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Titel |
Coupling of climate models and ice sheet models by surface mass balance gradients: application to the Greenland Ice Sheet |
VerfasserIn |
M. M. Helsen, R. S. W. Wal, M. R. Broeke, W. J. Berg, J. Oerlemans |
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 ; 6, no. 2 ; Nr. 6, no. 2 (2012-03-08), S.255-272 |
Datensatznummer |
250003476
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Publikation (Nr.) |
copernicus.org/tc-6-255-2012.pdf |
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Zusammenfassung |
It is notoriously difficult to couple surface mass balance (SMB) results from
climate models to the changing geometry of an ice sheet model. This problem
is traditionally avoided by using only accumulation from a climate model, and
parameterizing the meltwater run-off as a function of temperature, which is
often related to surface elevation (Hs). In this study, we propose a
new strategy to calculate SMB, to allow a direct adjustment of SMB to a
change in ice sheet topography and/or a change in climate forcing. This
method is based on elevational gradients in the SMB field as computed by a
regional climate model. Separate linear relations are derived for ablation
and accumulation, using pairs of Hs and SMB within a minimum search
radius. The continuously adjusting SMB forcing is consistent with climate
model forcing fields, also for initially non-glaciated areas in the
peripheral areas of an ice sheet. When applied to an asynchronous coupled ice
sheet – climate model setup, this method circumvents traditional temperature
lapse rate assumptions. Here we apply it to the Greenland Ice Sheet (GrIS).
Experiments using both steady-state forcing and glacial-interglacial forcing
result in realistic ice sheet reconstructions. |
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