 |
| Titel |
Technical Note: A numerical test-bed for detailed ice nucleation studies in the AIDA cloud simulation chamber |
| VerfasserIn |
R. J. Cotton, S. Benz, P. R. Field, O. Möhler, M. Schnaiter |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 7, no. 1 ; Nr. 7, no. 1 (2007-01-18), S.243-256 |
| Datensatznummer |
250004358
|
| Publikation (Nr.) |
 copernicus.org/acp-7-243-2007.pdf |
|
|
|
|
|
| Zusammenfassung |
The AIDA (Aerosol Interactions and Dynamics in the Atmosphere) aerosol and
cloud chamber of Forschungszentrum Karlsruhe can be used to test the ice
forming ability of aerosols. The AIDA chamber is extensively instrumented
including pressure, temperature and humidity sensors, and optical particle
counters. Expansion cooling using mechanical pumps leads to ice
supersaturation conditions and possible ice formation. In order to describe
the evolving chamber conditions during an expansion, a parcel model was modified to account for diabatic heat and
moisture interactions with the chamber walls. Model results are shown for a
series of expansions where the initial chamber temperature ranged from
−20°C to −60°C and which used desert dust as ice forming
nuclei. During each expansion, the initial formation of ice particles was
clearly observed. For the colder expansions there were two clear ice
nucleation episodes.
In order to test the ability of the model to represent the changing chamber
conditions and to give confidence in the observations of chamber temperature
and humidity, and ice particle concentration and mean size, ice particles
were simply added as a function of time so as to reproduce the observations
of ice crystal concentration. The time interval and chamber conditions over
which ice nucleation occurs is therefore accurately known, and enables the
model to be used as a test bed for different representations of ice
formation. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|