Sentinel-1 SAR Interferometry for Surface Deformation Monitoring in Low-Land Permafrost Areas

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.

Space‐Based Observations for Understanding Changes in the Arctic‐Boreal Zone

“…This makes interferometric SAR and other methods feasible to generate digital elevation models (DEM) and map changes in elevation or surface roughness characteristics applicable for permafrost monitoring (Alasset et al, ; Kääb et al, ). The InSAR method is a powerful tool to monitor both (1) short term changes in landscape (summer surface displacements) due to soil freeze/thaw cycle in the active layer (Rouyet et al, ; Strozzi et al, ) and long‐term changes in landscape potentially due to the changes in permafrost condition (Liu et al, ; Rouyet et al, ). Rouyet et al () also show that InSAR observations can be used to contribute to investigations of geomorphology and ground thermal conditions.…”

Investigation of a Small Landslide in the Qinghai-Tibet Plateau by InSAR and Absolute Deformation Model

“…In frozen ground regions, the surface displacements were the result of multiple factors. As Strozzi [82] stated in research of low-land permafrost: we had to bear in mind that the maps and graphs measured by SAR not only represent surface displacement but also changes in ionospheric, soil moisture, snow-cover and vegetation conditions. Some researches, as shown in Table 2, tried to separate the factors to explain the relationship between the factors and deformation to further reveal the mechanism and process in permafrost region.…”

“…In the process of measurement, error description was essential. Only a thorough validation with in-situ data would permit full quantitative assessment of the displacement maps [82]. Bedrock was a commonly used reference, followed by LiDAR, GPS point, artificial reflectors and intercompare results from different sensors.…”

A Review of Earth Observation-Based Analyses for Major River Basins

“…Instead, lake ice phenology was studied using TerraSAR-X time-series for a period of three years in the Lena river delta [224]. In addition, we found studies investigating permafrost in the Arctic river basins Lena, Yukon, and Kolyma [30,[226][227][228][229]. Soil erosion in permafrost riverbanks was analyzed for a regional study area in the Lena river delta using TerraSAR-X time-series [227].…”