Abstract ID: 3.11339 | Accepted as Talk | Talk/Oral | TBA | TBA

Permafrost is a crucial component of the Earth’s cryosphere, influencing global climate systems, ecosystems, and human infrastructure. While well-studied in the Arctic, the Alps, and other permafrost regions, similar research on permafrost degradation remains limited in the Himalayas. Understanding permafrost degradation in this region is important due to its implications for related hazards such as landslides, ground instability, landscape changes and glacial lake outburst floods (GLOFs). To frequently monitor these landscapes, we employed a large-scale remote sensing approach, interferometric synthetic aperture radar (InSAR) in the Tso Kar valley, Ladakh to observe seasonal and annual ground deformation. This analysis offers insights to permafrost degradation and seasonal freeze-thaw cycle of active layer thickness (ALT). We utilized Sentinel-1A/B SAR data acquired from March 2019 to November 2023 to monitor seasonal and annual surface deformation using SBAS-InSAR approach. Two inversion algorithms, least squares (LS) and weighted least squares (WLS), were applied to estimate the time-series deformation patterns. Our findings indicate that the seasonal deformation amplitude ranges from 10 to 25mm and the annual mean vertical deformation trend varies from -10 to -30mm/yr. To further characterize ground deformation, we combined data from both ascending and descending passes to derive the vertical and horizontal component of the deformation. Since line-of-sight (LOS) displacement alone cannot be directly linked to permafrost thawing or ALT changes, computing vertical deformation component is essential. Our preliminary findings indicate cumulative vertical deformation ranging from -10 to -40mm and the East-West movement between -15 to 18mm over study period. These preliminary results show noticeable variations in seasonal and annual ground deformation patterns suggesting ongoing changes in permafrost dynamics. This underscores the critical need for comprehensive studies in the Indian Himalayas to better understand permafrost dynamics, assess associated hazards, and establish long-term monitoring strategies. Given the limitations of C-band SAR data, alternative SAR datasets such as NISAR and ALOS should be explored, for long-term monitoring. Simultaneously, there is an urgent need for extensive ground temperature monitoring to effectively study and model the current state of permafrost degradation and active layer dynamics on a broader spatial scale.