Revealing large-scale permafrost dynamics and environmental controls in mid-latitude regions using InSAR: A case study in Mongolia

Permafrost degradation is a critical challenge in the context of global warming, yet large-scale monitoring in mid-latitude permafrost zones remains notably scarce. Ground deformation, as a consequence of thaw of ice-rich permafrost, can be quantified through satellite remote sensing. This study, for the first time, employed an improved Small Baseline Subset (SBAS) InSAR technology to 3566 Sentinel-1 images from 2017 to 2021, obtaining large-scale ground deformation covering the entire permafrost region of Mongolia (∼ 568,000 km 2 ). Our results reveal significant spatial variability in surface deformation, with 11.25% of the area showing notable subsidence of >5 mm/year and 11.92% exhibiting substantial seasonal deformation amplitude of >5 mm. We identified three distinct degradation patterns: ecosystem-driven patchy subsidence in central Mongolian foothills, topography-climate controlled stripe-like subsidence in the Altai Mountains, and hydrothermal-driven concentrated subsidence in enclosed basins. Statistical analyses indicated synergistic environmental controls: regional climate system (mean annual surface temperature, snow cover, precipitation) acts as the primary driver, local soil-vegetation system (soil organic carbon content, vegetation cover) regulates the ground's specific response, and topography (slope, aspect) further shapes the spatial pattern of permafrost deformation. The positive feedback between seasonal deformation and long-term subsidence was quantified, highlighting seasonal dynamics as an early-warning indicator for future thaw-vulnerable areas. This research fills a critical gap in mid-latitude permafrost monitoring and provides a feasible framework for climate adaption and sustainable management in Mongolia and similar global permafrost regions.