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| Titel |
Reconstructing basal boundary conditions in a regional ice sheet model: Application to Jakobshavn Isbræ |
| VerfasserIn |
M. Habermann, D. A. Maxwell, M. Truffer |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250058774
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| Zusammenfassung |
| A crucial assumption in all ice sheet models concerns the nature and parametrization of the
basal boundary condition. Direct observations on large spatial scales are not possible, but
inverse methods can be used to determine the distribution of basal properties from surface
measurements. We developed open-source iterative inverse algorithms and applied them to
PISM, a hybrid ice sheet model that solves a combination of the Shallow Ice and
Shallow Shelf Approximations. In a regional-scale model of Jakobshavn Isbræ,
the fastest flowing ice stream of Greenland, we invert for basal stickiness over the
entire drainage basin. The sensitivity of the reconstructed basal stickiness to the
following modeling choices is evaluated: temperature distribution within the ice,
definition of the misfit functional, tolerance for the stopping criterion and initial
estimates of basal stickiness. The effects and the management of missing data are
analyzed.
In 2002 the floating tongue of Jakobshavn Isbræ disintegrated catastrophically, leading to
increased speeds and rapid thinning of the inland ice. Detailed velocity maps from before and
after this breakup allow us to compare retrieved basal parameters and to track the continuing
evolution of the basal boundary condition. |
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