Horizontal Scales of Motion in Atmospheric Free Convection Observed during the GATE Experiment

Abstract

An investigation of the dominant horizontal scale of motion in free convection, using data from GATE, principally from the NOAA acoustic sounder, is described. The horizontal scale was seen to vary from two times the depth of the convection layer at high instabilities to six times the depth at low instabilities. Aircraft data indicate the dominance of similar scales of motion. Small-scale humidity fluctuations were found to contribute approximately 30% of the acoustic echo intensity, with the remainder due to fluctuations of temperature.