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| Titel |
Three-dimensional full-Stokes modelling of the grounding line dynamics |
| VerfasserIn |
Lionel Favier, Olivier Gagliardini, Gael Durand, Thomas Zwinger |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250046916
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| Zusammenfassung |
| The West part of Antarctica is mostly constituted of floating marine ice shelves, connected to
the continent through grounded ice streams. The dynamics of the grounding line, i.e. the line
dividing the grounded ice stream from the downstream ice shelf, has a major influence on the
whole ice sheet mass balance. Most of the ice-sheet models use simplifications of the flow
equations (do not include all the stress gradients) and are known to incorrectly represent the
dynamics of the grounding line dynamics. Recently, parametrization of the ice flux
at the grounding line has been proposed in the idealistic case of a 2D flow line
model (Schoof 2007 JGR), and is pragmatically exported to 3D ice sheet models
(Pollard 2009 Nature). Here, we present prognostic simulations based on numerical
solutions of the full-Stokes equations for the dynamics of marine ice sheets. A
contact problem is solved to determine where ice is floating or in contact to the
bedrock, in order to compute the grounding line position, around which a constant and
refined grid is maintained by the use of moving mesh techniques. Such an approach,
recently developed and validated for 2D flow line simulations, is here extended to
more realistic 3D geometries. Simulations are performed using the open-source
finite-element code Elmer/Ice deploying parallel computing techniques. The 3D version of
the model is first evaluated using a simple geometry extruded from 2D results.
Then, starting from an initial steady state, various perturbations in the mechanical
properties, the bed topography and the basal friction, spatially uniform or not, are
applied. Such an approach allows to evaluate the validity of a flux parametrization
in 2D and investigate the validity of using such a parametrization in a 3D case. |
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