Atmospheric electrical profiles below three meters

Passive antennas were used to make precise measurements of potential at heights of 0.25, 0.50, 1.0, and 3.0 m. These measurements, combined with space charge measurements at ground level and at 1.0 m, permit construction of reasonably definite potential gradient and space-charge profiles up to the 3.0-m height. Profiles are exhibited for three types of fair weather situations: (1) normal daytime, (2) nighttime with wind speed greater than 1 m sec−1, and (3) nighttime with wind speed below 0.5 m sec−1. Profiles for the first two situations are of the type to be expected in the presence of electrode effect and eddy diffusion. In the nighttime low-wind situation, on the average, a stratum of dense positive space charge approximately 0.25 m deep lies next to the ground; negative space charge of moderate density is present above this for the rest of the 3 m. This space charge profile would appear to be a manifestation of the presence of a shallow stratum of relatively intense ionization close to the ground during the nighttime periods of low wind, and thus of the accumulation of Rn222 and Rn220; radioactive elements in the soil near the surface also would contribute.