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  • AWI_Envi; AWI_PerDyn; AWI_Perma; Permafrost Research; Permafrost Research (Periglacial Dynamics) @ AWI; Polar Terrestrial Environmental Systems @ AWI  (1)
  • AWI_Envi; AWI_Perma; Permafrost Research; Polar Terrestrial Environmental Systems @ AWI  (1)
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  • 1
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    Unknown
    PANGAEA
    In:  Supplement to: Antonova, Sofia; Sudhaus, Henriette; Strozzi, Tazio; Zwieback, Simon; Kääb, Andreas; Heim, Birgit; Langer, Moritz; Bornemann, Niko; Boike, Julia (2018): Thaw subsidence of a yedoma landscape in Northern Siberia, measured in situ and estimated from TerraSAR-X interferometry. Remote Sensing, 10(4), 494, https://doi.org/10.3390/rs10040494
    Publication Date: 2023-03-16
    Description: 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.
    Keywords: AWI_Envi; AWI_PerDyn; AWI_Perma; Permafrost Research; Permafrost Research (Periglacial Dynamics) @ AWI; Polar Terrestrial Environmental Systems @ AWI
    Type: Dataset
    Format: application/zip, 3 datasets
    Location Call Number Limitation Availability
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  • 2
    facet.materialart.
    Unknown
    PANGAEA
    In:  Supplement to: Antonova, Sofia; Kääb, Andreas; Heim, Birgit; Langer, Moritz; Boike, Julia (2016): Spatio-temporal variability of X-band radar backscatter and coherence over the Lena River Delta, Siberia. Remote Sensing of Environment, 182, 169-191, https://doi.org/10.1016/j.rse.2016.05.003
    Publication Date: 2023-05-12
    Description: Satellite-based monitoring strategies for permafrost remain under development and are not yet operational. Remote sensing allows indirect observation of permafrost, a subsurface phenomenon, by mapping surface features or measuring physical parameters that can be used for permafrost modeling. We have explored high temporal resolution time series of TerraSAR-X backscatter intensity and interferometric coherence for the period between August 2012 and September 2013 to assess their potential for detecting major seasonal changes to the land surface in a variety of tundra environments within the Lena River Delta, Siberia. The TerraSAR-X signal is believed to be strongly affected by the vegetation layer, and its viability for the retrieval of soil moisture, for example, is therefore limited. In our study individual events, such as rain and snow showers, that occurred at the time of TerraSAR-X acquisition, or a refrozen crust on the snowpack during the spring melt were detected based on backscatter intensity signatures. The interferometric coherence showed marked variability; the snow cover onset and snow melt periods were identified by significant reduction in coherence. Principal component analysis provided a good spatial overview of the essential information contained in backscatter and coherence time series and revealed latent relationships between both time series and the surface temperature. The results of these investigations suggest that although X-band SAR has limitations with respect to monitoring seasonal land surface changes in permafrost areas, high-resolution time series of TerraSAR-X backscatter and coherence can provide new insights into environmental conditions.
    Keywords: AWI_Envi; AWI_Perma; Permafrost Research; Polar Terrestrial Environmental Systems @ AWI
    Type: Dataset
    Format: application/zip, 2 datasets
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
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