising and more accurate results may be achieved using fine resolution coherence images. However, the effects of weather on tandem coherence in urban areas should be investigated and taken into account. 2001 IEEE.
BibTeX:
@conference{Fanelli200169,
  author = {Fanelli, A. and Ferri, M. and Santoro, M. and Vitale, A.},
  title = {Analysis of coherence images over urban areas in the extraction of buildings heights},
  booktitle = {IEEE/ISPRS Joint Workshop on Remote Sensing and Data Fusion over Urban Areas, DFUA 2001},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {2001},
  pages = {69-73},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84960917203&doi=10.1109%2fDFUA.2001.985729&partnerID=40&md5=8e3971fbe7bd735b420fdf932b3bd7ba},
  doi = {10.1109/DFUA.2001.985729}
}
Ingold T, Matzler C, Kampfer N and Heimo A (2001), "Aerosol optical depth measurements by means of a Sun photometer network in Switzerland", Journal of Geophysical Research Atmospheres. Vol. 106(D21), pp. 27537-27554. Blackwell Publishing Ltd.
Abstract: Within the Swiss Atmospheric Radiation Monitoring program (CHARM) the Swiss Meteorological Institute - MeteoSwiss operates a network of presently six Sun photometer stations. Aerosol optical depths (AOD) at 368, 500, and 778 nm were determined from measurements of the relative direct solar irradiance, primarily to provide climatological information relevant in particular to climate change studies. The six instruments are located at various sites representative of high and low altitudes at the north and south part of the Alps in areas free from urban pollution in Switzerland. AOD time series of recordings back to 1991 are discussed, when data were first collected at Davos. An important aerosol layer is often present over stations at lower sites, showing seasonal variability and regional differences for the observed tropospheric aerosols. A classification scheme for synoptic weather types was applied to separate the AOD data into groups corresponding to different atmospheric transport conditions. On average, lower AODs are measured within advective weather situations than within convective ones. However, at the high Alpine sites such a classification is incomplete for AOD characterization due to orographically induced vertical motion. Monthly averaged values of AOD at 500 nm ranged from 0.05 during winter up to 0.3 in summer. The scale height of the aerosol optical depth is found to be 1-2 km depending on season. The high mountain sites are more suitable to the study stratospheric aerosols, for example, the change of the aerosol content and of its size distribution due to Mount Pinatubo eruption was clearly identified at Davos. In 1996 the aerosol optical depth returned to pre-Pinatubo values. Minimum AODs of ≈0.004-0.007 measured at 500 nm in 1997 are in good agreement with widely reported aerosol optical depth measurements of the stratospheric background aerosols. Besides the Pinatubo-affected period aerosol characterization by means of the Ångstrom power law exhibits on average a mean wavelength exponent of 1.3-1.8. A climatology of the AOD data obtained between 1994 and 2000 in both space and time has been established. Copyright 2001 by the American Geophysical Union.
BibTeX:
@article{Ingold200127537,
  author = {Ingold, T. and Matzler, C. and Kampfer, N. and Heimo, A.},
  title = {Aerosol optical depth measurements by means of a Sun photometer network in Switzerland},
  journal = {Journal of Geophysical Research Atmospheres},
  publisher = {Blackwell Publishing Ltd},
  year = {2001},
  volume = {106},
  number = {D21},
  pages = {27537-27554},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035654596&doi=10.1029%2f2000JD000088&partnerID=40&md5=a17f8e2c7d1fed40698862078c1a1b41},
  doi = {10.1029/2000JD000088}
}
Ingold T, Matzler C, Wehrli C, Heimo A, Kampfer N and Philipona R (2001), "Ozone column density determination from direct irradiance measurements in the ultraviolet performed by a four-channel precision filter radiometer", Applied Optics. Vol. 40(12), pp. 1989-2003.
Abstract: Ultraviolet light was measured at four channels (305, 311, 318, and 332 nm) with a precision filter radiometer (UV-PFR) at Arosa, Switzerland (46.78°, 9.68°, 1850mabove sea level), within the instrument trial phase of a cooperative venture of the Swiss Meteorological Institute MeteoSwiss! and the Physikalisch-Meteorologisches Observatorium DavosyWorld Radiation Center. We retrieved ozonecolumn density data from these direct relative irradiance measurements by adapting the Dobson standard method for all possible single-difference wavelength pairs and one double-difference pair (305/311 and 305/318) under conditions of cloud-free sky and of thin clouds (cloud optical depth, 2.5 at 500 nm). All UV-PFR retrievals exhibited excellent agreement with those of collocated Dobson and Brewer spectrophotometers for data obtained during two months in 1999. Combining the results of the error analysis and the findings of the validation, we propose to retrieve ozone-column density by using the 305/311 single difference pair and the double-difference pair. Furthermore, combining both retrievals by building the ratio of ozone-column density yields information that is relevant to data quality control. Estimates of the 305/311 pair agree with measurements by the Dobson and Brewer instruments within 1% for both the mean and the standard deviation of the differences. For the double pair these values are in a range up to 1.6%. However, this pair is less sensitive to model errors. The retrieval performance is also consistent with satellite-based data from the Earth Probe Total Ozone Mapping Spectrometer (EP-TOMS) and the Global Ozone Monitoring Experiment instrument (GOME). 2001 Optical Society of America.
BibTeX:
@article{Ingold20011989,
  author = {Ingold, T. and Matzler, C. and Wehrli, C. and Heimo, A. and Kampfer, N. and Philipona, R.},
  title = {Ozone column density determination from direct irradiance measurements in the ultraviolet performed by a four-channel precision filter radiometer},
  journal = {Applied Optics},
  year = {2001},
  volume = {40},
  number = {12},
  pages = {1989-2003},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0007433841&doi=10.1364%2fAO.40.001989&partnerID=40&md5=edc2d6d58a5a209e5fe60f0c29d07d15},
  doi = {10.1364/AO.40.001989}
}
Strozzi T, Tosi L, Teatini P, Wegmüller U, Carbognin L, Werner C and Wiesmann A (2001), "SAR interferometry confirms the present land stability of Venice", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1321-1323.
Abstract: The city of Venice is very vulnerable to loss in land elevation as a result of subsidence and eustacy because of its small elevation above sea level. The alarm of the scientific community related to this persistent problem is increasing because of the forecasts of sea level rise caused by global warming. In order to evaluate the present relative settlement of Venice, a study has been performed by combining high precision levelling surveys and SAR interferometry. The analysis points out at an unprecedented detail the present ground stability of the city.
BibTeX:
@conference{Strozzi20011321,
  author = {Strozzi, T. and Tosi, L. and Teatini, P. and Wegmüller, U. and Carbognin, L. and Werner, C. and Wiesmann, A.},
  title = {SAR interferometry confirms the present land stability of Venice},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2001},
  volume = {3},
  pages = {1321-1323},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035575238&partnerID=40&md5=4bf3044c52acca4d99dbb8166d6640fb}
}
Strozzi T, Wegmüller U, Tosi L, Bitelli G and Spreckels V (2001), "Land subsidence monitoring with differential SAR interferometry", Photogrammetric Engineering and Remote Sensing. Vol. 67(11), pp. 1261-1270.
Abstract: The potential of differential SAR interferometry for land subsidence monitoring is reported on. The principle of the technique and the approach to be used on a specific case are first presented. Then significant results using SAR data from the ERS satellites for various sites in Germany, Mexico, and Italy, representing fast (m/year) to slow (mm/year) deformation velocities, are discussed. The SAR interferometric displacement maps are validated with available leveling data. The accuracy of the subsidence maps produced, the huge SAR data archive starting in 1991, the expected continued availability of SAR data, and the maturity of the required processing techniques lead to the conclusion that differential SAR interferometry is suitable for operational monitoring of land subsidence.
BibTeX:
@article{Strozzi20011261,
  author = {Strozzi, T. and Wegmüller, U. and Tosi, L. and Bitelli, G. and Spreckels, V.},
  title = {Land subsidence monitoring with differential SAR interferometry},
  journal = {Photogrammetric Engineering and Remote Sensing},
  year = {2001},
  volume = {67},
  number = {11},
  pages = {1261-1270},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034760223&partnerID=40&md5=238af32cc49251589937158dfd043e3f}
}
Werner C, Strozzi T, Wiesmann A, Wegmüller U, Murray T, Pritchard H and Luckman A (2001), "Complimentary measurement of geophysical deformation using repeat-pass SAR", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 7, pp. 3255-3258.
Abstract: Differential radar interferometry has proven to be an excellent method to measure displacements associated with geophysical phenomena such as glacier flow, subsidence, tectonic plate motion, and earthquake displacement. Since the technique utilizes the interferometric phase, it is limited in cases where large displacements in the slant range direction result in complete decorrelation. Similarly, if the surface deformation causes rotation of the scene or other disturbance the interferometric signal will be lost. The geophysical displacement field can also be measured via incoherent or coherent cross-correlation of small image chips. This method has the advantages that it does not require phase unwrapping In cases where there is some degree of interferometric coherence between data acquisitions, the single-look complex image speckles themselves become features that can be accurately tracked. This method is complimentary to the phase-based approach since it works well with the large displacements. Examples for the successful application of the two techniques are found in the mapping of the velocity fields of surging glaciers and displacement fields of major earthquakes. Furthermore, image cross-correlation measurements yield the two-dimensional displacement field while measurements of the phase yield deformation only along the line-of-sight. Accuracy of the cross-correlation method is dependent on the scene content, correlation, and image chip size.
BibTeX:
@conference{Werner20013255,
  author = {Werner, C. and Strozzi, T. and Wiesmann, A. and Wegmüller, U. and Murray, T. and Pritchard, H. and Luckman, A.},
  title = {Complimentary measurement of geophysical deformation using repeat-pass SAR},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2001},
  volume = {7},
  pages = {3255-3258},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035569067&partnerID=40&md5=00a4a9e605e05e4109c18810a5f97764}
}
Wiesmann A, Wegmüller U, Honikel M, Strozzi T and Werner C (2001), "Potential and methodology of satellite based SAR for hazard mapping", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 7, pp. 3262-3264.
Abstract: SAR and InSAR data have a high potential for change detection due to their "all weather" capability and the day/night access of the sensors. Here we investigate the potential and methodology for forest storm, flood, and avalanche mapping with ERS1/2 data. In our methodology process models are used to describe the targets before, during and/or after the hazard event. Very important are the good relative calibration and accurate coregistration of the different information layers. The presented results demonstrate the good potential of multitemporal SAR and InSAR data for hazard mapping.
BibTeX:
@conference{Wiesmann20013262,
  author = {Wiesmann, A. and Wegmüller, U. and Honikel, M. and Strozzi, T. and Werner, C.L.},
  title = {Potential and methodology of satellite based SAR for hazard mapping},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {2001},
  volume = {7},
  pages = {3262-3264},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035571743&partnerID=40&md5=b6d8ccbb15bb2bd175a736f218fc8f2e}
}
Castel T, Martinez J-M, Beaudoin A, Wegmüller U and Strozzi T (2000), "ERS INSAR data for remote sensing hilly forested areas", Remote Sensing of Environment. Vol. 73(1), pp. 73-86. Elsevier Science Inc, New York, NY, United States.
Abstract: ERS INSAR data have proved to be of interest for forest applications. The interferometric coherence was found to be related to various land uses and forest types, while in some special cases (e.g., flat terrain) the interferometric phase has been linked to the forest height. This paper reports an investigation on the information content of the interferometric coherence over a hilly terrain supporting various land use types and large pine plantations. The approach includes the use of a Geographic Information System and multitemporal data to analyze the coherence behavior as a function of forest-type forest parameters and environmental factors such as meteorological and topographic effects. Coherence appears to be efficient to discriminate between forest types. However, topography and environmental conditions strongly affect the coherence and its estimation, pointing out the need for rejection of strong slopes areas (>15°) and the sensitivity to local meteorological/seasonal effects. Based on these observations, forest classification results are presented. Forest/nonforest discrimination is very efficient (accuracy >90%) using one-day interval acquisition. More detailed classification with discrimination between forest themes gives also good results. Then, we investigate the indirect link between coherence and forest parameters. The coherence is sensitive to the forest growth stage, making forest parameter retrieval possible using a simple straight-line model. Finally, the importance of wind upon temporal decorrelation is addressed, and a semiempirical correction is proposed. (C) Elsevier Science Inc., 2000.
ERS INSAR data have proved to be of interest for forest applications. The interferometric coherence was found to be related to various land uses and forest types, while in some special cases (e.g., flat terrain) the interferometric phase has been linked to the forest height. This paper reports an investigation on the information content of the interferometric coherence over a hilly terrain supporting various land use types and large pine plantations. The approach includes the use of a Geographic Information System and multitemporal data to analyze the coherence behavior as a function of forest-type forest parameters and environmental factors such as meteorological and topographic effects. Coherence appears to be efficient to discriminate between forest types. However, topography and environmental conditions strongly affect the coherence and its estimation, pointing out the need for rejection of strong slopes areas (>15°) and the sensitivity to local meteorological/seasonal effects. Based on these observations, forest classification results are presented. Forest/nonforest discrimination is very efficient (accuracy >90%) using one-day interval acquisition. More detailed classification with discrimination between forest themes gives also good results. Then, we investigate the indirect link between coherence and forest parameters. The coherence is sensitive to the forest growth stage, making forest parameter retrieval possible using a simple straight-line model. Finally, the importance of wind upon temporal decorrelation is addressed, and a semiempirical correction is proposed.
BibTeX:
@article{Castel200073,
  author = {Castel, T. and Martinez, J.-M. and Beaudoin, A. and Wegmüller, U. and Strozzi, T.},
  title = {ERS INSAR data for remote sensing hilly forested areas},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Science Inc, New York, NY, United States},
  year = {2000},
  volume = {73},
  number = {1},
  pages = {73-86},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033922230&doi=10.1016%2fS0034-4257%2800%2900083-3&partnerID=40&md5=785d7e56dc726cb328c9dd6b6d9f3edf},
  doi = {10.1016/S0034-4257(00)00083-3}
}
Costantini M, Rosen P and Werner C (2000), "Preventing and masking out unreliable results for critical quantitative applications of phase unwrapping", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 7, pp. 3199-3201. IEEE, Piscataway, NJ, United States.
Abstract: Phase unwrapping is the reconstruction of a phase function on a grid given its cyclical values (i.e., the values modulo 2π). Phase unwrapping is usually considered successful when errors are concentrated in small regions, and do not propagate throughout the data set. However, for certain applications, even errors on isolated pixels can be critical. For example, when building a digital terrain model (DEM) from synthetic aperture radar (SAR) interferometry, a wrong phase ambiguity can cause an height error of a hundred meters, which is clearly undesirable even for a few pixels. Here we present two approaches for preventing and masking out possible phase unwrapping errors, associated with the branch cut and the network flow based phase unwrapping methods, respectively. The methods are statistically validated on SAR interferometric data simulating the Shuttle Radar Topography Mission (SRTM) data. The tests performed show the validity of the proposed methods, and the importance of excluding possible unreliable phase unwrapping results.
BibTeX:
@conference{Costantini20003199,
  author = {Costantini, M. and Rosen, P.A. and Werner, C.L.},
  title = {Preventing and masking out unreliable results for critical quantitative applications of phase unwrapping},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {2000},
  volume = {7},
  pages = {3199-3201},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034543271&partnerID=40&md5=6237f4653cfd2f95f279f0d24bc70ce9}
}
Fanelli A, Santoro M, Vitale A, Murino P and Askne J (2000), "Understanding ERS Coherence over Urban Areas", In European Space Agency, (Special Publication) ESA SP. (461), pp. 2268-2275.
Abstract: C-band SAR interferometry has been widely used for several Earth related studies (topography, volcanology, forestry etc.). Nevertheless, not much attention has been paid to urban areas and coherence has been used for classification purposes only. In this study we focused on the meaning of coherence of an urban area and performed several analysis in order to understand what causes decorrelation. Two test sites have been considered: Gothenburg in Sweden and Naples in Italy. For both cities we had a reasonable number of coherence images with one-day and long-period acquisition interval. SAR amplitude images have also been considered. Using RGB colour composite combinations of SAR and InSAR imagery, we could relate the level of coherence of a part of a city either to topography, InSAR system geometry and position of the targets or to image processing or to structural typologies.
BibTeX:
@conference{Fanelli20002268,
  author = {Fanelli, A. and Santoro, M. and Vitale, A. and Murino, P. and Askne, J.},
  editor = {Sawaya-Lacoste H.},
  title = {Understanding ERS Coherence over Urban Areas},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {461},
  pages = {2268-2275},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0347361334&partnerID=40&md5=baca0daf70314dca8a58eaec72eddaec}
}
Ingold T, Schmid B, Matzler C, Demoulin P and Kampfer N (2000), "Modeled and empirical approaches for retrieving columnar water vapor from solar transmittance measurements in the 0.72, 0.82, and 0.94 μm absorption bands", Journal of Geophysical Research Atmospheres. Vol. 105(D19), pp. 24327-24343. Blackwell Publishing Ltd.
Abstract: A Sun photometer (18 channels between 300 and 1024 nm) has been used for measuring the columnar content of atmospheric water vapor (CWV) by solar transmittance measurements in absorption bands with channels centered at 719, 817, and 946 nm. The observable is the band-weighted transmittance function defined by the spectral absorption of water vapor and the spectral features of solar irradiance and system response. The transmittance function is approximated by a three-parameter model. Its parameters are determined from MODTRAN and LBLRTM simulations or empirical approaches using CWV data of a dual-channel microwave radiometer (MWR) or a Fourier transform spectrometer (FTS). Data acquired over a 2-year period during 1996-1998 at two different sites in Switzerland, Bern (560 m above sea level (asl)) and Jungfraujoch (3580 m asl) were compared to MWR, radiosonde (RS), and FTS retrievals. At the low-altitude station with an average CWV amount of 15 mm the LBLRTM approach (based on recently corrected line intensities) leads to negligible biases at 719 and 946 nm if compared to an average of MWR, RS, and GPS retrievals. However, at 817 nm an overestimate of 2.7 to 4.3 mm (18-29%) remains. At the high-altitude station with an average CWV amount of 1.4 mm the LBLRTM approaches overestimate the CWV by 1.0, 1.4, and 0.1 mm (58, 76, and 3%) at 719, 817, and 946 nm, compared to the FTS instrument. At the low-altitude station, CWV estimates, based on empirical approaches, agree with the MWR within 0.4 mm (2.5% of the mean); at the high-altitude site with a factor of 10 less water vapor the agreement of the SPM with the FTS is 0.0 to 0.2 mm (1 to 9% of the mean CWV there). Sensitivity analyses show that for the conditions met at the two stations with CWV ranging from 0.2 to 30 mm, the retrieval errors are smallest if the 946 nm channel is used. Copyright 2000 by the American Geophysical Union.
BibTeX:
@article{Ingold200024327,
  author = {Ingold, T. and Schmid, B. and Matzler, C. and Demoulin, P. and Kampfer, N.},
  title = {Modeled and empirical approaches for retrieving columnar water vapor from solar transmittance measurements in the 0.72, 0.82, and 0.94 μm absorption bands},
  journal = {Journal of Geophysical Research Atmospheres},
  publisher = {Blackwell Publishing Ltd},
  year = {2000},
  volume = {105},
  number = {D19},
  pages = {24327-24343},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033665341&doi=10.1029%2f2000JD900392&partnerID=40&md5=d2fcd2957b68a1512882909b122b1187},
  doi = {10.1029/2000JD900392}
}
Luckman A, Baker J and Wegmüller U (2000), "Repeat-pass interferometric coherence measurements of disturbed tropical forest from JERS and ERS satellites", Remote Sensing of Environment. Vol. 73(3), pp. 350-360. Elsevier Science Inc, New York, NY, United States.
Abstract: The phase coherence between repeat-pass SAR observations of a tropical forest region was investigated as a source of information for biophysical characteristics in regenerating and undisturbed areas of forest. SAR imagery was acquired and interferometric coherence maps were derived for a 1-day repeat pair at C-band, using ERS-1 and ERS-2, and for 44-day and 132-day repeats at L-band, using JERS. The backscattering coefficient and coherence characteristics were analyzed in conjunction with biomass density estimates determined from field measurements and land cover characteristics derived from an annual sequence of Landsat TM imagery. The results demonstrate that repeat-pass coherence adds significantly to the information available from SAR imagery of tropical forest. (C) Elsevier Science Inc., 2000.
The phase coherence between repeat-pass SAR observations of a tropical forest region was investigated as a source of information for biophysical characteristics in regenerating and undisturbed areas of forest. SAR imagery was acquired and interferometric coherence maps were derived for a 1-day repeat pair at C-band, using ERS-1 and ERS-2, and for 44-day and 132-day repeats at L-band, using JERS. The backscattering coefficient and coherence characteristics were analyzed in conjunction with biomass density estimates determined from field measurements and land cover characteristics derived from an annual sequence of Landsat TM imagery. The results demonstrate that repeat-pass coherence adds significantly to the information available from SAR imagery of tropical forest.
BibTeX:
@article{Luckman2000350,
  author = {Luckman, A. and Baker, J. and Wegmüller, U.},
  title = {Repeat-pass interferometric coherence measurements of disturbed tropical forest from JERS and ERS satellites},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Science Inc, New York, NY, United States},
  year = {2000},
  volume = {73},
  number = {3},
  pages = {350-360},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034284584&doi=10.1016%2fS0034-4257%2800%2900110-3&partnerID=40&md5=ae6380d55a8d8a8bb4cf04931da5c5e5},
  doi = {10.1016/S0034-4257(00)00110-3}
}
Luckman A, Tansey K, Strozzi T, Skinner L and Balzter H (2000), "Global forest classification using JERS and tandem ERS data", In European Space Agency, (Special Publication) ESA SP. (461), pp. 1804-1809.
Abstract: One of the main objectives of the remote sensing, and the scientific community in general, is the development of models and algorithms that are applicable at the global scale. This is especially true for improving methods of forest inventory for carbon accounting. A forest classification scheme based entirely on satellite SAR data, developed for a large area of Siberian Taiga forest and tested using Russian forestry service ground data is applied to different forested systems elsewhere in the world. The scheme is based on tandem ERS coherence and JERS backscatter and stratifies the forest into 6 classes including three timber volume classes. Thirty-five test sites in Siberia, each between 20,000 and 100,000 ha in size, are used to develop the classification algorithm and a further 12 Siberian sites were used in its validation. After accuracy assessment the algorithm was applied to tropical and managed, temperate forest test sites. The results, quantified using kappa statistics, for forests very different in structure to Russian Boreal Forests are surprisingly good although differences in the quality of ground truth make comparisons difficult.
BibTeX:
@conference{Luckman20001804,
  author = {Luckman, A. and Tansey, K. and Strozzi, T. and Skinner, L. and Balzter, H.},
  editor = {Sawaya-Lacoste H.},
  title = {Global forest classification using JERS and tandem ERS data},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {461},
  pages = {1804-1809},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0347991639&partnerID=40&md5=45cb7b3671f07ead08cd818e4c88b41c}
}
Luo X, Askne J, Smith G, Santoro M and Fransson J (2000), "An analysis of insar coherence of boreal forests based on electromagnetic scattering modeling", In European Space Agency, (Special Publication) ESA SP. (461), pp. 1090-1101.
Abstract: In this paper an electromagnetic scattering model, RT2, and a semi-empirical model, interferometric water cloud model (IWCM), were used to simulate backscatter and coherence of boreal forest at C-band. The coherence is related to the backscattering coefficients of the vegetation and the underlying ground surface, and the transmissivity of forests via the IWCM model where interactions between vegetation and ground are ignored at C-band. Using RT2, backscattering contributions from the vegetation and the ground, and the transmissivity of forests were simulated and compared with basic assumptions in IWCM. It has been found that IWCM contains all the important mechanisms affecting forest coherence and backscattering. Simulations of backscattering coefficient and coherence by the electromagnetic model agree well with ERS SAR experimental data from a test site, Kattbole, in the central part of Sweden and the IWCM model fitting. The effects of soil and vegetation moisture were also simulated.
BibTeX:
@conference{Luo20001090,
  author = {Luo, X. and Askne, J. and Smith, G. and Santoro, M. and Fransson, J.E.S.},
  editor = {Sawaya-Lacoste H.},
  title = {An analysis of insar coherence of boreal forests based on electromagnetic scattering modeling},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {461},
  pages = {1090-1101},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0347991676&partnerID=40&md5=f8885fa4fad9ef12be181e1a0464259d}
}
Matzler C (2000), "A simple snowpack/cloud reflectance and transmittance model from microwave to ultraviolet: The ice-lamella pack", Journal of Glaciology. Vol. 46(152), pp. 20-24. International Glaciology Society.
Abstract: Modeling the reflectance and transmittance of strong volume scatterers is a delicate task. Slightly different approaches can lead to different results, making comparisons difficult. Here a simple, analytic multiple-scattering model is presented as a possible reference for comparisons and also for better understanding of the physics involved. The model quantifies the transmittance and reflectance of homogeneously distributed scatterers within slabs of any thickness. The simplicity of the model is given by the one-dimensional geometry, a system consisting of freely arranged ice lamellae in air. Although direct application of the model will be limited, it gives a spectral description of ice clouds and snowpacks over a very broad spectral range from microwave to ultraviolet. As well as the transmittance and reflectance, the model gives the emittance through Kirchhoff's law. Comparison with other models shows, on the one hand, agreement with current snow models in the spectral description, and on the other, some quantitative inconsistencies between all of them. It appears that the lamella pack produces the same optical spectra as an average snow model, with spherical ice grains whose radius corresponds to about the lamella thickness, whereas microwave spectra appear to be slightly different.
BibTeX:
@article{Matzler200020,
  author = {Matzler, C.},
  title = {A simple snowpack/cloud reflectance and transmittance model from microwave to ultraviolet: The ice-lamella pack},
  journal = {Journal of Glaciology},
  publisher = {International Glaciology Society},
  year = {2000},
  volume = {46},
  number = {152},
  pages = {20-24},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0342368238&doi=10.3189%2f172756500781833476&partnerID=40&md5=f250e3947619cc50a6b7e830deea1f10},
  doi = {10.3189/172756500781833476}
}
Matzler C and Standley A (2000), "Technical note: Relief effects for passive microwave remote sensing", International Journal of Remote Sensing. Vol. 21(12), pp. 2403-2412.
Abstract: The signal of a microwave radiometer observing a land surface from space is composed of surface and atmospheric contributions, both of which depend on the relief. For proper interpretation of the data these effects should be quantified and, if necessary, taken into account. Relief effects are twofold. First, the path through the atmosphere between the surface and the sensor depends on the altitude of the emitting surface, thus leading to a height-dependent atmospheric influence. The effect can be taken into account by standard atmospheric radiative transfer models if the elevation of the surface and the atmospheric state are known. Second, more relevant for the present discussion is the variable topography of land surfaces, consisting of slopes, ridges and valleys, sometimes with characteristic alignments, and surfaces surrounded by elevated terrain. These surfaces interact radiatively, not only with the atmosphere, but also with each other, leading to the tendency to enhance the effective emission. Under such circumstances, deviations occur from the standard hemispheric emission of a horizontal surface. The interactions do not only depend on topography and emissivity, but also on the bistatic scattering behaviour. Special attention will be paid to the radiation enhancement in a landscape of Lambertian surfaces with elevated horizons. As an example, simulated data for southern Norway are shown. 2000 Taylor & Francis Group, LLC.
