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| Titel |
Ice nucleation properties of mineral dust particles: determination of onset RHi, IN active fraction, nucleation time-lag, and the effect of active sites on contact angles |
| VerfasserIn |
G. Kulkarni, S. Dobbie |
| 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. 1 ; Nr. 10, no. 1 (2010-01-08), S.95-105 |
| Datensatznummer |
250007894
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| Publikation (Nr.) |
 copernicus.org/acp-10-95-2010.pdf |
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| Zusammenfassung |
| A newly developed ice nucleation experimental set up was used to investigate
the heterogeneous ice nucleation properties of three Saharan and one Spanish
dust particle samples. It was observed that the spread in the onset relative
humidities with respect to ice (RHi) for Saharan dust particles varied
from 104% to 110%, whereas for the Spanish dust from 106% to
110%. The elemental composition analysis shows a prominent Ca feature in
the Spanish dust sample which could potentially explain the differences in
nucleation threshold. Although the spread in the onset RHi for the
three Saharan dust samples were in agreement, the active fractions and
nucleation time-lags calculated at various temperature and RHi
conditions were found to differ. This could be due to the subtle variation
in the elemental composition of the dust samples, and surface irregularities
like steps, cracks, cavities etc. A combination of classical nucleation
theory and active site theory is used to understand the importance of these
surface irregularities on the nucleability parameter, contact angle that is
widely used in ice cloud modeling. These calculations show that the surface
irregularities can reduce the contact angle by approximately 10 degrees. |
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