This study examines the performance of two regional models focusing on the diurnal variations in precipitation over East Asia during July 2006. The Weather Research and Forecasting (WRF) model and National Centers for Environmental Prediction (NCEP) Regional Spectral Model (RSM) are forced by NCEP/Department of Energy (DOE) reanalysis. First, the Tropical Rainfall Measuring Mission (TRMM) satellite measurement rainfall is validated by Global Precipitation Climatology Project (GPCP) and ground measurement, Automatic Weather System (AWS) over South Korea.

The preliminary results showed that the RSM performs better than the WRF in synoptic-field simulation, whereas the precipitation is better in the WRF than in the RSM. In particular, heavy rainfall over Korea is very well reproduced by the WRF, which is too weak by the RSM. The diurnal variation of the precipitation and temperature in both models reveal that the modeled diurnal variation of precipitation is too strong as compared to that from the observed. Also, daytime convection is overestimated by both model, with a stronger amplitude by the WRF.