BibTeX:
@article{Matzler20002403,
  author = {Matzler, C. and Standley, A.},
  title = {Technical note: Relief effects for passive microwave remote sensing},
  journal = {International Journal of Remote Sensing},
  year = {2000},
  volume = {21},
  number = {12},
  pages = {2403-2412},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033889625&doi=10.1080%2f01431160050030538&partnerID=40&md5=7c12c4ad01157516f4217d8021a9c64c},
  doi = {10.1080/01431160050030538}
}
Matzler C, Wiesmann A and Strozzi T (2000), "Simulation of microwave emission and backscattering of layered snowpacks by a radiative transfer model, and validation by surface-based experiments", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 1548-1550. IEEE, Piscataway, NJ, United States.
Abstract: A thermal Microwave Emission Model of Layered Snowpacks (MEMLS) was developed for the frequency range, 5 to 100 GHz. It is based on six-flux radiative transfer to describe multiple volume scattering, absorption, and refractive effects. MEMLS is a physical model with a semi-empirical part in the description of the scattering coefficient, and later this element was completed by a fully physical scattering theory. Model validation included surface-based radiometer experiments and detailed in-situ data. In a further step to be presented here, we tested MEMLS by using Chandrasekhar's H-Functions. Here we show how they can be applied to a refractive medium such as snow. As an effect of refraction a Lambert-like behavior is obtained. Since the formalism is bistatic, it also delivers the backscattering coefficient, yielding the link to radar data. Data from active and passive microwave experiments will be used to test the models.
BibTeX:
@conference{Matzler20001548,
  author = {Matzler, C. and Wiesmann, A. and Strozzi, T.},
  title = {Simulation of microwave emission and backscattering of layered snowpacks by a radiative transfer model, and validation by surface-based experiments},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {2000},
  volume = {4},
  pages = {1548-1550},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034540561&partnerID=40&md5=a510338b61816f581f687dd5f6008e6f}
}
Santoro M, Askne J, Dammert P, Fransson J and Smith G (2000), "Retrieval of Biomass in Boreal Forest from Multi-temporal ERS-1/2 Interferometry", In European Space Agency, (Special Publication) ESA SP. (478), pp. 401-408.
Abstract: It is well known that C-band repeat-pass InSAR coherence can more accurately predict boreal forest stem volume than microwave radar backscatter. In this paper two boreal forest areas have been studied, one in Finland and one in Sweden. In spite of the small number of forest stands (approximately 40 stands at each site with mean area of 7 ha and stem volume range of 350 m 3/ha and 550 m3/ha) a division in two halves has been made, one considered as reference stands and one as test stands. The observed coherence and backscatter values have been fitted to the interferometric water cloud model and a multi-temporal combination of up to seven InSAR pairs has been performed. For one of the test sites the accuracy of the best single pair is 36 m3/ha (equal to 22 tons/ha), while a multi-temporal combination increases the accuracy to 21 m3/ha (equal to 13 tons/ha). For the other test site the values are 91 m3/ha, and 89 m 3/ha respectively. The results in this case are believed to be caused by differences between species distribution and also by weather conditions. We conclude that in some cases multi-temporal InSAR is able to provide extremely good stem volume estimates.
BibTeX:
@conference{Santoro2000401,
  author = {Santoro, M. and Askne, J. and Dammert, P.B.G. and Fransson, J.E.S. and Smith, G.},
  title = {Retrieval of Biomass in Boreal Forest from Multi-temporal ERS-1/2 Interferometry},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {478},
  pages = {401-408},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0347651371&partnerID=40&md5=d594f7f22b82480741adbf396ed6c853}
}
Santoro M, Askne J, Smith G, Dammert P and Fransson J (2000), "Boreal Forest Monitoring with ERS Coherence", In European Space Agency, (Special Publication) ESA SP. (461), pp. 335-346.
Abstract: C-band repeat-pass InSAR coherence from ERS-1/-2 satellites has been shown to be a valuable parameter for retrieval of stem volume in boreal forests, being more accurate than microwave radar backscatter. In this work we have presented a procedure to estimate stem volume from coherence measurements, obtained with careful InSAR processing due to the low coherence of forested areas. At first a boreal forest test site, located in Sweden, with 42 homogeneous stands has been studied (mean area 7 ha and stem volume range of 350 m3/ha); a division in two halves has been made, one considered as training stands and one as test stands. By means of the interferometric water cloud model, backscatter and coherence observations have been related to stem volume and a multi-temporal combination of single-image estimates has been performed using up to 9 pairs. Higher accuracy was obtained using coherence, the best being 21 m3/ha (equal to 12.6 tons/ha) from a single pair and 10 m3/ha (equal to 6 tons/ha) from a multi-temporal combination of four pairs. The retrieval procedure has been successively applied to a large area surrounding the local test site (4235 km2) on a pixel basis and forest stem volume maps have been produced. Having used the 42 stands as a training set and 133 NFI plots located in the area as a test set, the multi-temporal approach based on the four most accurate pairs from the local area analysis gave an accuracy of 58 m3/ha (ca. 35 tons/ha). Because of the unavailability of ground-truth data in the large area, the retrieval procedure could not be tested at a stand level. Results are very good at stand level and promising at plot level.
BibTeX:
@conference{Santoro2000335,
  author = {Santoro, M. and Askne, J. and Smith, G. and Dammert, P.B.G. and Fransson, J.E.S.},
  editor = {Sawaya-Lacoste H.},
  title = {Boreal Forest Monitoring with ERS Coherence},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {461},
  pages = {335-346},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0347359110&partnerID=40&md5=3eb8635f73cf8de6c711eb945f438a13}
}
Strozzi T, Dammert P, Wegmüller U, Martinez J-M, Askne J, Beaudoin A and Hallikainen M (2000), "Landuse mapping with ERS SAR interferometry", IEEE Transactions on Geoscience and Remote Sensing. Vol. 38(2 I), pp. 766-775. IEEE, United States.
Abstract: Two landuse maps and a forest map of three different areas in Europe were completed with ERS SAR interferometry. The test sites represent various geomorphological regions with different cover types. In this article, the mapping algorithms are presented, the results are summarized, and the potential and limitations of ERS SAR interferometry for landuse mapping are discussed. Overall, the results suggest that landuse classification accuracies on the order of 75% are possible with, in the best case, simultaneous forest and nonforest accuracies of around 80-85%. The presence of topography reduces the performance.
BibTeX:
@article{Strozzi2000766,
  author = {Strozzi, T. and Dammert, P.B.G. and Wegmüller, U. and Martinez, J.-M. and Askne, J.I.H. and Beaudoin, A. and Hallikainen, M.T.},
  title = {Landuse mapping with ERS SAR interferometry},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {IEEE, United States},
  year = {2000},
  volume = {38},
  number = {2 I},
  pages = {766-775},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033879942&doi=10.1109%2f36.842005&partnerID=40&md5=2d90dae148ddacb46ed68a4d6f0820c7},
  doi = {10.1109/36.842005}
}
Strozzi T, Luckman A and Murray T (2000), "The evolution of a glacier surge observed with the ERS satellites", In European Space Agency, (Special Publication) ESA SP. (461), pp. 851-857.
Abstract: A time series of ERS-1/2 SAR data from September 1991 to September 1998 was used to monitor the complete surge cycle of Monacobreen in Northwest Svalbard. Significant information for the study of this glacier was provided to glaciologists by the analysis of the backscattering coefficient images (in particular for the position and the crevasses of the front of the glacier), by the use of differential SAR interferometry in descending and ascending mode to retrieve displacement and height maps, and by applying coherence and feature tracking where surge velocities exceed the regime within which interferometric phase could be usefully interpreted. The result for Monacobreen is a complete map of temporal and spatial velocity structure from the beginning of the surge to its end.
BibTeX:
@conference{Strozzi2000851,
  author = {Strozzi, T. and Luckman, A. and Murray, T.},
  editor = {Sawaya-Lacoste H.},
  title = {The evolution of a glacier surge observed with the ERS satellites},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {461},
  pages = {851-857},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0346730957&partnerID=40&md5=3df7b8ead81112bbcff03d9780383cca}
}
Strozzi T, Tosi L, Carbognin L, Wegmüller U and Galgaro A (2000), "Monitoring Land Subsidence in the Euganean Geothermal Basin with Differential SAR Interferometry", In European Space Agency, (Special Publication) ESA SP. (478), pp. 167-176.
Abstract: Land subsidence of the Euganean Geothermal Basin, Italy, is a well-known process which is related to the geothermal groundwater withdrawal. Up to 1991 the maximum rate of land subsidence has been 1 cm/year as observed from precision levelling surveys. From 1991 to 1995 a decrease of land lowering due to a regulation of groundwater withdrawal has been measured. In this study the question of a convenient use of differential SAR interferometry for land subsidence mapping in the Euganean Geothermal Basin was addressed using a time series of ERS-1 and ERS-2 SAR data from 1992 to 1996. Multiple interferograms were combined into a single subsidence map in order to reduce errors caused by atmospheric phase distortions, phase unwrapping, baseline estimation and noise. The analysis revealed a clear subsidence signal over Abano Terme with a maximum annual subsidence velocity of 4 mm/year that is in agreement with the results of the last levelling surveys performed in 1991 and 1995. The comparison of SAR interferometry and levelling surveys also indicates advantages and disadvantages of both techniques, individually used, that should be considered for an accurate, rationale and cost-effective monitoring of subsidence. In any case an integrated survey could provide the best way to investigate the regional subsidence process.
BibTeX:
@conference{Strozzi2000167,
  author = {Strozzi, T. and Tosi, L. and Carbognin, L. and Wegmüller, U. and Galgaro, A.},
  title = {Monitoring Land Subsidence in the Euganean Geothermal Basin with Differential SAR Interferometry},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {478},
  pages = {167-176},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0346421093&partnerID=40&md5=4bec3b5e996d28e9a8e00c58119159af}
}
Strozzi T, Wegmüller U, Werner C and Wiesmann A (2000), "Measurement of slow uniform surface displacement with mm/year accuracy", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 2239-2241. IEEE, Piscataway, NJ, United States.
Abstract: Interferogram stacking, a technique to improve the relative accuracy of SAR interferometric surface displacement mapping based on a combination of multiple interferograms, is presented. Its potential and usefulness is demonstrated with the land subsidence cases of Bologna and the Euganean Geothermal Basin (Italy). For one of the investigated cases the potential to map slow uniform surface displacements at mm/year accuracy is confirmed by the validation with levelling data.
BibTeX:
@conference{Strozzi20002239,
  author = {Strozzi, Tazio and Wegmüller, Urs and Werner, Charles and Wiesmann, Andreas},
  title = {Measurement of slow uniform surface displacement with mm/year accuracy},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {2000},
  volume = {5},
  pages = {2239-2241},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034542959&partnerID=40&md5=5b39ae6d55d97ecdb5574f0ccc647cc6}
}
Wegmüller U, Strozzi T, Farr T and Werner C (2000), "Arid land surface characterization with repeat-pass SAR interferometry", IEEE Transactions on Geoscience and Remote Sensing. Vol. 38(2 I), pp. 776-781. IEEE, United States.
Abstract: Repeat pass ERS SAR interferometry was used to map different surface types of the Death Valley Salt Pan. At this arid site, the surface roughness varies between extremely smooth (salt lakes, clay pan) and very rough (alluvial fans, eroded salt formations). The moisture varies from very dry (alluvial fans) to wet (wet clay, salt crust with water ponds) with seasonal changes in certain areas. While the surface geometry is stable for certain surface types (alluvial fans, thick salt crusts), it changes for others as a result of the changing water level and erosion by wind and rain. The changing surface roughness, moisture, and vegetation conditions cause large variations of the backscattering and coherence. This information is used to distinguish different surface types. Furthermore, interferometry was used to map the topographic height. In a second part of the study, the potential of the degree of coherence to retrieve information on the vegetation density and the surface erosion was evaluated.
BibTeX:
@article{Wegmuller2000776,
  author = {Wegmüller, U. and Strozzi, T. and Farr, T. and Werner, C.L.},
  title = {Arid land surface characterization with repeat-pass SAR interferometry},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {IEEE, United States},
  year = {2000},
  volume = {38},
  number = {2 I},
  pages = {776-781},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033871379&doi=10.1109%2f36.842006&partnerID=40&md5=96b145791343e5a43a058aa0eaa526ae},
  doi = {10.1109/36.842006}
}
Wegmüller U, Strozzi T and Tosi L (2000), "ERS and ENVISAT differential SAR interferometry for subsidence monitoring", In European Space Agency, (Special Publication) ESA SP. (461), pp. 203-210.
Abstract: This paper reports on the potential of differential SAR interferometry to map land subsidence. After a presentation of the methodology, the focus will be on feasibility demonstration and accuracy assessment The theoretical considerations are verified with the selected cases Ruhrgebiet, Mexico City, Bologna, and Euganean Geothermal Basin, representing fast (m/year) to slow (mm/year) deformation velocities. The accuracy of the generated deformation maps and the maturity of the required processing techniques lead to the conclusion that differential SAR interferometry has a very high potential for operational mapping of land subsidence. The high reliability of the ERS satellites, with the huge data archive starting in 1991, strongly supports this application. The planned ENVISAT ASAR has the potential to maintain good data availability into the future. This will, nevertheless, strongly depend on the sensor operation strategy.
BibTeX:
@conference{Wegmuller2000203,
  author = {Wegmüller, U. and Strozzi, T. and Tosi, L.},
  editor = {Sawaya-Lacoste H.},
  title = {ERS and ENVISAT differential SAR interferometry for subsidence monitoring},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {461},
  pages = {203-210},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0347361418&partnerID=40&md5=42c43704f8b7276cc336bd57c16768c8}
}
Wegmüller U, Strozzi T, Werner C, Wiesmann A, Benecke N and Spreckels V (2000), "Monitoring of mining-induced surface deformation in the Ruhrgebiet (Germany) with SAR interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 6, pp. 2771-2773. IEEE, Piscataway, NJ, United States.
Abstract: Subsurface coal mining causes significant surface deformations. In this contribution the potential and limitations of ERS repeat-pass differential SAR interferometry for mining induced surface deformation monitoring is evaluated based on the example of the German Ruhrgebiet. ERS data in ascending and descending mode, including Tandem pairs suited to estimate the topography related phase, are used for the analysis. Especially for urban areas the technique performs well as confirmed through validation with mining information. The main limiting factor identified is temporal decorrelation of the signal which does not allow estimation of surface deformation velocities in forested and in many cases agricultural areas.
BibTeX:
@conference{Wegmuller20002771,
  author = {Wegmüller, Urs and Strozzi, Tazio and Werner, Charles and Wiesmann, Andreas and Benecke, Norbert and Spreckels, Volker},
  title = {Monitoring of mining-induced surface deformation in the Ruhrgebiet (Germany) with SAR interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {2000},
  volume = {6},
  pages = {2771-2773},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034543281&partnerID=40&md5=463af4694336acc4b5479b1d4679b342}
}
Wegmüller U, Strozzi T, Wiesmann A and Werner C (2000), "Land subsidence mapping with ERS interferometry: Evaluation of maturity and operational readiness", In European Space Agency, (Special Publication) ESA SP. (478), pp. 243-251.
Abstract: Differential SAR interferometry with ERS data has a high potential for surface displacement mapping in the mm to m range. Such displacement information is of interest for the monitoring of phenomena as land subsidence, land slides, earthquakes, volcano swelling, and ice motion. In this contribution the maturity and operational readiness of the SAR interferometric technique are discussed, focusing on the subsidence application. The investigation is based on examples representing displacement velocities between a few mm/year and several m/year. Based on the investigated examples it is concluded that SAR interferometric subsidence mapping reached operational readiness.
BibTeX:
@conference{Wegmuller2000243,
  author = {Wegmüller, U. and Strozzi, T. and Wiesmann, A. and Werner, C.},
  title = {Land subsidence mapping with ERS interferometry: Evaluation of maturity and operational readiness},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {478},
  pages = {243-251},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0346421070&partnerID=40&md5=150f8b80cda682a6eac87b66d401d6bb}
}
Werner C, Wegmüller U, Strozzi T and Wiesmann A (2000), "GAMMA SAR and interferometric processing software", In European Space Agency, (Special Publication) ESA SP. (461), pp. 211-219.
Abstract: The GAMMA Modular SAR Processor (MSP), Interferometric SAR Processor (ISP), Differential Interferometry and Geocoding Software (DIFF&GEO), and Land Application Tools (LAT) are modular software packages useful to process synthetic aperture radar (SAR) images. Data of both spaceborne and airborne sensors including ERS-1/2, JERS-1, SIRC, SEASAT, RADARSAT StripMap mode, and the single-pass Dornier DOSAR interferometer have been successfully processed interferometrically. State of the art algorithms have been implemented to achieve accurate processing of the data while permitting timely processing of large data sets. Recent projects completed with the software include generation of a continental scale mosaic of Siberia consisting of more 700 JERS scenes in the frame of the SIBERIA project and the generation of subsidence maps for Bologna, Abano, and Mexico City. User-friendly display tools and full documentation in HTML language complements the software. Both binary and source code licenses are available. Recent developments included the adaptation of the software to the PC operating systems LINUX and NT and the improvement of the functionality for differential SAR interferometry. Furthermore, as part of our ERS AO3 project (ERS AO3-175), software demonstration, training, and testing examples have been developed for distribution to users. Development in the near future will include the adaptation of the software to the processing of ENVISAT ASAR (with data provided through ENV AO-210) and ALOS PALSAR (ALOS AO proposal accepted) data.
BibTeX:
@conference{Werner2000211,
  author = {Werner, C. and Wegmüller, U. and Strozzi, T. and Wiesmann, A.},
  editor = {Sawaya-Lacoste H.},
  title = {GAMMA SAR and interferometric processing software},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {461},
  pages = {211-219},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0347991717&partnerID=40&md5=04eab5fdaf72eab776082144d628fe3d}
}
Werner CL, Wiesmann A, Siegert F and Kuntz S (2000), "JERS INSAR DEM generation for Borneo", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 2248-2250. IEEE, Piscataway, NJ, United States.
Abstract: The Sebuku-Sembakung area of north-eastern Kalimantan, Indonesia (Borneo) has been proposed by the WWF as a national park because of its large biodiversity with habitats including various types of tropical forests and swamps. Currently, only low resolution DEM data exists for the area. This has motivated an effort to produce a topographic map of the region using L-Band repeat pass interferometry with JERS-1 data. Significant coverage exists for the area and passes were selected on the basis of coverage, time interval and baseline. Regions with sufficient interferometric correlation for DEM production over the 44 day repeat interval are mangrove and tidal swamp forests. Other surface classes including peat swamp, Lowland Mixed and Hill Dipterocarp forest have lower correlation that precludes generation accurate topography from the available JERS-1 data in these areas.
BibTeX:
@conference{Werner20002248,
  author = {Werner, Charles L. and Wiesmann, Andreas and Siegert, Florian and Kuntz, Steffen},
  title = {JERS INSAR DEM generation for Borneo},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {2000},
  volume = {5},
  pages = {2248-2250},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034548174&partnerID=40&md5=b406b6c6378ca91bdc59057736e19e66}
}
Wiesmann A, Demargne L, Ribbes F, Honikel M, Yesou H and Wegmüller U (2000), "Forest storm damage assessment with ERS tandem data", In European Space Agency, (Special Publication) ESA SP. (461), pp. 913-921.
Abstract: A novel method to map storm damage in forest is discussed. It is shown that damaged forest areas can be clearly discriminated from undamaged forest. The presented approach is based on the temporal behavior of the interferometric correlation using 2 ERS tandem pairs, one before and one after the storm. The method was successfully applied in several regions of France and Switzerland sustaining a wide applicability of the approach. The results are compared with in-situ and optical satellite data validating the good reliability of the technique.
BibTeX:
@conference{Wiesmann2000913,
  author = {Wiesmann, A. and Demargne, L. and Ribbes, F. and Honikel, M. and Yesou, H. and Wegmüller, U.},
  editor = {Sawaya-Lacoste H.},
  title = {Forest storm damage assessment with ERS tandem data},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {461},
  pages = {913-921},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0346100390&partnerID=40&md5=aa24abe562b0443013c84b2029335c2a}
}
Wiesmann A, Fierz C and Matzler C (2000), "Simulation of microwave emission from physically modeled snowpacks", Annals of Glaciology. Vol. 31, pp. 397-401.
Abstract: Detailed knowledge of snowpack properties is crucial for the interpretation and modeling of thermal microwave radiation. Here we use two well-known snow models, Crocus and SNTHERM, to obtain snow profiles from meteorological data. These profiles are compared with pit profiles and used as input to the Microwave Emission Model of Layered Snowpacks (MEMLS) for the simulation of microwave radiation. The snow-profile data can be applied almost directly. Adaptation is needed only in the conversion of the grain-size used in the snow models to the correlation length used in the emission model; it is based on empirical fits. The resulting emissivitics are compared with in situ microwave measurements. The computed snow depths are in good agreement with observations. Comparison of selected profiles shows that Crocus is in good agreement with the pit profile, but the density of simulated melt-freeze crusts is underestimated. The SNTHERM profiles show no such crusts, and the density deviates from the pit profiles. The computed temporal behavior of the snowpack emissivity is reasonable. Comparison of selected situations with in situ measurements indicates good agreement. However, the polarization difference tends to be underestimated because of inaccuracies in the simulation of density profiles. The results show the potential of combined snow-physical and microwave-emission models for understanding snow signatures and for developing snow algorithms for microwave remote sensing. Based on the frequency-selective penetration and on the high sensitivity to snow texture, density and wetness, microwave radiometry can offer a new dimension to snow physics. Potential applications are described.
BibTeX:
@article{Wiesmann2000397,
  author = {Wiesmann, A. and Fierz, C. and Matzler, C.},
  title = {Simulation of microwave emission from physically modeled snowpacks},
  journal = {Annals of Glaciology},
  year = {2000},
  volume = {31},
  pages = {397-401},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034496993&partnerID=40&md5=c051600a6304d3450ab10998f8ac6989}
}
Wiesmann A, Wegmüller U, Strozzi T and Werner C (2000), "JERS INSAR coherence over Siberian boreal forest", In European Space Agency, (Special Publication) ESA SP. (461), pp. 2092-2096.
Abstract: In the frame of the EC Environment and Climate Program project, SIBERIA, an extensive forest map for a part of Siberia was produced using state-of-the art satellite data and remote sensing techniques. Among other sensors the JERS SAR was used. In this contribution the focus is on the JERS data mosaicing and the JERS coherence interpretation.
BibTeX:
@conference{Wiesmann20002092,
  author = {Wiesmann, A. and Wegmüller, U. and Strozzi, T. and Werner, C.L.},
  editor = {Sawaya-Lacoste H.},
  title = {JERS INSAR coherence over Siberian boreal forest},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {2000},
  number = {461},
  pages = {2092-2096},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0346100364&partnerID=40&md5=eb30599ff36bb27b16ea0cf869d77fee}
}
Wiesmann A, Wegmüller U, Strozzi T and Werner CL (2000), "Use of JERS SAR within the boreal forest mapping project SIBERIA", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. 13-15. IEEE, Piscataway, NJ, United States.
Abstract: In the frame of the EC Environment and Climate Program project, SIBERIA, an extensive forest map for a part of Siberia will be produced using state-of-the art satellite data and remote sensing techniques. Among other sensors the JERS SAR will be used. In this contribution important steps in the JERS processing will be discussed, including radiometric calibration, geocoding, and final products.
BibTeX:
@conference{Wiesmann200013,
  author = {Wiesmann, Andreas and Wegmüller, Urs and Strozzi, Tazio and Werner, Charles L.},
  title = {Use of JERS SAR within the boreal forest mapping project SIBERIA},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {2000},
  volume = {1},
  pages = {13-15},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034546936&partnerID=40&md5=5ca5c04c58a05bbe5980d1e06bf1f059}
}
Dammert PB and Wegmüller U (1999), "DEM generation over forested terrain with ERS and JERS SAR interferometry", Doktorsavhandlingar vid Chalmers Tekniska Hogskola. (1547), pp. 1-22. Chalmers Tekniska Hogskola, Goteborg, Sweden.
Abstract: SAR interferometry digital elevation models (INSAR DEMs) over boreal forested terrain were retrieved using the spaceborne sensors ERS-1/2 and JERS-1. In spite of the normally low forest coherence for ERS-1/2 and JERS-1 (in this case down to around 0.1) and long orbit repeat time for JERS-1 (44 days), high-quality DEMs were retrieved from seven interferometric pairs over an area in northern Sweden. The RMS errors were usually below 5 m for the ERS cases and down to 7 m for the JERS cases when comparing with a high-quality external reference DEM (at 50 m postings). As expected, DEM errors were the smallest in cases of high overall coherence. Atmospheric disturbances were present in at least two cases, rendering one case (the summer ERS DEM case) almost useless. The trees in a forest also interact with the measurements and an extra height is added over the forests in the DEM. Three forest stands in the area were investigated and it was shown that there is a positive height bias over boreal forests and it may vary a lot between different INSAR DEMs. In the present case, the best DEMs were obtained with ERS, partly due to better interferometric baselines than the JERS cases, with an accuracy of 3 m RMS which is comparable to the 2.5 m error of the external reference DEM.
BibTeX:
@article{Dammert19991,
  author = {Dammert, Patrik B.G. and Wegmüller, Urs},
  title = {DEM generation over forested terrain with ERS and JERS SAR interferometry},
  journal = {Doktorsavhandlingar vid Chalmers Tekniska Hogskola},
  publisher = {Chalmers Tekniska Hogskola, Goteborg, Sweden},
  year = {1999},
  number = {1547},
  pages = {1-22},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033294613&partnerID=40&md5=d5e563054d127a06c6452566055213e2}
}
Dammert PB and Wegmüller U (1999), "JERS INSAR DEM quality assessment for a boreal test site", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 1930-1932. IEEE, Piscataway, NJ, United States.
Abstract: Two JERS-1 differential interferograms were analyzed over a boreal test site with forests in northern Sweden. Although the 44-day repeat-orbit, the coherence was adequate to generate one JERS-1 DEM. The RMS error was 7.9 m at 50 m postings. The extra height introduced by forest covers was close to the real tree height in the area.
BibTeX:
@conference{Dammert19991930,
  author = {Dammert, Patrik B.G. and Wegmüller, Urs},
  title = {JERS INSAR DEM quality assessment for a boreal test site},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1999},
  volume = {4},
  pages = {1930-1932},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033331903&partnerID=40&md5=013a214d795c5646d8b7b99ad332d48b}
}
Joughin I, Gray L, Bindschadler R, Price S, Morse D, Hulbe C, Mattar K and Werner C (1999), "Tributaries of West Antarctic ice streams revealed by RADARSAT interferometry", Science. Vol. 286(5438), pp. 283-286.
Abstract: Interferometric RADARSAT data are used to map ice motion in the source areas of four West Antarctic ice streams. The data reveal that tributaries, coincident with subglacial valleys, provide a spatially extensive transition between slow inland flow and rapid ice stream flow and that adjacent ice streams draw from shared source regions. Two tributaries flow into the stagnant ice stream C, creating an extensive region that is thickening at an average rate of 0.49 meters per year. This is one of the largest rates of thickening ever reported in Antarctica.
