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| Titel |
A continuous spectral aerosol-droplet microphysics model |
| VerfasserIn |
Z. J. Lebo, J. H. Seinfeld |
| 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. 23 ; Nr. 11, no. 23 (2011-12-08), S.12297-12316 |
| Datensatznummer |
250010251
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| Publikation (Nr.) |
 copernicus.org/acp-11-12297-2011.pdf |
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| Zusammenfassung |
| A two-dimensional (2-D) continuous spectral aerosol-droplet microphysics
model is presented and implemented into the Weather Research and Forecasting
(WRF) model for large-eddy simulations (LES) of warm clouds. Activation and
regeneration of aerosols are treated explicitly in the calculation of
condensation/evaporation. The model includes a 2-D spectrum that encompasses
wet aerosol particles (i.e., haze droplets), cloud droplets, and drizzle
droplets in a continuous and consistent manner and allows for the explicit
tracking of aerosol size within cloud droplets due to collision-coalescence.
The system of differential equations describing condensation/evaporation
(i.e., mass conservation and energy conservation) is solved simultaneously
within each grid cell. The model is demonstrated by simulating a marine
stratocumulus deck for two different aerosol loadings (100 and
500 cm−3), and comparison with the more traditional microphysics
modeling approaches (both 1-D bin and bulk schemes) is evaluated. The
simulations suggest that in a 1-D bin microphysics scheme, without
regeneration, too few particles are produced and hence the mode of the
droplet size spectrum occurs at a larger size relative to the 2-D bin model
results. Moreover, with regeneration, the 1-D scheme produces too many small
droplets and thus shifts the mode toward smaller sizes. These large shifts in
the droplet size distribution can potentially have significant effects on the
efficiency of the collision-coalescence process, fall speeds, and ultimately
precipitation. |
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