雪雲の電気的構造

Abstract

The electrical and precipitation-physical structures of snow clouds were observed by means of "Altielectrographs", "Snow Crystal Sondes", electric charge sondes and the usual radiosondes on the Ishikari Coast, Hokkaido in the winter seasons of 1969 and 1970, simultaneously with ground-based observation.The following results were obtained.1. A thick layer of positive space charge was found generally distributed in the middle layer of the snow clouds. The charge was carried by small snow' crystals. A thin layer of negative space charge was found below the layer of positive space charge. This charge was carried by large snow crystals.2. Local positive space charges carried by positively charged graupel pellets frequently existed in the active regions in the lower portion or below the cloud base. This probably caused the electrical structure of snow clouds to be complicated.3. Good correspondences between the patterns of electrical structures observed in clouds and on the ground showed that the structure aloft was transported by the descent of graupel pellets and snow crystals to the ground without any remarkable modifications.4. The positive electrification of graupel pellets were presumably caused by the collision with neighboring unrimed snow crystals in the warm temperature region between -5°C and -10°C levels.