OBSERVATIONAL STUDY OF MICROPHYSICS IN THE STRATIFORM REGION AND TRANSITION REGION OF A MIDLATITUDE MESOSCALE CONVECTIVE COMPLEX

Cloud microphysical data observed with PMS probes have been combined with radar and other in-situ data collected by a NOAA P-3 aircraft that flew through the stratiform and transition regions of a mesoscale convective complex(MCC).The combined data have been analyzed with respect to the mescscale structure of the storm systems.The characteristics of ice particles in the transition and stratiform regions were quite differeat.The ice particle concentrations in the transition region were about 4 to 6 times that found in the stratiform region,and the size of ice particles in the stratiform region was about twice that in the transition region.The relatively lower radar reflectivity in the transition region is a result of smaller particle sizes.The main precipitation particle growth mechanisms are riming and aggregation in the transition region ard the aggregation process predominates in the stratiform region referred from the microphysical structures.The aggregation starts in the upper,colder levals but becomes more efficient as the particles approach the melting layer.