On the Periodicity of Thunderstorm

Abstract

By means of the periodogram method and Takahasi's method we tried to find the periodicity of thunderstorm. The data which we have used are taken from the report on thunderstorms in Japan published by the Central Meteorological Observatory of Japan for the years 1933 to 1938.
The result of the statistics shows that the periodicities of 14 and 21 days are remarkable, which are multiples of 7 days. Besides, 4, 5, 7, 9, 16, 18 and 27 days are rather doubtful. As is well known, periods based on 7 days are generally found in other meteorological phenomena in the conntry, and so we cannot insist these to be the proper periods of thunderstorm only.