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| Titel |
Parameterization of homogeneous ice nucleation for cloud and climate models based on classical nucleation theory |
| VerfasserIn |
V. I. Khvorostyanov, J. A. Curry |
| 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 ; 12, no. 19 ; Nr. 12, no. 19 (2012-10-11), S.9275-9302 |
| Datensatznummer |
250011505
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| Publikation (Nr.) |
 copernicus.org/acp-12-9275-2012.pdf |
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| Zusammenfassung |
A new analytical parameterization of homogeneous ice nucleation is developed
based on extended classical nucleation theory including new equations for
the critical radii of the ice germs, free energies and nucleation rates as
simultaneous functions of temperature and water saturation ratio. By
representing these quantities as separable products of the analytical
functions of temperature and supersaturation, analytical solutions are found
for the integral-differential supersaturation equation and concentration of
nucleated crystals. Parcel model simulations are used to illustrate the
general behavior of various nucleation properties under various conditions,
for justifications of the further key analytical simplifications, and for
verification of the resulting parameterization.
The final parameterization is based upon the values of the supersaturation
that determines the current or maximum concentrations of the nucleated ice
crystals. The crystal concentration is analytically expressed as a function
of time and can be used for parameterization of homogeneous ice nucleation
both in the models with small time steps and for substep parameterization in
the models with large time steps. The crystal concentration is expressed
analytically via the error functions or elementary functions and depends
only on the fundamental atmospheric parameters and parameters of classical
nucleation theory. The diffusion and kinetic limits of the new
parameterization agree with previous semi-empirical parameterizations. |
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