Glacial isostatic adjustment modelling affecting global ocean mass estimates

From both GRACE missions we get time variable information from the Earth’s gravity field since 2002. The monthly time series obtained from science centers can be represented as a surface water layer. By sampling the oceans we obtain a mass against time signal which is the barystatic component of the sea level rise signal. Hereby we need to correct for the effect of glacial isostatic adjustment which is also observed by the GRACE missions. The GIA correction determines for a part the implementation of the geocenter correction that is used during the GRACE data processing. Depending on the processing choice to represent ocean mass and the GIA correction that is required we find barystatic sea level rates varying between 1.9 and 2.4 mm/yr whereby we remark that the uncertainty is larger than previously expected.