Reply on RC2

Abstract

The Totten Glacier in East Antarctica is of major climatic interest because of the large fluctuations of its grounding line and potential vulnerability to climate change. Here, we use a series of high-resolution, regional NEMO-LIM-based experiments, which include an explicit treatment of ocean–ice shelf interactions as well as a representation of grounded icebergs and fast ice, to investigate the changes in ocean–ice interactions in the Totten Glacier area between the last decades (1995–2014) and the end of the 21st century (2081–2100) under SSP4–4.5 climate change conditions. By the end of the 21st century, the wide areas of multiyear fast ice simulated in the recent past are replaced by small patches of first year fast ice along the coast, which decreases the total summer sea ice extent. The Antarctic Slope Current is accelerated by more than 90 % and the Totten ice shelf melt rate is increased by 41 % due to enhanced warm water intrusions into its cavity. The representation of fast ice dampens the ice shelf melt rate increase, as the Totten ice shelf melt rate increase reaches 58 % when fast ice is not taken into account. The Moscow University ice shelf melt rate increase is even more impacted by the representation of fast ice, with a 1 % melt rate increase with fast ice, compared to a 38 % increase without a fast ice representation. This highlights the importance of including representation of fast ice to simulate realistic ice shelf melt rate increase in East Antarctica under warming conditions.