Characteristic Changes of the Changma Season in the 2000s

Abstract

The purpose of this study is to investigate the characteristic changes of the Changma season in the 2000s. To accomplish this goal, we have used daily rainfall data collected over nearly 40 years (1971 to 2010). The average summer precipitation data including the Changma season were collected from 16 weather stations that are placed across the three major regions (i.e. central region, southern region, and Jeju region) as Korea Meteorological Administration divided. These precipitation data were analyzed to find out characteristic changes of the Changma season. Results of the precipitation data comparison among the major regions that, monthly average precipitation in the central region was the highest in July; its precipitation tended to increase from May to September. In the southern region, the precipitation amount was lowest in June and tended to increase in May, September, and August. In the Jeju region, the precipitation has been the highest in June and July for the past 30 years, whereas September has been highest month in the last 10 years. The precipitation amount in the Jeju region decreased both in June and July, whereas it tended to grow in May, August and September. A correlation coefficient formula by Karl Pearson has been used to find out correlations between the Changma season and the precipitation of the major regions in 2000s and normal years. It was found that the correlation coefficient has decreased from 0.723 to 0.524 in the 2000s (2001 to 2010) compared to normal years (1971 to 2000).