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Titel |
Shortwave radiative forcing and efficiency of key aerosol types using AERONET data |
VerfasserIn |
O. E. García, J. P. Díaz, F. J. Expósito, A. M. Díaz, O. Dubovik, Y. Derimian, P. Dubuisson, J.-C. Roger |
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 ; 12, no. 11 ; Nr. 12, no. 11 (2012-06-12), S.5129-5145 |
Datensatznummer |
250011232
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Publikation (Nr.) |
copernicus.org/acp-12-5129-2012.pdf |
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Zusammenfassung |
The shortwave radiative forcing (ΔF) and the radiative forcing
efficiency (ΔFeff) of natural and anthropogenic aerosols have
been analyzed using estimates of radiation both at the Top (TOA) and at the
Bottom Of Atmosphere (BOA) modeled based on AERONET aerosol retrievals. Six
main types of atmospheric aerosols have been compared (desert mineral dust,
biomass burning, urban-industrial, continental background, oceanic and free
troposphere) in similar observational conditions (i.e., for solar zenith
angles between 55° and 65°) in order to compare
the nearly same solar geometry. The instantaneous ΔF averages
obtained vary from −122 ± 37 Wm−2 (aerosol optical depth, AOD,
at 0.55 μm, 0.85 ± 0.45) at the BOA for the mixture of desert
mineral dust and biomass burning aerosols in West Africa and
−42 ± 22 Wm−2 (AOD = 0.9 ± 0.5) at the TOA for the pure
mineral dust also in this region up to −6 ± 3 Wm−2 and
−4 ± 2 Wm−2 (AOD = 0.03 ± 0.02) at the BOA and the TOA,
respectively, for free troposphere conditions. This last result may be taken
as reference on a global scale. Furthermore, we observe that the more
absorbing aerosols are overall more efficient at the BOA in contrast to at
the TOA, where they backscatter less solar energy into the space. The
analysis of the radiative balance at the TOA shows that, together with the
amount of aerosols and their absorptive capacity, it is essential to consider
the surface albedo of the region on which they are. Thus, we document that in
regions with high surface reflectivity (deserts and snow conditions)
atmospheric aerosols lead to a warming of the Earth-atmosphere system. |
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