Classification of Localized Heavy Rainfall Events in South Korea

Abstract

Characteristics of localized heavy rainfall events (LHREs) in South Korea are analyzed using high-resolution precipitation reanalysis data from the Korea Meteorological Administration (KMA). The LHREs, defined as summertime heavy rainfall events with 30 mm/h or more, are detected using in-situ measurements, and their spatio-temporal structures are classified into the three groups using precipitation reanalysis data. The first group is mainly composed of band-type precipitation around the central regions of South Korea (CHREs). The second group predominantly consists of LHREs in the southern regions (SHREs). The third group contains diverse and isolated rainfall events (IHREs). Each group exhibits a different rainfall persistency, diurnal cycle, and occurrence frequency. In general, CHREs peak mostly in July and have shorter time scales compared to SHREs. SHREs are more nocturnal in nature with maximum frequencies in both July and August. IHREs, which consist of 47% of total LHREs, are composed of both nocturnal rainfall events in the southern coastal regions and daytime rainfall events in the inland regions. These results suggest that LHREs in South Korea have multiple characteristics and cannot be simply explained by one or two representative mechanisms.