EGU22-4786
https://doi.org/10.5194/egusphere-egu22-4786
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Simulating the evolution of the Antarctic Ice Sheet including 3D GIA feedback during the Last Glacial Cycle

Caroline van Calcar1,2, Roderik van de Wal2,3, Bas Blank1, Bas de Boer4, and Wouter van der Wal1,5
Caroline van Calcar et al.
  • 1Faculty of Aerospace Engineering, Delft University of Technology, Delft, 2629 HS, The Netherlands (c.j.vancalcar@tudelft.nl)
  • 2Institute for Marine and Atmospheric research Utrecht, Utrecht University, Utrecht, 3508 TA, The Netherlands
  • 3Department of Physical Geography, Utrecht University, Utrecht, 3584 CB, The Netherlands
  • 4Earth and Climate Cluster, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, 1081 HV, The Netherlands
  • 5Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, 2628 CN, The Netherlands

Changes in ice load over time deform the Earth’s crust and mantle. This effect, Glacial Isostatic Adjustment (GIA), induces vertical deformation of the bedrock of the Antarctic continent and impacts the grounding line position which is critical for the dynamical state of the Antarctic Ice Sheet (AIS). GIA introduces a negative feedback and stabilizes the ice sheet evolution, hence GIA modelling is important for transient studies. Most ice dynamic models use a two-layer flat Earth approach with a laterally homogenous relaxation time or a layered Earth approach with a laterally homogenous viscosity (1D) to compute the bedrock deformation. However, viscosity of the Earth’s interior varies laterally (3D) and radially with several orders of magnitude across the Antarctic continent. Here we present a new coupled 3D GIA – ice dynamic model which can run over hundred thousands of years with a resolution of 500 years. The method is applied using various 1D and 3D rheologies. Results show that the present-day ice volume is 3 % lower when using a 1D viscosity of 1021 Pa·s than using a 3D viscosity. However, local differences in grounding line position maybe up to a hundred kilometres around the Ronne and the Ross Ice Shelfs, and ice thickness differences are up to a kilometre for present day conditions when comparing 1D rheologies and 3D rheologies. The difference between the use of various 3D rheologies is significantly smaller. These results underline and quantify the importance of including local GIA feedback effects in ice dynamic models when simulating the Antarctic Ice Sheet evolution over the Last Glacial Cycle.

How to cite: van Calcar, C., van de Wal, R., Blank, B., de Boer, B., and van der Wal, W.: Simulating the evolution of the Antarctic Ice Sheet including 3D GIA feedback during the Last Glacial Cycle, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4786, https://doi.org/10.5194/egusphere-egu22-4786, 2022.