The June 22 tropical squall line observed during COPT 81 experiment: Electrical signature associated with dynamical structure and precipitation

Abstract

The tropical convection experiment COPT 81 (Convection Profonde Tropicale) was carried out near Korhogo (Northern Ivory Coast) during May and June 1981. The June 22 squall line was observed using meteorological and electrical equipment. The frontal part was characterized by a heavy precipitation core associated with strong convection. It was followed by a region of weak precipitation and a wide area of stratiform rain. The characteristic of this squall line resides in the two‐dimensional structure of the observed three‐dimensional wind fields, with intense convection ahead of the heavy precipitation core. Electrical measurements indicate that electrostatic field changes, at ground level, occurred in the weak precipitation zone and in the stratiform precipitation region. No particular electrical activity was observed in the most convective but shallow part of the squall line. A classical dipole structure appeared within the stratiform area. The stationary electrical structure was coherent with the stationary dynamics and precipitation pattern of the squall line.