In this study, the simulation skills of the RegCM4.0 for the current climate (1981-2005) focusing on the extreme temperature were evaluated. The spatial resolution of model is 25 km and simulation domain is the CORDEX-East Asia phase 2. And the ERA-Interim data was used as the boundary forcing of RegCM4.0. The simulation skills were evaluated with the ground observed data provided by the Korea Meteorological Administration (KMA), Global Historical Climate Network (GHCN), the NCEP Climate Forecast System Reanalysis (CFSR), and Japanese 55-year Reanalysis (JRA-55). As in many studies, the extreme climate events (e.g., hot days, tropical night days, maximum and minimum temperature of 95th percentile) were defined by absolute and percentile methods.
The RegCM4.0 relatively well simulated the spatial distribution and inter-annual variability of daily maximum and minimum temperature. But it underestimated the inter-annual variability of daily maximum and minimum temperature, diurnal temperature range, and the number of hot days, tropical night days, and the temperature extremes defined by percentile methods. And RegCM4.0 underestimated the number, trend, and temporal standard deviation of temperature extremes over East Asia defined by the percentile methods compared to that of CFSR. On the contrary, the RegCM4.0 overestimated the number and inter-annual variability of icing days and frost day. In general, the simulation skills of RegCM4.0 for the extreme temperatures are clearly dependent on the extreme types, geographic locations and validation dataset. The validation results showed that sophistication of model physics and resolution are needed to improve the simulation performance of RegCM4.0 for extreme temperatures. And the reliable verification data for the extreme temperature over the East Asian region are needed for the detailed evaluation of regional climate model.