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| Titel |
Upper air relaxation in regional climate model improves resolved interannual variability of the surface mass balance of Antarctica |
| VerfasserIn |
Willem Jan van de Berg, Brooke Medley, Erik van Meijgaard |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250110441
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| Publikation (Nr.) |
 EGU/EGU2015-10436.pdf |
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| Zusammenfassung |
| The surface mass balance (SMB) determines the variability of the mass balance of the
Antarctic Ice sheet on sub-decadal timescales. Since continent-wide SMB cannot
be measured, it must be modeled and regional climate models (RCMs) generally
outperform global reanalyses in the representation of total mass flux and the spatial
distribution of SMB. However, if RCMs are only forced with reanalysis on their lateral
boundaries, the representation of the interannual variability of SMB deteriorates
significantly.
In this study we show how to improve the resolved interannual variability in RCM
modeled SMB. For this purpose we use annual SMB observations in the Thwaites
drainage basin in Antarctica derived from airborne radar reflections and the RCM
RACMO2. RACMO2, driven by ERA-Interim, better represents the mean spatial
SMB pattern in this basin than ERA-Interim. However, without relaxation in the
interior, RACMO2 poorly resolves the observed interannual SMB variability. If we
gently relax the temperature and wind field in the upper atmosphere in RACMO2 to
ERA-Interim, RACMO2 gets the best of both. Upper air relaxation little changes
the mean SMB and spatial pattern compared to the original RACMO2 output, but
allows RACMO2 to resolve the observed interannual SMB as good as ERA-Interim. |
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