In this work, we leverage data from the Gravity Recovery and Climate Experiment (GRACE) satellite to force the Community Earth System Model version 2 (CESM2), a global climate model, to explore the impacts of freshwater discharge from the Antarctic Ice Sheet (AIS) on Southern Ocean and global ocean dynamics. As the planet warms, the AIS is rapidly losing mass. Most of this mass loss is concentrated in a region referred to as the West Antarctic Ice Sheet (WAIS). This AIS mass loss is typically not well represented in global climate models as many models do not have an active ice sheet component meaning that the AIS doesn't interact with the land, ocean, atmosphere, or sea ice regimes. To mimic AIS mass loss, we use data from the GRACE satellite, which measures changes to the Earth's gravity field, to create a freshwater forcing that we then input directly into the ocean component of CESM2. Running the model out to 2100 under Shared Socioeconomic Pathway 5-8.5, we compare output from our satellite-based freshwater forcing simulation to a control simulation with the same parameterizations but constant freshwater forcing. We find that the addition of freshwater into the Southern Ocean results in higher Southern Hemisphere sea ice extent, relatively cooler sea surface temperatures, and a relatively stronger Atlantic Meridional Overturning Circulation by the end of the 21st century.
tessa.gorte@colorado.edu
Atmospheric and Oceanic Sciences Graduate Student, CU Boulder