Thermokarst subsidence in Central Yakutia revealed by ALOS/ALOS-2 InSAR analysis
Abstract
Surface deformation in Arctic regions underlain by ice-rich permafrost is induced by the melting of massive ground ice, which is known as thermokarst. Thermokarst development can change the local land use and affects the local socio-economy. Central Yakutia in Eastern Siberia is one of the regions where ice-rich permafrost is broadly distributed. The remarkable surface subsidence due to thermokarst has been observed in recent years, which causes destruction of infrastructure in this area. In order to better understand landform changes including thermokarst subsidence, inundation, and thermos-hydrological erosions, knowledge about the deformation rates and spatial distribution of the phenomena is essential. Remote sensing technique, especially Interferometric Synthetic Aperture Radar (InSAR), has a possibility to monitor the thermokarst subsidence and seasonal surface displacement over the permafrost regions. Recent studies of permafrost monitoring using SAR data have been reported, and SAR could provide essential information to understand thawing process of ice-rich permafrost.
In this study, we used ALOS/PALSAR (2007-2011) and ALOS-2/PALSAR-2 (2015-2019) data to investigate ground subsidence caused by thermokarst development. GAMMA software was used to generate Single Look Complex data from Lv1.0 data in ALOS/PALSAR and Lv1.1 data in ALOS-2/PALSAR-2. We generated some interferograms and applied stacking procedure. Assuming ground displacement is only vertical component, the LOS change was converted to vertical displacement using incidence angle. As a result, we detected ground subsidence with a rate of 0.5-4 cm/yr in Mayya, Amga, and Churapcha from PALSAR and PALSAR-2 InSAR stacking. In Mayya, the subsidence signals are found in numerous open areas (deforested areas), and the PALSAR-2 results clearly show the spatial distribution of the subsidence corresponding to visible observation of thermokarst development in high-resolution optical images.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C13E1371A
- Keywords:
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- 0702 Permafrost;
- CRYOSPHERE;
- 0708 Thermokarst;
- CRYOSPHERE;
- 0768 Thermal regime;
- CRYOSPHERE;
- 0774 Dynamics;
- CRYOSPHERE