BibTeX:
@article{Joughin1999283,
  author = {Joughin, I. and Gray, L. and Bindschadler, R. and Price, S. and Morse, D. and Hulbe, C. and Mattar, K. and Werner, C.},
  title = {Tributaries of West Antarctic ice streams revealed by RADARSAT interferometry},
  journal = {Science},
  year = {1999},
  volume = {286},
  number = {5438},
  pages = {283-286},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033536643&doi=10.1126%2fscience.286.5438.283&partnerID=40&md5=d03424c9035c1cc64d69387450ff1ac7},
  doi = {10.1126/science.286.5438.283}
}
Matzler C and Wiesmann A (1999), "Extension of the microwave emission model of layered snowpacks to coarse-grained snow", Remote Sensing of Environment. Vol. 70(3), pp. 317-325. Elsevier Science Inc, New York, NY, United States.
Abstract: The microwave emission model of layered snowpacks (MEMLS) is a multilayer and multiple-scattering radiative transfer model developed for dry winter snow using an empirical parametrization of the scattering coefficient (se the copanion article). A limitation is in the applicable range of frequencies and correlation lengths. In order to extend the model, a physical determination of the volume-scattering coefficients, describing the coupling between the six fluxes, is developed here, based on the improved Born approximation. An exponential spatial autocorrelation function was selected. With this addition, MEMLS obtains a complete physical basis. The extended model is void of free parameters. The validation was done with two types of experiments made at the alpine test site, Weissfluhjoch: 1) radiometry at 11 GHz, 21 GHz, 35 GHz, 48 GHz, and 94 GHz of winter snow samples on a blackbody and on a metal plate, respectively, and 2) radiometric monitoring at 4.9 GHz, 10.4 GHz, 21 GHz, 35 GHz, and 94 GHz of coarse-grained crusts growing and decaying during melt-and-refreeze cycles. Digitized snow sections were used to measure snow structure in both experiments. The coarsest grains were found in the refrozen crusts with a correlation length up to 0.71 mm; the winter snow samples had smaller values, from 0.035 mm for new snow to about 0.33 mm for depth hoar. Good results have been obtained in all cases studied so far.
The microwave emission model of layered snowpacks (MEMLS) is a multilayer and multiple-scattering radiative transfer model developed for dry winter snow using an empirical parametrization of the scattering coefficient (se the copanion article). A limitation is in the applicable range of frequencies and correlation lengths. In order to extend the model, a physical determination of the volume-scattering coefficients, describing the coupling between the six fluxes, is developed here, based on the improved Born approximation. An exponential spatial autocorrelation function was selected. With this addition, MEMLS obtains a complete physical basis. The extended model is void of free parameters. The validation was done with two types of experiments made at the alpine test site, Weissfluhjoch: 1) radiometry at 11 GHz, 21 GHz, 35 GHz, 48 GHz, and 94 GHz of winter snow samples on a blackbody and on a metal plate, respectively, and 2) radiometric monitoring at 4.9 GHz, 10.4 GHz, 21 GHz, 35 GHz, and 94 GHz of coarse-grained crusts growing and decaying during melt-and-refreeze cycles. Digitized snow sections were used to measure snow structure in both experiments. The coarsest grains were found in the refrozen crusts with a correlation length up to 0.71 mm; the winter snow samples had smaller values, from 0.035 mm for new snow to about 0.33 mm for depth hoar. Good results have been obtained in all cases studied so far.
BibTeX:
@article{Matzler1999317,
  author = {Matzler, C. and Wiesmann, A.},
  title = {Extension of the microwave emission model of layered snowpacks to coarse-grained snow},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Science Inc, New York, NY, United States},
  year = {1999},
  volume = {70},
  number = {3},
  pages = {317-325},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-17544400907&doi=10.1016%2fS0034-4257%2899%2900047-4&partnerID=40&md5=3c44c1f310b780e92af4109c7a77c7c4},
  doi = {10.1016/S0034-4257(99)00047-4}
}
Schwank M, Muller U, Hauert R, Rossi R, Volkert M and Wintermantel E (1999), "Production of a microelectrode for intracellular potential measurements based on a Pt/Ir needle insulated with amorphous hydrogenated carbon", Sensors and Actuators, B: Chemical. Vol. 56(1), pp. 6-14. Elsevier Sequoia SA, Lausanne.
Abstract: A new microelectrode is presented, based on an electrochemically etched Pt/Ir needle with a high aspect ratio and a radius of curvature smaller than 1 μm. The needle is electrically insulated by a thin (15 to 20 nm) insulation film made of hydrogenated amorphous carbon (a-C:H). In order to use the needle as a microelectrode, the very end is made conductive again through a local oxygen plasma. The localization of the plasma is achieved in a specially designed scanning tunneling microscope (STM) working in a high pressure oxygen atmosphere. The reduction of the total resistance after the local plasma treatment was proved by measuring the transition resistance between the needle and a 0.1 M NaCl solution. It is supposed that the two processes responsible for the decrease of the resistance are: (a) the reduction of the thickness of the a-C:H insulation by reactive oxygen ion etching, (b) transformation of the a-C:H film into a more graphitic-like state (increased content of sp2 bondings) by a thermal process. The functioning of this new type of electrode was tested by measuring the transmembrane potential of mouse liver cells in vitro.
BibTeX:
@article{Schwank19996,
  author = {Schwank, M. and Muller, U. and Hauert, R. and Rossi, R. and Volkert, M. and Wintermantel, E.},
  title = {Production of a microelectrode for intracellular potential measurements based on a Pt/Ir needle insulated with amorphous hydrogenated carbon},
  journal = {Sensors and Actuators, B: Chemical},
  publisher = {Elsevier Sequoia SA, Lausanne},
  year = {1999},
  volume = {56},
  number = {1},
  pages = {6-14},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0344771073&doi=10.1016%2fS0925-4005%2899%2900026-X&partnerID=40&md5=bffeba458df2ea3561265c39fef115b7},
  doi = {10.1016/S0925-4005(99)00026-X}
}
Solimini D, Le Toan T, Schmullius C, Borgeaud M, Wegmüller U, Guissard A, Quegan S, Moreno J and Hoekman D (1999), "European RAdar-Optical Research Assemblage (ERA-ORA)", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 5, pp. 2729. IEEE, Piscataway, NJ, United States.
Abstract: The ERA-ORA is a co-operative project initiated with the objective of improving the radar data analysis and utilization tools developed by European researchers for Earth observation from space. This project strives to enlarge the available research tools by joining different sets of experimental data and theoretical models. A virtual Distributed Library (DL) will be organized, implemented and made electronically accessible both to the participants and subsequently to the open scientific community.
BibTeX:
@conference{Solimini19992729,
  author = {Solimini, D. and Le Toan, T. and Schmullius, C. and Borgeaud, M. and Wegmüller, U. and Guissard, A. and Quegan, S. and Moreno, J.F. and Hoekman, D.H.},
  title = {European RAdar-Optical Research Assemblage (ERA-ORA)},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1999},
  volume = {5},
  pages = {2729},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033333135&partnerID=40&md5=031b819e91fb58c138e1a944ff61e50e}
}
Strozzi T, Dammert P, Wegmüller U, Martinez J-M, Askne J, Beaudoin A and Hallikainen M (1999), "Landuse mapping with ERS SAR interferometry", Doktorsavhandlingar vid Chalmers Tekniska Hogskola. (1547), pp. 1-20. Chalmers Tekniska Hogskola, Goteborg, Sweden.
Abstract: Two landuse maps and a forest map of three different areas in Europe were completed with ERS SAR interferometry. The test sites represent various geomorphological regions with different cover types. In this article the mapping algorithms are presented, the results are summarized, and the potential and limitations of ERS SAR interferometry for landuse mapping are discussed. Overall, the results suggest that landuse classification accuracies on the order of 75% are possible with, in the best case, simultaneous forest and non-forest accuracies of around 80-85%. The presence of topography reduces the performance.
BibTeX:
@article{Strozzi19991,
  author = {Strozzi, Tazio and Dammert, Patrik and Wegmüller, Urs and Martinez, Jean-Michel and Askne, Jan and Beaudoin, Andre and Hallikainen, Martti},
  title = {Landuse mapping with ERS SAR interferometry},
  journal = {Doktorsavhandlingar vid Chalmers Tekniska Hogskola},
  publisher = {Chalmers Tekniska Hogskola, Goteborg, Sweden},
  year = {1999},
  number = {1547},
  pages = {1-20},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033295334&partnerID=40&md5=913e748471f7c83e93e01db0eda03853}
}
Strozzi T, Dammert P, Wegmüller U, Martinez J-M, Beaudoin A, Askne J and Hallikainen M (1999), "Forest mapping with SAR interferometry", Earth Observation Quarterly. (62), pp. 17-20.
Abstract: Forest maps of three European regions were completed with ERS SAR interferometry. The test areas represent different forest types and geomorphological regions. The mapping algorithms used were similar in all cases and well suitable for forest observation. In this contribution the methodology applied and the results achieved are presented and the potential and limitations of ERS SAR interferometry for forest mapping discussed.
BibTeX:
@article{Strozzi199917,
  author = {Strozzi, T. and Dammert, P. and Wegmüller, U. and Martinez, J.-M. and Beaudoin, A. and Askne, J. and Hallikainen, M.},
  title = {Forest mapping with SAR interferometry},
  journal = {Earth Observation Quarterly},
  year = {1999},
  number = {62},
  pages = {17-20},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032847825&partnerID=40&md5=322b3878dd665b57abdd88b8a6aabaae}
}
Strozzi T and Wegmüller U (1999), "Land subsidence in Mexico City mapped by ERS differential SAR interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 1940-1942. IEEE, Piscataway, NJ, United States.
Abstract: Land subsidence is a sever problem in Mexico City. The city is built on highly compressible clays and by reason of strong groundwater extraction a total subsidence of more than nine meters has been observed over the last century. ERS differential SAR interferometry was used to map the subsidence of Mexico City between December 1995 and September 1997. For some areas subsidence velocities of more than 30 cm per year with strong spatial gradients of the vertical movements were identified. This remote sensing technique, unique for spatial coverage and resolution, can give significant information for a rational management of the aquifer system, for the planning of new structures and for actions to preserve damaged buildings.
BibTeX:
@conference{Strozzi19991940,
  author = {Strozzi, Tazio and Wegmüller, Urs},
  title = {Land subsidence in Mexico City mapped by ERS differential SAR interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1999},
  volume = {4},
  pages = {1940-1942},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033343831&partnerID=40&md5=5fcdf163ccd9bb24030742dc3f1d058a}
}
Strozzi T, Wegmüller U, Luckman A and Balzter H (1999), "Mapping deforestation in Amazon with ERS SAR interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 767-769. IEEE, Piscataway, NJ, United States.
Abstract: Deforestation in a part of the Rondonia State in the Brazilian Amazon has been mapped by means of ERS SAR interferometry. The thematic information of the one day coherence, the backscattering intensity and the temporal change of backscattering intensity were used jointly in this analysis. The results show that along the Cuiaba - Porto Velho road a large area has been deforested for timber extraction, shifting cultivation and permanent agriculture and pasture.
BibTeX:
@conference{Strozzi1999767,
  author = {Strozzi, Tazio and Wegmüller, Urs and Luckman, Adrian and Balzter, Heiko},
  title = {Mapping deforestation in Amazon with ERS SAR interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1999},
  volume = {2},
  pages = {767-769},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033337523&partnerID=40&md5=a9449c60ab1bdb9ad399ba232f18408e}
}
Strozzi T, Wegmüller U and Matzler C (1999), "Mapping wet snowcovers with SAR interferometry", International Journal of Remote Sensing. Vol. 20(12), pp. 2395-2403.
Abstract: The capability of mapping wet snowcovers by means of Synthetic Aperture Radar (SAR) is well known. However, using only the backscattering intensity at C-band, there still remain some incertitudes regarding the effect of either rough snow surfaces or very small liquid water contents for measurements performed at small incidence angles. Since the European remote sensing (ERS) satellites usually operate at 23 incidence angle, it is important to consider these effects. This paper shows that these difficulties can be overcome using repeatpass SAR interferometry. ERS data over a part of the Netherlands and a part of Switzerland are used as illustrative examples. In the situations examined the occurrence of wet snow could not be directly observed by means of the backscattering intensity, but the use of the degree of coherence allowed an easy discrimination. The results are validated with in situ measurements. 1999 Taylor & Francis Group, LLC.
BibTeX:
@article{Strozzi19992395,
  author = {Strozzi, T. and Wegmüller, U. and Matzler, C.},
  title = {Mapping wet snowcovers with SAR interferometry},
  journal = {International Journal of Remote Sensing},
  year = {1999},
  volume = {20},
  number = {12},
  pages = {2395-2403},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0345425734&doi=10.1080%2f014311699212083&partnerID=40&md5=26f458987a2fa37a48484c4c988a7e20},
  doi = {10.1080/014311699212083}
}
Wegmüller U (1999), "Automated terrain corrected SAR geocoding", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1712-1714. IEEE, Piscataway, NJ, United States.
Abstract: A technique for automated terrain corrected SAR geocoding is presented. Instead of operator selected control points the presented method uses cross-correlation with a SAR intensity image simulated from the Digital Elevation Model to refine the geocoding transformation.
BibTeX:
@conference{Wegmuller19991712,
  author = {Wegmüller, Urs},
  title = {Automated terrain corrected SAR geocoding},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1999},
  volume = {3},
  pages = {1712-1714},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033318671&partnerID=40&md5=dc721983acfcd2a6a32c6543cad62b06}
}
Wegmüller U and Matzler C (1999), "Rough bare soil reflectivity model", IEEE Transactions on Geoscience and Remote Sensing. Vol. 37(3 I), pp. 1391-1395. IEEE, Piscataway, NJ, United States.
Abstract: A semiempirical model for the reflectivity of rough bare soil is presented. One of the main objectives of this new model development was to derive a simple model with few model parameters and a wide applicability. A large number of ground-based measurements in the 1-100-GHz range at H- and V-polarization and incidence angles between 20° and 70° were used for the model development.
BibTeX:
@article{Wegmuller19991391,
  author = {Wegmüller, U. and Matzler, C.},
  title = {Rough bare soil reflectivity model},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1999},
  volume = {37},
  number = {3 I},
  pages = {1391-1395},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032653607&doi=10.1109%2f36.763303&partnerID=40&md5=31f0c6420c3e692f04eabc18089a92c6},
  doi = {10.1109/36.763303}
}
Wegmüller U, Strozzi T and Bitelli G (1999), "Validation of ERS differential SAR interferometry for land subsidence mapping: the Bologna case study", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 1131-1133. IEEE, Piscataway, NJ, United States.
Abstract: The city of Bologna, Italy, is ideal to assess the potential of ERS differential SAR interferometry for land subsidence mapping in urban areas for a couple of reasons: the subsiding area is large and presents important velocities of the vertical movements; there is a typical spatial gradient of the vertical movements; many ERS SAR frames are available; a large scientific community is involved in the study of subsidence; a large amount of levelling data is available. We analyzed a time series of ERS- 1/2 data from August 1992 to May 1996 and compared the subsidence maps derived from ERS SAR interferometry and levelling surveys. We conclude that for the mapping of land subsidence in urban environments ERS differential SAR interferometry is complementary to levelling surveys and GPS with regard to cost effectiveness, resolution and accuracy.
BibTeX:
@conference{Wegmuller19991131,
  author = {Wegmüller, Urs and Strozzi, Tazio and Bitelli, Gabriele},
  title = {Validation of ERS differential SAR interferometry for land subsidence mapping: the Bologna case study},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1999},
  volume = {2},
  pages = {1131-1133},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033317689&partnerID=40&md5=797fa4c60edfba4cefdfce69f123eea2}
}
Wiesmann A and Matzler C (1999), "Microwave emission model of layered snowpacks", Remote Sensing of Environment. Vol. 70(3), pp. 307-316. Elsevier Science Inc, New York, NY, United States.
Abstract: A thermal microwave emission model of layered snowpacks (MEMLS) was developed for the frequency range 5-100 GHz. It is based on radiative transfer, using six-flux theory to describe multiple volume scattering and absorption, including radiation trapping due to total reflection and a combination of coherent and incoherent superpositions of reflections between layer interfaces. The scattering coefficient is determined empirically from measured snow samples, whereas the absorption coefficient, the effective permittivity, refraction, and reflection at layer interfaces are based on physical models and on measured ice dielectric properties. The number of layers is only limited by computer time and memory. A limitation of the empirical fits and thus of MEMLS is in the range of observed frequencies and correlation lengths (a measure of grain size). First model validation for dry winter snow was successful. An extension to larger grains is given in a companion article (Matzler and Wiesmann, 1999). The objective of the present article is to describe and illustrate the model and to pave the way for further improvements. MEMLS has been coded in MATLAB. It forms part of a combined land-surface-atmosphere microwave emission model for radiometry from satellites (Pulliainen et al., 1998).
A thermal microwave emission model of layered snowpacks (MEMLS) was developed for the frequency range 5-100 GHz. It is based on radiative transfer, using six-flux theory to describe multiple volume scattering and absorption, including radiation trapping due to total reflection and a combination of coherent and incoherent superpositions of reflections between layer interfaces. The scattering coefficient is determined empirically from measured snow samples, whereas the absorption coefficient, the effective permittivity, refraction, and reflection at layer interfaces are based on physical models and on measured ice dielectric properties. The number of layers is only limited by computer time and memory. A limitation of the empirical fits and thus of MEMLS is in the range of observed frequencies and correlation lengths (a measure of grain size). First model validation for dry winter snow was successful. An extension to larger grains is given in a companion article. The objective of the present article is to describe and illustrate the model and to pave the way for further improvements. MEMLS has been coded in MATLAB. It forms part of a combined land-surface-atmosphere microwave emission model for radiometry from satellites.
BibTeX:
@article{Wiesmann1999307,
  author = {Wiesmann, A. and Matzler, C.},
  title = {Microwave emission model of layered snowpacks},
  journal = {Remote Sensing of Environment},
  publisher = {Elsevier Science Inc, New York, NY, United States},
  year = {1999},
  volume = {70},
  number = {3},
  pages = {307-316},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0342723782&doi=10.1016%2fS0034-4257%2899%2900046-2&partnerID=40&md5=f7998c2065785d40dda97633d85c05a8},
  doi = {10.1016/S0034-4257(99)00046-2}
}
Wiesmann A, Strozzi T and Wegmüller U (1999), "JERS SAR processing for the boreal forest mapping project SIBERIA", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 2115-2117. IEEE, Piscataway, NJ, United States.
Abstract: In the frame of the EC environment and Climate Programme project, SIBERIA, an extensive forest map for a part of Siberia will be produced using state-of-the art satellite data and remote sensing techniques. Among other sensors the JERS SAR will be used. In this contribution important steps in the JERS processing will be discussed, including radiometric calibration, geocoding, and fine registration to ERS data. In addition, a preliminary comparison of the registered ERS and JERS σ° values is presented.
BibTeX:
@conference{Wiesmann19992115,
  author = {Wiesmann, Andreas and Strozzi, Tazio and Wegmüller, Urs},
  title = {JERS SAR processing for the boreal forest mapping project SIBERIA},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1999},
  volume = {4},
  pages = {2115-2117},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033346430&partnerID=40&md5=99543ee71b1cd47c49e0d0a91aae914a}
}
Fujiwara S, Yarai H, Ozawa S, Tobita M, Murakami M, Nakagawa H, Nitta K, Rosen P and Werner C (1998), "Surface displacement of the March 26, 1997 Kagoshima-ken-hokuseibu earthquake in Japan from synthetic aperture radar interferometry", Geophysical Research Letters. Vol. 25(24), pp. 4541-4544. American Geophysical Union, Washington.
Abstract: A JERS 1 differential L-band synthetic aperture radar (SAR) interferogram of the March 26, 1997 Kagoshima-ken-hokuseibu earthquake (Mw = 6.1) in southwestern Japan shows about 9 cm peak-to-peak coseismic surface displacement in the radar line-of-sight (LOS) direction. A permanent GPS array detected 1 to 2 cm horizontal displacements from this earthquake. By inverting the SAR and GPS data together, we estimated a fault mechanism without any seismological data. A theoretical radar LOS displacement pattern from a single fault model of the earthquake motion matches the SAR and GPS observations closely. The model assumes left lateral slip of 0.46 cm with rake angle of 19° on a rectangular fault plane of dimensions 11 km (width) by 12 km (length). We demonstrate that L-band SAR interferometry can describe several cm surface displacement in detail and construct a fault model. However, despite the acquisitions being during the cold season, there are apparent water vapor signatures in the interferogram with equivalent path delays of up to 1.5 cm.
A JERS 1 differential L-band synthetic aperture radar (SAR) interferogram of the March 26, 1997 Kagoshima-ken-hokuseibu earthquake (MW=6.1) in southwestern Japan shows about 9 cm peak-to-peak coseismic surface displacement in the radar line-of-sight (LOS) direction. A permanent GPS array detected 1 to 2 cm horizontal displacements from this earthquake. By inverting the SAR and GPS data together, we estimated a fault mechanism without any seismological data. A theoretical radar LOS displacement pattern from a single fault model of the earthquake motion matches the SAR and GPS observations closely. The model assumes left lateral slip of 0.46 cm with rake angle of 19°on a rectangular fault plane of dimensions 11 km (width) by 12 km (length). We demonstrate that L-band SAR interferometry can describe several cm surface displacement in detail and construct a fault model. However, despite the acquisitions being during the cold season, there are apparent water vapor signatures in the interferogram with equivalent path delays of up to 1.5 cm.
BibTeX:
@article{Fujiwara19984541,
  author = {Fujiwara, S. and Yarai, H. and Ozawa, S. and Tobita, M. and Murakami, M. and Nakagawa, H. and Nitta, K. and Rosen, P.A. and Werner, C.L.},
  title = {Surface displacement of the March 26, 1997 Kagoshima-ken-hokuseibu earthquake in Japan from synthetic aperture radar interferometry},
  journal = {Geophysical Research Letters},
  publisher = {American Geophysical Union, Washington},
  year = {1998},
  volume = {25},
  number = {24},
  pages = {4541-4544},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032535265&doi=10.1029%2f1998GL900191&partnerID=40&md5=908a6a641610fa9dd0a9e110658b9535},
  doi = {10.1029/1998GL900191}
}
Goldstein R and Werner C (1998), "Radar interferogram filtering for geophysical applications", Geophysical Research Letters. Vol. 25(21), pp. 4035-4038. American Geophysical Union, Washington.
Abstract: The use of SAR interferometry is often impeded by decorrelation from thermal noise, temporal change, and baseline geometry. Power spectra of interferograms are typically the sum of a narrow-band component combined with broad-band noise. We describe a new adaptive filtering algorithm that dramatically lowers phase noise, improving both measurement accuracy and phase unwrapping, while demonstrating graceful degradation in regions of pure noise. The performance of the filter is demonstrated with SAR data from the ERS satellites over the Jakobshavns glacier of Greenland.
The use of SAR interferometry is often impeded by decorrelation from thermal noise, temporal change, and baseline geometry. Power spectra of interferograms are typically the sum of a narrow-band component combined with broad-band noise. We describe a new adaptive filtering algorithm that dramatically lowers phase noise, improving both measurement accuracy and phase unwrapping, while demonstrating graceful degradation in regions of pure noise. The performance of the filter is demonstrated with SAR data from the ERS satellites over the Jakobshavns glacier of Greenland.
BibTeX:
@article{Goldstein19984035,
  author = {Goldstein, R.M. and Werner, C.L.},
  title = {Radar interferogram filtering for geophysical applications},
  journal = {Geophysical Research Letters},
  publisher = {American Geophysical Union, Washington},
  year = {1998},
  volume = {25},
  number = {21},
  pages = {4035-4038},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032216011&doi=10.1029%2f1998GL900033&partnerID=40&md5=73701bfa6dc554b7d55b6e1e46348256},
  doi = {10.1029/1998GL900033}
}
Luckman A, Baker J and Wegmüller U (1998), "Repeat-pass interferometric coherence measurements of tropical forest from JERS and ERS satellites", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 1828-1830. IEEE, Piscataway, NJ, United States.
Abstract: Interferometric coherence maps from 1-day repeat ERS and 44, 88 and 132-day repeat JERS data are derived and compared to biomass density estimates from a tropical forest area in Brazil. Results show that phase coherence adds significantly to the information available from these data.
BibTeX:
@conference{Luckman19981828,
  author = {Luckman, Adrian and Baker, John and Wegmüller, Urs},
  editor = {Anon},
  title = {Repeat-pass interferometric coherence measurements of tropical forest from JERS and ERS satellites},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1998},
  volume = {4},
  pages = {1828-1830},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031638771&partnerID=40&md5=147336bc773199bfeba0ed56ec3cafd2}
}
Martinez J, Beaudoin A, Wegmüller U, Le Toan T and Strozzi T (1998), "Influence of biophysical, meteorological and topographic factors on multidate ERS tandem data acquired over forested terrain", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 1818-1821. IEEE, Piscataway, NJ, United States.
Abstract: Interferometry with ERS1/2 SAR appears as a new promising tool for forest observations. With four ERS tandem pairs acquired during one year, this paper investigates the influence of biophysical, meteorological and topographic factors on such data. It is shown that the degree of coherence has a potential for discrimination between forest types. It appears also that it is correlated with the NDVI, the stem volume and stand density. Moreover, we studied how seasonal and meteorological effects influence the degree of coherence, in particular it appears that it is very useful for snow cover detecting. However topography affects strongly the coherence and its estimation, pointing out the need for semi-empirical correction or rejection of strong slopes areas.
BibTeX:
@conference{Martinez19981818,
  author = {Martinez, J.M. and Beaudoin, A. and Wegmüller, U. and Le Toan, T. and Strozzi, T.},
  editor = {Anon},
  title = {Influence of biophysical, meteorological and topographic factors on multidate ERS tandem data acquired over forested terrain},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1998},
  volume = {4},
  pages = {1818-1821},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031628958&partnerID=40&md5=44bcace32caeed5bb948d8373955681d}
}
Martinez J, Beaudoin A, Wegmüller U and Strozzi T (1998), "Classification of land-cover and forest types using multidate ERS tandem data acquired over hilly terrain", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 1809-1811. IEEE, Piscataway, NJ, United States.
Abstract: Repeat-pass interferometry with ERS SAR satellite appears to be very useful for land cover mapping. Using 4 ERS tandem pairs, this paper studies the results of forest mapping over hilly terrain. For a given tandem pair, it appears that coherence is far better than backscatter to discriminate forest from non-forest. Using additional pairs plus seasonal backscatter change images at appropriate seasons allows to discriminate various classes within the forest theme with satisfactory accuracy. However, it was found that local weather effects (snow, freezing) and strong slopes degrade the classification accuracy, which should be further addressed in a global classification strategy.
BibTeX:
@conference{Martinez19981809,
  author = {Martinez, J.M. and Beaudoin, A. and Wegmüller, U. and Strozzi, T.},
  editor = {Anon},
  title = {Classification of land-cover and forest types using multidate ERS tandem data acquired over hilly terrain},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1998},
  volume = {4},
  pages = {1809-1811},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031628957&partnerID=40&md5=ff8015e83c756b34ebd0b1ee5a4fd01c}
}
Matzler C (1998), "Improved Born approximation for scattering of radiation in a granular medium", Journal of Applied Physics. Vol. 83(11), pp. 6111-6117. American Institute of Physics Inc..
