EVIDENCE OF A SOLAR INFLUENCE ON THE ATMOSPHERIC ELECTRIC ELEMENTS AT MAUNA LOA OBSERVATORY

The monitored atmospheric electric elements at Mauna Loa Observatory, Hawaii, have provided good evidence of a direct solar influence on some of the electric elements recorded at the mountain observatory. An analysis of the data has shown that following a solar flare eruption, both the air-earth conduction current and the electric field, measured during fair weather at Mauna Loa, usually exceeded their established normal values. For the 1-year measurement period from September 1960 to September 1961, nearly one-third of the days were considered as “disturbed” solar days due to solar flare activity. The mean value of the air-earth conduction current and the electric field on “disturbed” solar days exceeded that of the “quiet” solar days by about 10 percent. During the month of July 1961, a period of spectacular solar activity, the highest sustained values of the year for the air-earth current and the electric field were recorded with the normal 24-hr. values being exceeded by as much as 35 percent, and for one 6-hr. period following a multiple flare burst, by 7.5 percent. The influence of corpuscular solar radiation on the earth-ionosphere electric circuit and upon the global thunderstorm activity are discussed.