Drainage of Kronshtadskiy subglacial lake in Antarctica observed by double-differential SAR interferometry

Hundreds of subglacial lakes in Antarctica have been reported by using radio-echo sounding and satellite altimetry, but the detection of small and short-lived hydrological events has remained challenging due to limited spatial and temporal resolution. In this study, we applied the Double-Differential Interferometric Synthetic Aperture Radar (DDInSAR) technique to analyze surface-elevation changes associated with the Kronshtadskiy subglacial lake near the Amery Ice Shelf, East Antarctica. A total of 77 DDInSAR interferograms were generated from DInSAR interferograms with a 24-day temporal baseline by using Sentinel-1 SAR images acquired between 2016 and 2021. A rapid drainage event was observed at a circular-shaped subglacial lake with an area of 61 km 2 . The associated volume loss of the subglacial water was 78.0 million cubic meters (Mm 3 ). Most of the total subsidence (6.37 m) at the center of the subglacial lake occurred during 2016–2017, with a subsidence rate of 2.54 m/yr, followed by a marked decrease to 0.88 m/yr in 2018 and to less than 0.30 m/yr during 2019–2021. Comparison with satellite altimetry data from CryoSat-2 and ICESat-2 confirmed the overall subsidence trend. This study demonstrates the effectiveness of DDInSAR for monitoring subglacial hydrology in fast-flowing polar environments.