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| Titel |
High sensitivity of tidewater outlet glacier dynamics to shape |
| VerfasserIn |
E. M. Enderlin, I. M. Howat, A. Vieli |
| 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 ; 7, no. 3 ; Nr. 7, no. 3 (2013-06-28), S.1007-1015 |
| Datensatznummer |
250017982
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| Publikation (Nr.) |
 copernicus.org/tc-7-1007-2013.pdf |
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| Zusammenfassung |
| Variability in tidewater outlet glacier behavior under
similar external forcing has been attributed to differences in outlet shape
(i.e., bed elevation and width), but this dependence has not been
investigated in detail. Here we use a numerical ice flow model to show that
the dynamics of tidewater outlet glaciers under external forcing are highly
sensitive to width and bed topography. Our sensitivity tests indicate that
for glaciers with similar discharge, the trunks of wider glaciers and those
grounded over deeper basal depressions tend to be closer to flotation, so
that less dynamically induced thinning results in rapid, unstable retreat
following a perturbation. The lag time between the onset of the perturbation
and unstable retreat varies with outlet shape, which may help explain
intra-regional variability in tidewater outlet glacier behavior. Further,
because the perturbation response is dependent on the thickness relative to
flotation, varying the bed topography within the range of observational
uncertainty can result in either stable or unstable retreat due to the same
perturbation. Thus, extreme care must be taken when interpreting the future
behavior of actual glacier systems using numerical ice flow models that are
not accompanied by comprehensive sensitivity analyses. |
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