Table of Contents

Calving

Elmer/Ice includes the ability to predict and simulate the evolution of a calving glacier in 2D and in 3D.

Both the 2D and 3D calving models implement the 'Crevasse Depth Calving Criterion', which predicts calving events based on the penetration of surface and basal crevasses (Benn et al. 2007). However, most of the effort involves what happens after calving is predicted (i.e. mesh adaptation & interpolation), so other calving models maybe implemented with relative ease.

Any queries about calving in Elmer/Ice should be directed to Joe Todd.

2D Calving

The 2D calving model operates on flowline domains, and consists of 2 main solvers: Calving2D which computes crevasse penetration and predicts calving events, and TwoMeshes which modifies the mesh geometry in response to calving.

A simple 2D calving test case can be found in elmerice/Tests/Calving2D.

3D Calving

The 3D calving model is significantly more complex and computationally demanding than the 2D case, due to the comparative difficulty of identifying calving events in a 3D domain (Calving3D), as well as the requirement for complete remeshing following calving events (Remesh).

A 3D test case can be found at elmerice/Tests/Calving3D. Out of the box, this test is likely to fail due to an issue with gmsh (see External Dependencies below)

External Dependencies:

GMSH - The meshing and remeshing associated with the 3D calving model requires gmsh to be installed on your system, somewhere in your PATH.

NETCDF - for real applications, the GridDataReader solver is useful for reading in things like bed elevation, temperature, slip coefficient etc. This depends on netcdf.

Stability & Robustness

The repeated unsupervised remeshing in the 3D calving model occasionally produces low-quality or degenerate 3D elements, which cause problems for the flow solution. Various strategies have been employed in the Remesh solver to reduce the frequency of these problematic meshes. Additionally, the auxiliary solver CheckFlowConvergence can be used to check that the flow solution has converged, and take appropriate action if not.

Typical Workflow

References:

Benn, D. I., Warren, C. R., & Mottram, R. H. (2007). Calving processes and the dynamics of calving glaciers. Earth-Science Reviews, 82(3–4), 143–179. DOI: 10.1016/j.earscirev.2007.02.002

Todd, J., & Christoffersen, P. (2014). Are seasonal calving dynamics forced by buttressing from ice mélange or undercutting by melting? Outcomes from full-Stokes simulations of Store Glacier, West Greenland. The Cryosphere, 8(6), 2353–2365. https://doi.org/10.5194/tc-8-2353-2014

problems/calving.txt · Last modified: 2017/04/17 19:33 by jtodd
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