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| Titel |
Direct and semi-direct impacts of absorbing biomass burning aerosol on the climate of southern Africa: a Geophysical Fluid Dynamics Laboratory GCM sensitivity study |
| VerfasserIn |
C. A. Randles, V. Ramaswamy |
| 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. 20 ; Nr. 10, no. 20 (2010-10-19), S.9819-9831 |
| Datensatznummer |
250008836
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| Publikation (Nr.) |
 copernicus.org/acp-10-9819-2010.pdf |
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| Zusammenfassung |
| Tropospheric aerosols emitted from biomass burning reduce solar radiation at
the surface and locally heat the atmosphere. Equilibrium simulations using an
atmospheric general circulation model (GFDL AGCM) indicate that strong
atmospheric absorption from these particles can cool the surface and increase
upward motion and low-level convergence over southern Africa during the dry
season. These changes increase sea level pressure over land in the biomass
burning region and spin-up the hydrologic cycle by increasing clouds,
atmospheric water vapor, and, to a lesser extent, precipitation. Cloud
increases serve to reinforce the surface radiative cooling tendency of the
aerosol. Conversely, if the climate over southern Africa were hypothetically
forced by high loadings of scattering aerosol, then the change in the
low-level circulation and increased subsidence would serve to decrease
clouds, precipitation, and atmospheric water vapor. Surface cooling
associated with scattering-only aerosols is mitigated by warming from cloud
decreases. The direct and semi-direct climate impacts of biomass burning
aerosol over southern Africa are sensitive to the total amount of aerosol
absorption and how clouds change in response to the aerosol-induced heating
of the atmosphere. |
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