Electrode effect at a mountain station

Abstract

Electric space charge densities have been computed from the measurements of atmospheric poterrtial made at 0.25 m, 0.50 m and 1 m above the ground. The potential was measured using Crozier's passive anterrna technique at Gulmarg (2700 m). The results indicate the presence of a considerable amount of net negative space charge at the 0.50 m level at the station throughout the day and night (in fair weather) under calm or light wind conditions and in the absence of snow at or around the station. At 0.25 m a greater magnitude of negative space charge was observed which disappeared soon after the sunrise and a considerable positive charge appeared which persisted during the main convective period. The results are seen to be in general agreement with Hoppel's (1969) theoretical prediction of charge stratification under stable conditions with the negative space charge in an upper region and the positive in the lower region next to the ground. A strong electrode effect was observed for a number of days after an unusually long spell of heavy rain. This has been explained in terms of the reduction of radioactive emanations from the soil due to excessive moisture. Further evidence of the electrode effect was found from the measurements of polar conductivities carried out close to a one metre thick snow surface.