Impact of lateral and radial viscosity variations on vertical land motion in view of Antarctic GIA

Glacial isostatic adjustment (GIA) is identified as a crucial feedback mechanism between ice-sheet dynamics and viscoelastic deformation of the solid Earth. In addition, the interpretation of geodetically inferred ice-mass change requires the consideration of a realistic GIA correction. Specifically in Antarctica, regions of low mantle viscosity can significantly impact ice sheet dynamics due to different feedback strengths.

In this study we discuss the effect of lateral viscosity contrasts on the response of the solid Earth to ice-mass changes in view of bedrock displacement and geoid change. Considering different geometries of low-viscosity bodies, we infer their impact on geodetic observables. As the main question we will investigate to which extent geodetically inferred viscosity values are biased due to the fact that, in general, they are based on assuming a  viscosity structure that only varies with depth. Furthermore, such structural features might also impact the interaction between the solid-Earth and the Antarctic ice-sheet dynamics.

This work contributes to the German Climate Modeling Initiative PALMOD.