Two Types of Vertical Electrical Structures in Stratiform Precipitation Regions of Mesoscale Convective Systems

Abstract

Electric field (E) soundings in the stratiform regions and transition zones of mesoscale convective systems (MCSs) are reported. Most of the E soundings were made during the 1991 Cooperative Oklahoma Profiler Studies (COPS-91). Multiple E soundings were made in several MCSs. All of the E soundings collected here can be grouped into one of two types. Within each type the soundings and the inferred charge structures are remarkably similar from one place in an MCS to another and from one MCS to another. The charge regions inferred from the E soundings are hundreds of meters thick and have charged densities up to 5.3 nCm?3. Typically, the maximum E in the soundings is about 100 kV m?1. Here, E soundings from three classes of MCSs are discussed. The bow-echo MCSs have simpler vertical charge structures with tour main charge regions, while squall-line MCSs and predominantly stratiform MCSs have five main charge regions. In all of the E soundings there is a substantial region of charge and a large E at or near 0°C.