Enhanced Role of Convection in Future Hourly Rainfall Extremes Over South Korea. Issue 22 (15th November 2022) - Lee, Donghyun
Abstract: A convection‐permitting regional climate model (CPRCM) with 2.5 km resolution has been simulated over South Korea for current and future conditions, and the role of convection in the scaling of hourly extreme precipitation (EP) with temperature is examined. It is found that the CPRCM can reproduce the observed super Clausius‐Clapeyron (C‐C) scaling for hourly EP. Precipitation type estimated based on the convective available potential energy reveals the important role of convection in the super C‐C scaling. Fraction of convective rainfall events increases rapidly with temperature, and the contribution of convection becomes dominant in future simulations under high‐emission scenarios. In the late 21st century, as temperature ranges shift to warmer conditions, unprecedented hourly extreme rainfall events are projected to occur particularly during the late summer season. Future changes in hourly extreme events are found to be affected much by boundary conditions from different global climate models. Plain Language Summary: The role of convection in the scaling of hourly extreme precipitation (EP) with temperature is examined using convection‐permitting regional climate model simulations. The convection‐permitting model has been simulated over South Korea with 2.5 km resolution for current and future conditions. The model is found to capture the observed super Clausius‐Clapeyron (C‐C) scaling, which is underestimated by a low resolution simulation based on convective parameterization. When analyzing contributions of convective versus non‐convective type events based on convective available potential energy, convective events are found to be more important in shaping the super C‐C scaling. As the proportion of convective precipitation increases rapidly with warming, the role of convection in the scaling becomes dominant. Future projections under high emission scenarios indicate the occurrence of unprecedented hourly EP events during the late summer season. It is also found that global climate model boundary conditions affect the EP‐temperature scaling by providing different background warming rates. Key Points: Convection‐permitting model reproduces the observed super Clausius‐Clapeyron scaling for hourly extreme precipitation over South Korea Precipitation type analysis using convective available potential energy reveals the important role of convection in the scaling The role of convection becomes dominant in the high‐emission scenario, resulting in unprecedented extreme rainfall events in late summer