Greenland wintertime buried lake drainage and ice dynamics response

Buried lakes are widely distributed on the Greenland Ice Sheet (GrIS) after summer. Some of these lakes may drain over winter, thereby delivering meltwater into the ice sheet and potentially influencing ice flow dynamics. However, to date, only a limited number of buried lake drainages (BLDs) have been identified and their spatiotemporal dynamics across the GrIS remain unclear. Here we first detect pan-GrIS wintertime BLDs by integrating Sentinel-1 and -2 satellite imagery and ArcticDEM data, and then investigate potential ice velocity anomalies (IVAs) triggered by BLDs using ice velocity data. The results show that a total of 167 complete and partial BLDs are identified over seven winters from 2017 to 2023 on the GrIS, including 25 cascade drainages. Ten significant IVAs are observed in association with BLDs, and they may lead to net increases in annual ice motion. A representative cascade drainage further reveals that partial BLDs may result from the combined effects of the fracture location and depression topography. Meanwhile, the depression topography and associated water storage capacity may be markedly altered by wintertime drainage. Notably, beyond triggering IVAs of up to ~50%, some BLDs can even trigger rerouting of subglacial hydrologic pathways within a few days.