10:45 AM - 12:15 PM
[ACG46-P11] Ground surface displacement along the coast of the Laptev Sea in Northeastern Siberia detected by InSAR
Keywords:Permafrost, Tundra, Northeastern Siberia, Interferometric Synthetic Aperture Radar, ALOS-2, Sentinel-1
Recent climate changes have impacted on permafrost degradation. Ground temperature records in the continuous permafrost regions in the Arctic have increased over past decades (Biskaborn et al., 2019), raising concerns about hydrological and landscape changes as well as lives in local people due to permafrost thawing. Particularly in the high-latitude Arctic, the rate of permafrost temperature per decade has been up to about 1℃ and increased active-layer thicknesses have been observed since the 1990s in some regions. However, there is a lack of observational studies covering the vast and remote area of northeastern Siberia, and it is essential for observational results that can be linked to those obtained by modeling studies on a broad regional scale.
Interferometric Synthetic Aperture Radar (InSAR) is a useful tool to measure surface displacement by calculating phase difference between two different SAR data. InSAR has been utilized to reveal geophysical phenomena related to surface displacement such as crustal deformation and glacier flow. Number of application studies of InSAR to permafrost monitoring has been increasing, and InSAR has become one of essential tools for understanding permafrost dynamics. This study used ALOS-2 L-band SAR data obtained from 2015 to 2022 and Sentinel-1 C-band SAR data obtained from 2017 to 2021 to derive surface displacement related to ground freeze/thaw cycle in the vicinity of settlement in Naiba (N70.85°, E130.74°). We applied InSAR time-series analysis (Berardino et al., 2002; Schmidt and Bürgmann, 2003; Biggs et al., 2007; Yanagiya and Furuya, 2020; Abe et al., 2022) to as many interferograms by ALOS-2 as possible in order to calculate cumulative surface displacement from 2015 to 2022. We also derived seasonal surface displacement using Sentinel-1 stacked interferograms to compare the spatial distribution with that from ALOS-2.
Preliminary results of ALOS-2 showed that inter-annual line-of-sight (LOS) lengthening (i.e., subsidence) presumably related to permafrost thaw was detected in several areas along the coastline as well as the vicinity of settlement in Naiba. Significant subsidence greater than 10 cm was also observed at a site of tundra fire that occurred during the summer of 2017. Seasonal LOS lengthening (subsidence) in summer and shortening (uplift) in early winter up to a few centimeters were detected in Sentinel-1 stacked interferograms. The magnitude of the seasonal displacements varied each year, which may be related to temperature and summer precipitation. Both low and high centered polygons are distributed in this area, and we are going to discuss the relationship between their development, ground surface displacement, and local topography.
Interferometric Synthetic Aperture Radar (InSAR) is a useful tool to measure surface displacement by calculating phase difference between two different SAR data. InSAR has been utilized to reveal geophysical phenomena related to surface displacement such as crustal deformation and glacier flow. Number of application studies of InSAR to permafrost monitoring has been increasing, and InSAR has become one of essential tools for understanding permafrost dynamics. This study used ALOS-2 L-band SAR data obtained from 2015 to 2022 and Sentinel-1 C-band SAR data obtained from 2017 to 2021 to derive surface displacement related to ground freeze/thaw cycle in the vicinity of settlement in Naiba (N70.85°, E130.74°). We applied InSAR time-series analysis (Berardino et al., 2002; Schmidt and Bürgmann, 2003; Biggs et al., 2007; Yanagiya and Furuya, 2020; Abe et al., 2022) to as many interferograms by ALOS-2 as possible in order to calculate cumulative surface displacement from 2015 to 2022. We also derived seasonal surface displacement using Sentinel-1 stacked interferograms to compare the spatial distribution with that from ALOS-2.
Preliminary results of ALOS-2 showed that inter-annual line-of-sight (LOS) lengthening (i.e., subsidence) presumably related to permafrost thaw was detected in several areas along the coastline as well as the vicinity of settlement in Naiba. Significant subsidence greater than 10 cm was also observed at a site of tundra fire that occurred during the summer of 2017. Seasonal LOS lengthening (subsidence) in summer and shortening (uplift) in early winter up to a few centimeters were detected in Sentinel-1 stacked interferograms. The magnitude of the seasonal displacements varied each year, which may be related to temperature and summer precipitation. Both low and high centered polygons are distributed in this area, and we are going to discuss the relationship between their development, ground surface displacement, and local topography.