Spatiotemporal Variability of Regional Rainfall Frequencies in South Korea for Different Periods

Abstract

Understanding regional as well as temporal variations in probability rainfall is essential for addressing climate change-related hydrological issues. Few studies have conducted spatial analyses on probability rainfall using up-to-date rainfall data, which is crucial to comprehend regional rainfall variations for effective flood management and hydraulic structure design. In this study, we analyzed the spatiotemporal variations of probability rainfall factors in South Korea using 61 rainfall stations and four rainfall periods (years) (recent-10, 2011–2020; recent-20, 2001–2020; recent-30, 1991–2020; recent-40, 1981–2020). We mapped probability rainfall information, including probability rainfall intensities (20, 30, and 40 mm/h), return periods (10, 20, 50, and 100 years), rainfall durations (1, 2, 6, and 24 h), and rainfall depth. Results revealed wide variations in the northern and southwest inland regions based on rainfall periods. Decadal annual rainfall analysis revealed that the north and southwest inland regions indicated lower recent decadal rainfall than that in previous decades, while decadal annual rainfall in the southeast inland region remained constant. The generated spatial and temporal distribution maps offer valuable insights for comprehending the variation in probability rainfall factors across different time periods in South Korea, with practical implications for the planning and design of hydraulic structures.