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| Titel |
Parameterizing the competition between homogeneous and heterogeneous freezing in ice cloud formation – polydisperse ice nuclei |
| VerfasserIn |
D. Barahona, A. Nenes |
| 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 ; 9, no. 16 ; Nr. 9, no. 16 (2009-08-19), S.5933-5948 |
| Datensatznummer |
250007578
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| Publikation (Nr.) |
 copernicus.org/acp-9-5933-2009.pdf |
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| Zusammenfassung |
| This study presents a comprehensive ice cloud formation parameterization
that computes the ice crystal number, size distribution, and maximum
supersaturation from precursor aerosol and ice nuclei. The parameterization
provides an analytical solution of the cloud parcel model equations and
accounts for the competition effects between homogeneous and heterogeneous
freezing, and, between heterogeneous freezing in different modes. The
diversity of heterogeneous nuclei is described through a nucleation spectrum
function which is allowed to follow any form (i.e., derived from classical
nucleation theory or from observations). The parameterization reproduces the
predictions of a detailed numerical parcel model over a wide range of
conditions, and several expressions for the nucleation spectrum. The average
error in ice crystal number concentration was −2.0±8.5% for
conditions of pure heterogeneous freezing, and, 4.7±21% when both
homogeneous and heterogeneous freezing were active. The formulation
presented is fast and free from requirements of numerical integration. |
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