hide
Free keywords:
-
Abstract:
A major uncertainty in determining the mass balance of the Antarctic ice sheet from satellite gravimetry, and to
a lesser extent altimetry, measurements is the poorly known correction for the glacial isostatic adjustment (GIA)
of the solid Earth. Although much progress has been made in consistently modelling ice-sheet evolution and
related bedrock deformation, predictions of GIA remain ambiguous due to the sparsity of geodetic and geological
constraints. Here, we present an improved geodetic GIA estimate based on GRACE, Envisat/ICESat/CryoSat-2 and
GPS measurements. Using viscoelastic response functions of the radial displacement and gravity field change to
a disc load forcing, we estimate GIA based on multiple space-geodetic observations, making use of their different
sensitivities to surface and solid Earth processes. The approach allows us to consider a laterally varying lithosphere
thickness and mantle viscosity in Antarctica, and particularly investigate the effect of a low-viscosity asthenosphere
and a ductile layer in the elastic lithosphere in West Antarctica. We compare our GIA estimate with published
estimates and results from numerical modelling, and evaluate its impact on the determination of ice-mass balance
in Antarctica from GRACE and CryoSat-2. The results presented are the final results of the Support To Science
Element Project REGINA and its Supplementary Study of the European Space Agency, www.regina-science.eu.
