Electrical conductivity of air in thunderstorm environment at a mountain station

Abstract

Measurements of electrical conductivity of air have been made under the conditions of negative potential gradient resulting from thunder clouds at Gulmarg (2700 m). Seven thundery situations have been discussed. Abormal conductivities have been recorded especially after the field changes sign from a large negative to either a positive or a small negative value. Positive polar conductivity showed increase whenever wind appeared to come from the direction of the thunder cloud. On a number of occasions the general level of conductivity was found to be higher in the morning which was followed by a thunderstorm occurring in the evening arid atleast on one occasion large negative ions were recorded about 12 hours before the occurrence of the thunderstorm. Positive polar conductivity invariably dropped to zero value under negative potential gradient much greater than 100 V m^-l. The results seem to be in general agreement with the theoretical observations of Amiram (1972) and are relevant to the observations made by Chalmers (1967) on abnormal conductivity.