小氷期における東アジアの強風災害とその変動

抄録

 Climate variations in East Asia during the Little Ice Age are reconstructed using wind records together with chronicles of weather disasters in Japan and China, as well as weather observations from Okinawa in the 1850s. The results of analyses are as follows: (1) On the basis of numerous records that remain for the southern coast of Japan and the south-eastern coast of China, it appears that many rainstorm disasters occurred during the summer period in both Japan and China. They usually took place one or two months later in Japan than in China; (2) Observations in Naha show that, when air pressure drops considerably, wind speed is very high and its direction rotates. Following unusual air pressure falls in Naha, strong winds caused disasters in China or in Japan. It is thought that these events are linked to movements of typhoons; (3) Increases in windstorm damage occurred during different periods in Japan and China. This may be related to changes in atmospheric circulation. Cool summer periods are observed around 1705, 1740, 1765, 1785, 1830, and 1845. The year 1855 marks a turning point between periods with prevailing cool states and periods with prevailing warm states.