Abstract: An improved Born approximation for volume scattering and absorption of electromagnetic radiation by a nonmagnetic, granular medium of small grains with large dielectric contrast is formulated. In this low-frequency approximation it is assumed that the permittivity of the medium is given by the effective-medium theory of Polder and van Santen which also provides an expression for the internal field. The model is used to derive formulas for the scattering and absorption coefficients of freely arranged spheres and spherical shells. In addition, measured dielectric properties are used to derive relevant model data of dry snow. In contrast to the conventional Born approximation, the results reproduce Rayleigh scattering for a single particle, and for a dense medium the scattering coefficient shows a nonlinear behavior with increasing density, comparable to the dense-medium radiative transfer theory. Characteristic differences of the spectra of the scattering coefficients result for the different particle types. 1998 American Institute of Physics.
BibTeX:
@article{Matzler19986111,
  author = {Matzler, C.},
  title = {Improved Born approximation for scattering of radiation in a granular medium},
  journal = {Journal of Applied Physics},
  publisher = {American Institute of Physics Inc.},
  year = {1998},
  volume = {83},
  number = {11},
  pages = {6111-6117},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0342512239&doi=10.1063%2f1.367496&partnerID=40&md5=b8a14787041b06fadab7e4bcae46178d},
  doi = {10.1063/1.367496}
}
Matzler C (1998), "microwave permittivity of dry sand", IEEE Transactions on Geoscience and Remote Sensing. Vol. 36(1), pp. 317-319.
Abstract: The complex, relative dielectric permittivity g of dry desert sand, collected at the Grand Erg Oriental in Ksar Ghilane, Tunisia, in October 1994, was measured with microwave resonators at frequencies between 0.245 and 6 GHz. The results are presented here. Whereas the real part g' is nearly independent of frequency, a monotonous decrease of the imaginary part g with increasing frequency is observed. The data can be fitted to a Debye relaxation spectrum with a relaxation frequency of about 0.27 GHz, leading to a nearly frequency-independent penetration depth of about l m over the range from 1-10 GHz. The spectrum can be explained by Maxwell-Wagner losses of semiconducting spheres embedded in a nonconducting sand medium. 1998 IEEE.
BibTeX:
@article{Matzler1998317,
  author = {Matzler, C.},
  title = {microwave permittivity of dry sand},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1998},
  volume = {36},
  number = {1},
  pages = {317-319},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031646485&doi=10.1109%2f36.655342&partnerID=40&md5=2c6ce6459c6b55d143815103da8456c1},
  doi = {10.1109/36.655342}
}
Rosen P, Werner C, Fielding E, Hensley S, Buckley S and Vincent P (1998), "Aseismic creep along the San Andreas Fault northwest of Parkfield, CA measured by radar interferometry", Geophysical Research Letters. Vol. 25(6), pp. 825-828. American Geophysical Union, Washington.
Abstract: ERS-1 radar images acquired 14 months apart studied by differential radar interferometry show the wide-area distribution of aseismic creep along the fault segment northwest of Parkfield, California. A sharp discontinuity in the interferometric phase of less than 2 cm equivalent line-of-sight displacement extends over 80 km in the differential interferogram, coincident with the mapped trace of the active San Andreas fault and consistent with the expected and measured fault motion. Although patterns of strain associated with the transition from locked to creeping are not dearly identifiable, a decrease in creep displacement from northwest to southeast along the fault is visible. The observations are in agreement with a model of elastic deformation constrained by in situ data that supports a maximum expected deformation signature of 10 mm across the image.
ERS-1 radar images acquired 14 months apart studied by differential radar interferometry show the wide-area distribution of aseismic creep along the fault segment northwest of Parkfield, California. A sharp discontinuity in the interferometric phase of less than 2 cm equivalent line-of-sight displacement extends over 80 km in the differential interferogram, coincident with the mapped trace of the active San Andreas fault and consistent with the expected and measured fault motion. Although patterns of strain associated with the transitioin from locked to creeping are not clearly identifiable, a decrease in creep displacement from northwest to southeast along the fault is visible. The observations are in agreement with a model of elastic deformation constrained by in situ data that supports a maximum expected deformation signature of 10 mm across the image.
BibTeX:
@article{Rosen1998825,
  author = {Rosen, P. and Werner, C. and Fielding, E. and Hensley, S. and Buckley, S. and Vincent, P.},
  title = {Aseismic creep along the San Andreas Fault northwest of Parkfield, CA measured by radar interferometry},
  journal = {Geophysical Research Letters},
  publisher = {American Geophysical Union, Washington},
  year = {1998},
  volume = {25},
  number = {6},
  pages = {825-828},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032520606&doi=10.1029%2f98GL50495&partnerID=40&md5=3e1459ff9475cf1fc911f7b1e1d61944},
  doi = {10.1029/98GL50495}
}
Schwank M, Muller U and Wintermantel E (1998), "The use of a high-pressure scanning tunneling microscope as a lithography tool for modifications of amorphous hydrogenated carbon films", Review of Scientific Instruments. Vol. 69(4), pp. 1792-1799. American Institute of Physics Inc..
Abstract: The use of a modified scanning tunneling microscope (STM) working in controlled oxygen atmospheres to create structures on the surface of a steel sample covered with 10 nm amorphous hydrogenated carbon (a-C:H) is presented. The STM lithography experiments showed the capability of producing either μm sized hills or holes depending on the oxygen pressure and the other parameters such as feedback-settings, bias-voltage, and setpoint-current. It will be shown that the hills were hollow and consisted of a locally delaminated a-C:H film induced by a dielectric breakdown between tip and sample. This explains the observed mobility and elasticity of the hills. Assuming total relaxation of the a-C:H film within the hills yielded the ratio h/d= 0.07-0.1. The measured geometries of the hills were in good agreement with the estimated ratios. The resistance of a hill formed by the local delamination of a-C:H was measured, yielding a semiconducting behavior. The gap voltage and the total resistance decreased irreversibly, which was interpreted as a transformation of the a-C:H film within the hill to a more graphitic state. Holes were only created when all of the following conditions were fulfilled: (a) O2 pressure greater than 1 bar, (b) low energy density dissipated in the a-C:H surface (no dielectric breakdown), (c) positive bias voltage ≥ 13 V between the sample and the tip. The Fowler-Nordheim plots log(I/U2) vs 1/U for the lithography experiments that led to holes were characteristic for field emission of electrons from the tip. From this it was concluded that the process responsible for hole formation is reactive oxygen etching. Other possible processes have been excluded experimentally and theoretically, respectively. For lithography experiments performed with the feedback system on, it was possible to find lithography parameters leading to a reproducible creation of holes. 1998 American Institute of Physics.
BibTeX:
@article{Schwank19981792,
  author = {Schwank, M. and Muller, U. and Wintermantel, E.},
  title = {The use of a high-pressure scanning tunneling microscope as a lithography tool for modifications of amorphous hydrogenated carbon films},
  journal = {Review of Scientific Instruments},
  publisher = {American Institute of Physics Inc.},
  year = {1998},
  volume = {69},
  number = {4},
  pages = {1792-1799},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0000282398&doi=10.1063%2f1.1148843&partnerID=40&md5=5c119387ce77175aa9dae5c36e61f950},
  doi = {10.1063/1.1148843}
}
Strozzi T and Matzler C (1998), "Backscattering measurements of alpine snowcovers at 5.3 and 35 GHz", IEEE Transactions on Geoscience and Remote Sensing. Vol. 36(3), pp. 838-848.
Abstract: This paper describes two network-analyzer (NA)based scatterometers at 5.3 (C-band) and 35 GHz (Ka-band) as well as snowcover measurements made in the Swiss and Austrian Alps between December 1993 and January 1996. First, the setup and the mode of operation of the scatterometers are discussed. Both instruments measure the backscattering coefficients 7 at hh, vv, vh, and vh polarizations and for incidence angles ranging from 0 to 70°. The accuracy of 7 is generally better than ±1.8 dB, and the scatterometers are well suited for signature studies of natural surfaces. During the two years, we performed many backscattering measurements of natural, strongly layered snowcovers and we investigated relationships between 7 and physical parameters of the snowcover. All measurements were collected in a signature catalogue. Here we report on results at 40° incidence angle. We found that the combined use of active sensors at 5.3 and 35 GHz allows the discrimination of various snowcover situations, if multitemporal information is available. In addition, we observed a relationship of 7 at 5.3 GHz with the integrated column height of liquid water and dependencies of 7 at 35 GHz on the height of the dry snow, on the volumetric liquid water content at the snow surface, and on the thickness of the refrozen crust at the snow surface. 1998 IEEE.
BibTeX:
@article{Strozzi1998838,
  author = {Strozzi, T. and Matzler, C.},
  title = {Backscattering measurements of alpine snowcovers at 5.3 and 35 GHz},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1998},
  volume = {36},
  number = {3},
  pages = {838-848},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0012560199&doi=10.1109%2f36.673677&partnerID=40&md5=8bd5ec38dbf8c363e8639d972c196a12},
  doi = {10.1109/36.673677}
}
Strozzi T and Wegmüller U (1998), "Delimitation of urban areas with SAR interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1632-1634. IEEE, Piscataway, NJ, United States.
Abstract: This paper addresses the problem of the identification and delimitation of urban areas with SAR interferometry. Three different classification methods are investigated and applied to ERS- 1/2 pairs over a part of Switzerland. The classification algorithms are based on the degree of coherence, the two backscatter intensities of the interferometric pair, and the texture of one backscatter image. ERS data acquired with different time intervals, baselines, and meteorological conditions are considered. The resulting urban maps are transformed into orthonormal coordinates and validated with the digital landuse map of the Swiss Federal Statistical Institute.
BibTeX:
@conference{Strozzi19981632,
  author = {Strozzi, Tazio and Wegmüller, Urs},
  editor = {Anon},
  title = {Delimitation of urban areas with SAR interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1998},
  volume = {3},
  pages = {1632-1634},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031629129&partnerID=40&md5=08dc8c3339a44be993305a6c712bba82}
}
Strozzi T and Wegmüller U (1998), "Forest map of a part of Switzerland", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 1802-1804. IEEE, Piscataway, NJ, United States.
Abstract: In the frame of the project EUFORA (European Forest Observations using Radars) a forest map of a part of Switzerland was completed with ERS SAR interferometry. Particular attention was paid to the realization of an accurate end product and to the presentation of the map. The data analysis, the classification method, the accuracy and visualization of the map are summarized in this contribution.
BibTeX:
@conference{Strozzi19981802,
  author = {Strozzi, Tazio and Wegmüller, Urs},
  editor = {Anon},
  title = {Forest map of a part of Switzerland},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1998},
  volume = {4},
  pages = {1802-1804},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031625295&partnerID=40&md5=16cb07b8188e05fdcca62059d0daf466}
}
Strozzi T, Wegmüller U and Matzler C (1998), "Using repeat-pass SAR interferometry for mapping wet snowcovers", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1650-1652. IEEE, Piscataway, NJ, United States.
Abstract: The capability of mapping wet snowcovers by means of SAR is well known. However, using only the backscattering intensity at C-Band there still remain some incertitudes regarding the effect of either rough snow surfaces or very small liquid water contents for measurements performed at small incidence angles. Since the ERS satellites usually operate at 23° incidence angle, it is important to consider these effects. In this paper we will show that these difficulties can be overcome using repeat-pass SAR interferometry. ERS data over a part of the Netherlands and a part of Switzerland are used as illustrative examples. In the situations examined the occurrence of wet snow could not be directly observed by means of the backscattering intensity, but the use of the degree of coherence allowed an easy discrimination. The results are validated with in-situ measurements and meteorological information.
BibTeX:
@conference{Strozzi19981650,
  author = {Strozzi, Tazio and Wegmüller, Urs and Matzler, Christian},
  editor = {Anon},
  title = {Using repeat-pass SAR interferometry for mapping wet snowcovers},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1998},
  volume = {3},
  pages = {1650-1652},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031633123&partnerID=40&md5=8a1a2d587a6cce62e30ed8376f4e30fb}
}
Tobita M, Ozawa S, Murakami M, Nakagawa H, Nitta K, Murakami M, Fujiwara S, Rosen P, Fielding E and Werner C (1998), "Deformation of the 1995 North Sakhalin earthquake detected by JERS-1/SAR interferometry", Earth, Planets and Space. Vol. 50(4), pp. 313-325.
Abstract: We present a map of the coseismic displacement field resulting from the North Sakhalin, Russia, May 28, 1995, earthquake. Raw radar signal data from the JERS-1 synthetic aperture radar instrument acquired in 28 April, 11 June, 25 July, and 7 September 1995 are used to generate a high-resolution, wide area map of the displacements by the two-pass differential interferometry method. The interferogram shows that an area of 60 km (EW) by 80 km (NS) experienced crustal deformations. The slip mechanism with fine structure is inverted using the displacement field of the SAR interferogram. This inversion of the SAR interferogram shows, 1) the rupture area extends to the south of the southernmost rupture trace on the surface, 2) slip varies from one to seven meters from the south to the northern part on the fault plane. A theoretical fringe pattern from the model of the earthquake motion matches the observations closely. We generate a full scene digital elevation model (DEM) by JERS-1 SAR interferometry and synthesize a four-pass interferogram. Comparison of the differential interferometry between the four-pass and two-pass interferograms shows that they are very similar and the both methods are reliable to show surface displacements using JERS-1 SAR. Correlation study of the Sakhalin interferograms indicates that low surface temperatures, below the freezing point, reduced the correlation probably because a freeze would alter the dielectric constant of the surface. In these Sakhalin interferograms, we find few spurious fringes due to the usual heterogeneous distribution of weather-related atmospheric and surface conditions, probably because of the low temperatures. We also present a map of the postseismic displacement field with the SAR interferometry. 1998, The Seismological Society of Japan, Society of Geomagnetism and Earth, Planetary and Space Sciences, The Volcanological Society of Japan, The Geodetic Society of Japan, The Japanese Society for Planetary Sciences. All rights reserved.
BibTeX:
@article{Tobita1998313,
  author = {Tobita, M. and Ozawa, S. and Murakami, M. and Nakagawa, H. and Nitta, K. and Murakami, M. and Fujiwara, S. and Rosen, P.A. and Fielding, E.J. and Werner, C.L.},
  title = {Deformation of the 1995 North Sakhalin earthquake detected by JERS-1/SAR interferometry},
  journal = {Earth, Planets and Space},
  year = {1998},
  volume = {50},
  number = {4},
  pages = {313-325},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-7844247179&doi=10.1186%2fBF03352118&partnerID=40&md5=54fd1a55fe2e5c02cb94f8327bf6190e},
  doi = {10.1186/BF03352118}
}
Wegmüller U, Strozzi T and Werner C (1998), "Land subsidence in the Po river valley, Italy", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1376-1378. IEEE, Piscataway, NJ, United States.
Abstract: In the frame work of ESA's Data User Programme, Gamma Remote Sensing addresses the use of differential SAR interferometry to map subsidence in the Po river Valley. After an introduction to the overall problem and the more traditional subsidence surveying methods the interferometric approach, preliminary results for an area around Bologna, and the potential and limitations of the interferometric technique will be discussed.
BibTeX:
@conference{Wegmuller19981376,
  author = {Wegmüller, Urs and Strozzi, Tazio and Werner, Charles},
  editor = {Anon},
  title = {Land subsidence in the Po river valley, Italy},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1998},
  volume = {3},
  pages = {1376-1378},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031620402&partnerID=40&md5=b0cd6f83035e11917a31da295082a0ab}
}
Wegmüller U, Werner C and Strozzi T (1998), "SAR interferometric and differential interferometric processing chain", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 1106-1108. IEEE, Piscataway, NJ, United States.
Abstract: We developed a SAR and interferometric processor suitable for all current SAR systems. The main modules of the processor are the Modular SAR Processor (MSP), the Interferometric SAR Processor (ISP), and the Differential Interferometry and Geocoding Module (DIFF&GEO). The potential and limitations of the selected algorithms and processing techniques are discussed. Typical results are shown in the presentation and in [1].
BibTeX:
@conference{Wegmuller19981106,
  author = {Wegmüller, Urs and Werner, Charles and Strozzi, Tazio},
  editor = {Anon},
  title = {SAR interferometric and differential interferometric processing chain},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1998},
  volume = {2},
  pages = {1106-1108},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031637064&partnerID=40&md5=0434073564b14340e02edabf72d8bb88}
}
Wiesmann A, Matzler C and Hiltbrunner D (1998), "Modeling microwave emission spectra of layered snowpacks", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1265-1267. IEEE, Piscataway, NJ, United States.
Abstract: A thermal Microwave Emission Model of Layered Snowpacks (MEMLS) [1] was developed for the frequency range, 5 to 100 GHz. It is based on radiative transfer, using six-flux theory to describe multiple volume scattering and absorption, including radiation trapping due to internal reflection and a combination of coherent and incoherent superpositions of reflections between layer interfaces. The scattering coefficient was determined empirically from measured snow samples, whereas the absorption coefficient, the effective permittivity, refraction and reflection at layer interfaces were based on physical models and on measured ice dielectric properties. The number of layers is only limited by computer time and memory. A limitation of the empirical fits and thus of MEMLS is in the range of observed frequencies and correlation lengths (a measure of grain size). First model validation for dry winter snow was successful. MEMLS has been coded in MATLAB. It forms part of a combined land-surface-atmosphere microwave radiation model for radiometry from satellites [2].
BibTeX:
@conference{Wiesmann19981265,
  author = {Wiesmann, A. and Matzler, C. and Hiltbrunner, D.},
  editor = {Anon},
  title = {Modeling microwave emission spectra of layered snowpacks},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1998},
  volume = {3},
  pages = {1265-1267},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031624470&partnerID=40&md5=baadb2d153b4168ec0ff58b2afa13b1e}
}
Wiesmann A, Matzler C and Weise T (1998), "Radiometric and structural measurements of snow samples", Radio Science. Vol. 33(2), pp. 273-289. American Geophysical Union.
Abstract: The interaction of microwaves with the natural snow cover strongly depends on the complex structure of the snowpack. In order to quantify this dependency, dedicated experiments were performed with homogeneous slabs of dry, natural snow samples measured over a frequency range from 11 to 94 GHz. A new method introduced by Matzler and Wegmüller [1995] and Weise [1996a] for determining the scattering and absorption behavior of test samples was applied and further developed by application of a multiple scattering model. Homogeneous samples of dry snow were (1) investigated using a set of portable, linearly polarized Dicke radiometers at frequencies of 11, 21, 35, 48 and 94 GHz, (2) characterized by temperature, grain size and shape, density and permittivity, and (3) structurally analyzed by digitized snow sections in order to obtain statistical information of the snow structure i.e. the autocorrelation function. During the winters 1994/1995 and 1995/1996 additional measurements of snow samples were made to extend the variability of the investigated snow types. Up to now, 20 samples, representing alpine snow in winter (that is, without melt metamorphism) have been collected during three winter campaigns. Here, we present the method and the radiative transfer model and show how it can be inverted to obtain scattering and absorption coefficients. A first assessment of the snow sample data is also presented. The results show good agreement between the measured and the theoreti-cal absorption coefficient. The scattering coefficient turns out to be a strong function of frequency and correlation length as expected from Rayleigh scattering. However, distinct differences can be noted.
BibTeX:
@article{Wiesmann1998273,
  author = {Wiesmann, A. and Matzler, C. and Weise, T.},
  title = {Radiometric and structural measurements of snow samples},
  journal = {Radio Science},
  publisher = {American Geophysical Union},
  year = {1998},
  volume = {33},
  number = {2},
  pages = {273-289},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032026899&doi=10.1029%2f97RS02746&partnerID=40&md5=6f52a51b747a2110554fe0bd98fea634},
  doi = {10.1029/97RS02746}
}
Goldstein R and Werner C (1997), "Radar ice motion interferometry", In European Space Agency, (Special Publication) ESA SP. (414 PART 2), pp. 969-970.
Abstract: We have used tandem pairs of ERS-1/2 radar observations of the Jakobshavn Glacier, in Greenland, for the purpose of estimating the ice motion. Interferograms are made from two such pairs, separated by the 35 day repeat cycle. Motion can be estimated from these without knowledge of the local topography. Although the temporal baseline of the interferograms was only one day, the correlation from the fast moving ice was very low. Because of the resulting phase noise, we have used a scene-dependent filter to help unwrap the interferograms. For the upper part of the glacier, the filter worked well. The filter and the measured ice motion are presented below.
BibTeX:
@conference{Goldstein1997969,
  author = {Goldstein, R. and Werner, C.},
  title = {Radar ice motion interferometry},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {1997},
  number = {414 PART 2},
  pages = {969-970},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-5244241397&partnerID=40&md5=c274f16a20aede625b87ca6e00b0e258}
}
Johnsen K-P, Darovskikh A, Heygster G and Wiesmann A (1997), "Microwave measurements of sea ice in the Kara and Laptev Sea", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 1675-1677. IEEE, Piscataway, NJ, United States.
Abstract: Radiometric measurements made during the Arctic-expedition ARK 12 of R.V. Polarstern in the Kara and Laptev Sea which took place from 12th July to 23th September 1996 are obtained using three Dicke Radiometers from the University of Bern (Switzerland) mounted on a sledge operating at 11, 21 and 35 GHz and measuring in horizontal and vertical polarization with incidence angles between 20 and 70 degrees. The observed brightness temperatures show a strong correlation with the snow thickness. The size of the snow grains is also important. Some examples of the data set are compared to a combined radiative transfer-strong fluctuation theory approach using a layer model describing the sea ice and calculating the emissivities of both polarizations.
BibTeX:
@conference{Johnsen19971675,
  author = {Johnsen, Klaus-Peter and Darovskikh, Andrei and Heygster, Georg and Wiesmann, Andreas},
  editor = {Anon},
  title = {Microwave measurements of sea ice in the Kara and Laptev Sea},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1997},
  volume = {4},
  pages = {1675-1677},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030650208&partnerID=40&md5=1682e4d35b6f80c37ae24cea61ee50dd}
}
Matzler C (1997), "Autocorrelation functions of granular media with free arrangement of spheres, spherical shells or ellipsoids", Journal of Applied Physics. Vol. 81(3), pp. 1509-1517. American Institute of Physics Inc..
Abstract: The decomposition of natural media, such as snow and soil, into grains or pores of variable size and shape is an ambiguous task, depending on how the grains and their size are defined. Volume scattering of electromagnetic waves, adsorption of molecules on the grain surface, percolation of a fluid through the pores, or sedimentation of grains in a fluid do not depend on such definitions; they can be characterized by more general structural parameters, examples of which are the specific surface s or the correction length pc, both being related to the spatial autocorrelation function (SAF). Therefore, physically meaningful structure information can be obtained even without specifying the grains, by adopting pc as an effective size. In order to get an understanding of how pc is related to the geometrical dimensions of simple particles, we compute the SAF and pc for single spheres, spherical shells, and for isotropically oriented ellipsoids; exact and approximate formulas are derived, plotted, and exact expressions of pc are found. A result is that Pc is not related to the maximum particle extent, but in all cases studied, Pc is close to the minimum, characteristic extent of the grain. The SAFs can be applied to the computation of volume scattering in the weak and strong fluctuation theory, respectively. Furthermore, it can be shown, based on an assumption of the free arrangement of impenetrable granules, that the SAF of an irregular medium is identical to the SAF of its particles. Thus the single-particle correlation is the dominant structure in media consisting of irregular granules. This result is in contrast to systems of spatially correlated particles, such as atoms in crystals or molecules in liquids. Although this work was driven by the need for a quantitative interpretation of remote sensing data of snow, the results may be applied to other disciplines as well. 1997 American Institute of Physics.
BibTeX:
@article{Matzler19971509,
  author = {Matzler, C.},
  title = {Autocorrelation functions of granular media with free arrangement of spheres, spherical shells or ellipsoids},
  journal = {Journal of Applied Physics},
  publisher = {American Institute of Physics Inc.},
  year = {1997},
  volume = {81},
  number = {3},
  pages = {1509-1517},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0000717984&doi=10.1063%2f1.363916&partnerID=40&md5=e5cb8d7fd5719ae18625e2a3430af678},
  doi = {10.1063/1.363916}
}
Matzler C, Strozzi T, Weise T, Floricioiu D-M and Rott H (1997), "Microwave snowpack studies made in the Austrian Alps during the SIR-C/X-SAR experiment", International Journal of Remote Sensing. Vol. 18(12), pp. 2505-2530.
Abstract: Surface-based microwave studies made in the Austrian Alps during the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/XSAR) experiment in April 1994 are described, and are compared with the SAR data. The SAR test region included glaciers and unglaciated surfaces which were snow covered. Clear differences between these two surface types were observed with the SIR-C/X-SAR. In addition, the angular dependencies of the backscattering were useful in order to distinguish between the accumulation and the ablation areas of the glaciers, and the snow-covered areas showed characteristic differences depending on the presence or absence of layers containing wet snow. The surface-based studies were carried out at an alpine meadow in the valley Kaunertal at an altitude of 2160 m. The measurements included snow-physical observations supported by microwave dielectric probes, microwave radiometers at 21 and 35GHz and polarimetric scatterometers at 5.3 and 35 GHz. The dielectric measurements were used to retrieve the liquid-water profile of the snowpack. Three main layers were observed: a wet bottom layer as a remnant of a warm period in March, a thick crust (i.e., the refrozen part of the old pack), and a fresh and mostly dry snow layer on top. Except for the top layer, the temporal changes were small during the observation period from 8 to 12 April 1994. The radiometric measurements made at 21 and 35GHz showed pronounced temporal variations of the brightness temperature in the afternoons due to melt-and-refreeze cycles in the fresh snow. The liquid water in the top layer was monitored by a special radiometric method using a metal plate at the bottom of this layer. The radiometer and scatterometer measurements revealed the refrozen crust as the dominant scatterer, especially at 35 GHz. However, the wet bottom layer inhibited the detection of signals scattered at the snow-ground interface and therefore reduced the backscatter at 5.3 GHz. The comparison of the C-band SAR data with those of the C-band scatterometer shows higher returns in the SAR data for the considered test site. Explanations for the differences are discussed. Nevertheless, also the SAR backscatter data are clearly lower in the zones where wet snow was present than in areas either covered by dry snow or which were snow-free. 1997 Taylor & Francis Group, LLC.
BibTeX:
@article{Matzler19972505,
  author = {Matzler, C. and Strozzi, T. and Weise, T. and Floricioiu, D.-M. and Rott, H.},
  title = {Microwave snowpack studies made in the Austrian Alps during the SIR-C/X-SAR experiment},
  journal = {International Journal of Remote Sensing},
  year = {1997},
  volume = {18},
  number = {12},
  pages = {2505-2530},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031205846&doi=10.1080%2f014311697217440&partnerID=40&md5=e75e76956adf3dcb8011b445756d9f1d},
  doi = {10.1080/014311697217440}
}
Schmid B, Matzler C, Heimo A and Kampfer N (1997), "Retrieval of optical depth and particle size distribution of tropospheric and stratospheric aerosols by means of sun photometry", IEEE Transactions on Geoscience and Remote Sensing. Vol. 35(1), pp. 172-182.
