Added Value of Very High Resolution in the Present and Future Climate Simulations over South Korea Using WRF Modeling System

This study is the first trial of the application of very high resolution (5 km) in long-term climate simulations focusing on the Korean peninsula. A one-way, double-nested modeling system consisting of the mother domain (20 km) and nested domain (5 km) in Weather Research and Forecasting (WRF) model is used to downscale reanalysis and multiple CMIP5 global climate model (GCM) simulations forced by Representative Concentration Pathway 8.5 (RCP8.5). The superiority of the very high resolution, in simulating extreme events and in the realism of the underlying physical mechanism, provides new insights into climate simulations over this narrow peninsula whose climate change signals are sensitive to the local topographical forcing. Not only are the changes in the mean and the extreme temperature and precipitation explored, but we also put an emphasis on the comparison among different resolutions and among different driving forces regarding the changes in the relationships between temperature and different types of precipitation. The more plausible relationships and more realistic portioning between convective and large-scale precipitation seen in the very high resolution simulation can enhance the confidence in precipitation projections in the warming climate. Also, this analysis may deepen our understanding of the future precipitation intensity changes, especially for the extreme events, as well as help us identify the added value of dynamical downscaling beyond spatial details.

Keywords Added value; Regional climate projection; High resolution, Climate change

Acknowledgments This study was supported by the Korea Environmental Industry & Technology Institute(KEITI) grant funded by the Ministry of Environment (Grant RE201901084).