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Abstract:
A major uncertainty in determining the mass balance of the Antarctic ice sheet from measurements of satellite gravimetry, and to a lesser extent satellite altimetry, is the poorly known correction for the ongoing deformation of the solid Earth caused by glacial isostatic adjustment (GIA). In the past decade, much progress has been made in consistently modelling the ice sheet and solid Earth interactions; however, forward-modelling solutions of GIA in Antarctica remain uncertain due to the sparsity of constraints on the ice sheet evolution, as well as the Earth's rheological properties. An alternative approach towards estimating GIA is the joint inversion of multiple satellite data - namely, satellite gravimetry, satellite altimetry and GPS, which reflect, with different sensitivities, trends of recent glacial changes and GIA. Crucial to the success of this approach is the accuracy of the space-geodetic data sets. Here, we present reprocessed rates of surface-ice elevation change (Envisat/ICESat; 2003-2009), gravity field change (GRACE; 2003-2009) and bedrock uplift (GPS; 1995-2013). The data analysis is complemented by the forward-modelling of viscoelastic response functions to disc load forcing, allowing us to relate GIA-induced surface displacements with gravity changes for different rheological parameters of the solid Earth. The data and modelling results presented here form the basis for the joint inversion estimate of present-day ice-mass change and GIA in Antarctica. This paper presents the first of two contributions summarizing the work carried out within a European Space Agency funded study, REGINA.
