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| Titel |
A novel optical freezing array for the examination of cooling rate dependence in heterogeneous ice nucleation |
| VerfasserIn |
Carsten Budke, Katharina Dreischmeier, Thomas Koop |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093466
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| Publikation (Nr.) |
 EGU/EGU2014-8205.pdf |
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| Zusammenfassung |
| Homogeneous ice nucleation is a stochastic process, implying that it is not only
temperature but also time dependent. For heterogeneous ice nucleation it is still under
debate whether there is a significant time dependence or not. In case of minor time
dependence it is probably sufficient to use a singular or slightly modified singular
approach, which mainly supposes temperature dependence and just small stochastic
variations.
We contribute to this discussion using a novel optical freezing array termed BINARY
(Bielefeld Ice Nucleation ARraY). The setup consists of an array of microliter-sized
droplets on a Peltier cooling stage. The droplets are separated from each other with a
polydimethylsiloxane (PDMS) spacer to prevent a Bergeron-Findeisen process, in which the
first freezing droplets grow at the expense of the remaining liquid ones due to their vapor
pressure differences. An automatic detection of nucleation events is realized optically by the
change in brightness during freezing. Different types of ice nucleating agents were tested
with the presented setup, e. g. pollen and clay mineral dust. Exemplarily, cooling rate
dependent measurements are shown for the heterogeneous ice nucleation induced by
Snomax®.
The authors gratefully acknowledge funding by the German Research Foundation (DFG)
through the project BIOCLOUDS (KO 2944/1-1) and through the research unit INUIT (FOR
1525) under KO 2944/2-1. We particularly thank our INUIT partners for fruitful collaboration
and sharing of ideas and IN samples. |
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