ISMIP-HOM benchmark experiments using Underworld

Numerical models have become an indispensable tool forunderstanding and predicting the flow of ice sheets and glaciers. Here wepresent the full-Stokes software package Underworld to the glaciologicalcommunity. The code is already well established in simulating complexgeodynamic systems. Advantages for glaciology are that it provides afull-Stokes solution for elastic-viscous-plastic materials and includesmechanical anisotropy. Underworld uses a material point method to track thefull history information of Lagrangian material points, of stratigraphiclayers and of free surfaces. We show that Underworld successfully reproducesthe 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 differentgeometries and highlight the need to be able to adapt the finite-elementgrid to discontinuous interfaces between materials with strongly differentproperties, such as the ice-bedrock boundary.

Automated summary

Numerical models are essential for understanding and predicting ice sheet and glacier flow, and the Underworld software package provides a full-Stokes solution and mechanical anisotropy for glaciological research. The use of a material point method allows for tracking the full history of material points, stratigraphic layers, and free surfaces. The software successfully reproduces results from other full-Stokes models and highlights the need for adaptive finite-element grids for discontinuous material interfaces.