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| Titel |
The importance of interstitial particle scavenging by cloud droplets in shaping the remote aerosol size distribution and global aerosol-climate effects |
| VerfasserIn |
J. R. Pierce, B. Croft, J. K. Kodros, S. D. D'Andrea, R. V. Martin |
| 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 ; 15, no. 11 ; Nr. 15, no. 11 (2015-06-05), S.6147-6158 |
| Datensatznummer |
250119790
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| Publikation (Nr.) |
 copernicus.org/acp-15-6147-2015.pdf |
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| Zusammenfassung |
| In this paper, we investigate the coagulation of interstitial aerosol
particles (particles too small to activate to cloud droplets) with cloud
drops, a process often ignored in aerosol-climate models. We use the
GEOS-Chem-TOMAS (Goddard Earth Observing System-Chemistry TwO-Moment Aerosol
Sectional) global chemical transport model with aerosol microphysics to
calculate the changes in the aerosol size distribution, cloud-albedo aerosol
indirect effect, and direct aerosol effect due to the interstitial
coagulation process. We find that inclusion of interstitial coagulation in
clouds lowers total particle number concentrations by 15–21% globally,
where the range is due to varying assumptions regarding activation diameter,
cloud droplet size, and ice cloud physics. The interstitial coagulation
process lowers the concentration of particles with dry diameters larger than
80 nm (a proxy for larger CCN) by 10–12%. These 80 nm particles are
not directly removed by the interstitial coagulation but are reduced in
concentration because fewer smaller particles grow to diameters larger than
80 nm. The global aerosol indirect effect of adding interstitial coagulation
varies from +0.4 to +1.3 W m−2 where again the range depends on
our cloud assumptions. Thus, the aerosol indirect effect of this process is
significant, but the magnitude depends greatly on assumptions regarding
activation diameter, cloud droplet size, and ice cloud physics. The aerosol
direct effect of the interstitial coagulation process is minor
(< 0.01 W m−2) due to the shift in the aerosol size distribution at
sizes where scattering is most effective being small. We recommend that this
interstitial scavenging process be considered in aerosol models when the size
distribution and aerosol indirect effects are important. |
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