Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 11, 2543-2554, 2017
https://doi.org/10.5194/tc-11-2543-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
09 Nov 2017
Ice shelf fracture parameterization in an ice sheet model
Sainan Sun1,4, Stephen L. Cornford2, John C. Moore3,4, Rupert Gladstone3, and Liyun Zhao4 1Laboratoire de Glaciologie, Université libre de Bruxelles, Brussels, Belgium
2Department of Geography, College of Science, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
3Arctic Centre, University of Lapland, Rovaniemi, 96101, Finland
4College of Global Change and Earth System Science, Beijing Normal University, 100082, Beijing, China
Abstract. Floating ice shelves exert a stabilizing force onto the inland ice sheet. However, this buttressing effect is diminished by the fracture process, which on large scales effectively softens the ice, accelerating its flow, increasing calving, and potentially leading to ice shelf breakup. We add a continuum damage model (CDM) to the BISICLES ice sheet model, which is intended to model the localized opening of crevasses under stress, the transport of those crevasses through the ice sheet, and the coupling between crevasse depth and the ice flow field and to carry out idealized numerical experiments examining the broad impact on large-scale ice sheet and shelf dynamics. In each case we see a complex pattern of damage evolve over time, with an eventual loss of buttressing approximately equivalent to halving the thickness of the ice shelf. We find that it is possible to achieve a similar ice flow pattern using a simple rule of thumb: introducing an enhancement factor ∼ 10 everywhere in the model domain. However, spatially varying damage (or equivalently, enhancement factor) fields set at the start of prognostic calculations to match velocity observations, as is widely done in ice sheet simulations, ought to evolve in time, or grounding line retreat can be slowed by an order of magnitude.

Citation: Sun, S., Cornford, S. L., Moore, J. C., Gladstone, R., and Zhao, L.: Ice shelf fracture parameterization in an ice sheet model, The Cryosphere, 11, 2543-2554, https://doi.org/10.5194/tc-11-2543-2017, 2017.
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Short summary
The buttressing effect of the floating ice shelves is diminished by the fracture process. We developed a continuum damage mechanics model component of the ice sheet model to simulate the process. The model is tested on an ideal marine ice sheet geometry. We find that behavior of the simulated marine ice sheet is sensitive to fracture processes on the ice shelf, and the stiffness of ice around the grounding line is essential to ice sheet evolution.
The buttressing effect of the floating ice shelves is diminished by the fracture process. We...
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