The characteristics of drought occurrence in North Korea and its comparison with drought in South Korea

摘要

The characteristics of the drought occurrence in North Korea over a period of 56 years (1952-2007) were analyzed by region, compared with those of South Korea, and graphed as a drought map for easy detection of the drought's history. To assess them, the Effective Drought Index (EDI), which was calculated from the daily precipitation data for 109 grids of the Korean Peninsula, was used. The daily precipitation data were extracted from the Asian Precipitation Highly Resolved Observational Data Integration towards Evaluation of Water Resources (APHRODITE). The characteristics of the drought occurrence in North Korea were summed up in the following five points. First, North Korea was divided into four drought sub-regions: the Northeastern region (G1), the Northern region (G2), the Central region (G3), and the Southern region (G4). Second, droughts occurred most frequently in G1 (28) and G4 (28 events) and least frequently in G3 (15 events). Third, in all sub-regions, short-term droughts lasting less than 100 days were the most frequent (53 % or higher) and the longest drought lasted 2,911 days (June 30, 1973 to June 20, 1981), which occurred in G3. Fourth, short-term droughts occurred mainly in spring, mid-term droughts (100-500 days) in spring and summer, and long-term droughts (over 500 days) in summer. Fifth, a dry period (monthly mean EDI <0) appeared in all sub-regions between 1973 and 1981 and between 1990 and 1993, and a strong negative precipitation anomaly appeared during each of these periods. When compared to the droughts in South Korea, those in North Korea were less frequent, but the mean duration was longer. Until 1979, droughts occurred almost at the same time in North Korea as South Korea, but beginning in 1980, the time differences between two regions became larger. Thus, the characteristics of the drought occurrence in North and South Korea differ.