Abstract: Aerosol optical depth measurements by means of ground-based Sun photometry were made in Bern, Switzerland during two and a half years primarily to provide quantitative corrections for atmospheric effects in remotely sensed data in the visible and near-infrared spectral region. An investigation of the spatial variability of tropospheric aerosol was accomplished in the summer of 1994 in the Swiss Central Plain, a region often covered by a thick aerosol layer. Intel-comparisons are made with two Sun photometers operated by the Swiss Meteorological Institute in Payerne (Swiss Central Plain) and Davos (Swiss Alps, 1590 m a.s.l.). By means of an inversion technique, columnar particle size distributions were derived from the aerosol optical depth spectra. Effective radius, columnar surface area, and columnar mass were computed from the inversion results. Most of the spectra measured in Bern exhibit an Angstromlaw dependence. Consequently, the inverted size distributions are very close to power-law distributions. Data collected during a four month calibration campaign in fall 1993 at a high-mountain station in the Swiss Alps (Jungfraujoch, 3580 m) allowed us to study optical properties of stratospheric aerosol. The extinction spectra measured have shown to be still strongly influenced by remaining aerosol of the June 1991 volcanic eruptions of Mount Pinatubo. Inverted particle size distributions can be characterized by a broad monodisperse peak with a mode radius around 0.25 /urn. Both aerosol optical depths and effective radii had not yet returned to pre-eruption values. Comparison of retrieved aerosol optical depth, columnar surface area and mass, with the values derived from lidar observations performed in GarmischPartenkirchen, Southern-Germany, yielded good agreement. 1997 IEEE.
BibTeX:
@article{Schmid1997172,
  author = {Schmid, B. and Matzler, C. and Heimo, A. and Kampfer, N.},
  title = {Retrieval of optical depth and particle size distribution of tropospheric and stratospheric aerosols by means of sun photometry},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1997},
  volume = {35},
  number = {1},
  pages = {172-182},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030736978&doi=10.1109%2f36.551945&partnerID=40&md5=39c79d983734a8edb8f7f71150bcca9d},
  doi = {10.1109/36.551945}
}
Schwank M, Schmutz W and Nussbaumer H (1997), "Irradiated red giant atmospheres in S-type symbiotic stars", Astronomy and Astrophysics. Vol. 319(1), pp. 166-175.
Abstract: We present non-LTE calculations for an expanding red giant's atmosphere ionized from the outside by the radiation of a nearby hot radiation source. We show that the hydrogen emission lines emerge from a narrow transition zone where hydrogen changes from ionized to neutral. In this region the Balmer lines are optically thick, and their profiles crucially depend on the magnitude of optical thickness which in turn, depends on the velocity gradient within that region. Balmer decrements of the model calculations depend on the densities in the recombination zone of the radiatively ionized wind. We find a large variety of complex line profiles, that in some cases could be mistaken for accretion disk profiles. The profiles depend on the velocity law in the formation zone at sub-sonic velocities, but contrary to expectation, the profiles do not reflect the terminal velocity of the wind. The central part of our model profiles compare well with the observed profile of the eclipsing binary SY Mus at maximum light.
BibTeX:
@article{Schwank1997166,
  author = {Schwank, M. and Schmutz, W. and Nussbaumer, H.},
  title = {Irradiated red giant atmospheres in S-type symbiotic stars},
  journal = {Astronomy and Astrophysics},
  year = {1997},
  volume = {319},
  number = {1},
  pages = {166-175},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0012096268&partnerID=40&md5=acb03bf5297dfa81698663b8380d488e}
}
Streck C and Wegmüller U (1997), "Investigation of ERS SAR data of the tandem mission for planning and monitoring of Siberian pipeline tracks", In European Space Agency, (Special Publication) ESA SP. (414 PART 1), pp. 441-447.
Abstract: Siberian pipelines, embedded in a mosaic of boreal forest, bogs, rivers, lakes and tundra, are undergoing stress due to varying heave displacements by thawing and freezing of the active permafrost layer. Problems such as the upward movement of the lighter gas pipelines arise due to the melting of frozen surface water in spring, or the downward movement in winter caused by the melting of the frozen soil around the pipeline. These varying movements of the pipeline, depending on the underground, the surface cover and the pipeline itself, may lead to cracks and severe damage. These problems require a permanent monitoring of existing and a careful planning of new pipeline tracks. Currently the pipelines are regularly monitored by visual inspection via helicopter. Planning information such as a DEM and a classification of the surface cover is derived mainly from optical remote sensing and field work. The potential of radar data as a possibly more reliable and cost effective source of information for the monitoring and planning of gas pipelines in the remote and hardly accessible regions of Nadym, Siberia, was investigated. Methods used included the interpretation of multitemporal SAR backscattering as well as SAR interferometric products using ERS-1/ERS-2 Tandem data. ERS SAR data proved to be a valuable alternative for the mapping of the pipelines. The study is being carried out as an ESA Pilot Project (A02.D129) and funded by the German Space Agency (DARA).
BibTeX:
@conference{Streck1997441,
  author = {Streck, C. and Wegmüller, U.},
  title = {Investigation of ERS SAR data of the tandem mission for planning and monitoring of Siberian pipeline tracks},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {1997},
  number = {414 PART 1},
  pages = {441-447},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-5244240472&partnerID=40&md5=d05219a14756e9b721b471b808fdc40a}
}
Strozzi T and Wegmüller U (1997), "Applications of SAR interferometry to land-cover mapping [Applications de l'interferometrie RSO pour l'etude de l'occupation des sols]", Bulletin - Societe Francaise de Photogrammetrie et de Teledetection. (148), pp. 114-119.
Abstract: In recent years significant progress was achieved in microwave remote sensing due to SAR interferometric data analysis. Data acquired during repeat orbits by the Synthetic Aperture Radar (SAR) sensors on the European Remote Sensing Satellites ERS-1 and 2 can be used for SAR interferometric data analysis. SAR interferometry combines SAR images acquired by two antennae on the same platform or by one antenna at different times during repeat orbits. The interferometric phase is a measure of the path length difference between the target and the two sensor positions. Topographic height, surface deformation occurring between the acquisition of the two images, and path length variations influence the interferometric phase. Hence, the geometrical information of the interferometric phase can be used to map heights and surface deformations. The degree of coherence is a measure for the variance of the interferometric phase and can be used together with the backscattering intensity to study terrain properties. The potential of SAR data for landuse classification, change detection and monitoring, and the retrieval of geophysical and biophysical parameters will be discussed based on examples.
BibTeX:
@article{Strozzi1997114,
  author = {Strozzi, T. and Wegmüller, U.},
  title = {Applications of SAR interferometry to land-cover mapping [Applications de l'interferometrie RSO pour l'etude de l'occupation des sols]},
  journal = {Bulletin - Societe Francaise de Photogrammetrie et de Teledetection},
  year = {1997},
  number = {148},
  pages = {114-119},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0040974233&partnerID=40&md5=924eb852cde27349c3a9b383f36675e5}
}
Strozzi T and Wegmüller U (1997), "Forest mapping with ERS SAR interferometry", In European Space Agency, (Special Publication) ESA SP. (414 PART 1), pp. 357-362.
Abstract: The geometric information contained in the interferometric phase and the potential of the interferometric correlation and of the two backscatter intensities of an interferometric pair for the classification of different surface types were combined in order to generate a forest map for a part of Switzerland Forest was mapped based on its low interferometric correlation, low backscatter change between the two images of the interferometric pair, and backscattering intensities around -10 dB. The described approach was applied to several ERS-1/2 Tandem pairs allowing to discuss the dependence of the result on system and scene parameters, including seasonal and meteorological effects. As a result of the short one day acquisition interval (as compared to the 3 and more days with ERS-1, only) less confusion occurred between forest stands, on one side, and vegetation on agricultural fields or low correlation by farming activities, on the other side This makes the approach with Tandem data more robust for application during spring, summer and fall The resulting landuse maps were transformed into orthonormal coordinates using the estimated topographic heights and validated with data of the Swiss Federal Statistical Institute. The potential of SAR interferometry for forest type discrimination was also investigated. For known forest stands the interferometric correlation was related to the forest type A reliable separation for deciduous, mixed, and coniferous forest stands was possible only with winter Tandem pairs.
BibTeX:
@conference{Strozz1997357,
  author = {Strozzi, T. and Wegmüller, U.},
  title = {Forest mapping with ERS SAR interferometry},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {1997},
  number = {414 PART 1},
  pages = {357-362},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-5244362568&partnerID=40&md5=2fcd375df00e6854e22e8437161c27f6}
}
Strozzi T, Wiesmann A and Matzler C (1997), "Active microwave signatures of snow covers at 5.3 and 35 GHz", Radio Science. Vol. 32(2), pp. 479-495. American Geophysical Union.
Abstract: During the last 3 years we performed in situ backscattering measurements on various natural snow covers at 5.3 and 35 GHz (C and Ka band, respectively). Most of the measurements were made at a test site above Davos in the Swiss Alps at 2540 m above sea level (asl), but studies were conducted also at other test sites in Switzerland and Austria at heights between 500 and 2200 m asl. The backscattering coefficient γ was measured at hh, vv, hv and vh polarization, together with physical parameters of the snow cover, like snow height, stratification, temperature, density, and permittivity. On the basis of ground information and on a simple distribution of γ, we identified signatures of object classes. The signatures were used in order to evaluate the capability of active microwave sensors at 5.3 and 35 GHz for the classification of snow covers. In addition, semiempirical algorithms for the retrieval of physical parameters of the snow cover, such as water equivalent, liquid water content, and thickness of the refrozen crust, were defined.
BibTeX:
@article{Strozzi1997479,
  author = {Strozzi, T. and Wiesmann, A. and Matzler, C.},
  title = {Active microwave signatures of snow covers at 5.3 and 35 GHz},
  journal = {Radio Science},
  publisher = {American Geophysical Union},
  year = {1997},
  volume = {32},
  number = {2},
  pages = {479-495},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85033161668&doi=10.1029%2f96RS03777&partnerID=40&md5=07bbef0c2bb7ffda8d039f324e3d1abf},
  doi = {10.1029/96RS03777}
}
Wegmüller U (1997), "Soil moisture monitoring with ERS SAR interferometry", In European Space Agency, (Special Publication) ESA SP. (414 PART 1), pp. 47-51.
Abstract: Soil moisture monitoring with repeat-pass ERS SAR data using interferometric signature analysis was investigated using data acquired over Middle Zeeland, The Netherlands, between January and March 1994 during 3-day repeat orbits. Bare and sparsely vegetated fields with constant surface roughness were identified based on its interferometric signatures. Such areas are most useful for soil moisture monitoring. Under the assumption of limited vegetation scattering and constant surface roughness, multi-temporal microwave backscattering data show a clear dependence on the soil moisture content of the upper most soil layer. For eight bare fields without roughness change the backscattering was related to the in-situ measured soil moisture and used to derive retrieval algorithms for the relative soil moisture change and the soil moisture. The relative soil moisture change is retrieved from the relative backscatter change (defined as difference of backscatter values in dB, or ratio [in dB] of absolute backscattering values). The absolute soil moisture can be estimated if the soil moisture is known for one reference data set. In the case of the Middle Zeeland data acquired during a period with frozen soils, i.e. very low soil moisture content, was used as moisture reference. The influence of the surface roughness on the soil moisture retrieval algorithm were also investigated. In a further step, the algorithms were applied to fields without in-situ data, allowing to retrieve soil moisture maps for larger areas.
BibTeX:
@conference{Wegmuller199747,
  author = {Wegmüller, U.},
  title = {Soil moisture monitoring with ERS SAR interferometry},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {1997},
  number = {414 PART 1},
  pages = {47-51},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-5244248248&partnerID=40&md5=136ce030ee4b2dec7e53ff87bb1af654}
}
Wegmüller U, Strozzi T and Werner C (1997), "Forest applications of ERS, JERS, and SIR-C SAR interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 790-792. IEEE, Piscataway, NJ, United States.
Abstract: In the past interferometric analysis of ERS-1/2 SAR data demonstrated a high potential for forest applications. In this study, the dependence of the SAR interferometric signatures on radar frequency, incidence angle, and polarization, and acquisition time interval were investigated. The results are used to discuss the feasibility of forest applications using SAR data of the Japanese Remote Sensing Satellite JERS, and the Shuttle Imaging Radar SIR-C.
BibTeX:
@conference{Wegmuller1997790,
  author = {Wegmüller, Urs and Strozzi, Tazio and Werner, Charles},
  editor = {Anon},
  title = {Forest applications of ERS, JERS, and SIR-C SAR interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1997},
  volume = {2},
  pages = {790-792},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030707062&partnerID=40&md5=3f324c92cfa7b14db944e23eb7d8f194}
}
Wegmüller U and Werner C (1997), "Gamma SAR processor and interferometry software", In European Space Agency, (Special Publication) ESA SP. (414 PART 3), pp. 1687-1692.
Abstract: Based on the previous work of C. Werner and U. Wegmuller in the frame of their research at the University of Zurich and Jet Propulsion Laboratory, as well as up to date algorithms published in the literature Gamma Remote Sensing developed its advanced SAR processing and interferometry software packages. The SAR processor and the interferometry software are modular software packages written in the widely supported ANSI-C language. The well documented structured code and stepwise processing approach permit users to experiment with new algorithms and applications. Data of both airborne and spaceborne sensors including ERS, JERS-1, SIR-C, and RADARSAT StripMap mode, and the Dornier DOSAR have been successfully processed interferometrically. The processor is currently being certified by ESA for ERS processing and RSI for RADARSAT. The overall design of the software, algorithms used, special features implemented, typical sequences for processing with the Modular SAR Processor (MSP) and the Interferometric SAR Processor (ISP), as well as a few examples for results will be presented.
BibTeX:
@conference{Wegmuller19971687,
  author = {Wegmüller, U. and Werner, C.},
  title = {Gamma SAR processor and interferometry software},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {1997},
  number = {414 PART 3},
  pages = {1687-1692},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-5244223739&partnerID=40&md5=1687c77ce58f9c3391546be124f531a4}
}
Wegmüller U and Werner C (1997), "Land applications using ERS-1/2 Tandem data", In European Space Agency, (Special Publication) ESA SP. (406 PART 2), pp. 97-111.
Abstract: The potential of ERS-1/2 data for landuse classification and change detection and monitoring is discussed. For repeat-pass interferometer systems, such as the ERS satellites, low interferometric correlation indicates random dislocation of the individual scatterers between the two acquisitions of an interferometric image pair. This additional information significantly improves the potential of SAR data for landuse classification, change detection, and the retrieval of geophysical and biophysical parameters. Results obtained with ERS-1/2 Tandem data will be presented and compared to results of the ERS-1 Commissioning and Ice Phases. Finally, a short overview on GAMMA Remote Sensing's products and user services will be given.
BibTeX:
@conference{Wegmuller199797,
  author = {Wegmüller, U. and Werner, C.L.},
  title = {Land applications using ERS-1/2 Tandem data},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {1997},
  number = {406 PART 2},
  pages = {97-111},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-5244302657&partnerID=40&md5=1a9484eb107fdd0988828aad38c598a2}
}
Wegmüller U and Werner C (1997), "Retrieval of vegetation parameters with SAR interferometry", IEEE Transactions on Geoscience and Remote Sensing. Vol. 35(1), pp. 18-24.
Abstract: The potential of SAR interferornetric techniques for the retrieval of vegetation parameters was investigated using ERS-1 data over agricultural and forested test sites. In a first experiment an interferometrically derived forest map was generated. The classification was based on the interferometric correlation and the backscatter intensities. The result was geocoded, using the interferometrically derived height map generated from the same ERS SAR data pair, and validated with a conventional digital forest map. Forest mapping accuracies of around 90% and better were achieved. In a second experiment, multitemporal data over an agricultural site were used to investigate the potential of repeat-pass interferometry to monitor farming activity, crop development, and soil moisture variations. The interferometric correlation was used as an indicator of dense vegetation and geometric change. It was possible, for example, to identify harvesting by the high correlation of the post-harvest bare or stubble field. Decreasing interferometric correlation was observed as a consequence of crop growth. 1997 IEEE.
BibTeX:
@article{Wegmuller199718,
  author = {Wegmüller, U. and Werner, C.},
  title = {Retrieval of vegetation parameters with SAR interferometry},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1997},
  volume = {35},
  number = {1},
  pages = {18-24},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030834944&doi=10.1109%2f36.551930&partnerID=40&md5=cdec0a2e52a5c3c91e7c6916934f3dbd},
  doi = {10.1109/36.551930}
}
Werner C, Rosen P, Hensley S, Fielding E and Buckley S (1997), "Detection of aseismic creep along the San Andreas fault near Parkfield, California with ERS-1 radar interferometry", In European Space Agency, (Special Publication) ESA SP. (414 PART 1), pp. 521-524.
Abstract: Parkfield, California lies an area along the San Andreas fault in Southern California that has experienced strong earthquakes at apparently regular intervals in historic times. Differential interferometric analysis of ERS data of this region reveals the wide-area distribution of creep along the moving fault segment over a 15 month interval. Removal of the interferometric phase related to the surface topography was done by simulation, of an interferogram in the absence of motion given a topographic map of the region. A sharp phase discontinuity in the differential interferogram is equivalent to approximately 1.5 cm change in the line of sight. This displacement is consistent with current models of motion along the fault. We compare the observed phase signature with a predictions of the differential phase based upon the Okada model for elastic deformation. The ERS differential interferometric data are compared with a 6 month differential interferogram collected by the NASA SIR-C L-Band instrument in 1994.
BibTeX:
@conference{Werner1997521,
  author = {Werner, C.L. and Rosen, P. and Hensley, S. and Fielding, E. and Buckley, S.},
  title = {Detection of aseismic creep along the San Andreas fault near Parkfield, California with ERS-1 radar interferometry},
  booktitle = {European Space Agency, (Special Publication) ESA SP},
  year = {1997},
  number = {414 PART 1},
  pages = {521-524},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-5244333436&partnerID=40&md5=5b2851e3f50f8886b95b62224fd07ac2}
}
Durden S and Werner C (1996), "Application of an interferometric phase unwrapping technique to dealiasing of weather radar velocity fields", Journal of Atmospheric and Oceanic Technology. Vol. 13(5), pp. 1107-1109. American Meteorological Society.
Abstract: Dealiasing of Doppler weather radar velocity measurements is analogous to the problem of phase unwrapping encountered in radar and optical interferometry. A technique developed for phase unwrapping in interferometric synthetic aperture radar is described and successfully applied to weather radar velocity dealiasing.
BibTeX:
@article{Durden19961107,
  author = {Durden, S.L. and Werner, C.L.},
  title = {Application of an interferometric phase unwrapping technique to dealiasing of weather radar velocity fields},
  journal = {Journal of Atmospheric and Oceanic Technology},
  publisher = {American Meteorological Society},
  year = {1996},
  volume = {13},
  number = {5},
  pages = {1107-1109},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-5244284202&doi=10.1175%2f1520-0426%281996%29013%3c1107%3aAOAIPU%3e2.0.CO%3b2&partnerID=40&md5=9a435dc21c7024920b5f7044973aaae5},
  doi = {10.1175/1520-0426(1996)013<1107:AOAIPU>2.0.CO;2}
}
Matzler C (1996), "Microwave permittivity of dry snow", IEEE Transactions on Geoscience and Remote Sensing. Vol. 34(2), pp. 573-581.
Abstract: The relative dielectric constant, or relative permittivity, c of dry snow, is independent of frequency from about 1 MHz up to the microwave range of at least 10 GHz. New measurements of e with improved accuracy were made with a specially designed resonator operating near 1 GHz. The coaxial sensor accurately defines the sample volume whose actual mass can be determined to give the density of the snow sample. A special electronic instrument, called resometer, enabled accurate and rapid measurements under field conditions. Some 90 measurements of different kinds of dry snow (fresh, old, wind-pressed snow, depth hoar, and refrozen crusts) were made at test sites in the Swiss and Austrian Alps. The data indicate that e is a function of snow density only, given that the standard deviation of 0.006 from the fitted curve is just due to the expected measurement errors. The interpretation of these data in terms of physical mixing theory favors the effective medium formula of Polder and van Santen. The data allow to relate the average axial ratio X as a function of ice volume fraction. Both prolate and oblate spheroids can explain the data. Independent reasoning gives preference to oblate particles. In both cases, the axial ratio increases with increasing fraction up to a critical value of 0.33, followed by a decrease at still higher fractions. The destructive metamorphism of slowly compacting snow explains the increase of X, while the following decrease might be due to sintering. So far, no effect on e by a liquid-like surface layer on the ice grains at temperatures between -10° C and 0°C has been observed. 1996 IEEE.
BibTeX:
@article{Matzler1996573,
  author = {Matzler, C.},
  title = {Microwave permittivity of dry snow},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1996},
  volume = {34},
  number = {2},
  pages = {573-581},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030106065&doi=10.1109%2f36.485133&partnerID=40&md5=7f4bd936de625456a3b45432eff510dc},
  doi = {10.1109/36.485133}
}
Wigneron J-P, Combal B, Wegmüller U and Matzler C (1996), "Estimation of microwave parameters of crops from radiometric measurements", International Journal of Remote Sensing. Vol. 17(14), pp. 2875-2880.
Abstract: A simple approach is developed to calculate the microwave characteristics of a crop canopy. The approach is based on passive microwave measurements which are acquired for at least two levels of the vegetation, during the crop development. The method is applied to estimate the optical depth and the single scattering albedo of wheat fields at C-band, from two data sets. The results are analysed for several configurations of the measurement system in terms of polarization and view angle. Application of this simple approach appears to be very useful to investigate the effect of the vegetation structure on the canopy microwave emission. 1996 Taylor & Francis Group, LLC.
BibTeX:
@article{Wigneron19962875,
  author = {Wigneron, J.-P. and Combal, B. and Wegmüller, U. and Matzler, C.},
  title = {Estimation of microwave parameters of crops from radiometric measurements},
  journal = {International Journal of Remote Sensing},
  year = {1996},
  volume = {17},
  number = {14},
  pages = {2875-2880},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030235999&doi=10.1080%2f01431169608949113&partnerID=40&md5=34da4f0057b404057be47318c5fd7ed2},
  doi = {10.1080/01431169608949113}
}
Goblirsch W, Werner C, Nuesch D and Faller N (1995), "Accuracy of interferometric elevation models generated from DOSAR airborne data", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. 770-774.
Abstract: This paper addresses the geometric aspects of DEM-generation from interferometric airborne SAR data. It explains realistic modelling of the interferometric imaging geometry and gives results from simulation of imaging geometry modelling errors. In principle geometric motion compensation can never be exact, therefore new methods are required to correct elevation errors in the DEM-generation process. With the help of one ground control patch, imaging geometry is determined and the phase differences calibrated. In order to obtain the highest possible precision in the generated DEM it is necessary to produce two differently filtered versions of the DEM. In this case singular heights of individual objects are better preserved in one DEM, whereas the elevation of large scale features is more precise in the other. As a result, the height resolution is approximately 1 m locally and the overall positioning precision lies near 2 m for the DOSAR test data, which is compared to the Swiss DHM25 and to individual ground features.
BibTeX:
@conference{Goblirsch1995770,
  author = {Goblirsch, Wolfgang and Werner, Charles and Nuesch, Daniel and Faller, Nick},
  title = {Accuracy of interferometric elevation models generated from DOSAR airborne data},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {1995},
  volume = {1},
  pages = {770-774},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029203632&partnerID=40&md5=540f0ce0a18b72b3d4ebe4790b85d6ab}
}
Holecz F, Wegmüller U, Rignot E and Wang Y (1995), "Observed radar backscatter from forested areas with terrain variations", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. 613-615.
Abstract: The purpose of this paper is to analyse and to quantify topographic effects on the scattering behavior of forested areas, and to discuss the consequences for forest biomass estimation. In this study P-band polarimetric AIRSAR data is investigated. This for two reasons, namely a) radar signals at low frequencies penetrate into the forest canopy and therefore are affected by topographic changes, and b) this frequency has the best sensitivity to forest biomass. The AIRSAR data was collected over the hilly region of the Bonanza Creek Experimental Forest in Alaska. As a first step the Synthetic Aperture Radar (SAR) data are calibrated considering the local topography using a Digital Elevation Model (DEM). The topographic effects on selected calibrated radar backscatter values for several forest stands located at different slopes and having approximately the same incidence angle are analysed and quantified. Results show that even at large incidence angles the backscattering coefficient is still affected by terrain changes. Therefore, if these variations are not considered, forest biomass errors of several tenths of tons/ha occur.
BibTeX:
@conference{Holecz1995613,
  author = {Holecz, Francesco and Wegmüller, Urs and Rignot, Eric and Wang, Yong},
  title = {Observed radar backscatter from forested areas with terrain variations},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {1995},
  volume = {1},
  pages = {613-615},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029178225&partnerID=40&md5=d9b82855bb201f107fc582b0844bf6b4}
}
Small D, Werner C and Nuesch D (1995), "Geocoding and validation of ERS-1 InSAR-derived digital elevation models", EARSeL. Vol. 4(2), pp. 26-39.
Abstract: Although the field of repeat-pass SAR interferometry (InSAR) has matured significantly in recent years, a comprehensive accuracy assessment of interferometrically produced Digital Elevation Models (DEMs) has been lacking. Rigorous quality control requires large areal comparisons to a high-quality reference DEM. We present here results from the generation of geocoded ERS-1 InSAR DEMs. The accuracy of InSAR-derived DEMs is best evaluated in the map geometry of the reference DEM. The preliminary InSAR processing steps are reviewed, the geocoding methodology is described, and the interferometrically derived heights are compared to the reference elevation model. -from Authors
BibTeX:
@article{Small199526,
  author = {Small, D. and Werner, C. and Nuesch, D.},
  title = {Geocoding and validation of ERS-1 InSAR-derived digital elevation models},
  journal = {EARSeL},
  year = {1995},
  volume = {4},
  number = {2},
  pages = {26-39},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029542407&partnerID=40&md5=f292f1e60e72cea2d8ceb277ff7f7ce7}
}
Strozzi T and Matzler C (1995), "In-situ backscattering measurements of snowcover with coherent scatterometers at 5.3 and 35 GHz", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 1502-1504. IEEE, Piscataway, NJ, United States.
Abstract: This paper presents backscattering measurements of snowcover with two scatterometers at 5.3 GHz (C-band) and 35 GHz (Ka-band). The data were recorded in the Swiss Alps on February 21 and 22, 1995 during stable, dry-snow conditions. The snow height varied from 1.25 to 1.40 m. Scattering profiles, the angular and spectral dependence of the backscattering coefficient γ and the amplitude of the correlation coefficient ρ at 5.3 GHz are shown. We found that the waves at C-band are mainly backscattered by the ground for incidence angles greater than 20°. At 35 GHz, the backscattering originates from within the snowcover.
BibTeX:
@conference{Strozzi19951502,
  author = {Strozzi, T. and Matzler, C.},
  editor = {Anon},
  title = {In-situ backscattering measurements of snowcover with coherent scatterometers at 5.3 and 35 GHz},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1995},
  volume = {2},
  pages = {1502-1504},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029228027&partnerID=40&md5=09ed72b088ab4d1d23ed22f0faeb31f1}
}
Wegmüller U and Werner C (1995), "Farmland monitoring with SAR interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. 544-546.
