Spatial-temporal evolution and projection of climate extremes in South Korea based on multi-GCM ensemble data

Abstract

Extreme climate can greatly impact social, environmental, and economic developments in human life. In this study, we evaluated the spatiotemporal trends of 21 extreme climate indices during 1975–2100 in South Korea based on observed climate data from 50 weather stations. Statistically bias-corrected daily data ensembled from 11 and 13 Global Climate Models (GCMs), archived in the Coupled Model Intercomparison Project Phases 5 and 6, respectively, were used to estimate future extreme climatology. Systematic biases in the raw GCM data were satisfactorily removed after the bias correction procedure. The extreme cold indices showed significant downward trends (p < 0.05) under both representative concentration pathway and socioeconomic concentration pathway scenarios. During the near future (2021–2060), the trends in extreme cold indices declined sharply, and during the far future (2061–2100), the trends were positive under the medium emission scenarios and moderately negative under the extreme emission scenarios. Extreme warming indices showed significant increasing trends (p < 0.05) and the change magnitude was larger than that of the extreme cold indices. Extreme warming was characterized by sharply increasing rates of severity and intensity during the near future and noticeably longer and more frequent warming events in the far future. South Korea was projected to receive substantially higher annual rainfall, particularly during the far future, featuring intense/heavy rainfall events during the monsoon season followed by dry winters. Change magnitudes of all extreme indices under RCP8.5 were much higher than those in the remaining scenarios. Compared to the rest of the country, coastal regions in the east, south, and west had more intense warming, while northern mountainous regions experienced more extreme cold. Extremely warm climatology increased steadily from coastal to inland and northern mountain regions, whereas extreme cold climatology gradually decreased from north to south. Our results showed that socially, environmentally and agriculturally important regions of South Korea were at higher risk of facing the detrimental impacts of extreme climatology.