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Abstract

Numerical models have become an indispensable tool for understanding and predicting the flow of ice sheets and glaciers. Here we present the full-Stokes software package Underworld to the glaciological community. The code is already well established in simulating complex geodynamic systems. Advantages for glaciology are that it provides a full-Stokes solution for elastic–viscous–plastic materials and includes mechanical anisotropy. Underworld uses a material point method to track the full history information of Lagrangian material points, of stratigraphic layers and of free surfaces. We show that Underworld successfully reproduces the results of other full-Stokes models for the benchmark experiments of the Ice Sheet Model Intercomparison Project for Higher-Order Models (ISMIP-HOM). Furthermore, we test finite-element meshes with different geometries and highlight the need to be able to adapt the finite-element grid to discontinuous interfaces between materials with strongly different properties, such as the ice–bedrock boundary

More details on this project can be seen here: Sachau, T., Yang, H., Lang, J., Bons, P.D. and Moresi, L., 2022. ISMIP-HOM benchmark experiments using Underworld. Geoscientific Model Development.

Files Description

File	Purpose
Exp_A_3D.py	3D model for the Experiment A in Sachau_et_al_2022.
Exp_B_2D.py	2D model for the Experiment B.
Exp_B_2D.ipynb	notebook of 2D model for the Experiment B.
Exp_B_3D.py	3D model for the Experiment B.
Exp_C_3D.py	3D model for the Experiment C.
Exp_D_2D.py	2D model for the Experiment D.
Exp_E_mixed-slip-version.py	2D model for the Experiment E with mixed slip.
Exp_E_mixed-no-slip-version.py	2D model for the Experiment E without slip.
Exp_F_3D.py	3D model for the Experiment F.
'velocity_10000.0.png'	image of velocity profile of Exp_B_2D.
'mesh_deform_default_swarm.png'	image of deformed mesh.
'Results-all-simulations.zip'	raw data of all simulations.
'Results-and-Figures.pdf'	figures used in Sachau et al. 2022.

Tests

This study uses Underworld to reproduce the benchmark models provided by ISMIP–HOM

Pattyn, F., Perichon, L., Aschwanden, A., Breuer, B., De Smedt, B., Gagliardini, O., Gudmundsson, G.H., Hindmarsh, R.C., Hubbard, A., Johnson, J.V. and Kleiner, T., 2008. Benchmark experiments for higher-order and full-Stokes ice sheet models (ISMIP–HOM). The Cryosphere, 2(2), pp.95-108.

Better to take notebook file Exp_B_2D.ipynb as a start.

Parallel Safe

3D model results can be obtained in parallel operation.