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| Titel |
Future projections of the Greenland ice sheet energy balance driving the surface melt |
| VerfasserIn |
B. Franco, X. Fettweis, M. Erpicum |
| 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. 1 ; Nr. 7, no. 1 (2013-01-02), S.1-18 |
| Datensatznummer |
250004441
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| Publikation (Nr.) |
 copernicus.org/tc-7-1-2013.pdf |
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| Zusammenfassung |
| In this study, simulations at 25 km resolution are performed over the Greenland
ice sheet (GrIS) throughout the 20th and 21st centuries, using the regional climate
model MAR forced by four RCP scenarios from three CMIP5 global circulation models
(GCMs), in order to investigate the projected changes of the surface energy balance
(SEB) components driving the surface melt. Analysis of 2000–2100 melt anomalies
compared to melt results over 1980–1999 reveals an exponential relationship of
the GrIS surface melt rate simulated by MAR to the near-surface air temperature
(TAS) anomalies, mainly due to the surface albedo positive feedback associated
with the extension of bare ice areas in summer. On the GrIS margins, the future
melt anomalies are preferentially driven by stronger sensible heat fluxes, induced
by enhanced warm air advection over the ice sheet. Over the central dry snow
zone, the surface albedo positive feedback induced by the increase in summer melt
exceeds the negative feedback of heavier snowfall for TAS anomalies higher than
4 °C. In addition to the incoming longwave flux increase associated with
the atmosphere warming, GCM-forced MAR simulations project an increase of the cloud
cover decreasing the ratio of the incoming shortwave versus longwave radiation and
dampening the albedo feedback. However, it should be noted that this trend in the
cloud cover is contrary to that simulated by ERA-Interim–forced MAR for recent
climate conditions, where the observed melt increase since the 1990s seems mainly
to be a consequence of more anticyclonic atmospheric conditions. Finally, no
significant change is projected in the length of the melt season, which
highlights the importance of solar radiation absorbed by the ice sheet surface
in the melt SEB. |
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