The Role of Aerosol Particles in the Formation of Raindrops and Hailstones in Severe Thunderstorms

Abstract Variable concentrations of different sized water-insoluble particles were found in bulk rainwater and single raindrops (liquid phase) and in hailstones (solid phase) collected from severe thunderstorms in the Colorado-Nebraska region. It was possible to draw the following conclusions from studies of aerosol particles transferred into the liquid phase of the storm: 1) aerosol particles constitute an intrinsic part of a convective cloud in a severe thunderstorm; 2) the size distribution of cloud droplets is extended to larger sizes by thepresence of giant aerosol particles (> 75 n diameter); 3) giant aerosol particles begin to accrete cloud droplets as soon as they enter the cloud; and 4) the size distribution of raindrops falling at the leading edge of a severe storm depends on the concentration of giant aerosol particles ingested by the storm. The presence of different sized particles in the solid phase led to the following conclusions: 1) transparenthailstones are formed from the frozen Equid ph...