Abstract:A hindcast for the heavy precipitation events occurring in the region of the Yangtze River and the Huaihe River in China from 24 June to 3 July 1998 was performed using the Beijing Climate Center Atmospheric General Circulation Model version 2.0.1 (BCC_AGCM2.0.1) of China Meteorological Administration. The BCC_AGCM2.0.1 model was run from 0000 UTC 24 June to 10 July 1998. The model initial values were generated by using the hourly temperature, vorticity, and divergence of NCEP reanalysis data to spin up for 10 days integration before the beginning of forecast. The results of hindcast experiment show that the predictability timescale of the 500-hPa geopotential heights over the whole globe is about 4－7 days, and that for the circulation field over China about 3－4 days. The spatial distribution of forecasted rainfall regions over China is nearly coincident with the observation during the first 3 days after initial forecast time, but the rainfall intensity has some regional differences between the hindcast and the observation. The predictability for forecasted daily precipitation at different thresholds is tested using BIA, ETS, and HK scores. In the 2 days of forecast, the BCC_AGCM2.0.1 model has high predictability for the daily precipitation above 5 mm and 10 mm, and the ETS score is above 0.25, the HK score above 0.4, the BIA score close to 1.0. But for the daily precipitation larger than 20 mm, the model has less predictability.
