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| Titel |
Sensitivity of Greenland Ice Sheet surface mass balance to surface albedo parameterization: a study with a regional climate model |
| VerfasserIn |
J. H. Angelen, J. T. M. Lenaerts, S. Lhermitte, X. Fettweis, P. Kuipers Munneke, M. R. Broeke, E. Meijgaard, C. J. P. P. Smeets |
| 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 (2012-10-23), S.1175-1186 |
| Datensatznummer |
250003795
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| Publikation (Nr.) |
 copernicus.org/tc-6-1175-2012.pdf |
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| Zusammenfassung |
| We present a sensitivity study of the surface mass balance (SMB) of the
Greenland Ice Sheet, as modeled using a regional atmospheric climate model,
to various parameter settings in the albedo scheme. The snow albedo scheme
uses grain size as a prognostic variable and further depends on cloud cover,
solar zenith angle and black carbon concentration. For the control experiment
the overestimation of absorbed shortwave radiation (+6%) at the K-transect
(west Greenland) for the period 2004–2009 is considerably reduced compared
to the previous density-dependent albedo scheme (+22%). To simulate
realistic snow albedo values, a small concentration of black carbon is
needed, which has strongest impact on melt in the accumulation area. A
background ice albedo field derived from MODIS imagery improves the agreement
between the modeled and observed SMB gradient along the K-transect. The
effect of enhanced meltwater retention and refreezing is a decrease of the
albedo due to an increase in snow grain size. As a secondary effect of
refreezing the snowpack is heated, enhancing melt and further lowering the
albedo. Especially in a warmer climate this process is important, since it
reduces the refreezing potential of the firn layer that covers the Greenland
Ice Sheet. |
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