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| Titel |
Present-day simulations of Vestfonna ice-cap (Svalbard) with Shallow-Ice and Full-Stokes models |
| VerfasserIn |
Martina Schäfer, Thomas Zwinger, Kati Laakso, John Moore |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250038698
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| Zusammenfassung |
| Svalbard is an archipelago in the Arctic Ocean. Nordaustlandet is the second largest island in
the archipelago. The island has two major ice-caps: Austfonna and Vestfonna. These ice-caps
on Nordaustlandet represent one of the largest ice-covered areas in the Eurasian
Arctic.
In the current project we focus on a present-day simulation of the Vestfonna ice-cap. In
this case the Vestfonna and Austfonna ice-caps can easily be modeled separately since the
two ice-caps are currently not connected. In a latter step once the dynamics of these ice-caps
is better understood, prognostic simulations over the last 120 ka including both ice-caps
together will be conducted.
Our main goals are to compare different types of ice-models (Shallow-Ice and Full
Stokes models) as well as to gain a better understanding of the occurrence of basal
sliding.
Even though low temperatures and low balance gradients generally result in low flow rates on
the glaciers of Svalbard, the Vestfonna ice-cap is characterized by fast-flow regions
(velocities over 100 m-
yr). The importance of sliding in these regions is shown and a Weertman
sliding law is adjusted to reproduce the present-day velocities as obtained from
measurements.
In this first step regions where sliding is important are identified from surface characteristics
like crevasses with the help of satellite or air-photos. Then, this purely geometrical definition
of sliding regions, will be extended to a criteria based on ice-temperature or water-content for
prognostic simulations.
The models used are a Full Stokes Finite Element Model (Elmer) as well as a Shallow-Ice
approximation model (Sicopolis). Both model outputs as well as present-day measurements
will be compared.
Data access was made possible by the Kinnvika IPY project consortium.
References:
Elmer: http://www.csc.fi/english/pages/elmer
Sicopolis: http://sicopolis.greveweb.net/ (Ralf Greve)
Kinnvika: http://www.kinnvika.net/ |
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