한반도에서 발생하는 가뭄의 주기에 관한 연구

Abstract

The periodicities of droughts occurred in Korea have been investigated. Analysis periods are divided into 1974-2005(Y32; 57 stations), 1914-2005(Y92; 5 stations), and 1778- 2005(Y228; Seoul station) due to differs the data lengths of available daily precipitation at each station. Seoul station only has the useful data for 1777-1907 measured by Korean traditional rain gauge that can informs about droughts before the 20th century. 6 years period have been appeared for 1870-1900, 1910-1950, 1960-2005 repeatedly. Of 4 seasons, summer drought have this periodicity. And all of the 5 clusters divided by characteristics of precipitation in Korea have this periodicity also. Moreover drought center trended to lean to the southward or westward of Tae-Back mountain. These mean that an unknown mechanism of precipitation in summer can induce droughts in Korea. In Y228, The frequency have been more decreased, but strength have been stronger in 20th century than those in 19th century. two extreme droughts(EDI<3.0) of all events for 228 years occurred in 1778 and 1900-1901 and have about 120 years interval. And when these occurred, drought years were maintained during some years continually. Therefor, the precaution is required to a recurrence probability of the extreme drought.