Parameterization of basal friction near grounding lines in a one-dimensional ice sheet model

Ice sheets and ice shelves are linked by the transition zone, the region where flow dominated by vertical shear stress makes a transition to flow dominated by extensional stress. Adequate resolution of the transition zone is necessary for numerically accurate ice sheet–ice shelf simulations. The req...

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Bibliographic Details
Main Authors: Leguy, G.R., Asay-Davis, X.S., Lipscomb, W.H.
Format: Article in Journal/Newspaper
Language:English
Published: München : European Geopyhsical Union 2014
Subjects:
550
Online Access:https://doi.org/10.34657/1180
https://oa.tib.eu/renate/handle/123456789/683
Description
Summary:Ice sheets and ice shelves are linked by the transition zone, the region where flow dominated by vertical shear stress makes a transition to flow dominated by extensional stress. Adequate resolution of the transition zone is necessary for numerically accurate ice sheet–ice shelf simulations. The required resolution depends on how the basal physics is parameterized. We propose a~new, simple parameterization of the effective pressure near the grounding line, combined with an existing friction law linking effective pressure to basal stress and sliding, in a one-dimensional, fixed-grid, vertically integrated model. This parameterization represents connectivity between the basal hydrological system and the ocean in the transition zone. Our model produces a smooth transition between finite basal friction in the ice sheet and zero basal friction in the ice shelf. In a set of experiments based on the Marine Ice Sheet Model Intercomparison Project (MISMIP), we show that with a smoother basal shear stress, the model yields accurate steady-state results at a fixed-grid resolution of ~1 km. publishedVersion