日本における100年確率日雨量と年降水量の長期変動

概要

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Secular change of probable daily rainfall and that of annual total precipitation are presented at more than fifty weather offices in Japan where data are available from before 1900 to 1978. Probable daily rainfalls with 100-year return period were calculated from time series of annual maximum daily precipitation with fifty-year duration till the year in concern. The following conclusions were obtained. (1) Secular change of probable daily rainfall with 100-year return period was found to be fairly large. It has happened, then, that the capability of such flood prevention works that were designed using data in periods with small probable rainfall values is only about a half for periods with large probable rainfall values. (2) The probable rainfall calculated in recent years is larger than that calculated in about 1940 or 1950 at many places where the probable rainfall is subject to larger variation. (3) The secular changes of annual total precipitation show the same tendency at most stations in each region. Around Kanto district, annual total precipitation has been smaller in amount since 1960; while, it has been larger in Hokkaido and around Kansai region since 1950. (4) Climatic change in annual total precipitation has been arisen in the Pacific Ocean side of the central part of Honshu where industry is developed and the population is large.
独立行政法人防災科学技術研究所の論文
1981-07-06