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| Titel |
Grounding-line migration in plan-view marine ice-sheet models: results of the ice2sea MISMIP3d intercomparison |
| VerfasserIn |
Frank Pattyn, Laura Perichon, Gael Durand, Olivier Gagliardini, Lionel Favier, Richard Hindmarsh, Thomas Zwinger, MISMIP3d participants |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250073538
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| Zusammenfassung |
| Predictions of marine ice-sheet behaviour require models able to simulate grounding line
migration. We present results of an intercomparison experiment for plan-view marine
ice-sheet models. Verification is effected by comparison with approximate analytical
solutions for flux across the grounding line using simplified geometrical configurations (no
lateral variations, no buttressing effects from lateral drag). A unique steady state grounding
line position exists for ice sheets on a downward sloping bed under those simplified
conditions. Perturbation experiments specifying spatial (lateral) variation in basal sliding
parameters permitted the evolution of curved grounding lines, generating buttressing effects.
The experiments showed regions of compression and extensional flow across the grounding
line, thereby invalidating the boundary layer theory. Models based on the shallow
ice approximation, which neither resolve membrane stresses, nor reproduce the
approximate analytical results unless appropriate parameterizations for ice flux are
imposed at the grounding line, are invalid. Steady-state grounding line positions were
found to be dependent on the level of physical model approximation. Models that
only include membrane stresses result in ice sheets with a larger span than those
that also incorporate vertical shearing at the grounding line, such as higher-order
and full-Stokes models. From a numerical perspective, resolving grounding lines
requires a sufficiently small grid size ( |
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