"Warm rain" in cloud physics refers to the development of precipitation in clouds in the absence of ice crystals. Cloud droplets grown primarily through coalescence. The droplet size spectra observed in nature have shown both bi-modal and tri-modal distributions. Professor Brown has successfully explained the cause of such distributions by modeling both coalescence and the breakup process when droplets collide. Under this grant Professor Brown will further consider the effects of evaporation and the initial droplet size spectra in the evolution of the spectra. Since convective cloud models frequently cannot explicitly take into consideration the complex coalescence and collision-induced breakup, a refined parameterization, hence professor Brown's work, becomes even more important.
