Reply on RC2

Abstract

The Totten and Moscow University glaciers, located in East Antarctica, contain 5.1 m sea-level equivalent of ice and have been losing mass over recent decades. Using ICESat-2 laser altimetry repeat track analysis and satellite radar interferometry from Sentinel-1a/b SAR images, we mapped the grounding line locations of these two glaciers between 2017 and 2021. We detected pervasive grounding line retreat along the ice plains at the glacier central trunk of Totten Glacier Ice Shelf (TGIS) and Moscow University Ice Shelf (MUIS), where the GL retreated 3.51 ± 0.49 km and 13.85 ± 0.08 km during 1996–2020, respectively. Using CryoSat-2 radar altimetry, we found that the observed grounding line retreats are coincident with high thinning rates and high ice velocities, indicating a mass loss pattern dominated by ice dynamics. We also identified two tide-modulated ocean channels on the Totten eastern ice shelf and the Moscow University western ice shelf, where the ocean channel widths are highly correlated with the tidal range. The opening of the Moscow University western ice shelf channel connects the two previously separated TGIS and MUIS systems, which might open a pathway for the warm modified circumpolar deep water entering the main MUIS cavity and facilitate further grounding line retreat.