Regional Glacial Isostatic Adjustment and CryoSat Elevation Rate Corrections in Antarctica (STSE-Project REGINA)
Sasgen, Ingo1; Bamber, Jonathan L.2; Clarke, Peter3; Horvath, Alexander4; Horwath, Martin4; Hurkmans, Ruud T.W.L.2; Klemann, Volker1; Pail, Roland4; Petrie, Elizabeth3; Schoen, Nana W.5
1GFZ Potsdam, GERMANY; 2University of Bristol, UNITED KINGDOM; 3Newcastle University, UNITED KINGDOM; 4TU München, GERMANY; 5University of Bristol, GERMANY

A major uncertainty in determining ice-mass balances from gravimetric, and, to a lesser extent, from altimetric measurements is the necessity to correct mass trends for the viscous flow in the Earth's interior related to the glacial isostatic adjustment (GIA), causing gravity field disturbances and surface displacement. Both types of uncertainties need to be considered, at a regional scale, to reliably determine the amount and errors of space-geodetic estimates of the ice sheet contribution to sea level rise. Current GIA models suffer from the poorness of observational constraints on the ice sheet evolution and lack of knowledge on the Earth’s rheological structure, and, at the same time, lack of representing GIA signals at smaller spatial scales, for example associated with ductile flow in the crust underneath Antarctica. Within ESAs Support to Science Element (STSE), the project REGINA aims at exploiting the full potential of present-day space-geodetic observations as constraints for Antarctica GIA; namely, the static gravity field measured with GOCE, temporal gravity field variations measured with GRACE, GPS surface displacements, and ice sheet topographic change from CryoSat altimetry. Together with advanced GIA modeling, the project aims at tightening GIA predictions, thus reducing uncertainties in gravimetric and topographic change corrections, in particular for CryoSat. The following presentation provides an overview of the benefits and challenges of different data sets in separating present-day ice-mass change and GIA and the effect of a refined crustal structure on the imprint of the GIA in the gravity field and surface deformation in Antarctica.