On the Geographical Featur_??_s of the Thunderstorms in Japan

[摘要] In this paper the present author studied statistically on the seasonal variations of the days with thunderstorms for almost all of the meteorological stations of this country.In the mountainous part of the Japan proper the thunderstorm of heat type shows an extraordinary predominance. At the coastal part, the summer time does not contribute to the formation of thunderstorms so much as in the inland part, but in the colder season, i.e. autumn and winter, the thunderstorms are experienced very frequently.The Pacific coast of the south of the Japan proper experiences as much thunderstorms in autumn as in summer, while at the Japan sea coast of the northern half of the Japan proper, the seasonal features are shown very markedly. Namely, in the northeastern coast of the Japan sea, ranging from Sapporo (about Lat. 43° N), to Anbetu (about Lat. 50° N), the thunderstorms occur most frequently in September; at the Japan sea coast of the Japan proper, ranging from Sapporo to the south of Akita (about Lat. 39° N), the maximum frequency of the days with thunderstorms occurs in October; the Japan sea coast ranging from the north of Niigata (about Lat. 38° N) to the neighbourings of Wakasa bay (about Lat. 36° N) experiences the thunderstorms most frequently in November. In other words, the Japan sea coast has a marked geographical feature to the occurence of thunderstorm and the month of the maximum frequency travels southwards from Karahuto to the middle part of the Japan proper as the colder season advances. This characteristic feature may throw a light upon the investigation of the mechanism of the formation of thunderstorm on the point of view to show some climatical states preferable to the occurence of thunderstorm.

[学科分类] 大气科学