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| Titel |
Modelling snow accumulation on Greenland in Eemian, glacial inception, and modern climates in a GCM |
| VerfasserIn |
H. J. Punge, H. Gallée, M. Kageyama, G. Krinner |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 8, no. 6 ; Nr. 8, no. 6 (2012-11-05), S.1801-1819 |
| Datensatznummer |
250005970
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| Publikation (Nr.) |
 copernicus.org/cp-8-1801-2012.pdf |
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| Zusammenfassung |
| Changing climate conditions on Greenland influence the snow
accumulation rate and surface mass balance (SMB) on the ice sheet
and, ultimately, its shape. This can in turn affect local climate
via orography and albedo variations and, potentially, remote areas
via changes in ocean circulation triggered by melt water or calving
from the ice sheet. Examining these interactions in the IPSL global model
requires improving the representation of snow at the ice sheet
surface. In this paper, we present a new snow scheme implemented in LMDZ,
the atmospheric component of the IPSL coupled model. We
analyse surface climate and SMB on the Greenland ice sheet under
insolation and oceanic boundary conditions for modern, but also for
two different past climates, the last glacial inception
(115 kyr BP) and the Eemian (126 kyr BP). While being
limited by the low resolution of the general circulation model (GCM), present-day SMB is on the
same order of magnitude as recent regional model findings. It is
affected by a moist bias of the GCM in Western Greenland and a dry
bias in the north-east. Under Eemian conditions, the SMB decreases
largely, and melting affects areas in which the ice sheet surface is today at high altitude,
including recent ice core drilling sites as NEEM. In contrast,
glacial inception conditions lead to a higher mass balance overall
due to the reduced melting in the colder summer climate. Compared
to the widely applied positive degree-day (PDD) parameterization of
SMB, our direct modelling results suggest a weaker sensitivity of
SMB to changing climatic forcing.
For the Eemian climate, our model simulations using interannually varying
monthly mean forcings for the ocean surface temperature and sea ice
cover lead to significantly higher SMB in southern Greenland compared to
simulations forced with climatological monthly means. |
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