A26. Antarctic and Greenland Continental Shelf Circulation

Title

Influence of Antarctic and Greenland Continental Shelf Circulation on High-latitude Oceans in E3SM

Authors

Julie L. McClean, Sarah. T. Gille, Fiamma Straneo, Mathew E. Maltrud, Detelina P. Ivanova, Theresa Morrison, André Palóczy, Peter Gleckler, and Elizabeth C. Hunke

Abstract

Melting along the ice sheet margins of Antarctica and Greenland has accelerated over past decades releasing freshwater into the ocean. Water properties and stratification are subsequently altered and, in turn, ocean circulation patterns and sea-ice distributions along with mesoscale structures and mixing via density changes, and ultimately the meridional overturning circulation. Our objective is to evaluate the impact of freshwater input caused by ice melt within global Energy Exascale Earth System Model (E3SM) and Coupled Model Intercomparison Project6 (CMIP6) “HighResMIP” simulations, with goals both to advance understanding of the critical processes and also to identify the most useful metrics for cross-comparing meltwater input within multiple models. Two generations of E3SM, forced with reanalysis atmospheric fluxes, are used in the first instance to study melt effects on the Greenland and Antarctic continental shelves/slopes as well as property exchanges with adjacent interior basins. E3SMv0 and v1 simulations that are eddy-permitting in the study regions and have no freshwater surplus representations are compared with a counterpart E3SMv0 simulation with freshwater surpluses and a mesoscale eddy-resolving configuration, also with surpluses. These comparisons will shed light on the importance of including freshwater surpluses and resolving mesoscale eddies when modeling change and variability over the past decades in high latitudes. Fully-coupled HighResMIP simulations and fully-coupled E3SMv1 run under the HighResMIP protocol, although without surpluses, will also be evaluated to understand feedbacks among the ocean, sea-ice, and atmospheric model components, providing a broader context to interpret the importance of the freshwater releases.