RESUME / ABSTRACT  




Microphysics of cold clouds



par/by

Alexei Korolev

Cloud Physics and Severe Weather Research Division






Results of in-situ measurements of microphysics of cold clouds will be presented here. The data were collected from the NRC Convair-580 during seven field campaigns between 1994 and 2004.

The presentation will be focused on following issues:

1.Ice particle habits from in-situ measurements. Occurrence of different habits versus temperature. Occurrence of pristine ice forms (hexagonal columns and plates). Aspect ratio and roundness of ice particles.

2. Microphysics of mixed phase and ice clouds. Ice water fraction (IWC/TWC) at different temperatures, ice and droplet concentrations, LWC, IWC, TWC, ice particle sizes vs. temperature. Occurrences of ice, liquid and mixed phase clouds. Problem of existing of sustained mixed clouds.

3. Relative humidity in ice, mixed and liquid clouds: theoretical consideration and in-situ measurements. Generalization of Squires equation for mixed phase clouds and its solution for quasi-steady conditions. Time of phase relaxation in ice, mixed and liquid clouds. Observation of the relative humidity in clouds with different phase composition and comparison with the theory.