InSAR observations of ground deformation in permafrost and agricultural regions of an arid river basin

Abstract

The Shiyang River Basin (SRB) in northwestern China is facing critical water stresses due to extensive groundwater exploitation for irrigation activities. With catchment hydrology strongly influenced by upstream permafrost areas undergoing rapid changes under climate change, the reliability of future water supply to downstream areas is uncertain. This study applies Sentinel-1 Interferometric Synthetic Aperture Radar time series analysis to characterise spatiotemporal patterns in ground deformation linked to cryospheric and hydrological changes associated with upstream permafrost degradation and downstream groundwater extraction.

Results show that agricultural areas exhibit rapid long-term (2015-2024) subsidence rates of up to -23 mm/year and large seasonal amplitudes of ground motion (up to 35 mm), with seasonal cycles characterised by summer subsidence and winter uplift, consistent with irrigation-driven groundwater depletion and recharge. In permafrost areas, widespread subsidence and seasonal deformation was observed with strong spatial variability indicative of long-term permafrost thaw, active layer freeze-thaw cycles with a dependency of underlying cryospheric mechanisms on topography and local soil conditions. The findings highlight the nature of catchment-wide hydrological changes from anthropogenic groundwater extraction and climate-driven permafrost degradation in the SRB, demonstrating the effectiveness of InSAR as a monitoring tool for supporting groundwater management and tracking changes in alpine hydrology.