Health & Environmental Research Online (HERO)


Print Feedback Export to File
2675170 
Journal Article 
Contact freezing: a review of experimental studies 
Moreno, LAL; Stetzer, O; Lohmann, U 
2013 
Yes 
Atmospheric Chemistry and Physics
ISSN: 1680-7316
EISSN: 1680-7324 
13 
19 
9745-9769 
WOS:000325654900005 
This manuscript compiles both theoretical and experimental information on contact freezing with the aim to better understand this potentially important but still not well quantified heterogeneous freezing mode. There is no complete theory that describes contact freezing and how the energy barrier has to be overcome to nucleate an ice crystal by contact freezing. Experiments on contact freezing conducted using the cold plate technique indicate that it can initiate ice formation at warmer temperatures than immersion freezing. Additionally, a qualitative difference in the freezing temperatures between contact and immersion freezing has been found using different instrumentation and different ice nuclei. There is a lack of data on collision rates in most of the reported data, which inhibits a quantitative calculation of the freezing efficiencies. Thus, new or modified instrumentation to study contact nucleation in the laboratory and in the field are needed to identify the conditions at which contact nucleation could occur in the atmosphere. Important questions concerning contact freezing and its potential role for ice cloud formation and climate are also summarized.