The distribution of convective and mesoscale precipitation in GATE radar echo patterns.

Abstract

Quantitative radar data have been used to divide individual radar echoes observed in GATE into convective and mesoscale components. Echoes less than 102 km2 in area were considered, by virtue of their small time and space scales, to be entirely convective. Larger echoes were composed partly of convective regions, and partly of horizontally uniform mesoscale regions. The mesoscale regions were apparently associated with widespread precipitating anvil clouds in GATE cloud clusters. About 40% of the total precipitation in GATE fell in these mesoscale regions. Increasing amounts of convective precipitation were associated with echoes of increasing maximum height. Major events of mesoscale anvil rainfall were always associated with convective echoes which had maximum tops reaching the level of zero buoyancy, and they tended to occur when the large-scale upward motion was enhanced. -from Authors