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Comparison of hybrid schemes for the combination of shallow approximations in numerical simulations of the Antarctic Ice Sheet

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Please use this identifier to cite or link to this item:http://hdl.handle.net/2115/64418

Title: Comparison of hybrid schemes for the combination of shallow approximations in numerical simulations of the Antarctic Ice Sheet
Authors: Bernales, Jorge Browse this author
Rogozhina, Irina Browse this author
Greve, Ralf Browse this author
Thomas, Maik Browse this author
Issue Date: 27-Jan-2017
Publisher: Copernicus Publications on behalf of the European Geosciences Union (EGU)
Journal Title: The Cryosphere
Volume: 11
Issue: 1
Start Page: 247
End Page: 265
Publisher DOI: 10.5194/tc-11-247-2017
Abstract: The shallow ice approximation (SIA) is commonly used in ice-sheet models to simplify the force balance equations within the ice. However, the SIA cannot adequately reproduce the dynamics of the fast flowing ice streams usually found at the margins of ice sheets. To overcome this limitation, recent studies have introduced heuristic hybrid combinations of the SIA and the shelfy stream approximation. Here, we implement four different hybrid schemes into a model of the Antarctic Ice Sheet in order to compare their performance under present-day conditions. For each scheme, the model is calibrated using an iterative technique to infer the spatial variability in basal sliding parameters. Model results are validated against topographic and velocity data. Our analysis shows that the iterative technique compensates for the differences between the schemes, producing similar ice-sheet configurations through quantitatively different results of the sliding coefficient calibration. Despite this we observe a robust agreement in the reconstructed patterns of basal sliding parameters. We exchange the calibrated sliding parameter distributions between the schemes to demonstrate that the results of the model calibration cannot be straightforwardly transferred to models based on different approximations of ice dynamics. However, easily adaptable calibration techniques for the potential distribution of basal sliding coefficients can be implemented into ice models to overcome such incompatibility, as shown in this study.
Type: article
URI: http://hdl.handle.net/2115/64418
Appears in Collections:雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

Submitter: Greve Ralf

 

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