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| Titel |
The Arctic response to remote and local forcing of black carbon |
| VerfasserIn |
M. Sand, T. K. Berntsen, J. E. Kay, J. F. Lamarque, Ø. Seland, A. Kirkevåg |
| 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 ; 13, no. 1 ; Nr. 13, no. 1 (2013-01-09), S.211-224 |
| Datensatznummer |
250017547
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| Publikation (Nr.) |
 copernicus.org/acp-13-211-2013.pdf |
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| Zusammenfassung |
| Recent studies suggest that the Arctic temperature response to black carbon
(BC) forcing depend strongly on the location of the forcing. We investigate
how atmospheric BC in the mid-latitudes remotely influence the Arctic
climate, and compare this with the response to atmospheric BC located in the
Arctic itself. In this study, idealized climate simulations are carried out
with a fully coupled Earth System Model, which includes a comprehensive
treatment of aerosol microphysics. In order to determine how BC transported
to the Arctic and BC sources not reaching the Arctic impact the Arctic
climate, atmospheric BC concentrations are scaled up in the mid-latitudes
(28–60° N) and in the Arctic (60–90° N), respectively. Estimates of the impact
on the Arctic energy budget are represented by analyzing radiation fluxes at
the top of the atmosphere and at the surface, surface turbulent fluxes, and
meridional heat transport in the atmosphere. Our calculations show that
increased BC forcing in the Arctic atmosphere reduces the surface air
temperature in the Arctic with a corresponding increase in the sea-ice
fraction, despite the increased planetary absorption of sunlight. The
analysis indicates that this effect is due to a combination of a
weakening of the northward heat transport caused by a reduction in the
meridional temperature gradient and a dimming at the surface. On the other
hand we find that BC forcing at the mid-latitudes warms the Arctic surface
significantly and decreases the sea-ice fraction. Our model calculations
indicate that atmospheric BC forcing outside the Arctic may be more
important for the Arctic climate change than the forcing in the Arctic
itself. These results suggest that mitigation strategies for the Arctic
climate should also address BC sources in locations outside the Arctic even
if they do not contribute much to BC in the Arctic. |
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