A STUDY ON THE PREDICT ABILITY OF GRAPES MODEL OVER SOUTH CHINA: COMPARISONS BY TWO INITIALIZATION CONDITIONS BETWEEN ECMWF AND NCEP

Abstract

This paper aims to assess the performances of different model initialization conditions (ICs) and lateral boundary conditions between two global models (GMs), i. e., the European Centre for Medium-Range Weather Forecasts (ECMWF) and National Centers for Environmental Prediction (NCEP), on the accuracy of the Global / Regional Assimilation and Prediction System (GRAPES) forecasts for south China. A total of 3-month simulations during the rainy season were examined and a specific case of torrential rain over Guangdong Province was verified. Both ICs exhibited cold biases over south China, as well as a strong dry bias over the Pearl River Delta (PRD). In particular, the ICs from the ECMWF had a stronger cold bias over the PRD region and a more detailed structure than NCEP. In general, the NCEP provided a realistic surface temperature compared to the ECMWF over south China. Moreover, GRAPES initialized by the NCEP had better simulations of both location and intensity of precipitation than by the ECWMF. The results presented in this paper could be used as a general guideline to the operational numerical weather prediction that uses regional models driven by the GMs.