Simulation skills of RegCM4 forced by HadGEM-AO for the diurnal variations of temperature and precipitation over South Korea

English Abstract:

In this study, we assessed the simulation skills of RegCM4 for the diurnal variations of temperature and precipitation over South Korea using the 30-year (1981-2010) fine-scale simulation results over North-East Asian region. The simulations performed by RegCM4 with 12.5 km of horizontal resolution driven by the Hadley Center Global Environmental Model version 2 coupled with the Atmosphere–Ocean (HadGEM2-AO). The model configuration is same as the study of Hong et al.(2013) and simulation skills of RegCM4 were evaluated with the hourly observations of Korea Meteorological Administration (KMA). In general, the simulations skills of RegCM4 for the diurnal variations of temperature and precipitation vary depending the geographic locations and seasons. RegCM4 well simulated the diurnal variation of temperature as compared with KMA observation, with better skills during morning and significantly less skills during afternoon, regardless of months. The less skills of RegCM4 during afternoon are mainly caused by the significant under-simulation of temperature over inland areas without regard to seasons. As the results, the magnitude of diurnal range of temperature strongly underestimated in inland areas. However, the simulations skills for diurnal variations of precipitation are not so promising, in particular, during summer, with relatively better skills during afternoon and significantly less skills during early morning. The significant underestimation of precipitation during early morning at the western area of the Korean peninsula resulted in the low spatial correlations and underestimation of variance compared to the observations.