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| Titel |
On the discrepancies between theoretical and measured below-cloud particle scavenging coefficients for rain – a numerical investigation using a detailed one-dimensional cloud microphysics model |
| VerfasserIn |
X. Wang, L. Zhang, M. D. Moran |
| 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 ; 11, no. 22 ; Nr. 11, no. 22 (2011-11-29), S.11859-11866 |
| Datensatznummer |
250010224
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| Publikation (Nr.) |
 copernicus.org/acp-11-11859-2011.pdf |
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| Zusammenfassung |
| Existing theoretical formulations for the size-resolved scavenging
coefficient Λ(d) for atmospheric aerosol particles scavenged by rain predict
values lower by one to two orders of magnitude than those estimated from
field measurements of particle-concentration changes for particles smaller
than 3 μm in diameter. Vertical turbulence is not accounted for in the
theoretical formulations of Λ(d) but does contribute to the
field-derived estimates of Λ(d) due to its influence on the overall
concentration changes of aerosol particles in the layers undergoing
impaction scavenging. A detailed one-dimensional cloud microphysics model
has been used to simulate rain production and below-cloud particle
scavenging, and to quantify the contribution of turbulent diffusion to the
overall Λ(d) values calculated from particle concentration changes. The
relative contribution of vertical diffusion to below-cloud scavenging is
found to be largest for submicron particles under weak precipitation
conditions. The discrepancies between theoretical and field-derived
Λ(d) values can largely be explained by the contribution of vertical diffusion
to below-cloud particle scavenging for all particles larger than 0.01 μm
in diameter for which field data are available. The results presented
here suggest that the current theoretical framework for Λ(d) can provide a
reasonable approximation of below-cloud aerosol particle scavenging by rain
in size-resolved aerosol transport models if vertical diffusion is also
considered by the models. |
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