Hourly extreme rainfall projections over South Korea using convection permitting climate simulations

Abstract

This study analyzes the impact of climate change on the summertime hourly extreme rainfall event (HER) over South Korea. The UKESM-forced regional climate model is utilized to simulate HER over South Korea in the historical (2001-2005) and future periods (2091-2095) under the SSP1-2.6 and SSP5-8.5 scenarios at a convection-permitting resolution (2.5 km). A significant increase in future HER intensity and frequency appears in July, with the frequency increases about two times for SSP1-2.6 and about 3.7 times for SSP5-8.5 scenarios. The month of maximum HER frequency is also projected to shift from August to July. When clustering the HERs into six representative weather patterns, SSP5-8.5 scenarios show a predominant increase in weather patterns characterized by a frontal boundary between low and high pressure in July. Our results suggest that the future sub-seasonal evolution of HER over South Korea may change with the intensification of subtropical high and the deepening of mid-level trough according to different future scenarios.