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| Titel |
A simple inverse method for the distribution of basal sliding coefficients under ice sheets, applied to Antarctica |
| VerfasserIn |
D. Pollard, R. M. DeConto |
| 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. 5 ; Nr. 6, no. 5 (2012-09-12), S.953-971 |
| Datensatznummer |
250003780
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| Publikation (Nr.) |
 copernicus.org/tc-6-953-2012.pdf |
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| Zusammenfassung |
| Variations in intrinsic bed conditions that affect basal sliding, such as
the distribution of deformable sediment versus hard bedrock, are important
boundary conditions for large-scale ice-sheet models, but are hard to
observe and remain largely uncertain below the modern Greenland and
Antarctic ice sheets. Here a very simple model-based method is described for
deducing the modern spatial distribution of basal sliding coefficients. The
model is run forward in time, and the basal sliding coefficient at each grid
point is periodically increased or decreased depending on whether the
local ice surface elevation is too high or too low compared to observed in areas
of unfrozen bed. The method considerably reduces large-scale errors in
Antarctic ice elevation, from several 100s to several 10s of meters in most
regions. Remaining ice elevation errors over mountain ranges such as the
Transantarctics are further improved by parameterizing the possible effect
of sub-grid topography in the basal sliding law, representing sliding in
deep valleys. Results are compared with modern velocity data, and various
sensitivity tests are described in Appendices. |
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