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| Titel |
CCN activation and cloud processing in sectional aerosol models with low size resolution |
| VerfasserIn |
H. Korhonen, V.-M. Kerminen, K. E. J. Lehtinen, M. Kulmala  |
| 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 ; 5, no. 9 ; Nr. 5, no. 9 (2005-09-27), S.2561-2570 |
| Datensatznummer |
250003076
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| Publikation (Nr.) |
 copernicus.org/acp-5-2561-2005.pdf |
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| Zusammenfassung |
| We investigate the influence of low size resolution, typical to sectional
aerosol models in large scale applications, on cloud droplet activation and
cloud processing of aerosol particles. A simplified cloud model with five
approaches to determine the fraction of activated particles is compared with
a detailed reference model under different atmospheric conditions. In
general, activation approaches which assume a distribution profile within
the critical model size sections predict the cloud droplet concentration
most accurately under clean and moderately polluted conditions. In such
cases, the deviation from the reference simulations is below 15% except
for very low updraft velocities. In highly polluted cases, the concentration
of cloud droplets is significantly overestimated due to the inability of the
simplified model to account for the kinetic limitations of the droplet
growth. Of the profiles examined, taking into account the local shape of the
particle size distribution is the most accurate although in most cases the
shape of the profile has little relevance. While the low resolution cloud
model cannot reproduce the details of the out-of-the-cloud aerosol size
distribution, it captures well the amount of sulphate produced in
aqueous-phase reactions as well as the distribution of the sulphate between
the cloud droplets. Overall, the simplified cloud model with low size
resolution performs well for clean and moderately polluted regions that
cover most of the Earth's surface and is therefore suitable for large scale
models. It can, however, show uncertainties in areas with strong pollution from anthropogenic sources. |
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