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| Titel |
A three-dimensional full Stokes model of the grounding line dynamics: effect of a pinning point beneath the ice shelf |
| VerfasserIn |
L. Favier, O. Gagliardini, G. Durand, T. Zwinger |
| 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. 1 ; Nr. 6, no. 1 (2012-01-20), S.101-112 |
| Datensatznummer |
250003377
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| Publikation (Nr.) |
 copernicus.org/tc-6-101-2012.pdf |
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| Zusammenfassung |
| The West Antarctic ice sheet is confined by a large area of ice shelves, fed
by inland ice through fast flowing ice streams. The dynamics of the grounding
line, which is the line-boundary between grounded ice and the downstream ice
shelf, has a major influence on the dynamics of the whole ice sheet. However,
most ice sheet models use simplifications of the flow equations, as they do
not include all the stress components, and are known to fail in their
representation of the grounding line dynamics. Here, we present a 3-D full
Stokes model of a marine ice sheet, in which the flow problem is coupled with
the evolution of the upper and lower free surfaces, and the position of the
grounding line is determined by solving a contact problem between the
shelf/sheet lower surface and the bedrock. Simulations are performed using
the open-source finite-element code Elmer/Ice within a parallel environment.
The model's ability to cope with a curved grounding line and the effect of a
pinning point beneath the ice shelf are investigated through prognostic
simulations. Starting from a steady state, the sea level is slightly
decreased to create a contact point between a seamount and the ice shelf. The
model predicts a dramatic decrease of the shelf velocities, leading to an
advance of the grounding line until both grounded zones merge together,
during which an ice rumple forms above the contact area at the pinning point.
Finally, we show that once the contact is created, increasing the sea level
to its initial value does not release the pinning point and has no effect on
the ice dynamics, indicating a stabilising effect of pinning points. |
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