Flood Forecasting Of The Three Gorges Intervening Basin Based On The Coupling Of Meteorology And Hydrology

The Three Gorges Project is a large water conservancy project with functions of flood control,power generation,irrigation,navigation and ecology.The flow of the three gorges reservoir prediction is of great importance to developing the comprehensive benefits of the three gorges project.Three gorges reservoir discharge is composed of three parts: Cuntan hydrological station discharge,Wujiang wulong hydrological station discharge and Three gorges interval discharge.Interval inflow and confluence speed is fast and flow directly into the reservoir area,which has a very important influence on the safe operation and optimal operation of the Three Gorges Project.Therefore,this paper chooses the Three Gorges region as the research area to carry out the coupled meteorological and hydrological flood prediction research.The main research contents of this paper are as follows:(1)A WRF mesoscale numerical weather model for the Three Gorges region was established.To pick out the parameterization scheme is applicable to the three gorges interval of rainfall simulation,four kinds of cloud micro-physical plan,and three kinds of cumulus convection parameterization scheme is composed of 12 kinds of combination,in the summer of 2020,to simulate the two typical rainfall events based on root mean square error,mean absolute error,torque coefficient of correlation and TS score index to evaluate the result of the simulation.According to the evaluation results,a parameterization scheme with the best simulation effect is selected.(2)The large-scale distributed VIC land surface model of the Three Gorges region was established,and four typical sub-basins in the region were selected for model parameter calibration and verification.The simulation effect of the VIC model in the whole region was verified by the flow data of the Three Gorges reservoir inflow and the flow data of Cuntan Wulong Hydrological Station during 2019-2020.The results show that the VIC model has good applicability in the region of the Three Gorges,and improves the prediction accuracy of the flood inflow into the Three Gorges reservoir.(3)The WRF model and the VIC model in the Three Gorges region were unidirectional coupled to carry out the coupled meteorological and hydrological flood prediction.Four typical flood processes in the summer of 2020 were forecast and tested by using two models,namely rainfall forecast and no rainfall forecast.The results show that the prediction model based on the coupling of meteorology and hydrology does not significantly prolong the forecast period of the flood peak of the Three Gorges Reservoir.However,under the condition of rainfall forecast,the prediction accuracy of the model for the flood peak discharge of the Three Gorges Reservoir is higher,which can improve the prediction accuracy of the flood.