Datensatz

Zusammenfassung

The Antarctic Ice Sheet is the largest but also the most uncertain potential contributor to future sea level rise. Understanding involved feedback mechanisms require physically-based models. Confidence in future projections can be improved by models that reproduce past ice sheet changes and present change rates. The complex interaction between ice, bedrock and sea level plays an important role for the stability of marine ice sheets with characteristic response time scales varying regionally between years and thousands of years due to the heterogeneous Earth structure underneath Antarctica and the interacting ice sheet dynamics.We have coupled the VIscoelastic Lithosphere and MAntle model (VILMA) to the Parallel Ice Sheet Model (PISM v2.0, www.pism.io) and have run simulations over the last two glacial cycles. In this framework, VILMA considers both, viscoelastic deformations of the solid Earth by considering a three-dimensional mantle-viscosity distribution and a gravitationally self-consistent mass redistribution in the ocean by solving for the sea-level equation. PISM solves for the stress balance for a changing bed topography, which can be updated with coupling intervals up to 1 year in view of fast changes in ice sheet flow and grounding line dynamics.Here, we show results of coupled PISM-VILMA simulations scored against a database of geological constraints around Antarctica (AntICE2), including sea level index points and GPS uplift rates. We discuss the implications of a three-dimensional Earth structure over one-dimensional profiles for Antarctic ice sheet changes. This project is part of the German Climate Modeling Initiative PalMod.