三峡工程大江截流期降水预报方案研究

Precipitation Forecasting during River Closure

三峡工程大江和围堰施工历经长江枯水期和汛期．对水情预报提出了很高的要求。长江来水主要靠大气降雨，因此，开展坝址以上流域降雨预报研究是重要的、研究内容包括汛期降水预报方案和枯水期预报方案、短期和中期暴雨预报。对1994、1995年0～24h、21～48h预报的准确率分别为34％、31％。1996年汛期三峡西段、东段24h预报准确率分别达到46％、35％、中、短期预报相结合，填补了三峡区间中期暴雨预报的空白。

The water in the Yangtze river mainly comes from the precipitation,therefore,astudy on the precipitation forecasting within the catchment above the dam is very important. Thestudy scope includes the precipitation forecasting during the flood and dry periods, and short-and - long -term storm forecasting. The forecasting accuracy of 34 % and 31 % are reached for 0- 24 h and 24 - 48h,respectively. for the years 1994 and 1995. The accuracy of 46 % and 35% reached for 24h within the western and the eastern parts of the Three Gorges for the flood periodin 1996. The combination of the mid and short term storm forecasting has filled in the gap in themid - term storm forecasting for the Three Gorges area.