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| Titel |
Sensitivity of basal conditions in an inverse model: Vestfonna ice cap, Nordaustlandet/Svalbard |
| VerfasserIn |
M. Schäfer, T. Zwinger, P. Christoffersen, F. Gillet-Chaulet, K. Laakso, R. Pettersson, V. A. Pohjola, T. Strozzi, J. C. Moore |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 6, no. 4 ; Nr. 6, no. 4 (2012-07-17), S.771-783 |
| Datensatznummer |
250003691
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| Publikation (Nr.) |
 copernicus.org/tc-6-771-2012.pdf |
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| Zusammenfassung |
| The dynamics of Vestfonna ice cap (Svalbard) are dominated by fast-flowing
outlet glaciers. Its mass balance is poorly known and affected dynamically by
these fast-flowing outlet glaciers. Hence, it is a challenging target for
ice flow modeling. Precise knowledge of the basal conditions and
implementation of a good sliding law are crucial for the modeling of this
ice cap. Here we use the full-Stokes finite
element code Elmer/Ice to model the 3-D flow over the whole ice cap. We use a
Robin inverse method to infer the basal friction from the surface velocities
observed in 1995. Our results illustrate the importance of the basal friction
parameter in reproducing observed velocity fields. We also show the importance
of having variable basal friction as given by the inverse method to reproduce the
velocity fields of each outlet glacier – a simple parametrization of basal
friction cannot give realistic velocities in a forward model. We study the
robustness and sensitivity of this method with respect to different
parameters (mesh characteristics, ice temperature, errors in topographic and
velocity data). The uncertainty in the observational parameters and input
data proved to be sufficiently small as not to adversely affect the fidelity of
the model. |
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