Assessment and Feature of Waterspouts around Japan Coast

Abstract

Statistical features of waterspouts in Japan were investigated based on the tornado data base during 23 years from 1991 to 2013. Because a large number of waterspouts were reported after 2007, the tornado probability of each prefecture was different from that of the previous studies. The tornado probability exceeded 5 tornadoes/10000km²/year in 7 prefectures and 0.2 tornadoes/10⁶person/year in 9 prefectures, respectively. Tottori prefecture is the highest values of the tornado probability in Honshu island, considering the waterspouts during 2007 to 2013. It is important to make clear the generation point, the vortex structure, the organization mechanism and the frequency of the waterspouts around the Japan coastal region.