Laboratory experiments to simulate ice particles in cirrus and convective clouds will investigate conditions for break up and separation of electric charge. A system will be constructed to generate monodisperse ice crystals of selected size and shape whose optical properties will be examined in a specially designed and constructed optical system. Results will be compared with field data already obtained during flights through hurricanes, maritime convective cells off Florida, convective feeder clouds in North Dakota and new data to be obtained on the NOAA P3 during CAPE (1991). This will include measurements of electric field and microphysical evolution (ice particles, coalescence drops and their electric charge) as convective clouds evolve overland in Florida. Results will also be compared with radiation and other aircraft data obtained by higher flying aircraft in cirrus as it becomes available. A simple numerical model of heat evolution in convective clouds will be constructed applicable to assessing the vertical heat budget of deep convective cloud systems involving both ice and coalescence precipitation processes.
