Phenomena of the Aerological Atmospheric Electricity
Investigations of the electric phenomena in the free atmosphere have been carried out since the beginning of the present century. An increase of conductivity with altitude was first shown by measurements on manned balloons, which were made in Germany during the period of 1905-20. Continuous registration of conductivity up to a maximum altitude of 22 km was made during the flight of the stratosphere balloon Explorer II.
Idrac made a number of balloon soundings of the vertical electric field intensity over France during 1926-27. Some of them reached over the altitude of 15 km, and their registrations indicated the increase of the potential gradient in the lower stratosphere. Recently, soundings with radio sondes were developed exceedingly, and measurements of conductivity were made up to 100, 000 feet above sea level in U. S. A. Potential gradient measurements with radio sondes were also carried out in Belgium and India.
On the other hand, a number of measurements with air-crafts and gliders in the troposphere were made, and it was found that the atmospheric electric phenomena in the lower troposphere were closely related to the exchange layer. Registrations of potential gradient and air-earth current on high mountains were carried out chiefly in Germany, and the relations between the “Austausch" layer and the atmospheric electricity were discussed.
Measurements in the lower atmosphere were made with captive balloons, on towers or on small hills, and it was found that the variations of the electric elements near the ground were remarkably affected by the temperature inversions.