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| Titel |
Experimental investigation of homogeneous freezing of sulphuric acid particles in the aerosol chamber AIDA |
| VerfasserIn |
O. Möhler, O. Stetzer, S. Schaefers, C. Linke, M. Schnaiter, R. Tiede, H. Saathoff, M. Krämer, A. Mangold, P. Budz, P. Zink, J. Schreiner, K. Mauersberger, W. Haag, B. Kärcher, U. Schurath |
| 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 ; 3, no. 1 ; Nr. 3, no. 1 (2003-02-20), S.211-223 |
| Datensatznummer |
250000720
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| Publikation (Nr.) |
 copernicus.org/acp-3-211-2003.pdf |
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| Zusammenfassung |
| The homogeneous freezing of supercooled
H2SO4/H2O solution droplets was investigated in the aerosol chamber AIDA
(Aerosol Interactions and Dynamics in the Atmosphere) of Forschungszentrum
Karlsruhe. 24 freezing experiments were performed at temperatures between
189 and 235 K with aerosol particles in the diameter range 0.05 to 1 µm. Individual experiments started at homogeneous temperatures and
ice saturation ratios between 0.9 and 0.95. Cloud cooling rates up to -2.8
K min-1 were simulated dynamically in the chamber by expansion cooling using a mechanical pump. Depending on
the cooling rate and starting temperature, freezing threshold relative humidities were exceeded after expansion time periods
between about 1 and 10 min. The onset of ice formation was measured with three independent methods showing good agreement
among each other. Ice saturation ratios measured at the onset of ice formation increased from about
1.4 at 231 K to about 1.75 at 189 K. The experimental data set including
thermodynamic parameters as well as physical and chemical aerosol analysis provides a good basis for microphysical model applications. |
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