11th Conference on Atmospheric Radiation and the 11th Conference on Cloud Physics

Wednesday, 5 June 2002
Microphysical observations of cirrus and wave clouds
R. Paul Lawson, SPEC Inc., Boulder, CO; and B. A. Baker and C. G. Schmitt
Poster PDF (3.6 MB)
Measurements in cirrus and wave clouds using jet aircraft equipped with standard cloud particle probes, the Cloud Particle Imager (CPI) and the Nevzorov total water content probe are presented. The CPI now makes it possible to determine the habit of ice particles as small as 50 microns. New software algorithms are used to automatically classify the habits of cloud particles and compute ice water content. Results are presented from Learjet flights in cirrus clouds over Utah, Colorado and Oklahoma, and wave cloud flights over the Front Range of the Rocky Mountains.

Data collected in cirrus suggest that the ice particle concentration is dominated by small (< 50 micron) particles, and the concentration of these particles is much higher (> 1000 L-1) than commonly reported in the literature. The habits of the larger particles in cirrus are dominated by rosettes, except in the lower regions of deep cirrus, which display sideplane growth and aggregates, and in very cold (T < -60 C) cirrus, where clear plates are observed. Particle concentrations in wave clouds are also very high, exceeding 1000 L-1, and like cirrus clouds, crystal habits are dominated by rosettes, except in the lower regions of deep wave clouds, where sideplane growth and aggregates are also observed. Interpretations of cloud microphysical processes that may generate these particle characteristics in cirrus and wave clouds are presented.

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