Ice Mass Variation in Antarctica from GRACE Over 2002-2011

We detect the mass balance of the Antarctica ice sheet from GRACE for the recent period July 2002 through March 2011. Land hydrology contamination was corrected through global hydrological models and glacial isostatic adjustment (GIA) of the solid Earth since last deglaciation using the IJ05 model, and then a forward model was employed to adjust to bias due to smoothing filters and GRACE's limited resolution. The results show that there are two significant turning points for ice mass losses or gains near the early 2006 and the end of 2008. The ice mass losses in West Antarctica have accelerated dramatically during 2009-2011, while in East Antarctica the rate is positive, mainly caused by snow accumulation. Over the whole studying period, ice loss rates in West Antarctica (-108 +/- 36Gt/yr) are still significantly larger than the increase in East Antarctica (+72 +/- 24) Gt/yr. Thus, the total Antarctica contribution to sea level rise is slightly negative -0.18 +/- 0.02mm/yr. The rapid change of the regional ice mass in Antarctic, in the course of only several years, suggests that the Antarctica ice sheet mass balance is more sensitive to regional climate conditions than considered before.