Vertical Motion of Patterns in Radar Records of Showers

Abstract

A technique is described for finding an “effective pattern fallspeed” from arrays of radar data taken at different times and different heights. A weather radar whose antenna scans in three dimensions at many elevation angles inevitably takes a few minutes to record the three dimensional structure of precipitation patterns. The effective pattern fallspeed allows this rather coarse sampling time to be improved and enables the precipitation pattern to be extrapolated to the ground with the time resolution improved by a factor of about 5 to 1 min. Comparing the distance moved by a storm in this time with the spatial resolution of the radar suggests that this is close to the upper limit of useful time resolution.