High-Resolution, Antarctic Ice Sheet Simulations forced by Submarine Melting Simulated by the Accelerated Climate Model for Energy

Friday, December 16, 2016 - 13:40
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The capability for simulating sub-ice shelf circulation and submarine melting and freezing has recently been added to the U.S. Department of Energy’s Accelerated Climate Model for Energy (ACME). With this new capability, we use an eddy permitting ocean model to conduct two sets of simulations in the spirit of Spence et al. (GRL, 41, 2014), who demonstrate increased warm water upwelling along the Antarctic coast in response to poleward shifting and strengthening of Southern Ocean westerly winds. These characteristics, symptomatic of a positive Southern Annual Model (SAM), are projected to continue into the 21st century under anthropogenic climate change (Fyfe et al., J. Clim., 20, 2007). In our first simulation, we force our climate model using repeat cycles of the standard CORE interannual forcing dataset (Large and Yeager; Clim. Dyn.,33, 2009). These melt rates are used to force our high-resolution (30-to-1 km) ice sheet model, MPAS-Land Ice, offline and to derive a quasi-steady state ice sheet model initial condition. In our second simulation, we force our climate model using an altered version of CORE interannual forcing, based on the latter half of the full time series, which we take as a proxy for a future climate state biased towards a positive SAM. Melt rate anomalies from this second simulation are then used to force our ice sheet model offline out to year 2100. We compare ocean model states and sub-ice shelf melt rates with observations and present estimates for Antarctic Ice Sheet mass loss from our simulations.