Constraining the mass balance of East Antarctica

We investigate the mass balance of East Antarctica for the period 2003-2013 using a Bayesian statistical framework. We combine satellite altimetry, gravimetry, and GPS with prior assumptions characterizing the underlying geophysical processes. We run three experiments based on two different assumptions to study possible solutions to the mass balance. We solve for trends in surface mass balance, ice dynamics, and glacial isostatic adjustment. The first assumption assigns low probability to ice dynamic mass loss in regions of slow flow, giving a mean dynamic trend of 17 ± 10 Gt yr-1 and a total mass imbalance of 57 ± 20 Gt yr-1. The second assumption considers a long-term dynamic thickening hypothesis and an a priori solution for surface mass balance from a regional climate model. The latter results in estimates 3 to 5 times larger for the ice dynamic trends but similar total mass imbalance. In both cases, gains in East Antarctica are smaller than losses in West Antarctica.