PRECIPITATION CHARGE AND SIZE MEASUREMENTS IN THE STRATIFORM REGION OF 2 MESOSCALE CONVECTIVE SYSTEMS

We measured the charge and size of precipitation particles with instru mented free balloons in the trailing stratiform regions of two differe nt mesoscale convective systems (MCSs) in Oklahoma. Each of these stra tiform regions had a different type of vertical electric field structu re, one of each of the two types commonly found in MCS stratiform regi ons. Using an instrument that measured precipitation charge from 4 to 400 pC and equivalent diameters from 0.8 to 8.0 mm, are found that (1) the particles measured were not the major charge carriers in these st orms, implying that smaller particles were responsible for the measure d field, (2) there was no obvious relation between precipitation charg e and size or polarity and size, (3) the precipitation size distributi on in and near the transition zone consisted of two independent popula tions, one centered at 2.6 mm and one at 4.9 mm, (4) the two lower cha rge layers in these storms were likely created by in situ charging pro cesses, and (5) net precipitation charge density was small because nea rly equal amounts of positive and negative precipitation charge existe d at all altitudes measured.