Extended Abstract

a, without precipitation in future b, with precipitation in 12 h futurec, with precipitation in 24 h future d, with precipitation in 36 h futureFigure2flood discharge hydrograph considering expected flood flow of different phases5. ConclusionsPrecipitation is one of the most important information in flood forecasting, while precipitation inforecast period has a direct impact on the flood forecasting accuracy, the longer the foreseen period is,the greater the impact on the forecast result is. Therefore the article bases on previous human studies,takes the Zhang River Basin floods during the flood season in 2008 in Hubei for example, uses AREMmodel forecast results as precipitation in forecast period to input the hydrological model, and make thetest on the i mpact of c onsidering precipitation in fo recast pe riod on flood forecast re sults, itsconclusions are as follows:(1) Du ring the fl ood forecast, under the conditions of rai nfall occurring i n the future , comparedwithout consid ering precipitation in forecas t period, the fl ood forecast result of consideringprecipitation in forecast period exist the obvious improvements, the max can get 50 % improvements,and it can make forecast on flood process in advance during the whole rain process.(2) Although that the precipitation in fo recast period is cons idered, there still is the differencebetween the flood forecast result and actual condition, the differences shows that the forecast accuracyof the precipitation in forecast period need to be improved further.(3) The impact of the precipitation in forecast period on the flood forecast accuracy have been notedby mo re an d mor e hy drologist and meteorologist, modern weather fo recast t echnology pr ovides agood technical support to offer the precipitation in forecast period during the flood forecasting. Withthe devel opment o f modern operation system, es pecially is QPE and QPF, the high s patial and-179-