Airborne and Spaceborne Mapping and Analysis of the Subglacial Lake D2 in David Glacier, Terra Nova Bay, Antarctica

Abstract

During the 2018-2019 Antarctic summer, the Korea Polar Research Institute and the University of Texas Institute for Geophysics collaborated on a helicopter-based ice-penetrating radar (IPR) survey over the active subglacial lake D2 (SLD2), located in the midstream of the David Glacier, Terra Nova Bay, Antarctica. This study investigates the relationship between SLD2 water levels and fluctuations in glacial surface elevation (up to 3.6 m) and delineates subglacial lakes within the study area. We provide a comprehensive analysis based on integrated data from IPR (2018), Sentinel-1 double-differential interferogram synthetic aperture radar (DDInSAR) (2017-2022), ICESat-2 laser altimeter (2019-2022), and KOMPSAT-5 synthetic aperture radar (2021 and 2023). The concave bedrock structure and low hydraulic head areas concentrate subglacial meltwater, facilitating water accumulation and retention, forming a lake. The SLD2 lake complex is identified based on bed topography, hydraulic gradient, and relative bed reflection intensity. Its area is approximately 1/9.2 of the lake area estimated through remote sensing. Our analysis suggests that variations in water supply and discharge along the subglacial channel network influence lake water levels, as evidenced by a surface elevation increase of up to 3.69 m in the SLD2 area from 2019 to 2022. Additionally, the presence of crevasses and incoherence in the DDInSAR imagery suggests that these subglacial lakes impact glacier flow velocity.