Observation of the Subglacial Lake in the David Glacier area in Victoria Land

Abstract

The Antarctic Ice Sheet, which has a significant impact on current sea level changes and climate changes, is one of the international scientific issues. An aviation platform is a useful research approach that is used in many countries to minimize the disadvantages of accessibility throughout Antarctica. This study describes the research conducted using the helicopter-based IPR system (HiCARS2) which is developed by Korea Polar Research Institute (KOPRI) and University of Texas Institute for Geophysics (UTIG). During the 2016/17 and 2018/19 Summer Seasons, KOPRI and UTIG conducted researches using HiCARS2 to find out the presence of unknown subglacial lakes and the detailed size of lakes (David 1, 2) in the David Glacier area in Victoria Land. In the first round of survey in the 2016/17 season, we looked for potential candidate lakes and conducted a second round of survey in the 2018/19 season to observe the detailed information of subglacial lakes on the David 2 area identified by Smith et al. (2009) and Blankenship et al. (2009).

We obtained the altitude at the air-snow interface of the David glacier and at the glacier-bedrock interface from the results. Glacier water flows and its route was identified from the glacier-bed reflection power and topographic information. The Cryosat-2 data in 2010-2014 did not detect the elevation changes in from the D1 area but detected the elevation change slightly in the D2 area. In the first round of survey, no flat and strong reflection that could infer the presence of lakes was found in the D1 area. However, in the second survey, we found a small valley with a width of about 3 km appears in the D2 area and high reflection intensity appears in the same area. The valley is topographically shaped to be easy to collect water and the higher reflection intensity of this area is interpreted because the dielectric constant of the water is larger than the bedrock.