Aircraft Soundings of Potential Gradient, Space Charge and Conduction Current, and Their Relation to Precipitation

Abstract

Forty-five aircraft electrical soundings were flown to an altitude of 3 km MSL over West Plains, Mo., during the summer of 1963. Measurements were taken of the vertical electrical potential gradient and polar conductivities. Calculations were made of the electrical potential at 2.9 km plus the vertical variation of space charge and conduction current density. The potential gradient usually increased with altitude in the first 300?600 m above the surface, and then gradually decreased to the top of the sounding. The soundings were compared with the occurrence or nonoccurrence of precipitation in the 5 hr following each sounding. The magnitude of the gradient between 2 and 3 km was found to correlate well with the presence or absence of high pressure systems in the area, but it was concluded that precipitation is not necessarily preceded by a unique large-scale set of atmospheric electrical conditions in the lower atmosphere.