わが国と中国における自然災害の発生頻度特性

Abstract

Occurrence frequency of natural disasters generated by potentially hazardousatmospheric phenomena include typhoon, heavy raifall, drought is investigated bythe analysis of numerous Chinese and Japanese historical documents which are richin climatological and phenological events of the past. Spectrum analysis shows thata predominant 170-years cycle which approximately corresponds to five times ofBruckner cycle (35 years) can be detected in the time-series of occurrence offlooding and drought in China. In Japan, however, due to not enough many olddocuments and the small number of natural disaster occurrence, this cycle is notclear but in flooding the periodicity of 170-years exists. From the view point oflong-term changes, the disaster occurs under large influence of climate change. Atlow temperature, especially at the Little Ice Age, the scale of natural disaters suchas flooding and drought may grow large. Climatic hazards producing disasters witheconomic, political and social repercussions have always been important to changeestablished social system.