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| Titel |
Summer Arctic sea ice albedo in CMIP5 models |
| VerfasserIn |
T. Koenigk, A. Devasthale, K.-G. Karlsson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 4 ; Nr. 14, no. 4 (2014-02-20), S.1987-1998 |
| Datensatznummer |
250118418
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| Publikation (Nr.) |
 copernicus.org/acp-14-1987-2014.pdf |
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| Zusammenfassung |
Spatial and temporal variations of summer sea ice albedo over the Arctic are
analyzed using an ensemble of historical CMIP5 model simulations. The results
are compared to the CLARA-SAL product that is based on long-term satellite
observations. The summer sea ice albedo varies substantially among CMIP5
models, and many models show large biases compared to the CLARA-SAL product.
Single summer months show an extreme spread of ice albedo among models; July
values vary between 0.3 and 0.7 for individual models. The CMIP5 ensemble
mean, however, agrees relatively well in the central Arctic but shows too
high ice albedo near the ice edges and coasts. In most models, the ice albedo
is spatially too uniformly distributed. The summer-to-summer variations seem
to be underestimated in many global models, and almost no model is able to
reproduce the temporal evolution of ice albedo throughout the summer fully.
While the satellite observations indicate the lowest ice albedos during
August, the models show minimum values in July and substantially higher
values in August. Instead, the June values are often lower in the models than
in the satellite observations. This is probably due to too high surface
temperatures in June, leading to an early start of the melt season and too
cold temperatures in August causing an earlier refreezing in the models. The
summer sea ice albedo in the CMIP5 models is strongly governed by surface
temperature and snow conditions, particularly during the period of melt onset
in early summer and refreezing in late summer.
The summer surface net solar radiation of the ice-covered Arctic areas is
highly related to the ice albedo in the CMIP5 models. However, the impact of
the ice albedo on the sea ice conditions in the CMIP5 models is not clearly
visible. This indicates the importance of other Arctic and large-scale
processes for the sea ice conditions. |
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