Spatial Characteristics and Controlling Factors of Permafrost Deformation in the Qinghai–Tibet Plateau Revealed Through InSAR Measurements

Accelerated climate warming has intensified permafrost degradation across the Qinghai-Tibet Plateau (QTP), profoundly impacting regional hydrological cycles and carbon fluxes. Surface deformation observed in permafrost areas offers valuable insights into the extent of this degradation. However, the spatial patterns and controlling factors of permafrost deformation across the entire QTP remain poorly understood. This study reveals the long-term and seasonal deformation characteristics of permafrost regions across the entire QTP using Sentinel-1 SAR imagery (primarily from 2019 to 2021) through time-series InSAR combined with a permafrost deformation model. Notably, it provides the first plateau-wide characterization of the spatial distribution of seasonal deformation. In addition, the dominant factors controlling both long-term and seasonal deformation were identified with the geographic detector method. The results demonstrate that permafrost regions experience significantly higher surface subsidence rates (−2.46 mm/year) than seasonally frozen areas (−0.54 mm/year). Spatially, ice-rich permafrost regions with lower thermal stability exhibit higher subsidence rates. The average seasonal deformation amplitude in permafrost areas is 3.85 mm, with larger values concentrated in flat basins and areas surrounding lakes and rivers. Moreover, spatial variability of long-term deformation is mainly controlled by solar radiation and precipitation, and both are positively correlated with deformation rates. Slope is the primary driver of spatial variation in seasonal deformation amplitude. These findings highlight the critical role of surface energy, moisture, and terrain in permafrost dynamics. The study demonstrates the potential of integrating time-series InSAR with geospatial analysis to support large-scale permafrost monitoring and estimation of ground-ice meltwater across the QTP.