Abstract: The potential of SAR interferometry for change monitoring is discussed. The selected application, farmland monitoring, is particularly challenging for its frequent changes due to farming activity, vegetation development, and meteorological influences. ERS repeat-pass SAR interferometry was used to map different types of change. Furthermore, such change was monitored, i.e. a time interval for the occurrence of the change could be indicated, using time series of repeat-pass ERS SAR data. During the winter season agricultural fields are usually bare of sparsely covered with vegetation. Therefore, high interferometric correlation is observed for most fields. Under these circumstances repeat-pass SAR interferometry allows the monitoring of farming activities (mechanical cultivation) and soil moisture changes. During the main growing season low interferometric correlation results from both, dense vegetation and farming activities. Harvesting can be recognized by the high interferometric correlation of the post-harvest bare or stubble fields.
BibTeX:
@conference{Wegmuller1995544,
  author = {Wegmüller, U. and Werner, C.L.},
  title = {Farmland monitoring with SAR interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  year = {1995},
  volume = {1},
  pages = {544-546},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029190510&partnerID=40&md5=edb91fcab8146f54070246b5839032af}
}
Wegmüller U, Werner C, Nuesch D and Borgeaud M (1995), "Land-surface analysis using ERS-1 SAR interferometry", ESA Bulletin. Vol. 81, pp. 30-37.
Abstract: The European Remote Sensing Satellite ERS-1, lauched by ESA in 1991, carries an Active Microwave Instrument (AMI). During several phases of its operations, ERS-1 has been operated in almost exact repeat orbits with periods of 3 and 35 days. The data acquired during these repeat orbits can be used to perform repeat-pass SAR interferometry. The excellence of ERS-1's orbit and attitude control system and the high reliability of its SAR system result in excellent interferograms. -Authors
BibTeX:
@article{Wegmuller199530,
  author = {Wegmüller, U. and Werner, C.L. and Nuesch, D. and Borgeaud, M.},
  title = {Land-surface analysis using ERS-1 SAR interferometry},
  journal = {ESA Bulletin},
  year = {1995},
  volume = {81},
  pages = {30-37},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028880109&partnerID=40&md5=501e26bfd9df3500b6c485aa4fba59bc}
}
Wegmüller U and Werner CL (1995), "SAR Interferometric Signatures of Forest", IEEE Transactions on Geoscience and Remote Sensing. Vol. 33(5), pp. 1153-1161.
Abstract: The potential of SAR interferometry for forest mapping and monitoring is discussed. It is shown that forest can clearly be discriminated from other land categories. Furthermore it is possible to distinguish a number of forest types. The presented approach is based on the SAR interferometric correlation and the backscatter intensities using ERS-1 SAR repeat-pass data. Baseline, time interval, and seasonal dependences were analyzed, substantiating a wide applicability of the approach. Data over an Alaskan test site were used to extend the results found over temperate forest to boreal forest and to demonstrate the potential of the described technique over remote areas. In addition, repeat-pass SAR interferometry was found to be particularly sensitive to change. Examples for the recognition of freezing, mechanical cultivation of agricultural fields, and canopy growth are shown. 1995 IEEE
BibTeX:
@article{Wegmuller19951153,
  author = {Wegmüller, U. and Werner, Charles L.},
  title = {SAR Interferometric Signatures of Forest},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1995},
  volume = {33},
  number = {5},
  pages = {1153-1161},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029368134&doi=10.1109%2f36.469479&partnerID=40&md5=a6dd20add5bcd7b3020f7ee1ec89065b},
  doi = {10.1109/36.469479}
}
Weise T and Matzler C (1995), "Radiometric and structural measurements of snow samples", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1762-1764. IEEE, Piscataway, NJ, United States.
Abstract: A new method to determine the scattering and absorption behavior of dry snow based on radiometric measurements will be presented. Brightness temperatures of homogeneous samples were measured in the frequency range from 11 to 94 GHz to calculate transmissivities and reflectivities including a type of attenuation coefficient. Full characterization of the samples has been done including determination of autocorrelation functions. We will discuss the relationship between radiometric and physical parameters of the snow samples.
BibTeX:
@conference{Weise19951762,
  author = {Weise, Thomas and Matzler, Christian},
  editor = {Anon},
  title = {Radiometric and structural measurements of snow samples},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1995},
  volume = {3},
  pages = {1762-1764},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029237941&partnerID=40&md5=4cde73960e980777ea5245b953c48ecf}
}
Hiltbrunner D, Matzler C and Wiesmann A (1994), "Monitoring land surfaces with combined DMSP-SSM/I and ERS-1 Scatterometer data", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 1945-1947. IEEE, Piscataway, NJ, United States.
Abstract: Microwave data from the DMSP-SSM/I sensor (Hollinger et al., 1987) and the ERS-1 Scatterometer (Vass & Handoll, 1991) are used to monitor the temporal behaviour of deserts, forests and snow-covered areas. The SSM/I brightness temperatures were spatially interpolated using the algorithm proposed by Poe (1990). In order to detect the different land surface types according to their spectral signature, the surface emissivity has to be derived from the satellite brightness temperatures. This requires the knowledge of the physical temperature of the earth surface. Our approach for determining the physical surface temperature consists of a linear combination of SSM/I 19 GHz brightness temperatures. Ground measurements of surface temperature are in good agreement with the estimated physical temperature (rms = 2.63K). The agreement is worse for temperatures below 273.15K. The estimated physical temperatures are used to derive the emissivity of selected land surface types (deserts, forests) from SSM/I measurements. While dry deserts and tropical rain forests showed, as expected, virtually no seasonal variations, large variations in emissivity at 37 GHz for the Siberian forest regions were noticed. Together with the scatterometer data this observation can be interpreted as melting snow within the observed area.
BibTeX:
@conference{Hiltbrunner19941945,
  author = {Hiltbrunner, D. and Matzler, C. and Wiesmann, A.},
  title = {Monitoring land surfaces with combined DMSP-SSM/I and ERS-1 Scatterometer data},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1994},
  volume = {4},
  pages = {1945-1947},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028752552&partnerID=40&md5=e17e2761c851d49ed32b4f0c6f9d62c0}
}
Holecz F, Meier E, Piesbergen J, Wegmüller U and Nuesch D (1994), "Radiometric calibration of airborne SAR imagery", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 1096-1098. IEEE, Piscataway, NJ, United States.
Abstract: A method to compute a fully calibrated airborne synthetic aperture radar (SAR) image is presented. In a first step the data is processed taking motion compensation errors into account by using the Reflectivity Displacement Method (RDM). This paper focusses on the second step, namely the rigorous determination of the backscattering coefficient σ0 and γ. To determine the exact local area and the local incidence angle, high precision flight path data, a high resolution digital elevation model (DEM), as well as sensor and processor characteristics need to be considered. Radiometric distortions due to the antenna diagram, to the reciprocal value of the third power of the slant range, and to the sine of the local incidence angle are also corrected, by taking into account aircraft displacements and terrain height variations. Magnitude data of the E-SAR system of the German Aerospace Research Establishment (DLR) collected over a hilly region in Switzerland are used to demonstrate the calibration technique.
BibTeX:
@conference{Holecz19941096,
  author = {Holecz, Francesco and Meier, Erich and Piesbergen, Jens and Wegmüller, Urs and Nuesch, Daniel},
  title = {Radiometric calibration of airborne SAR imagery},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1994},
  volume = {2},
  pages = {1096-1098},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028733746&partnerID=40&md5=d02b3a4806d7eea5f90a4254d6fae0fd}
}
Matzler C (1994), "Microwave (1-100 GHz) Dielectric Model of Leaves", IEEE Transactions on Geoscience and Remote Sensing. Vol. 32(4), pp. 947-949.
Abstract: A semiempirical formula for the complex dielectric permittivity of leaves from different plants is found from a comparison of published measurements covering the frequency range from 1 to 100 GHz. The explicit parameters are the drymatter fraction mdof the leaf and the permittivityεsw of saline water with a salinity of about 1 percent. The physical part of the formula is its basis on εsw, while the empirical part is its linearity with md. The formula is applicable to fresh leaves; their md values are in the range 0.1 md 0.5. A test indicates that besides the mdvariation and the spectral dependence the formula also describes the temperature variation correctly. 1994 IEEE
BibTeX:
@article{Matzler1994947,
  author = {Matzler, C.},
  title = {Microwave (1-100 GHz) Dielectric Model of Leaves},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1994},
  volume = {32},
  number = {4},
  pages = {947-949},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028464477&doi=10.1109%2f36.298024&partnerID=40&md5=c25c2b2965ab8a14810dbd06c9fb8c1f},
  doi = {10.1109/36.298024}
}
Matzler C (1994), "Microwave transmissivity of a forest canopy: Experiments made with a beech", Remote Sensing of Environment. Vol. 48(2), pp. 172-180.
Abstract: The microwave brightness temperatures over a frequency range from 1 GHz to 100 GHz were monitored below a large beech tree (Fagus silvatica L.) from August 1987 to August 1988, and several observations were added in the following 2 years until the beech was felled. The data were used to compute microwave transmissivities and opacities of the vegetation canopy. The results show that the transmissivities are influenced by wind, temperature, and liquid water, leaves play a dominant role, especially at frequencies above 5 GHz. With increasing frequency, also, the inhomogeneity of branches and leaves becomes more and more pronounced. An interesting result is the anticorrelation found between the microwave opacity of the test beech and a regional forest-damage parameter. These results are based on the full 4-year observation period. Potential applications of microwave radiometric tree observations are the study of the waterstatus in vegetation, the estimation of forest-canopy parameters, and the development and the validation of microwave propagation models. 1994.
BibTeX:
@article{Matzler1994172,
  author = {Matzler, C.},
  title = {Microwave transmissivity of a forest canopy: Experiments made with a beech},
  journal = {Remote Sensing of Environment},
  year = {1994},
  volume = {48},
  number = {2},
  pages = {172-180},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028431033&doi=10.1016%2f0034-4257%2894%2990139-2&partnerID=40&md5=e7bd040eafaacc91e5060f185b09dce9},
  doi = {10.1016/0034-4257(94)90139-2}
}
Matzler C (1994), "Passive microwave signatures of landscapes in winter", Meteorology and Atmospheric Physics. Vol. 54(1-4), pp. 241-260. Springer-Verlag.
Abstract: The successful application of passive microwave sensors requires signatures for the unambiguous inversion of the remote sensing data. Due to the large number of object types and large variability of physical properties, the inversion of data from land surfaces is a delicate and often ambiguous task. The present paper is a contribution to the assessment of multi-frequency passive microwave signatures of typical objects on land in winter. We discuss the behaviour of measured emissivities at vertical and horizontal polarization over the frequency range of 5 to 100 GHz (incidence angle of 50 degrees) of water and bare soil surfaces, grass and snowcovers under various conditions. These data and their variabilities lead us toward a classificaion algorithm for some, but not all object classes. Most snowcovers can easily be discriminated from other surfaces, difficulties occur for fresh powder snow if 94 GHz data are not available. The problem of wet snow has found a solution by using a certain combination of observables. In addition to snowcover types we find large differences between frozen and unfrozen bare soil. On the other hand the different situations of grasscovers show all very similar emissivities. For the estimation of physical parameters we propose algorithms for certain object classes. The estimation of surface temperature, especially for snow-free land, seems to be feasible, also the estimation of the snow liquid water content at the surface. For estimating soil moisture lower frequencies (e.g. 1.4 GHz) should be used. For the estimation of the Water Equivalent, WE, we cannot yet find a definitive solution. Certain correlations exist for dry winter snow between WE and observables at frequencies between 10 and 35 GHz. Especially the polarization difference at 10 GHz shows a monotonous increase with increasing WE. Algorithms using higher frequencies are more sensitive to WE, however, they are subject to ambiguities. 1994 Springer-Verlag.
BibTeX:
@article{Matzler1994241,
  author = {Matzler, C.},
  title = {Passive microwave signatures of landscapes in winter},
  journal = {Meteorology and Atmospheric Physics},
  publisher = {Springer-Verlag},
  year = {1994},
  volume = {54},
  number = {1-4},
  pages = {241-260},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-21844506689&doi=10.1007%2fBF01030063&partnerID=40&md5=2299e23b70ea9b00f95877b624868fdc},
  doi = {10.1007/BF01030063}
}
Souyris J, Wang L, Hsu C, Kong J, Le Toan T, Boudier N, Yueh S, Wegmüller U and Matzler C (1994), "Inversion of soil moisture with radar backscattering data", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1392-1394. IEEE, Piscataway, NJ, United States.
Abstract: In this paper, inversion of soil moisture with radar backscattering data is investigated. First, the influence of surface roughness on the radar backscatter has been studied using several existing theoretical approaches. The simulation results showed a very strong sensitivity of the radar backscattering coefficients on the variations of the parameters characterizing the surface roughness. In order to assess the use of multifrequency or multipolarization data for soil moisture inversion without full knowledge of the surface roughness parameters, neural networks are applied to simulated data. The copolarized multifrequency data have been simulated using the IEM model and the multipolarized data (co and crosspolarization) have been simulated using a polarimetric model we developed under the Small Perturbation assumption.
BibTeX:
@conference{Souyris19941392,
  author = {Souyris, J.C. and Wang, L. and Hsu, C.C. and Kong, J.A. and Le Toan, T. and Boudier, N. and Yueh, S.H. and Wegmüller, U. and Matzler, C.},
  title = {Inversion of soil moisture with radar backscattering data},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1994},
  volume = {3},
  pages = {1392-1394},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028742065&partnerID=40&md5=105ff8ed3eb63cb8d766ea88dd468848}
}
Wegmüller U, Holecz F, Wang Y and Kattenborn G (1994), "Theoretical sensitivity of ERS-1 SAR backscatter over forest", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 4, pp. 2477-2479. IEEE, Piscataway, NJ, United States.
Abstract: A theoretical microwave backscatter model was used to simulate the sensitivity of ERS-1 SAR data over temperate forest to SAR system, forest stand, and environmental parameters. Of particular interest were the simulations of the temperature dependence of the backscattering coefficient under consideration of the partial freezing of the soil and plant water at temperatures below 0°C and of leaf and needle biomass variations as they occur due to the seasonal development and as a consequence of stress and disease.
BibTeX:
@conference{Wegmuller19942477,
  author = {Wegmüller, U. and Holecz, F. and Wang, Y. and Kattenborn, G.},
  title = {Theoretical sensitivity of ERS-1 SAR backscatter over forest},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1994},
  volume = {4},
  pages = {2477-2479},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028730893&partnerID=40&md5=ad86e97f0ceecd9b62d9144ab51a655b}
}
Wegmüller U, Matzler C, Schanda E and Huppi R (1994), "Active and Passive Microwave Signature Catalog on Bare Soil (2-12 GHz)", IEEE Transactions on Geoscience and Remote Sensing. Vol. 32(3), pp. 698-702.
Abstract: The ground-based radiometer-scatterometer system of the University of Bern, RASAM, measures brightness temperatures and backscattering coefficients at frequencies between 2 and 12 GHz. Between 1984 and 1992 many campaigns were carried out on agricultural fields. Data from more than 70 bare agricultural soils have now been organized in a bare soil signature catalogue [1]. In addition to the microwave data, detailed ground-truth information was collected including highly accurate surface roughness profiles. Information on the data base is given, together with short descriptions of the instruments and measurement procedures. 1994 IEEE.
BibTeX:
@article{Wegmuller1994698,
  author = {Wegmüller, U. and Matzler, C. and Schanda, E. and Huppi, R.},
  title = {Active and Passive Microwave Signature Catalog on Bare Soil (2-12 GHz)},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1994},
  volume = {32},
  number = {3},
  pages = {698-702},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028426097&doi=10.1109%2f36.297987&partnerID=40&md5=1b2d54a2fe73f692966ac5509346396b},
  doi = {10.1109/36.297987}
}
Wegmüller U, Werner C, Nueesch D and Sieber A (1994), "Interferometric signatures of temperate forest from ERS-1 SAR data", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. 292-294. IEEE, Piscataway, NJ, United States.
Abstract: The potential of SAR interferometry for forest mapping and monitoring is discussed. It is shown that forest can clearly be discriminated from other land categories. Furthermore it is possible to distinguish a number of forest types. Our approach is based on the SAR interferometric correlation and the backscatter intensities using ERS-1 SAR repeat orbit data.
BibTeX:
@conference{Wegmueller1994292,
  author = {Wegmüller, U. and Werner, C.L. and Nueesch, D.R. and Sieber, A.},
  title = {Interferometric signatures of temperate forest from ERS-1 SAR data},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {IEEE, Piscataway, NJ, United States},
  year = {1994},
  volume = {1},
  pages = {292-294},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028742309&partnerID=40&md5=5c12165b6aa35fc14bba8719849e22d6}
}
Zebker H, Rosen P, Goldstein R, Gabriel A and Werner C (1994), "On the derivation of coseismic displacement fields using differential radar interferometry: the Landers earthquake", Journal of Geophysical Research. Vol. 99(B10), pp. 19,617-19,634.
Abstract: We present a map of the coseismic displacement field resulting from the Landers, California, June 28, 1992, earthquake derived using data acquired from an oribiting high-resolution radar system. We achieve results more accurate than previous space studies and similar in accuracy to those obtained by conventional field survey techniques. Data from the ERS 1 synthetic aperture radar instrument acquired in April, July, and August 1992 are used to generate a high-resolution, wide area map of the displacements. The data represent the motion in the direction of the radar line of sight to centimeter level precision of each 30m resolution element in a 113km by 90km image. Our coseismic displacement contour map gives a lobed pattern consistent with theoretical models of the displacement field from the earthquake. -from Authors
BibTeX:
@article{Zebker1994,
  author = {Zebker, H.A. and Rosen, P.A. and Goldstein, R.M. and Gabriel, A. and Werner, C.L.},
  title = {On the derivation of coseismic displacement fields using differential radar interferometry: the Landers earthquake},
  journal = {Journal of Geophysical Research},
  year = {1994},
  volume = {99},
  number = {B10},
  pages = {19,617-19,634},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0005392714&partnerID=40&md5=65743549547666a7b99f3e91461132c7}
}
Zebker H, Werner C, Rosen P and Hensley S (1994), "Accuracy of Topographic Maps Derived from ERS-1 Interferometric Radar", IEEE Transactions on Geoscience and Remote Sensing. Vol. 32(4), pp. 823-836.
Abstract: A interferometric radar technique for topographic mapping of surfaces promises a high-resolution approach to the generation of digital elevation models. We present here analyses of data collected by the synthetic aperture radar instrument on-board the ERS-1 satellite on successive orbits. Use of a single satellite in a nearly repeating orbit is attractive for reducing cost and spaceborne hardware complexity; also it permits inference of changes in the surface from the correlation properties of the radar echoes. The data have been reduced to correlation maps and digital elevation models. The correlation maps show that temporal correlation decreases significantly with time, but not necessarily at a constant well-defined rate, likely depending on environmental factors. When correlation among passes remains high, however, it is possible to form digital elevation models. Analyses of noise expected in ERS-1 interferometric data collected over Alaska and the southwestern United States indicate that maps with relative errors less than 5 m rms are possible in some regions. However, orbit uncertainties imply that tie points are required in order to reduce absolute height errors to a similar magnitude. We find that about 6 tie points per 40 × 40 km scene with 5 m rms or better height accuracy are needed to keep systematic map height errors below 5 m rms. The performance of the ERS-1 radar system for topographic applications, though useful for a variety of regional and local discipline studies, may be improved with respect to temporal decorrelation errors and absolute height acuity by modifying the orbit repeat period and incorporating precise orbit determination techniques. The resulting implementation will meet many, but not all, objectives of a global mapping mission. 1994 IEEE
BibTeX:
@article{Zebker1994823,
  author = {Zebker, H.A. and Werner, C.L. and Rosen, P.A. and Hensley, S.},
  title = {Accuracy of Topographic Maps Derived from ERS-1 Interferometric Radar},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1994},
  volume = {32},
  number = {4},
  pages = {823-836},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028468323&doi=10.1109%2f36.298010&partnerID=40&md5=211cb2a0ad8fe52d7a96980485b1a161},
  doi = {10.1109/36.298010}
}
Small D, Werner C and Nuesch D (1993), "Baseline modelling for ERS-1 SAR interferometry", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 3, pp. 1204-1206. Publ by IEEE, Piscataway, NJ, United States.
Abstract: An automated system for generating interferograms is presented, including coarse and fine registration, calculation of the interferogram, baseline estimation, and planar phase removal. Adaptive filtering, phase unwrapping, and baseline estimation are then performed to calculate the height model. Methods for the precise estimation of the interferometric baseline using ground control points are presented, and height residuals are compared. Test result are tabulated for an ERS-1 scene pair acquired over the Bonn area in Germany during March 1992. Of the methods tried, a three parameter iterative non-linear least squares procedure produces the best baseline model for use in generating digital elevation models.
BibTeX:
@conference{Small19931204,
  author = {Small, David and Werner, Charles and Nuesch, Danie},
  editor = {Fujimura Sadao},
  title = {Baseline modelling for ERS-1 SAR interferometry},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Publ by IEEE, Piscataway, NJ, United States},
  year = {1993},
  volume = {3},
  pages = {1204-1206},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0027815369&partnerID=40&md5=f35848c20b702e1ba61b88b2beafc4ef}
}
Wegmüller U (1993), "Signature research for crop classification by active and passive microwaves", International Journal of Remote Sensing. Vol. 14(5), pp. 871-883.
Abstract: During the last six years we have carried out a series of ground-based microwave measurements on agricultural fields. Bare soils, corn (maize), wheat, sugar-beet, potatoes, grass, canola (rape), oat, and rye were observed under various conditions and phenological stages. Our calibrated radiometer-scatterometer system, RASAM, operates at frequencies between 3 and 11 GHz. The brightness temperature was measured at horizontal and vertical polarization, and the back scattering coefficient at HH, W, HV, and VH polarization, all at incidence angles from 0° to 70°. In addition we measured soil and vegetation parameters. The data are stored in our signature data base. In this article the signature data base is reviewed with respect to crop classification. We find that between mid-June and mid-July it is possible to distinguish the dominant crops of Switzerland (cereals, com, sugar-beet, potatoes, canola and grass) with two carefully chosen active or passive microwave parameters. The use of multi-temporal data for crop classification is discussed. Microwave remote sensing is able to collect multi-temporal data reliably due to its relative independence of weather conditions. Finally, the signature data base is used to illustrate the signatures of agricultural fields for the system configuration that will be used by the active microwave instrument on the ERS-1 satellite. 1993 Taylor & Francis Group, LLC.
BibTeX:
@article{Wegmuller1993871,
  author = {Wegmüller, U.},
  title = {Signature research for crop classification by active and passive microwaves},
  journal = {International Journal of Remote Sensing},
  year = {1993},
  volume = {14},
  number = {5},
  pages = {871-883},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0027334215&doi=10.1080%2f01431169308904383&partnerID=40&md5=7033dca9f8f5f77eb5dc297288a88e05},
  doi = {10.1080/01431169308904383}
}
Matzler C (1992), "Ground-based observations of atmospheric radiation at 5, 10, 21, 35, and 94 GHz", Radio Science. Vol. 27(3), pp. 403-415.
Abstract: Atmospheric observations made with ground‐based, multifrequency radiometers (f = 4.9, 10.4, 21, 35, and 94 GHz) for the original purpose of microwave signature research for remote sensing of snowpacks, sea ice, and vegetation were analyzed. The tipping‐curve method was used both for radiometric calibration and for the determination of the zenith opacities. The data were grouped into three regions with different locations and different altitudes (10, 570, and 2550 m) above sea level. Key parameters are air temperature and atmospheric zenith opacities at each frequency. The large number of different (nonprecipitating) conditions provide statistical properties of atmospheric attenuation. Especially high correlation was found between the opacities at 35 and 94 GHz. For cloudless subsets of the data these opacities are also highly correlated with the ones at 21 GHz. Estimation of the total atmospheric contents of water vapor V and cloud liquid water L was made from the opacities at 21, 35, and 94 GHz. Whereas V is clearly correlated with the surface air temperature, large L values are clustered around temperatures near 0°C. Comparison with radiosonde measurements indicates a standard deviation in V of 0.22 cm and a bias of −0.11 cm. Consistency tests of liquid water estimates show a standard deviation of 0.03 mm. Copyright 1992 by the American Geophysical Union.
BibTeX:
@article{Matzler1992403,
  author = {Matzler, C.},
  title = {Ground-based observations of atmospheric radiation at 5, 10, 21, 35, and 94 GHz},
  journal = {Radio Science},
  year = {1992},
  volume = {27},
  number = {3},
  pages = {403-415},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0026868403&doi=10.1029%2f91RS03052&partnerID=40&md5=5b1e03a28a87685bc3c7b4a6300dd5c0},
  doi = {10.1029/91RS03052}
}
Saatchi S and Wegmüller U (1992), "Modeling and measurement of microwave emission and backscattering from bare soil surfaces", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 2, pp. 1190-1192. Institute of Electrical and Electronics Engineers Inc..
Abstract: A multi-frequency ground based radiometer-scatterometer system working at frequencies between 3.0 GHz and 11.0 GHz has been used to study the effect of soil moisture and roughness on microwave emission and backscattering. In this study two problems are of particular interest, the freezing and thawing effect of the soil surface and the changes of the surface roughness due to rain and erosion. To analyze the combined active and passive data a scattering model based on physical optics approximation for the low frequency and geometrical optics approximation for high frequency has been developed. The model is used to calculate the bistatic scattering coefficients from the surface. Then, by considering the conservation of energy, the result has been integrated over a hemisphere above the surface to calculate the emissivity. The model simulations compares with the measured data. The backscattering and emission model has been coupled in conjunction with the observed data in order to extract soil moisture and surface roughness. IEEE 1992.
BibTeX:
@conference{Saatchi19921190,
  author = {Saatchi, S. and Wegmüller, U.},
  editor = {Williamson R., Stein T.},
  title = {Modeling and measurement of microwave emission and backscattering from bare soil surfaces},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {1992},
  volume = {2},
  pages = {1190-1192},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964529059&doi=10.1109%2fIGARSS.1992.578380&partnerID=40&md5=4966515414b15d46f3ef6e8c8f8799ca},
  doi = {10.1109/IGARSS.1992.578380}
}
Wegmüller U and Guerra A (1992), "Dielectric measurement using an open ended coaxial line with an extended center conductor", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. Vol. 1, pp. 443-445. Institute of Electrical and Electronics Engineers Inc..
Abstract: A widely used approach to measure permittivity is to measure the complex reflection coefficient of an open ended coaxial line placed in contact with a test sample. This method is well-documented in literature. An open-ended coaxial line may be described by an equivalent circuit The concentration of the fields fringing into the dielectric medium is represented by a capacitor. Its capacitance can be tuned and optimized for the desired range of dielectric constants by changing the line's dimension. Using a network-analyzer this method is attractive because of its technical simplicity and because it can be applied over a large spectral range. This method works best for liquid samples. For the measurement of non-liquid materials problems can arise. Theory and measurements showed that the sensor is only sensitive to a small volume in front of its open end, therefore inhomogeneities can affect the measurement. A perfect preparation is needed to provide a good contact between the tip and the dielectric medium. And sometimes the dimension of the sensor cannot be freely chosen as it is the case for the measurement of the dielectric constant of the xylem layer of a living tree. The influence of the installation of the sensor on the trees water status must be minimized by using a small sensor. In such cases the capacitance cannot be optimized as described above. By extending the center conductor of the open ended coaxial line some of the above mentioned problems can be avoided. One improvement is that it provides an additional tool to tune the capacitance of the sensor, namely by adjusting the length of the extension. Therefore the measurement accuracy can be optimized. The sensor also becomes sensitive to a larger volume. The result of a comparative study of a flush and extended tipped probes is that the sensitivity to measure the dielectric constant of trees has been notably increased due to the extension of the center conductor.
