Spatial and temporal comparisons of droughts over Korea with east asia

摘要

To investigate the spatial and temporal relationships of drought occurrence and intensity between Korea and East Asia, the Standardized Precipitation Index (SPI), calculated from Climatic Research Unit (CRU) monthly precipitation data, was used from 1951 to 1996. It is found that the frequency of occurrence of droughts in Korea has significant time intervals of 2-3 and 5-8 years and has been increasing since the 1980s. Correlation and composite analyses showed that the occurrence of droughts over central eastern China, Manchuria, and the north coast of Japan was highly correlated with those in Korea. However, the time scales of occurrence of droughts over the three regions were different. Droughts in eastern China represented in-phase variations with those in Korea with a time interval of 5-8 year, whereas those in Manchuria occurred with a time interval of 15 years, and those in Japan had no coincident variations. To assess the feasibility of usage of proxy climate data in eastern China for the research of droughts in Korea during the pre-instrumental period, dry-wet indices in six regions of eastern China were correlated to the SPI values in Korea for the period of 1951-92 considering several time scales. Dry-wet indices of region V showed a larger correlation and the most similar trend to the droughts in Korea with a time scale of 5-11 years. This suggested an effective utilization of historical records and other proxy data in eastern China to understand extreme climatic events in Korea for the past 500 years.