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| Titel |
Estimates of aerosol radiative forcing from the MACC re-analysis |
| VerfasserIn |
N. Bellouin, J. Quaas, J.-J. Morcrette, O. Boucher |
| 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. 4 ; Nr. 13, no. 4 (2013-02-21), S.2045-2062 |
| Datensatznummer |
250018424
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| Publikation (Nr.) |
 copernicus.org/acp-13-2045-2013.pdf |
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| Zusammenfassung |
| The European Centre for Medium-range Weather Forecast (ECMWF) provides an
aerosol re-analysis starting from year 2003 for the Monitoring Atmospheric
Composition and Climate (MACC) project. The re-analysis assimilates total
aerosol optical depth retrieved by the Moderate Resolution Imaging
Spectroradiometer (MODIS) to correct for model departures from observed
aerosols. The re-analysis therefore combines satellite retrievals with the
full spatial coverage of a numerical model. Re-analysed products are used
here to estimate the shortwave direct and first indirect radiative forcing of
anthropogenic aerosols over the period 2003–2010, using methods previously
applied to satellite retrievals of aerosols and clouds. The best estimate of
globally-averaged, all-sky direct radiative forcing is
−0.7 ± 0.3 Wm−2. The standard deviation is obtained by a
Monte-Carlo analysis of uncertainties, which accounts for uncertainties in
the aerosol anthropogenic fraction, aerosol absorption, and cloudy-sky
effects. Further accounting for differences between the present-day natural
and pre-industrial aerosols provides a direct radiative forcing estimate of
−0.4 ± 0.3 Wm−2. The best estimate of globally-averaged,
all-sky first indirect radiative forcing is
−0.6 ± 0.4 Wm−2. Its standard deviation accounts for
uncertainties in the aerosol anthropogenic fraction, and in cloud albedo and
cloud droplet number concentration susceptibilities to aerosol changes. The
distribution of first indirect radiative forcing is asymmetric and is bounded
by −0.1 and −2.0 Wm−2. In order to decrease uncertainty ranges,
better observational constraints on aerosol absorption and sensitivity of
cloud droplet number concentrations to aerosol changes are required. |
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