Geodetic and geomorphologic data assimilation into a coupled ice sheet / solid Earth model for separating present and past ice sheet behavior in Antarctica

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The Antarctic ice sheet (AntIS) is a key element in the climate system; its albedo influences the surface radiative balance, the discharge of freshwater mainly by iceberg calving and sub-glacial melting causes sea-level change, alters the ocean’s thermohaline circulation and influences the sea-ice extent, which in turn controls the heat release from the ocean to the atmosphere. The proposed project aims at understanding the current and past evolution of the AnIS with simulations of a coupled ice sheet / solid Earth model, constrained by geodetic data of the ongoing glacialisostatic adjustment (GIA) and geological evidence of the ice sheet geometry. GRACE (2002 to today), ICESat (2003 to 2009) and GPS (1995 to today) observations are combined to most accurately quantify the temporally-varying AntIS mass balance within the satellite era, and separate it from the GIA contributions in the data sets. The past evolution of the ice sheet will be simulated with a coupled ice sheet / solid Earth model; data assimilation techniques will be explored and applied allowing including geodetic constraints on GIA, as well as geomorphologic evidence of the ice sheet height and extent during the Holocene. Climate model output will provide improved forcing fields of precipitation and temperature for the Holocene, which will be statistically parameterized and adjusted within the range of uncertainties in the assimilated model runs. The project uniquely employs geodetic and geologic data to bridge between the present and past climate-driven evolutions of the AntIS.