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| Titel |
A steady-state analysis of the temperature responses of water vapor and aerosol lifetimes |
| VerfasserIn |
G.-J. Roelofs |
| 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. 16 ; Nr. 13, no. 16 (2013-08-21), S.8245-8254 |
| Datensatznummer |
250085639
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| Publikation (Nr.) |
 copernicus.org/acp-13-8245-2013.pdf |
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| Zusammenfassung |
| The dominant removal mechanism of soluble aerosol is wet deposition. The
atmospheric lifetime of aerosol, relevant for aerosol radiative forcing, is
therefore coupled to the atmospheric cycling time of water vapor. This study
investigates the coupling between water vapor and aerosol lifetimes in a
well-mixed atmosphere. Based on a steady-state study by Pruppacher and
Jaenicke (1995) we describe the coupling in terms of the processing
efficiency of air by clouds and the efficiencies of water vapor
condensation, of aerosol activation, and of the transfer from cloud water to
precipitation. We extend this to expressions for the temperature responses
of the water vapor and aerosol lifetimes. Previous climate model results
(Held and Soden, 2006) suggest a water vapor lifetime temperature response
of +5.3 ± 2.0% K−1. This can be used as a first guess for the
aerosol lifetime temperature response, but temperature sensitivities of the
aerosol lifetime simulated in recent aerosol–climate model studies extend
beyond this range and include negative values. This indicates that other
influences probably have a larger impact on the computed aerosol lifetime
than its temperature response, more specifically changes in the spatial
distributions of aerosol (precursor) emissions and precipitation patterns,
and changes in the activation efficiency of aerosol. These are not
quantitatively evaluated in this study but we present suggestions for model
experiments that may help to understand and quantify the different factors
that determine the aerosol atmospheric lifetime. |
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