Elmer/Ice – a new approach to ice sheet modelling

14.01.2008

CSC's open source multi-physics simulation package Elmer has been successfully adapted to simulations of ice-sheets and glaciers.

In contrary to earlier ice-sheet simulation codes, Elmer solves the complete unscaled set of equations (Full-Stokes, thermo-mechanically coupled) which enables the code to be applied to areas such as ice-domes and ice-sheet margins with ice-streams and attached ice-shelves (i.e., floating ice nourished by inland ice). As ice domes usually are locations for ice-core drill sites and the dynamics at the margins is essential to determine the future trends in sea level rise, Elmer provides a viable tool to investigate actual problems in Glaciology.

Ice is a complex material: Compressible near the surface (snow, firn) or quasi-incompressible in its compact form. The single ice-crystal is one of the most anisotropic materials occurring in nature leading to a sometimes very pronounced anisotropy in polycrystalline ice. In addition, the viscous properties of ice are highly temperature dependent, making ice-sheet modeling an inherently thermo-mechanically coupled problem, including also melting at the surface and especially at the bedrock. All these aspects have been addressed using Elmer.

The material ice is something between a highly viscous liquid and a deforming solid body. As Elmer uses the finite element method (FEM) it is excellently suited to cover both aspects, fluid- and solid mechanics.

The increased resolution of these models bring along that Full-Stokes ice sheet models have to utilize high performance computing (HPC) facilities. The parallel version of Elmer performs well in runs utilizing several hundreds processors simultaneously, opening the possibility for high resolution simulations of continental size ice-bodies, such as the Greenland ice sheet.

The model currently is used at the Arctic Centre at the University of Lapland, Rovaniemi, the Iowa State University, Ames, USA, the Institute for Low Temperature Science (ILTS), Hokkaido University, Sapporo, Japan and at the Laboratoire de Glaciologie et Géophysique de l'Environnement (LGGE), Grenoble, France. An international workshop at LGGE scheduled for mid February with participants from Belgium, France, Norway and the United Kingdom is likely to increase the community of Elmer users amongst Glaciologists.

CSC

CSC, the Finnish IT center for science, is administered by the Ministry of Education. CSC is a non-profit company providing IT support and resources for academia, research institutes and companies: modeling, computing and information services. CSC provides Finland’s widest selection of scientific software and databases and Finland’s most powerful supercomputing environment that researchers can use via the Funet network.

Publications:

CSC Report on Computational Science in Finland 2006-2007

Zwinger T., R. Greve, O. Gagliardini , T. Shiraiwa and M. Lyly, "A full Stokes-flow thermo-mechanical model for firn and ice applied to the Gorshkov crater glacier, Kamchatka" Annals of Glaciol., 45, 29-37, (2007)

Gagliardini O., D. Cohen, P. Råback and T. Zwinger,. "Finite-Element Modeling of Subglacial Cavities and Related Friction Law." J. of Geophys. Res., Earth Surface, 112, F02027, (2007)

Gillet-Chaulet F., O. Gagliardini , J. Meyssonnier, T. Zwinger and J. Ruokolainen, "Flow-induced anisotropy in polar ice and related icesheet flow modelling.”  J. Non-Newtonian Fluid Mech., 134, p. 33-43, (2006)

Le Meur E., O. Gagliardini, T. Zwinger, J. Ruokolainen "Glacier flow modelling: a comparison of the Shallow Ice Approximation and the full-Stokes equation", C. R. Physique, 5, 709-722, (2004)

Additional information:

Thomas Zwinger (thomas.zwinger[at]csc.fi).

Elmer: http://www.csc.fi/elmer

            http://sourceforge.net/projects/elmerfem

ILTS:   http://www.lowtem.hokudai.ac.jp/english/