Ice Nucleating Properties of Ice Residuals using Two Ice Nucleation Chambers
Abstract
Our understanding of the specific properties that govern the heterogeneous nucleation of ice are limited, and for the same reason, heterogeneous ice nucleation is very difficult to represent adequately in cloud models. In this laboratory study we evaluated the immersion freezing properties of ice residuals (IRs) at a temperature ranging from -26 to -34 degC using two continuous-flow diffusion chamber-style ice nucleation chambers coupled with a virtual impactor and heat exchanger. Ice was nucleated on the total ambient aerosol through an immersion freezing mechanism in an ice nucleation chamber (chamber 1). The larger ice crystals formed in chamber 1 were separated and sublimated to obtain IRs, and the frozen fraction of these IRs was investigated in a second ice nucleation chamber (chamber 2). We find that frozen fraction of IRs was higher than total ambient aerosol particles, but we did not see frozen fraction = 1 for IRs at warmer temperatures. This indicates that it is not necessary that all IRs will nucleate ice next time (a common perception), but sublimation process can deactivate the IRs by altering its properties.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A11H2318K
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0320 Cloud physics and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0340 Middle atmosphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3311 Clouds and aerosols;
- ATMOSPHERIC PROCESSES