29 Nov 2022
 | 29 Nov 2022

Simulation of a fully coupled 3D GIA – ice-sheet model for the Antarctic Ice Sheet over a glacial cycle

Caroline Jacoba van Calcar, Roderik S. W. van de Wal, Bas Blank, Bas de Boer, and Wouter van der Wal

Abstract. Glacial Isostatic Adjustment (GIA) has a stabilizing effect on the evolution of the Antarctic Ice Sheet by reducing the grounding line migration that follows ice melt. The timescale and strength of this feedback depend on the spatially varying viscosity of the Earth’s mantle. Most studies assume a relatively high laterally homogenous response time of the bedrock. However, viscosity is spatially variable with a high viscosity beneath East Antarctica, and a low viscosity beneath West Antarctica. For this study, we have developed a new method to couple a 3D GIA model and an ice-sheet model to study the interaction between the Solid Earth and the Antarctic Ice Sheet during the last glacial cycle. The feedback effect into account on a high temporal resolution by using coupling time steps of 500 years. We applied the method using the ice-sheet model ANICE, a 3D GIA FE model, and results from a seismic model to determine the patterns in the viscosity. The results of simulations over the Last Glacial Cycle show that differences in viscosity of an order of magnitude can lead to differences in grounding line position up to 500 km, to differences in ice thickness in the order of 1.5 km. These results underline and quantify the importance of including local GIA feedback effects in ice-sheet models when simulating the Antarctic Ice Sheet evolution over the Last Glacial Cycle.

Caroline Jacoba van Calcar et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-1328', Pippa Whitehouse, 11 Jan 2023
  • CEC1: 'Comment on egusphere-2022-1328', Juan Antonio Añel, 13 Jan 2023
    • AC1: 'Reply on CEC1', Caroline van Calcar, 16 Jan 2023
  • RC2: 'Comment on egusphere-2022-1328', Maryam Yousefi, 18 Jan 2023
  • RC3: 'Comment on egusphere-2022-1328', Volker Klemann, 30 Jan 2023

Caroline Jacoba van Calcar et al.

Caroline Jacoba van Calcar et al.


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Short summary
The waxing and waning of the Antarctic ice sheet caused the Earth’s surface to deform, which is stabilizing the ice sheet and mainly determined by the spatially variable viscosity of the mantle. Including this feedback in model simulations leads to significant differences in ice sheet extend and ice thickness at present day. The results underline and quantify the importance of including this local feedback effect in ice-sheet models when simulating the Antarctic Ice Sheet evolution.