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www.the-cryosphere-discuss.net/4/1063/2010/
doi:10.5194/tcd-4-1063-2010
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Parameterising the grounding line in ice sheet models
School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
Abstract. Realistic predictions of the behaviour of marine ice sheets require that models are able to robustly simulate grounding line migration. Fixed grid ice sheet models have been shown to exhibit inconsistent and hence unreliable grounding line migration behaviour, except at very high resolution not achievable in whole ice sheet simulations. In this study we present several different approaches to parameterising the grounding line. These are distinguished by choices regarding the ice thickness profile from the last grounded to the first floating grid point, and how this profile is allowed to impact on the gravitational driving stress and basal drag. We demonstrate that the most obvious choice of thickness parameterisation, linear interpolation from the last grounded to the first floating grid point, is not the most effective. We show that use of a grounding line parameterisation greatly improves performance, and that choice of a better grounding line parameterisation over a simpler one can bring further improvements, in terms of both accuracy and more self consistent behaviour, comparable to halving the grid resolution. The approach presented here to parameterising the grounding line does not in itself completely solve the grounding line problem, however it reduces requirements in terms of grid resolution. The parameterisations are presented in the context of a 1-D "shelfy-stream" flow-line model, but could be extended to cope with more than one dimension and other model formulations.
Discussion Paper (PDF, 1251 KB) Interactive Discussion (Closed, 4 Comments) Final Revised Paper (TC)
Notice on Discussion StatusCitation: Gladstone, R. M., Payne, A. J., and Cornford, S. L.: Parameterising the grounding line in ice sheet models, The Cryosphere Discuss., 4, 1063-1105, doi:10.5194/tcd-4-1063-2010, 2010. Bibtex EndNote Reference Manager XML
