Positive charge in the stratiform cloud of a mesoscale convective system
January 16, 2001
A balloon sounding of electric field in the trailing stratiform cloud of a bow echo mesoscale convective system reveals only two substantial in-cloud positive charge regions. These charge regions are located at altitudes of 5.1-5.6 km and 6.4-6.8 km, above the level of 0 degree C at 4.2 km. The two positive charge regions are the likely sources of six positive cloud-to-ground flashes with large peak currents (>32 kA) that occurred within 60 km of the balloon during its flight. The amount of charge transferred by three of these positive flashes that made Q bursts is calculated in the range of 97-196 C. Flashes of this sort are known to produce sprites and elves in the mesosphere. The positive charge regions in this stratiform cloud are substantially lower than the 10-km altitude commonly assumed for the positive charge in many sprite modeling studies.