Merging of convective clouds: cloud initiation, bridging, and subsequent growth

This study examines the growth of radar echoes from the time of their initiation to several minutes after they have merged. Three-dimensional radar reflectivity data were examined for two convective periods. Echoes that merged were initially taller and slightly larger than those that dissipated without merging, suggesting they were more vigorous and thus more likely to grow and join with another echo. While meteorological conditions on the two days were quite different, 25% of the mergers occurred between young echoes, 65% occurred between a young echo and a parent storm, and 10% occurred between echo cores from two different systems. Echo cores in this study appeared to merge primarily through horizontal expansion. -from Author