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| Titel |
Black carbon semi-direct effects on cloud cover: review and synthesis |
| VerfasserIn |
D. Koch, A. D. Genio |
| 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 ; 10, no. 16 ; Nr. 10, no. 16 (2010-08-18), S.7685-7696 |
| Datensatznummer |
250008713
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| Publikation (Nr.) |
 copernicus.org/acp-10-7685-2010.pdf |
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| Zusammenfassung |
| Absorbing aerosols (AAs) such as black carbon (BC) or dust absorb incoming
solar radiation, perturb the temperature structure of the atmosphere, and
influence cloud cover. Previous studies have described conditions under
which AAs either increase or decrease cloud cover. The effect depends on
several factors, including the altitude of the AA relative to the cloud and
the cloud type. We attempt to categorize the effects into several likely
regimes. Cloud cover is decreased if the AAs are embedded in the cloud
layer. AAs below cloud may enhance convection and cloud cover. AAs above
cloud top stabilize the underlying layer and tend to enhance stratocumulus
clouds but may reduce cumulus clouds. AAs can also promote cloud cover in
convergent regions as they enhance deep convection and low level convergence
as it draws in moisture from ocean to land regions. Most global model
studies indicate a regional variation in the cloud response but generally
increased cloud cover over oceans and some land regions, with net increased
low-level and/or reduced upper level cloud cover. The result is a net
negative semi-direct effect feedback from the cloud response to AAs. In some
of these climate model studies, the cooling effect of BC due to cloud
changes is strong enough to essentially cancel the warming direct effects. |
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