Hail and Raindrop Size Distributions from a Swiss Multicell Storm

Abstract

Time-resolved hail and raindrop size distributions measured simultaneously during a multicellular hailstorm are presented. The time variation of the size distributions allowed a detailed analysis of the structure of the hailswath. It consisted of four hail cells with a duration of 2?3 min each. The number density of the hailstones increased and the mean diameter decreased during the lifetime of a cell. The contributions of liquid water and ice water content to the total water W were about equal; W was never larger than 5 g m?3. The size distributions were well approximated by an exponential law. The mean distribution is given by NH (D) = 12 exp (?0.42D). The distributions are compared with measurements and calculations of other authors and the differences are discussed.