Changes on Frequency and Magnitude of Heavy Rainfall Events in Korea

The magnitude of 2-day maximum rainfall was examined to evaluate the frequency-magnitude relationships of heavy rainfall events in Korea using the partial duration series and the generalized extreme value distribution. The 2nd rainy period (Aug-Sep) has higher magnitude of 2-day maximum rainfall than the 1st rainy period (Jun-Jul), indicating that there will be a higher chance of occurrence of severe heavy rainfall events during the late summer and early fall. There were no big differences on the mean of partial duration series and the magnitude of 2-day maximum rainfall during the 1st rainy period. However, those for the 2nd rainy period showed a distinct increase suggesting the possible intensification of heavy rainfall events. It might be concluded that there was an increasing trend on intensities of heavy rainfall events in Korea and this would be mainly resulted from increase of the magnitude and frequency of heavy rainfall events during the 2nd rainy period. Tropical storms including typhoons might play an important role in increase of extreme rainfall events.