Fair-weather atmospheric electric potential gradient and space charge over central Illinois, summer 1960

Ground and airplane measurements of the natural fair-weather electric potential gradient and space charge over central Illinois during the summer of 1960 are reported. During the night the potential gradient at the surface is typically quite low, and the lower atmosphere is stratified with layers of positive and negative space charge having densities of several hundred elementary charges per cm3. Shortly after dawn, when convection begins, the potential gradient at the earth's surface rises rapidly and the strata overhead disappear. During the day the space-charge density in the mixing layer is seldom more than 1 elementary charge per cm3. Occasional singularities (outside this region) in the potential gradient and space charge resulting from manmade sources of charge are described.