Generating a map of subglacial discharge across Antarctica using MPAS-Albany Land Ice Model (MALI)
Courtney Shafer, University at Buffalo
The Antarctic Ice Sheet (AIS) primarily loses mass through ice shelf basal melting caused by the intrusion of warm circumpolar deep water (CDW) into ice shelf cavities. The warm water can thin the overlying ice shelves leading to the destabilization of the grounding zone (the region that separates grounded from floating ice), allowing an increased mass flux into the ocean. While basal melting through warm ocean water intrusion has a major effect on ice shelf stability, subglacial discharge, the outflow of meltwater across the grounding zone, could also have an important effect on the stability of the ice shelves. The release of the fresh, subglacial water into the ice shelf cavities creates a buoyant plume that captures and pulls the warm, ocean water with it across the ice shelf front, further melting the already vulnerable grounding zone. While this phenomenon is known, the interaction between subglacial discharge and ocean water on ice shelf basal melting is rarely accounted for within earth system and ocean modeling. In this work, I create a map of subglacial discharge across Antarctica using the MPAS-Albany Land Ice Model (MALI). The map is validated by regional observations of ice shelf melt rates as well as subglacial lakes across Antarctica. The map can then be used by ice and ocean modelers to project how ice shelves will evolve in the future, and how their potential collapse could impact the stability of the AIS and thus, sea level rise.
Abstract Author(s): C. Shafer