Title: What drives ice shelf melting in the Amundsen Sea, West Antarctica?
Abstract: Ice shelves and glaciers of the West Antarctic Ice Sheet are melting and thinning rapidly in the Amundsen Sea and Bellingshausen Sea, with consequences for global sea-level rise and ocean circulation. For example, approximately 10% of the observed sea-level rise has been attributed to the thinning of the West Antarctic Ice Sheet between 2005 and 2010, and the melting of ice shelves in the Amundsen Sea and Bellingshausen Sea will freshen the shelf water locally as well as downstream in the Ross Sea, which may influence the global thermohaline circulation. The reason for the high basal melting is warm Circumpolar Deep Water that intrudes via submarine glacial troughs located at the continental shelf break and flows into ice shelf cavities. This warm Circumpolar Deep Water reaches the grounding line, melts the glacier, and forms a buoyant mixture of Circumpolar Deep Water and meltwater, which spreads further downstream. Although it may seem simple, many different processes (e.g., large-scale atmosphere and ocean circulations, cross-shelf exchange, thermocline depth, cavity bathymetry, and air-sea interactions) control ice-shelf melt rates and thus the evolution of ice shelves and glaciers in the Amundsen Sea and Bellingshausen Sea. In this presentation, we will present the current understanding of how Circumpolar Deep Water intrudes onto the continental shelves, how it flows into ice-shelf cavities and interacts with ice shelves, and how glacial melt water travels out from the Amundsen Sea.