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| Titel |
Hindcasting to measure ice sheet model sensitivity to initial states |
| VerfasserIn |
A. Aschwanden, G. Aðalgeirsdóttir, C. Khroulev |
| 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. 4 ; Nr. 7, no. 4 (2013-07-10), S.1083-1093 |
| Datensatznummer |
250017987
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| Publikation (Nr.) |
 copernicus.org/tc-7-1083-2013.pdf |
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| Zusammenfassung |
| Validation is a critical component of model
development, yet notoriously challenging in ice sheet modeling. Here
we evaluate how an ice sheet system model responds to a given
forcing. We show that hindcasting, i.e. forcing a model with known or
closely estimated inputs for past events to see how well the output
matches observations, is a viable method of assessing model
performance. By simulating the recent past of Greenland, and comparing
to observations of ice thickness, ice discharge, surface speeds, mass
loss and surface elevation changes for validation, we find that the
short term model response is strongly influenced by the initial
state. We show that the thermal and dynamical states (i.e. the
distribution of internal energy and momentum) can be misrepresented
despite a good agreement with some observations, stressing the
importance of using multiple observations. In particular we identify
rates of change of spatially dense observations as preferred
validation metrics. Hindcasting enables a qualitative assessment of
model performance relative to observed rates of change. It thereby
reduces the number of admissible initial states more rigorously than
validation efforts that do not take advantage of observed rates of
change. |
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