[A-CG39] Science in the Arctic Region

[ACG39-06] Detection of surface displacement caused by permafrost in Lena river delta using Sentinel-1 InSAR

*Ryuji Yamaguchi¹ (1.Department of Natural History Sciences, Graduate School of Science, Hokkaido University)

Lena River Delta at 72° N, in Sakha Republic, Russia, is extensively underlain by permafrost, which is vulnerable to ongoing global warming. The impact of permafrost thawing spans from regional problems such as changes in surface topography and damages on infrastructure, to global problems such as the possible feedback of greenhouse gas emission. Direct monitoring of permafrost over a wide spatial coverage with fine resolution is infeasible. However, seasonal freeze-thaw cycle and inter-annual changes in permafrost can generate measurable surface displacements. Some previous studies report surface displacement signals in an island composing Lena River Delta by using In Situ measurement and satellite InSAR data. There are, however, few studies that comprehensively examined the surface deformation over the entire area in Lena River Delta.



InSAR can map surface displacements by taking phase differences at the same pixel locations, using two radar imaginaries. It has the advantage of high spatial resolution, wide spatial coverage, and no need to set any ground-based instruments. In this study, we examined surface displacements over Lena River Delta from March 2019 to December 2020 by InSAR, using radar image of Sentinel-1 launched by ESA.


As result, we detected larger inter-annual subsiding velocity in some islands than it around them, such as Kharadang Island, Dyanglakh Island, and Sobo-Sise Island all composed by Yedoma. The difference of subsidence between in the islands and around them are about 0.5-1.5 cm/year (LOS).