Recent changes in summer rainfall characteristics in Korea
Chang-Hoi Ho, Hee-Ae Kim, Yumi Cha, Hyeon‐Seok Do, Jinwon Kim, Joowan Kim, Seon Ki Park, Hee‐Dong Yoo
Abstract
This study investigates the long-term variation in the summer rainfall characteristics in Korea by analysing the amount and intensity of rainfall and the number of rainy days at 57 stations for the June–September period from 1976 to 2023. For the primary rainy season, from 22 June to 1 August, the amount of rainfall in the post-2000 period is greater than that in the pre-2000 period, whereas the number of rainy days remains similar throughout the entire period. Rainfall intensity increases until 2000, then remains nearly unchanged after 2000. For the secondary rainy season, from 2 August to 10 September, both the rainfall amount and number of rainy days in the post-2000 period are larger than those in the pre-2000 period; however, the increase in rain intensity is less pronounced than that in the primary rainy season. These rainfall changes for the two rainy intra-seasons are found to be closely related to the increase in the frequency of heavy rainfall events ( ≥ 80 mm day −1 ), especially in the Seoul metropolitan area and the southern coastal regions. Previous studies have attributed the changes in the primary rainy season to the decrease (increase) in stationary fronts (convective rainfall), whereas the changes in all fronts (stationary and occluded) and the reduced influence of tropical cyclones in August have been identified as the main contributor in the secondary rainy season. This study improves our understanding of the recent changes in summer rainfall characteristics in Korea.