Monitoring Subglacial Lake Activity in the David Glacier Region, East Antarctica, Using a DInSAR Displacement Integration Approach

초록

Subglacial lakes significantly influence ice sheet dynamics, necessitating precise monitoring of their activity. This study presents a novel approach that integrates differential interferometric synthetic aperture radar (DInSAR) displacements from Sentinel-1 data to estimate high-resolution time series of ice sheet surface elevation changes associated with subglacial lake activity. Applying this approach to the David Glacier region in East Antarctica from 2016 to 2023, we identified and analyzed the activity of Lake David(2) and newly identified subglacial lakes, David(2-1) and David(A). The ice sheet elevation changes derived from the DInSAR displacement integration showed strong agreement with Ice, Cloud, and land Elevation Satellite-2 observations and allowed for detailed monitoring of subglacial lake activity. The ice sheet surface above Lake David(A) showed a marked rise in early 2016 due to lake filling, followed by a stable period until 2020. A rapid surface decline occurred in late 2020 due to drainage. Since 2021, the surface decline has continued at slower rates, indicating gradual water level lowering. Lake David(2-1) filled by early 2021 and subsequently exhibited alternating drainage and filling. The ice sheet surface above Lake David(2) exhibited sustained uplift until 2020, attributed to continuous water filling, and then transitioned to a phase of drainage. Hydraulic potential-derived basal water pathways suggested that Lake David(A) was likely supplied by undetected inflows, while Lake David(2) primarily received water from a southern pathway rather than from Lake David(2-1). This study demonstrates the effectiveness of time-series DInSAR for subglacial lake monitoring, overcoming limitations of altimetry-only observations and providing insights into subglacial hydrology and ice sheet dynamics.

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