BibTeX:
@conference{Wegmuller1992443,
  author = {Wegmüller, U. and Guerra, A.G.},
  editor = {Williamson R., Stein T.},
  title = {Dielectric measurement using an open ended coaxial line with an extended center conductor},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {Institute of Electrical and Electronics Engineers Inc.},
  year = {1992},
  volume = {1},
  pages = {443-445},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84969641314&doi=10.1109%2fIGARSS.1992.576734&partnerID=40&md5=a326a5ae9ec013360c681cfc600eaede},
  doi = {10.1109/IGARSS.1992.576734}
}
Elachi C, Im E, Roth L and Werner C (1991), "Cassini Titan Radar Mapper", Proceedings of the IEEE. Vol. 79(6), pp. 867-880.
Abstract: Cassini Titan Radar Mapper is a multimode radar instrument designed to probe the optically inaccessible surface of Titan, Saturn's largest moon. The instrument is to be included in the payload of the Cassini Saturn Mission. The spacecraft is scheduled for launch in 1995 and is expected to arrive at Saturn and be inserted in orbit around Saturn in late 2003. The individual modes of Cassini Radar Mapper will allow surface imaging at few hundred meters resolution, and topographic mapping. The Mapper will be in operation during close flybys of Titan and will map  30% of Titan's surface in the course of the nominal mission. 1991 IEEE
BibTeX:
@article{Elachi1991867,
  author = {Elachi, C. and Im, E. and Roth, L.E. and Werner, C.L.},
  title = {Cassini Titan Radar Mapper},
  journal = {Proceedings of the IEEE},
  year = {1991},
  volume = {79},
  number = {6},
  pages = {867-880},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0026173177&doi=10.1109%2f5.90164&partnerID=40&md5=281aba02d070bf03a8f36fa082ee6afd},
  doi = {10.1109/5.90164}
}
Freeman A, Shen Y and Werner C (1990), "Polarimetric SAR Calibration Experiment Using Active Radar Calibrators", IEEE Transactions on Geoscience and Remote Sensing. Vol. 28(2), pp. 224-240.
Abstract: Active radar calibrators are used to derive both the amplitude and phase characteristics of a multichannel polarimetric SAR from the complex image data. Results are presented from an experiment carried out using the NASA/JPL DC-8 Aircraft SAR over a calibration site at Goldstone, California. As part of the experiment, polarimetric active radar calibrators, termed PARC's, with adjustable polarization signatures were deployed. Experimental results demonstrate that the PARCs can be used to successfully calibrate polarimetric SAR images. Restrictions on the application of the PARC calibration procedure are discussed. 1990 IEEE
BibTeX:
@article{Freeman1990224,
  author = {Freeman, A. and Shen, Y. and Werner, C.L.},
  title = {Polarimetric SAR Calibration Experiment Using Active Radar Calibrators},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1990},
  volume = {28},
  number = {2},
  pages = {224-240},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0025405042&doi=10.1109%2f36.46702&partnerID=40&md5=b7052974151d5ed9d4f345863330ed90},
  doi = {10.1109/36.46702}
}
Matzler C (1990), "Seasonal evolution of microwave radiation from an oat field", Remote Sensing of Environment. Vol. 31(3), pp. 161-173.
Abstract: Microwave brightness temperatures at five frequencies from 4.9 GHz to 94 GHz of an oat field were measured from seeding to harvest in 1989. The data were compared with observed soil and vegetation parameters. The reduction of the soil moisture sensitivity during the growth phase was quantitatively related to plant water content with data at 4.9 GHz. At higher frequencies the influence of vegetation is almost abruptly changing the emission with respect to the plant development. The different spectral and polarization behavior can be related to geometrical vegetation parameters such as leaf and panicle size and orientation. 1990.
BibTeX:
@article{Matzler1990161,
  author = {Matzler, C.},
  title = {Seasonal evolution of microwave radiation from an oat field},
  journal = {Remote Sensing of Environment},
  year = {1990},
  volume = {31},
  number = {3},
  pages = {161-173},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0025573143&doi=10.1016%2f0034-4257%2890%2990086-2&partnerID=40&md5=fde482fe71ea5109cc17bfea2af1fa4a},
  doi = {10.1016/0034-4257(90)90086-2}
}
Ostro S, Campbell D, Hine A, Shapiro I, Chandler J, Werner C and Rosema K (1990), "Radar images of asteroid 1627 Ivar", Astronomical Journal. Vol. 99(6), pp. 2012-2018. University of Chicago Press.
Abstract: Radar echoes from the near-Earth asteroid 1627 Ivar, whose orbit crosses the Earth's, reveal it to be about twice as long as it is wide, with a maximum dimension no less than 7 km and probably within 20% of 12 km. The surface is fairly smooth at centimeter-to-meter scales but appears irregular and nonconvex at kilometer scales.
BibTeX:
@article{Ostro19902012,
  author = {Ostro, S.J. and Campbell, D.B. and Hine, A.A. and Shapiro, I.I. and Chandler, J.F. and Werner, C.L. and Rosema, K.D.},
  title = {Radar images of asteroid 1627 Ivar},
  journal = {Astronomical Journal},
  publisher = {University of Chicago Press},
  year = {1990},
  volume = {99},
  number = {6},
  pages = {2012-2018},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0011636540&doi=10.1086%2f115482&partnerID=40&md5=2cc84ba54e1e032c6f86dcf70c7ce604},
  doi = {10.1086/115482}
}
Wegmüller U (1990), "The effect of freezing and thawing on the microwave signatures of bare soil", Remote Sensing of Environment. Vol. 33(2), pp. 123-135.
Abstract: To study the effect of a frozen soil layer on the microwave signatures of bare soil, we carried out measurements on frozen and unfrozen fields in winter. Our ground-based radiometer - scatterometer system, RASAM, works at frequencies between 3 GHz and 11 GHz. The brightness temperature was measured at horizontal and vertical polarization, the backscattering coefficient at HH, VV, HV, and VH polarization, all at incidence angles from 0° to 70°. In addition, we measured soil parameters such as moisture, roughness, and texture. The results are subdivided into three sections. First the microwave parameters measured during two diurnal freeze - thaw cycles of the soil are shown. For thawing the soil has three layers wet/frozen/wet and therefore different microwave properties than for freezing. Second frozen soil (thickness of the frozen layer is larger than the penetration depth of the radiation) is compared with unfrozen soil. For the horizontal polarization we separate the reflectivity into the Fresnel reflectivity and a roughness factor. The active data are compared with the geometrical-optics model at the higher frequencies and with the small-perturbation model at the lower frequencies. In addition the data are used to determine the sensitivity of the microwave parameters to soil liquid water content. Third the growth of a frozen soil layer is monitored. These data are used to test layered media models. Due to the scale height of surface roughness, which is of the order of the penetration depth of the radiation, the models do not agree well with the measurements. We find much better fits with a semiempirical formula. 1990.
BibTeX:
@article{Wegmuller1990123,
  author = {Wegmüller, U.},
  title = {The effect of freezing and thawing on the microwave signatures of bare soil},
  journal = {Remote Sensing of Environment},
  year = {1990},
  volume = {33},
  number = {2},
  pages = {123-135},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0025573325&doi=10.1016%2f0034-4257%2890%2990038-N&partnerID=40&md5=084208108dbb17e2f9b70aa1ca19b893},
  doi = {10.1016/0034-4257(90)90038-N}
}
Werner C and Im E (1990), "Cassini radar for remote sensing of Titan", In International Geoscience and Remote Sensing Symposium (IGARSS). Vol. 3, pp. 2089. Publ by IEEE, Piscataway, NJ, United States.
Abstract: Summary form only given. The combined orbiter/probe for the Cassini mission will be launched in 1996 and inserted into Saturn orbit in late 2002. Over the planned mission duration of 4 yr the orbiter will observe intensively the characteristics of Saturn and its many satellites. Realizing the potential scientific value of Titan surface measurements and the inherent limitations of the ground-based observations, the Cassini Titan Radar Mapper (C-TRM), a multimode imaging radar, has been included in the Cassini mission facility instrument package. In the baseline operation scenario, radar data from Titan will be collected during approximately 32 Titan flyby passes over the course of the mission. The C-TRM will operate in the following modes: altimeter, medium-resolution multibeam imager, high-resolution synthetic aperture radar (SAR) and scatterometer at 13.8 GHz, and subsurface sounder/altimeter at 2.25 GHz. Raw data from all the modes are processed by the radar data processing system (RDPS) into Level 1 and 2 data products. Level 1 processing of the imaging modes requires correlating the echoes and generating the multilook overlay images from single-look images. Level 2 products include map projections of the images and mosaics. Altimeter, scatterometer, and sounder echoes are pulse compressed and summed incoherently. These are then analyzed to provide information on altitude, backscatter strength, and, in the case of the sounder, subsurface depth profiles. Sampling locations of the data on Titan also are determined.
BibTeX:
@conference{Werner19902089,
  author = {Werner, C.L. and Im, E.},
  title = {Cassini radar for remote sensing of Titan},
  booktitle = {International Geoscience and Remote Sensing Symposium (IGARSS)},
  publisher = {Publ by IEEE, Piscataway, NJ, United States},
  year = {1990},
  volume = {3},
  pages = {2089},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0025530709&partnerID=40&md5=df5563ba99a6c4c262baf658b7a733b2}
}
Freeman A, Werner C and Klein J (1989), "Results of the 1988 NASA/JPL airborne SAR calibration campaign", In International Geoscience and Remote Sensing Symposium (IGARSS). Vol. 1, pp. 249-253.
Abstract: During the spring of 1988, the NASA/JPL multifrequency, multipolarization SAR (synthetic aperture radar) flew in series of calibration experiments over the Goldstone dry lake bed. An array of calibration devices was deployed, including dihedral and trihedral corner reflectors, polarimetric active radar calibrators, passive receivers, and CW (continuous wave) tone generators. The aim of the campaign was to calibrate both amplitude and phase of the resulting SAR images, over long and short time scales. The results of the analysis of the calibration data collected in the spring of 1988 are presented. Trihedral corner reflector signatures and certain image background measures are used to externally calibrate relative amplitude and phase between polarizations at a given frequency, and to calibrate across frequencies. Assessments are made of the calibration accuracy as a function of image frame position for each frequency, and the stability of the radar calibration over long and short time-scales.
BibTeX:
@conference{Freeman1989249,
  author = {Freeman, A. and Werner, C. and Klein, J.D.},
  title = {Results of the 1988 NASA/JPL airborne SAR calibration campaign},
  booktitle = {International Geoscience and Remote Sensing Symposium (IGARSS)},
  year = {1989},
  volume = {1},
  pages = {249-253},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0024779515&partnerID=40&md5=3f446f0ad7dc69df9b72c055476321d0}
}
Li H, Farhat N, Shen Y and Werner C (1989), "Image Understanding and Interpretation in Microwave Diversity Imaging", IEEE Transactions on Antennas and Propagation. Vol. 37(8), pp. 1048-1057.
Abstract: The microwave image of a conducting object is understood and interpreted in a new approach, based on the knowledge of the scattering mechanisms and the image reconstruction algorithm. The connection between various scattering mechanisms and the reconstructed images is then established. From this we can interpret what the image represents and predict what the image will look like for given spectral and angular windows. Several numerical and experimental examples are included to support this new interpretation approach. Successful interpretation and prediction of the microwave image are fundamental to research in several areas, including target identification, classification, radar cross-section reduction, and image distortion. 1989 IEEE
BibTeX:
@article{Li19891048,
  author = {Li, H.J. and Farhat, N.H. and Shen, Y. and Werner, C.L.},
  title = {Image Understanding and Interpretation in Microwave Diversity Imaging},
  journal = {IEEE Transactions on Antennas and Propagation},
  year = {1989},
  volume = {37},
  number = {8},
  pages = {1048-1057},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0024717203&doi=10.1109%2f8.34143&partnerID=40&md5=96439374f26dffff7973c8713ec6debc},
  doi = {10.1109/8.34143}
}
Matzler C and Huppi R (1989), "Review of signature studies for microwave remote sensing of snowpacks", Advances in Space Research. Vol. 9(1), pp. 253-265.
Abstract: A long-term program of microwave-signature studies at the alpine test site, Weissfluhjoch (2550m altitude), was completed in 1987. Besides passive microwave data at frequencies between 5 and 100 GHz backscatter data at 10 GHz were collected together with dielectric and structural properties as well as classical snow data. The same instrumentation was used from icebreakers to measure snow-covered sea ice. Complementary snow signatures were recently obtained by a new multichannel (1-12 GHz) radiometer-scatterometer at lower-altitude test sites for taking into account possible spatial variability of snow properties, and for extending the spectral coverage to lower frequencies. The results include algorithms for classifying snow types, for mapping snow, for determining the liquid water content of the snow surface, for monitoring melt and refreeze cycles, for estimating energy loss and water equivalent, respectively. We conclude by an updated definition of an optimum snow sensor system. 1989.
BibTeX:
@article{Matzler1989253,
  author = {Matzler, C. and Huppi, R.},
  title = {Review of signature studies for microwave remote sensing of snowpacks},
  journal = {Advances in Space Research},
  year = {1989},
  volume = {9},
  number = {1},
  pages = {253-265},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0001673858&doi=10.1016%2f0273-1177%2889%2990493-6&partnerID=40&md5=148221bf455a7755fedb7aacdbc89c89},
  doi = {10.1016/0273-1177(89)90493-6}
}
Rott H and Matzler C (1989), "Preface", Advances in Space Research. Vol. 9(1), pp. 231-232.
BibTeX:
@article{Rott1989231,
  author = {Rott, H. and Matzler, C.},
  title = {Preface},
  journal = {Advances in Space Research},
  year = {1989},
  volume = {9},
  number = {1},
  pages = {231-232},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0345240041&doi=10.1016%2f0273-1177%2889%2990490-0&partnerID=40&md5=b1b042f836fb100f0346ed418a67df79},
  doi = {10.1016/0273-1177(89)90490-0}
}
Wegmüller U, Matzler C and Schanda E (1989), "Microwave signatures of bare soil", Advances in Space Research. Vol. 9(1), pp. 307-316.
Abstract: Active and passive microwave signatures of bare soil were measured simultaneously with soil parameters as temperature, soil moisture, surface roughness, soil texture and permittivity. The results of three special situations, where only one soil parameter changed, are presented. In the first situation of freezing and thawing cycles only the permittivity is different. In the second situation four measurements of a bare soil are compared. At all four days the soil moisture is approximately the same, but the surface roughness changes due to erosion by rain. Third we measured a bare soil before and after a thunderstorm with hail. Again erosion smoothed the soil surface. Two days with the same soil moisture were selected. These measurements can now be used to test and create models. Microwave signatures of a frozen soil and of a soil after a thunderstorm are shown. 1989.
BibTeX:
@article{Wegmuller1989307,
  author = {Wegmüller, U. and Matzler, C. and Schanda, E.},
  title = {Microwave signatures of bare soil},
  journal = {Advances in Space Research},
  year = {1989},
  volume = {9},
  number = {1},
  pages = {307-316},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0011850802&doi=10.1016%2f0273-1177%2889%2990498-5&partnerID=40&md5=b01c2ddd07972c83f6845cf05b5e1187},
  doi = {10.1016/0273-1177(89)90498-5}
}
Freeman A, Werner C and Shen Y (1988), "Calibration of multipolarisation imaging radar", In Proc. IEEE Int. Geosci. Remote Sens. Symp.. , pp. 335-339. European Space Agency, ESTEC, Noordwijk; ESA SP-284.
Abstract: Without adequate radiometric and phase calibration of the system, it will not be possible to fully exploit the multipolarization capability of SAR systems like the Airborne Imaging Radar (AIR) and SIR-C. This paper describes an experiment designed to calibrate the AIR images, in terms of relative and absolute backscatter (σo) and relative phase between polarization channels. The calibration makes use of measurements made within the radar system itself (internal calibration) and using ground-based corner reflectors and transponders (external calibration). -from Authors
BibTeX:
@book{Freeman1988335,
  author = {Freeman, A. and Werner, C. and Yuhshen Shen},
  title = {Calibration of multipolarisation imaging radar},
  booktitle = {Proc. IEEE Int. Geosci. Remote Sens. Symp.},
  publisher = {European Space Agency, ESTEC, Noordwijk; ESA SP-284},
  year = {1988},
  pages = {335-339},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0024223404&partnerID=40&md5=f1b2f9f20dba2578096c8f5655a0a0fe}
}
Goldstein R, Zebker H and Werner C (1988), "Satellite radar interferometry: Two-dimensional phase unwrapping", Radio Science. Vol. 23(4), pp. 713-720.
Abstract: Interferometric synthetic aperture radar observations provide a means for obtaining high‐resolution digital topographic maps from measurements of amplitude and phase of two complex radar images. The phase of the radar echoes may only be measured modulo 2π; however, the whole phase at each point in the image is needed to obtain elevations. We present here our approach to “unwrapping” the 2π ambiguities in the two‐dimensional data set. We find that noise and geometrical radar layover corrupt our measurements locally, and these local errors can propagate to form global phase errors that affect the entire image. We show that the local errors, or residues, can be readily identified and avoided in the global phase estimation. We present a rectified digital topographic map derived from our unwrapped phase values. Copyright 1988 by the American Geophysical Union.
BibTeX:
@article{Goldstein1988713,
  author = {Goldstein, R.M. and Zebker, H.A. and Werner, C.L.},
  title = {Satellite radar interferometry: Two-dimensional phase unwrapping},
  journal = {Radio Science},
  year = {1988},
  volume = {23},
  number = {4},
  pages = {713-720},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0024045217&doi=10.1029%2fRS023i004p00713&partnerID=40&md5=a50cee5eb8b81822c5837ca3c56ccd2c},
  doi = {10.1029/RS023i004p00713}
}
Matzler C (1988), "Eddy Currents in Heterogeneous Mixtures", Journal of Electromagnetic Waves and Applications. Vol. 2(5-6), pp. 473-479.
Abstract: The interaction of electromagnetic waves with heterogeneous media can be described by mixing theory which is usually restricted to the dielectric permittivity. The particle size must be much smaller than the wavelength to avoid scattering, but otherwise there is no explicit size dependence on the effective permittivity of the mixture. In the present work an effect is considered which can give rise to a size-dependent diamagnetic permeability with sensible losses at microwave frequencies. The effect is based on eddy currents in a conducting component. An estimation of the influence of this effect on dielectric and diamagnetic properties is presented for wet snow. 1988 VSP.
BibTeX:
@article{Matzler1988473,
  author = {Matzler, C.},
  title = {Eddy Currents in Heterogeneous Mixtures},
  journal = {Journal of Electromagnetic Waves and Applications},
  year = {1988},
  volume = {2},
  number = {5-6},
  pages = {473-479},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-25944468887&doi=10.1163%2f156939388X00107&partnerID=40&md5=743387310ec67ba811a59a688388dbf6},
  doi = {10.1163/156939388X00107}
}
Matzler C and Schanda E (1987), "Towards the Definition of Optimum Sensor Specifications for Microwave Remote Sensing of Snow", In International Geoscience and Remote Sensing Symposium (IGARSS). (1), pp. 57-66. IEEE, New York, NY, USA.
Abstract: Summary form only given. Active and passive microwave remote sensing of sea ice offers the potential to obtain synoptic data of large expanses of remote, ice-covered oceans under all weather conditions irrespective of the amount of solar illumination. This is important for Arctic applications where much of the polar ice canopy is under clouds or in darkness. Measurement of summer sea-ice signatures were made in Fram Strait during June and July of 1983 and 1984. These data were acquired during participation in MIZEX (Marginal Ice Zone EXperiment), a multinational interdisciplinary effort for which the purpose is the study of the air-sea-ice interaction processes in the transition region where the more stable interior pack ice meets the open ocean. An objective of MIZEX was to define the geophysical processes which govern these interactions and to understand how these interactions influence ice-edge location, and ice-band formation.
BibTeX:
@article{Onstott19871401,
  author = {Matzler, C. and Schanda, E.},
  title = {Towards the Definition of Optimum Sensor Specifications for Microwave Remote Sensing of Snow},
  booktitle = {International Geoscience and Remote Sensing Symposium (IGARSS)},
  publisher = {IEEE, New York, NY, USA},
  year = {1987},
  number = {1},
  pages = {57-66},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0019899969&doi=10.1109%2fTGRS.1982.4307521&partnerID=40&md5=22e558d2106d14879318deb217eb1ee3}
}
Matzler C and Wegmüller U (1987), "Dielectric properties of freshwater ice at microwave frequencies", Journal of Physics D: Applied Physics. Vol. 20(12), pp. 1623-1630.
Abstract: So far, knowledge about the dielectric properties, especially the loss factor, of ice at microwave frequencies has been unsatisfactory. In this work the authors report on new measurements made over the frequency range from 2 to 100 GHz by a resonator method (2-10 GHz) and a radiometer method (10-100 GHz). Measurements were made with pure and with slightly saline (10 to 13 p.p.m.) ice. The results agree with the assumption of a single minimum of the dielectric loss at 2 to 4 GHz. For pure ice the data are a natural link between the measurements of Westphal made below 1 GHz and the far-infrared spectrum. The influence of small impurities on the dielectric loss is compared with the behaviour of sea ice, and it is found that the same linear relationship with salinity can be applied to both cases.
BibTeX:
@article{Matzler19871623,
  author = {Matzler, C. and Wegmüller, U.},
  title = {Dielectric properties of freshwater ice at microwave frequencies},
  journal = {Journal of Physics D: Applied Physics},
  year = {1987},
  volume = {20},
  number = {12},
  pages = {1623-1630},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0023535663&doi=10.1088%2f0022-3727%2f20%2f12%2f013&partnerID=40&md5=9d977f84628891a0357f1a89570a8db7},
  doi = {10.1088/0022-3727/20/12/013}
}
Onstott R, Grenfell T, Matzler C and Luther C (1987), "Evolution of microwave sea ice signatures during early summer and midsummer in the marginal ice zone", In International Geoscience and Remote Sensing Symposium (IGARSS). , pp. 1401-1402. IEEE, New York, NY, USA.
Abstract: Summary form only given. Active and passive microwave remote sensing of sea ice offers the potential to obtain synoptic data of large expanses of remote, ice-covered oceans under all weather conditions irrespective of the amount of solar illumination. This is important for Arctic applications where much of the polar ice canopy is under clouds or in darkness. Measurement of summer sea-ice signatures were made in Fram Strait during June and July of 1983 and 1984. These data were acquired during participation in MIZEX (Marginal Ice Zone EXperiment), a multinational interdisciplinary effort for which the purpose is the study of the air-sea-ice interaction processes in the transition region where the more stable interior pack ice meets the open ocean. An objective of MIZEX was to define the geophysical processes which govern these interactions and to understand how these interactions influence ice-edge location, and ice-band formation.
BibTeX:
@conference{Onstott19871401,
  author = {Onstott, R.G. and Grenfell, T.C. and Matzler, C. and Luther, C.A.},
  title = {Evolution of microwave sea ice signatures during early summer and midsummer in the marginal ice zone},
  booktitle = {International Geoscience and Remote Sensing Symposium (IGARSS)},
  publisher = {IEEE, New York, NY, USA},
  year = {1987},
  pages = {1401-1402},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0023171423&partnerID=40&md5=db2ad9f7b39eda1148500ad7fd10b9cd}
}
Onstott R, Grenfell T, Matzler C, Luther C and Svendsen E (1987), "Evolution of microwave sea ice signatures during early summer and midsummer in the marginal ice zone", Journal of Geophysical Research. Vol. 92(C7), pp. 6825-6835.
Abstract: Emissivities at frequencies from 5 to 94 GHz and backscatter at frequencies from 1 to 17 GHz were measured from sea ice in Fram Strait. The ice observed was primarily multiyear; the remainder, first-year ice, was often deformed. -from Authors
BibTeX:
@article{Onstott19876825,
  author = {Onstott, R.G. and Grenfell, T.C. and Matzler, C. and Luther, C.A. and Svendsen, E.A.},
  title = {Evolution of microwave sea ice signatures during early summer and midsummer in the marginal ice zone},
  journal = {Journal of Geophysical Research},
  year = {1987},
  volume = {92},
  number = {C7},
  pages = {6825-6835},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0023500538&doi=10.1029%2fJC092iC07p06825&partnerID=40&md5=de111a5f7ab246d2a3c5622d17bd5371},
  doi = {10.1029/JC092iC07p06825}
}
Reber B, Matzler C and Schanda E (1987), "Microwave signatures of snow crusts modelling and measurements", International Journal of Remote Sensing. Vol. 8(11), pp. 1649-1665.
Abstract: The particle-size dependence of microwave scattering from snow is investigated. Frozen crusts have been analysed, and the microstructure is described by correlation functions. Relations between the correlation length and various quantities such as ice-intercept lengths or volume-to-surface ratios are checked. The scattering is calculated using the Bom approximation and is linked to the emissivity through the albedo. The model yields good agreement with the microwave data from C to K bands, and the predicted particle-size dependence is verified. The claims that the variance and the correlation length of the permittivity fluctuations are the characteristic parameters are confirmed. Initial uncertainties with respect to the validity of the Born approximation for an air-ice mixture are clarified. 1987 Taylor & Francis Ltd.
BibTeX:
@article{Reber19871649,
  author = {Reber, B. and Matzler, C. and Schanda, E.},
  title = {Microwave signatures of snow crusts modelling and measurements},
  journal = {International Journal of Remote Sensing},
  year = {1987},
  volume = {8},
  number = {11},
  pages = {1649-1665},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0023523432&doi=10.1080%2f01431168708954805&partnerID=40&md5=da1d67ee7624b027172b1ff412d71809},
  doi = {10.1080/01431168708954805}
}
Svendsen E, Matzler C and Grenfell T (1987), "A model for retrieving total sea ice concentration from a spaceborne dual-polarized passive microwave instrument operating near 90 ghz", International Journal of Remote Sensing. Vol. 8(10), pp. 1479-1487.
Abstract: An algorithm has been developed for estimating total ice concentration from spaceborne high-frequency passive microwave instrumentation. The algorithm is intended for use with the coming Special Sensor Microwave/Imager (SSM/l) data giving a spatial resolution of 12 km. It is based on radiation physics and detailed millimetre wave surface signature measurements and can therefore be applied to other similar data. However, due to large effects on the signals caused by time varying atmospheric conditions and radiation properties of the ice, the algorithm is made self-adjusting. The atmospheric effects are implicitly treated as a smooth function of the ice concentration with tie points over open ocean and 100 per cent ice for each orbit. This means that the main errors are due to patches of heavy clouds and ice floes with atypical radiation properties. An error analysis indicates possible errors of the order of 5 percent for concentrations representative for the Arctic Basin, increasing with decreasing concentration. 1987 Taylor & Francis Ltd.
