気候ジャンプ

Abstract

A new concept Climatic Jump is proposed for an abrupt change of time average of cli-matic elements over a few decades, basing upon Lorenz's non-deterministic theory of climateand Iwashima's findings of possiblity of multiple stable solutions in a numerical model of theatmospheric general circulation. A simple method of detecting the Jump is proposed, takingaccount of statistical ambiguity in time mean. Applying this method to the climatic recordsover Japan, Climatic Jumps are detected for sea-level pressure, precipitation, sunshine dura-tion and maximum depth of snowcover around 1950, as well as the surface air temperature.Occurrence of some abrupt change in the atmospheric general circulation is suggested by thefact that almost simultaneous appearance of jumps could be detected commonly for all theclimatic elements taken here.