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| Titel |
Volume nucleation rates for homogeneous freezing in supercooled water microdroplets: results from a combined experimental and modelling approach |
| VerfasserIn |
M. E. Earle, T. Kuhn, A. F. Khalizov, J. J. Sloan |
| 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 ; 10, no. 16 ; Nr. 10, no. 16 (2010-08-27), S.7945-7961 |
| Datensatznummer |
250008730
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| Publikation (Nr.) |
 copernicus.org/acp-10-7945-2010.pdf |
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| Zusammenfassung |
| Temperature-dependent volume nucleation rate coefficients for supercooled
water droplets, JV(T), are derived from infrared extinction measurements in
a cryogenic laminar aerosol flow tube using a microphysical model. The model
inverts water and ice aerosol size distributions retrieved from experimental
extinction spectra by considering the evolution of a measured initial
droplet distribution via homogeneous nucleation and the exchange of
vapour-phase water along a well-defined temperature profile. Experiment and
model results are reported for supercooled water droplets with mean radii of
1.0, 1.7, and 2.9 μm. Values of mass accommodation coefficients for
evaporation of water droplets and vapour deposition on ice particles are
also determined from the model simulations. The coefficient for ice
deposition was found to be 0.031 ± 0.001, while that for water
evaporation was 0.054 ± 0.012. Results are considered in terms of the
applicability of classical nucleation theory to the freezing of
micrometre-sized droplets in cirrus clouds, with implications for the
parameterization of homogeneous ice nucleation in numerical models. |
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