BibTeX:
@article{Svendsen19871479,
  author = {Svendsen, E. and Matzler, C. and Grenfell, T.C.},
  title = {A model for retrieving total sea ice concentration from a spaceborne dual-polarized passive microwave instrument operating near 90 ghz},
  journal = {International Journal of Remote Sensing},
  year = {1987},
  volume = {8},
  number = {10},
  pages = {1479-1487},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0023436905&doi=10.1080%2f01431168708954790&partnerID=40&md5=da166c46bbd7891b7ca5110881eeffe1},
  doi = {10.1080/01431168708954790}
}
Burns B, Shuchman R, Matzler C and Dowdeswell J (1986), "ANALYSIS OF MULTICHANNEL SAR DATA OF SPITSBERGEN", In International Geoscience and Remote Sensing Symposium (IGARSS). , pp. 367-371. ESA Publ Div (ESA SP-254), Noordwijk, Ne.
Abstract: Multitemporal aircraft synthetic aperture radar (SAR) images obtained over Spitsbergen in the summer of 1984 are used to illustrate the application of SAR data to the identification and monitoring of features of glaciological interest. Snow cover on bare ground, on glaciers, and on moraines, as well as ice cover on lakes, can be clearly identified. Monitoring the up-glacier retreat of the snowline is also possible with SAR. This discrimination is based on relative backscatter signatures, and is shown to depend on the fequency and polarization of the radar wave. Other features such as terminal moraines are discriminated on the basis of topographic expression, which is enhanced with stereo images.
BibTeX:
@conference{Burns1986367,
  author = {Burns, B.A. and Shuchman, R. and Matzler, C. and Dowdeswell, J.},
  title = {ANALYSIS OF MULTICHANNEL SAR DATA OF SPITSBERGEN},
  booktitle = {International Geoscience and Remote Sensing Symposium (IGARSS)},
  publisher = {ESA Publ Div (ESA SP-254), Noordwijk, Ne},
  year = {1986},
  pages = {367-371},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0023023799&partnerID=40&md5=ef44ca4696e3515f11da04232fc6d654}
}
Denoth A, Foglar A, Weiland P, Matzler C, Aebischer H, Tiuri M and Sihvola A (1984), "A comparative study of instruments for measuring the liquid water content of snow", Journal of Applied Physics. Vol. 56(7), pp. 2154-2160.
Abstract: Different dielectric sensors for measuring the liquid water content of snow are compared and described in detail. The instruments make use of the significant difference in the dielectric properties of ice and liquid water at radio frequencies; they are operated with frequencies ranging from 1 MHz up to 1.3 GHz. Plate condensers in connection with ac bridges are used as sensors in the frequency range up to 100 MHz whereas open resonators are used in the GHz regime. Test measurements with the different sensors on homogeneous samples like dry sand and mixed and prepared snow showed the same results for the dielectric constant: the discrepancies are less than 1%. In the natural, inhomogeneous snow cover, the special properties of the different sensors appear. Snow wetness is calculated from the measured dielectric constant and the snow density using the model of Polder and van Santen. The comparative field measurements were made with Alpine snow in the Stubai Alps in Austria.
BibTeX:
@article{Denoth19842154,
  author = {Denoth, A. and Foglar, A. and Weiland, P. and Matzler, C. and Aebischer, H. and Tiuri, M. and Sihvola, A.},
  title = {A comparative study of instruments for measuring the liquid water content of snow},
  journal = {Journal of Applied Physics},
  year = {1984},
  volume = {56},
  number = {7},
  pages = {2154-2160},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0021510379&doi=10.1063%2f1.334215&partnerID=40&md5=4deb4d2e822382b20a83129f225daa0f},
  doi = {10.1063/1.334215}
}
Matzler C (1984), "(A sensor for the monitoring of the dielectric constant and wetness of snow). [Ein Sensor zur Messung der Dielektrizitatskonstante von Schnee.]", Zeitschrift fur Gletscherkunde und Glazialgeologie. Vol. 20, pp. 97-105.
Abstract: If a sensor is to monitor the development of the snowpack during a whole season, certain mechanical, optical, thermal and geometrical conditions must be fulfilled. It is shown that resonators consisting of short-circuited two-wire lines operating in the frequency range 0.3 to 1.3 GHz are suitable for this purpose. -from English summary
BibTeX:
@article{Matzler198497,
  author = {Matzler, C.},
  title = {(A sensor for the monitoring of the dielectric constant and wetness of snow). [Ein Sensor zur Messung der Dielektrizitatskonstante von Schnee.]},
  journal = {Zeitschrift fur Gletscherkunde und Glazialgeologie},
  year = {1984},
  volume = {20},
  pages = {97-105},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0021534834&partnerID=40&md5=e0fc74a8ac4f36b28e57e04d1dc4784b}
}
Matzler C, Aebischer H and Schanda E (1984), "Microwave Dielectric Properties of Surface Snow", IEEE Journal of Oceanic Engineering. Vol. 9(5), pp. 366-371.
Abstract: First results from a recently developed surface sensor for measuring the dielectric constant of snow at about 1 GHz are reported together with ground-based measurements of brightness temperatures between 4.9 and 94 GHz. The data are used to derive spectra of complex dielectric constants of wet snow for frequencies between 1 and 100 GHz. The result is simple: Debye relaxation spectra with a constant relaxation frequency of 9 GHz appear in contradiction to the mixing formula of Polder and van Santen. A way of resolving this discrepancy is presented. 1984 IEEE
BibTeX:
@article{Matzler1984366,
  author = {Matzler, C. and Aebischer, H. and Schanda, E.},
  title = {Microwave Dielectric Properties of Surface Snow},
  journal = {IEEE Journal of Oceanic Engineering},
  year = {1984},
  volume = {9},
  number = {5},
  pages = {366-371},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0021614970&doi=10.1109%2fJOE.1984.1145644&partnerID=40&md5=70acb07fb5711c85277dbb7b5950f9b9},
  doi = {10.1109/JOE.1984.1145644}
}
Matzler C, Ramseier R and Svendsen E (1984), "Polarization Effects in Sea-Ice Signatures", IEEE Journal of Oceanic Engineering. Vol. 9(5), pp. 333-338.
Abstract: Observations of microwave emissivities of multiyear sea ice showed anomalies at horizontal polarization in the frequency range from 5 to 35 GHz during the Norwegian Remote Sensing Experiment (NORSEX) [1] in September and October 1979. The effect can be explained by layers of solid ice present in the dry snow cover throughout the NORSEX area. A special experiment made on a typical multiyear floe confirms this explanation. Since the results also indicate that at 94 GHz the layers do not affect the radiation, a dual-polarized radiometer in the 90-GHz window is a promising sea-ice sensor. 1984 IEEE
BibTeX:
@article{Matzler1984333,
  author = {Matzler, C. and Ramseier, R.O. and Svendsen, E.},
  title = {Polarization Effects in Sea-Ice Signatures},
  journal = {IEEE Journal of Oceanic Engineering},
  year = {1984},
  volume = {9},
  number = {5},
  pages = {333-338},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0021580352&doi=10.1109%2fJOE.1984.1145646&partnerID=40&md5=78891cf59a0353d95f014d068de5e4ad},
  doi = {10.1109/JOE.1984.1145646}
}
Matzler C and Schanda E (1984), "Snow mapping with active microwave sensors", International Journal of Remote Sensing. Vol. 5(2), pp. 409-422.
Abstract: Hydrological interest in mapping snow concentrates on the phase of snow depletion when at least part of the snow cover is wet. In this situation, snow has a very low backscatter coefficient, smaller than almost any land surface at X- band. Together with the independence of cloud cover and time, this unique signature of snow enables frequent and regular mapping of snow even in rugged terrain. First results from a synthetic aperture radar experiment made during the melting season-even under unfavourable conditions-clearly indicate this potential. - The backscatter data used in this work are based on four seasons of scatterometen-measurements made on the alpine test site Weissfluhjoch, Davos, and on a comparison with additional backscatter data from groups in Europe and the U.S.A. 1984 Taylor & Francis Ltd.
BibTeX:
@article{Matzler1984409,
  author = {Matzler, C. and Schanda, E.},
  title = {Snow mapping with active microwave sensors},
  journal = {International Journal of Remote Sensing},
  year = {1984},
  volume = {5},
  number = {2},
  pages = {409-422},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0021286224&doi=10.1080%2f01431168408948816&partnerID=40&md5=8d2a0cc01a634f5977db5cb6395c0aa3},
  doi = {10.1080/01431168408948816}
}
Farrelly B, Johannessen J, Johannessen O, Svendsen E, Kloster K, Horjen I, Matzler C, Campbell W, Crawford J, Harrington R, Jones L, Swift C, Delnore V, Cavalieri D, Gloersen P, Hsiao S, Shemdin O, Thompson T, Ramseier R, Johannessen O and Campbell W (1983), "Norwegian remote sensing experiment in a marginal ice zone", Science. Vol. 220(4599), pp. 781-787.
Abstract: The Norwegian Remote Sensing Experiment in the marginal ice zone north of Svalbard took place in fall 1979. Coordinated passive and active microwave measurements were obtained from shipborne, airborne, and satellite instruments together with in situ observations. The obtained spectra of emissivity (frequency range, 5 to 100 gigahertz) should improve identification of ice types and estimates of ice concentration. Mesoscale features along the ice edge were revealed by a 1.215-gigahertz synthetic aperture radar. Ice edge location by the Nimbus 7 scanning multichannel microwave radiometer was shown to be accurate to within 10 kilometers.
BibTeX:
@article{Farrelly1983781,
  author = {Farrelly, B. and Johannessen, J.A. and Johannessen, O.M. and Svendsen, E. and Kloster, K. and Horjen, I. and Matzler, C. and Campbell, W.J. and Crawford, J. and Harrington, R. and Jones, L. and Swift, C. and Delnore, V.E. and Cavalieri, D. and Gloersen, P. and Hsiao, S.V. and Shemdin, O.H. and Thompson, T.W. and Ramseier, R.O. and Johannessen, O.M. and Campbell, W.J.},
  title = {Norwegian remote sensing experiment in a marginal ice zone},
  journal = {Science},
  year = {1983},
  volume = {220},
  number = {4599},
  pages = {781-787},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0020683189&doi=10.1126%2fscience.220.4599.781&partnerID=40&md5=16e3f40c635a6636665ecd5384a03306},
  doi = {10.1126/science.220.4599.781}
}
Schanda E, Matzler C and Kunzi K (1983), "Microwave remote sensing of snow cover", International Journal of Remote Sensing. Vol. 4(1), pp. 149-158.
Abstract: The extent of the snow cover, the stored amount of water and the state of the snow metamorphism, in particular the date of the snow-melt and the intensity of the run-off, are of prime importance to hydrology and water management in large regions as well as to weather and climate. Regular observations by satellite-borne sensors can substantially improve the information on the status and the dynamic behaviour of these hydrologic parameters on a global scale. Microwave radiometers or scatterometers as all-weather and day and night sensors are excellent tools for reliable observations of cloud-covered regions of the world. The interaction of microwaves with snow strongly depends on snow wetness and size and structure of snow grains. Multifrequency observations can be used to classify snow conditions, to estimate the water equivalent or dry snow and to determine the start of the melting period. Results of several years of ground-based microwave observations along with classical hydrologic measurements are discussed and experience with satellite-borne microwave radiometers for the determination of the extent and state of the northern hemispheric snow cover is reported. Conclusions are drawn to define optimum sensor specifications for satellite-borne microwave remote sensing of the snow cover. 1983 Taylor and Francis Ltd.
BibTeX:
@article{Schanda1983149,
  author = {Schanda, E. and Matzler, C. and Kunzi, K.},
  title = {Microwave remote sensing of snow cover},
  journal = {International Journal of Remote Sensing},
  year = {1983},
  volume = {4},
  number = {1},
  pages = {149-158},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0020642086&doi=10.1080%2f01431168308948536&partnerID=40&md5=70fece07876c48b79f77c6a3da19400f},
  doi = {10.1080/01431168308948536}
}
Bolle H, Kunzi K, Matzler C, Patil S, Rott H and Tiuri M (1982), "Snow cover parameter retrieval from Nimbus-7 SMMR data: final report of EARSeL Working Group 1. Outlook and recommendations, April 1982.", ESA Journal. Vol. 6(4), pp. 467-469.
Abstract: Concentrates on the potential of spaceborne passive microwave remote sensing in operational applications and includes some recommendations for future missions. -Authors
BibTeX:
@article{Bolle1982467,
  author = {Bolle, H.J. and Kunzi, K.F. and Matzler, C. and Patil, S. and Rott, H. and Tiuri, M.},
  title = {Snow cover parameter retrieval from Nimbus-7 SMMR data: final report of EARSeL Working Group 1. Outlook and recommendations, April 1982.},
  journal = {ESA Journal},
  year = {1982},
  volume = {6},
  number = {4},
  pages = {467-469},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0020378087&partnerID=40&md5=bfda0d5ebc6fe847185de1ab976e0878}
}
Matzler C and Schanda E (1982), "Towards the Definition of Optimum Sensor Specifications for Microwave Remote Sensing of Snow", IEEE Transactions on Geoscience and Remote Sensing. Vol. 20(1), pp. 57-66.
Abstract: The interaction of microwaves with snow strongly depends on parameters such as snow wetness and the size and structure of snow grains. Therefore microwave radiometry and scatterometry are excellent tools for remote sensing of the snowcover. Multifrequency radiometry can be used to classify snow as was shown with ground-based measurements of the period April-June 1977 at a high altitude Alpine test site. The continuation of the measurement program yielded data of 3 additional snow seasons with widely varying snow conditions, therefore the present information has become representative for alpine regions. Relationships between the brightness temperature and the water equivalents show a similar variation with snow type as in other snow regions, so that the range of validity of our data set is not restricted to the Alps. The problem of discriminating regions of wet snow from snow-free land is found to be solvable with microwave scatterometry. Two cluster analyses in factorial spaces of both the ground truth and the microwave data sets demonstrate the potential of microwave sensors to classify snow which is a prerequisite for snow algorithms retrieving hydrologic parameters. The results are used to define sensor specifications with optimum sensitivity for microwave remote sensing of snow. Copyright 1982 by The Institute of Electrical and Electronics Engineers, Inc.
BibTeX:
@article{Matzler198257,
  author = {Matzler, C. and Schanda, E.},
  title = {Towards the Definition of Optimum Sensor Specifications for Microwave Remote Sensing of Snow},
  journal = {IEEE Transactions on Geoscience and Remote Sensing},
  year = {1982},
  volume = {20},
  number = {1},
  pages = {57-66},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0019899969&doi=10.1109%2fTGRS.1982.4307521&partnerID=40&md5=22e558d2106d14879318deb217eb1ee3},
  doi = {10.1109/TGRS.1982.4307521}
}
Schanda E and Matzler C (1981), "Optimum characteristics for snow pack evaluation by microwave radiometry", Advances in Space Research. Vol. 1(10), pp. 151-162.
Abstract: Multi-year broadband microwave radiometry, single frequency scatterometry and thorough investigation of classical snow parameters at a high altitude alpine test area have revealed a clear distinction of three seasonal types of snow: In winter conditions, characterized by the absence of any melting metamorphism the water equivalent increasing to 20 centimeter is related with a decreasing brightness temperature, further increase of the water equivalent turns the brightness temperature to an almost linear increase, optimum at about 8 mm wavelength. In spring conditions the phases of melting an refreezing of the surface layer are discriminated by a complete reversal of the microwave brightness temperature spectrum around 2 centimeter wavelength in particular at horizontal polarization. In summer conditions the whole pack is wet, the microwave spectrum due to melting snow, like in spring conditions, shows surprizingly high brightness temperature, especially above 10 GHz. The penetration depth of 6 cm waves decreases from many meters in winter to centimeters in summer with almost proportionally smaller values for shorter wavelengths. 1981.
BibTeX:
@article{Schanda1981151,
  author = {Schanda, E. and Matzler, C.},
  title = {Optimum characteristics for snow pack evaluation by microwave radiometry},
  journal = {Advances in Space Research},
  year = {1981},
  volume = {1},
  number = {10},
  pages = {151-162},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-49149133118&doi=10.1016%2f0273-1177%2881%2990390-2&partnerID=40&md5=169010954da570f58b0f2cd029c0fb92},
  doi = {10.1016/0273-1177(81)90390-2}
}
Hofer R and Matzler C (1980), "Investigations on snow parameters by radiometry in the 3- to 60- mm wavelength region ( Alps).", Journal of Geophysical Research. Vol. 85(C1), pp. 453-460.
Abstract: We report on a 2-year period of monitoring parameters of a natural snowpack by ground-based microwave radiometry on a high-altitude Alpine test site. The microwave brightness temperatures are compared to a large set of ground-truth data. Three stages in the seasonal development of the snow cover are easily distinguishable which allow the prediction of the beginning of the snow melting. The moisture content of the melting surface layer is estimated by the aid of the typical daily variations of microwave brightness temperatures in spring. - from Authors
BibTeX:
@article{Hofer1980453,
  author = {Hofer, R. and Matzler, C.},
  title = {Investigations on snow parameters by radiometry in the 3- to 60- mm wavelength region ( Alps).},
  journal = {Journal of Geophysical Research},
  year = {1980},
  volume = {85},
  number = {C1},
  pages = {453-460},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0019227403&doi=10.1029%2fJC085iC01p00453&partnerID=40&md5=e791aaa30dfb149f0dae921246fa4674},
  doi = {10.1029/JC085iC01p00453}
}
Meylan P, Morazier C, Caloz R, Schanda E and Matzler C (1980), "SOIL MOISTURE DETERMINATION: EXPERIMENTS WITH PASSIVE MICROWAVE RADIOMETERS.", Conference Proceedings - European Microwave Conference. , pp. 256-260. Microwave Exhib and Publ, Ltd, Sevenoaks, Kent, Engl.
Abstract: Long term observational programs have been carried out to determine the relationship between emissivity and soil moisture on 3 test sites, representing 3 soil types. Five radiometers, whose frequencies are centered at 36, 21, 10. 5, 4. 9 and 1. 8 GHz, were used. An experiment was also conducted to determine the real penetration depth in a heavy soil.
BibTeX:
@article{Meylan1980256,
  author = {Meylan, P. and Morazier, C. and Caloz, R. and Schanda, E. and Matzler, Ch.},
  title = {SOIL MOISTURE DETERMINATION: EXPERIMENTS WITH PASSIVE MICROWAVE RADIOMETERS.},
  journal = {Conference Proceedings - European Microwave Conference},
  publisher = {Microwave Exhib and Publ, Ltd, Sevenoaks, Kent, Engl},
  year = {1980},
  pages = {256-260},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0019103976&partnerID=40&md5=2fb98c7b918269cedbe93587440535ee}
}
Matzler C, Hofer R, Wyssen D and Schanda E (1979), "ON THE PENETRATION OF MICROWAVES IN SNOW AND SOIL.", Proceedings of the International Symposium on Remote Sensing of Environment. Vol. 2, pp. 1243-1249. Environ Res Inst of Mich, Ann Arbor.
Abstract: A report is presented on the measurement of p by passive microwave remote sensing in the 1. 8 to 94 GHz range. The method is being applied to soil and snow. The microwave data used to estimate p are the three brightness temperatures of the sky, of the ground and of the same ground of a known thickness, lying on reflecting metal foil. The penetration depth determined with these data is slightly model dependent because of the unknown distribution of scattering layers. In order to estimate the uncertainty of p due to the model dependence we compare the results of two extreme situations, the results of which vary by less than a factor 2. The penetration depth of a humid loam soil was found to decrease from about 5 cm at 1. 8 GHz to 1. 5 cm at 36 GHz. On the other hand the penetration depth of snow is found to change drastically, according to the content of liquid water.
BibTeX:
@article{Matzler19791243,
  author = {Matzler, C. and Hofer, R. and Wyssen, D. and Schanda, E.},
  title = {ON THE PENETRATION OF MICROWAVES IN SNOW AND SOIL.},
  journal = {Proceedings of the International Symposium on Remote Sensing of Environment},
  publisher = {Environ Res Inst of Mich, Ann Arbor},
  year = {1979},
  volume = {2},
  pages = {1243-1249},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0018679393&partnerID=40&md5=9b36ab4316fe5d0e5aaf94d231c7adfd}
}
Matzler C (1976), "Continuous injection model for hard X-ray correlated microwave bursts", Solar Physics. Vol. 49(1), pp. 117-140. Kluwer Academic Publishers.
Abstract: Asymmetric magnetic field configurations in solar active regions hinder mildly relativistic electrons with magnetic moments suitable to produce microwave radiation from being trapped. Therefore the duration of stay of electrons in the microwave source region is much shorter (<0.2 s) than in the usually assumed trapping models. On this basis we construct a consistent model of hard X-ray correlated microwave bursts due to continuous injection of electrons into a pole field of an asymmetric magnetic loop (Figures 1 and 2). This resolves the discrepancy of the numbers of electrons needed to produce X-ray and radio emission. We compute gyrosynchrotron spectra with the assumption of conservation of the magnetic moment M in the microwave source. The consequence is an anticorrelation between the low frequency power index a of the microwave spectrum and the power index γ of the hard X-ray spectrum. In fact during the flare of May 18, 1972 γ increases with time while a is decreasing, so that γ+a= constant. Furthermore, it is shown that electrons with energies below 100 keV contribute significantly to the microwave radiation; they determine the low frequency spectrum completely. The model is able to explain the most often observed type C-spectra (Guidice and Castelli, 1975), but also flat spectra over one frequency decade. 1976 D. Reidel Publishing Company.
BibTeX:
@article{Matzler1976117,
  author = {Matzler, C.},
  title = {Continuous injection model for hard X-ray correlated microwave bursts},
  journal = {Solar Physics},
  publisher = {Kluwer Academic Publishers},
  year = {1976},
  volume = {49},
  number = {1},
  pages = {117-140},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749568093&doi=10.1007%2fBF00221489&partnerID=40&md5=4e1dde884d511606729e1609e0b982fa},
  doi = {10.1007/BF00221489}
}
Matzler C (1976), "Gyro-Synchrotronstrahlung im magnetischen Monopol als Quelle solarer Mikrowellenausbruche", Zeitschrift fur angewandte Mathematik und Physik ZAMP. Vol. 27(1), pp. 137. Birkhauser-Verlag.
BibTeX:
@article{Matzler1976137,
  author = {Matzler, C.},
  title = {Gyro-Synchrotronstrahlung im magnetischen Monopol als Quelle solarer Mikrowellenausbruche},
  journal = {Zeitschrift fur angewandte Mathematik und Physik ZAMP},
  publisher = {Birkhauser-Verlag},
  year = {1976},
  volume = {27},
  number = {1},
  pages = {137},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250384901&doi=10.1007%2fBF01595260&partnerID=40&md5=d873af8126efbb05f6950f434ca2366b},
  doi = {10.1007/BF01595260}
}
Wiehl H and Matzler C (1976), "Klassifizierung und analyse von solaren Eruptionen im cm-Wellengebiet", Zeitschrift fur angewandte Mathematik und Physik ZAMP. Vol. 27(1), pp. 137. Birkhauser-Verlag.
BibTeX:
@article{Wiehl1976137,
  author = {Wiehl, H. and Matzler, C.},
  title = {Klassifizierung und analyse von solaren Eruptionen im cm-Wellengebiet},
  journal = {Zeitschrift fur angewandte Mathematik und Physik ZAMP},
  publisher = {Birkhauser-Verlag},
  year = {1976},
  volume = {27},
  number = {1},
  pages = {137},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250386370&doi=10.1007%2fBF01595259&partnerID=40&md5=1d0e7cf2ca9ac98a805e1bbca004f47a},
  doi = {10.1007/BF01595259}
}
Magun A and Matzler C (1973), "On the observation of linear polarization of solar microwave bursts", Solar Physics. Vol. 30(2), pp. 489-496. Kluwer Academic Publishers.
Abstract: It is known that mode coupling may occur in quasi-transverse magnetic field regions of the solar corona, which produces linear polarization at microwave frequencies. A microwave polarimeter measuring all 4 Stokes parameters at 8.918 GHz simultaneously at three different highfrequency bandwidths (40 kHz, 400 kHz and 5 MHz) has been developed in order to observe the linear component and its Faraday rotation. The respective minimum detectable changes of the Stokes parameters I, Q, U and V are 9, 3 and 1 solar flux unit at an integration time of 1 s. For burst intensities greater than 300 solar flux units, the minimum detectable degree of linear and circular polarization is 1 %-3 %, depending on the bandwidth. Observations of 68 bursts showed that most of the bursts were circularly polarized. No linear polarization could be found within the limits of accuracy of our polarimeter. Two possible explanations for this result are discussed. The possibility of mode coupling however cannot be excluded from these first observations. 1973 D. Reidel Publishing Company.
BibTeX:
@article{Magun1973489,
  author = {Magun, A. and Matzler, Ch.},
  title = {On the observation of linear polarization of solar microwave bursts},
  journal = {Solar Physics},
  publisher = {Kluwer Academic Publishers},
  year = {1973},
  volume = {30},
  number = {2},
  pages = {489-496},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0009259371&doi=10.1007%2fBF00152678&partnerID=40&md5=61c9b3fa6cd7fdc86bbc5e9125244033},
  doi = {10.1007/BF00152678}
}
Matzler C (1973), "Spatial dispersion of Faraday rotation and its connexion with mode coupling", Solar Physics. Vol. 32(1), pp. 241-255. Kluwer Academic Publishers.
Abstract: It is shown that the lack of linear polarization in the microwave radiation of solar bursts (reported in a earlier paper) may be explained by spatial dispersion of Faraday rotation. The maximum source diameter s without noticeable destruction of linear polarization is determined by the electron density and the magnetic field strength in the volume, where the linear polarization is generated. In the case where linear polarization is produced by the radiation source, s is smaller than only 20 km. In the other case where linear polarization is produced by mode coupling in a quasi-transverse magnetic field in the corona, the s-values are found to range from 10 to 6000 km, which is still much smaller than the generally adopted sizes of microwave burst sources. The second case has been investigated for several models of magnetic fields. 1973 D. Reidel Publishing Company.
BibTeX:
@article{Matzler1973241,
  author = {Matzler, C.},
  title = {Spatial dispersion of Faraday rotation and its connexion with mode coupling},
  journal = {Solar Physics},
  publisher = {Kluwer Academic Publishers},
  year = {1973},
  volume = {32},
  number = {1},
  pages = {241-255},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250427881&doi=10.1007%2fBF00152740&partnerID=40&md5=e7b05656fdb792937257147c6b8337d9},
  doi = {10.1007/BF00152740}
}
Magun A and Matzler C (1972), "Observation of linear polarization of solar microwave bursts", Zeitschrift fur angewandte Mathematik und Physik ZAMP. Vol. 23(1), pp. 164-166. Birkhauser-Verlag.
BibTeX:
@article{Magun1972164,
  author = {Magun, A. and Matzler, C.},
  title = {Observation of linear polarization of solar microwave bursts},
  journal = {Zeitschrift fur angewandte Mathematik und Physik ZAMP},
  publisher = {Birkhauser-Verlag},
  year = {1972},
  volume = {23},
  number = {1},
  pages = {164-166},
  url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250470717&doi=10.1007%2fBF01593223&partnerID=40&md5=33a8382d2e79484b7c954dc96bed67f2},
  doi = {10.1007/BF01593223}
}