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| Titel |
An iterative inverse method to estimate basal topography and initialize ice flow models |
| VerfasserIn |
W. J. J. Pelt, J. Oerlemans  , C. H. Reijmer, R. Pettersson, V. A. Pohjola, E. Isaksson, D. Divine |
| 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 (2013-06-25), S.987-1006 |
| Datensatznummer |
250017981
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| Publikation (Nr.) |
 copernicus.org/tc-7-987-2013.pdf |
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| Zusammenfassung |
| We evaluate an inverse approach to reconstruct distributed bedrock topography
and simultaneously initialize an ice flow model. The inverse method involves
an iterative procedure in which an ice dynamical model (PISM) is run multiple
times over a prescribed period, while being forced with space- and
time-dependent climate input. After every iteration bed heights are adjusted
using information of the remaining misfit between observed and modeled
surface topography. The inverse method is first applied in synthetic
experiments with a constant climate forcing to verify convergence and
robustness of the approach in three dimensions. In a next step, the inverse
approach is applied to Nordenskiöldbreen, Svalbard, forced with height- and
time-dependent climate input since 1300 AD. An L-curve stopping criterion is
used to prevent overfitting. Validation against radar data reveals a high
correlation (up to R = 0.89) between modeled and observed thicknesses.
Remaining uncertainties can mainly be ascribed to inaccurate model physics,
in particular, uncertainty in the description of sliding. Results demonstrate
the applicability of this inverse method to reconstruct the ice thickness
distribution of glaciers and ice caps. In addition to reconstructing bedrock
topography, the method provides a direct tool to initialize ice flow models
for forecasting experiments. |
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