Research And Application On The Short-term Hydrological Forecasting Methods In The Ungauged Basins

Hydrological forecasting has always been a key scientific issue in the field of hydrology research.It provides an important scientific basis for water conservancy project construction and water resources dispatching decision-making.It is of great significance in flood control,drought resistance and rational development and utilization of water resources.However,due to the constraints of economic development,China has not yet established a complete hydrological forecasting and reporting system in some parts of China,and lacks a scientific and effective management mechanism for the site,resulting in a large number of hydrological data missing and missing measurements,making hydrological forecasting work difficult to carry out.Therefore,how to achieve effective hydrological forecasting in areas with insufficient data is a key issue to be solved urgently in the research of water resources comprehensive planning management in the new era.Short-term hydrological forecasting in the ungauged basins involves many basic theories and methods in the field of hydrology,and is a difficult and hot issue in the field of hydrological forecasting research in recent years.To this end,this paper takes the upper reaches of the Yangtze River as the research object,and carries out the research on the theory and method related to short-term hydrological forecasting in the data-free area,and has obtained a series of research results.The main research contents and innovations are as follows:(1)For the problem of lack of high-precision rainfall data in the no-data area,the TRMM 3B42 V7 satellite rainfall product was introduced,and the rainfall data of the ground station was used as the reference value to compare the spatial distribution of the two rainfall data in the upper reaches of the Yangtze River.Accuracy assessment of TRMM rainfall data was performed on daily scale and monthly scale to analyze the ability of satellite rainfall data to reflect “real” precipitation.The results show that: overall,TRMM satellite rainfall data has good applicability in the upper reaches of the Yangtze River.When the measured rainfall data is missing or the quality is not high,it can replace the ground station rainfall data to a certain extent.(2)In order to verify the application effect of satellite rainfall in hydrological forecasting,the satellite rainfall data and the ground station rainfall data are used as data to drive the watershed adaptive hydrological model,and the MOSCDE multi-objective optimization algorithm is used to determine the water volume error.The coefficient of the coefficient and the relative error of the flood peak are the target factors to determine and optimize the parameters of the hydrological model,and analyze the influence of different rainfall data inputs on the prediction accuracy of the model.The results show that the forecasting accuracy of the hydrological forecasting model driven by satellite rainfall data is slightly lower than that of the hydrological forecasting model driven by the measured rainfall.The overall forecasting accuracy is roughly the same,and the forecasting grades are all Grade A.Preferably,this is of great significance for short-term hydrological forecasting studies in the reference basins.(3)This scientific problem is determined around the parameters of hydrological model in the ungauged basins.Combining the characteristics of spatial similarity and attribute similarity,the principle of entropy weight fuzzy is introduced,and a new fuzzy comprehensive similarity method is proposed to determine the parameters of hydrological model in the ungauged basins.New is available.The study assumes that a sub-basin in the upper reaches of the Yangtze River is a ungauged basin,and the rest of the basins are dataflow basins.The data-free regional hydrology using fuzzy integrated similarity,spatial similarity,attribute similarity and global average parameterization method is compared and analyzed.The prediction accuracy of the model shows that the fuzzy comprehensive similarity transplantation method proposed in this paper has relatively high prediction accuracy,and the global average method has the worst prediction effect,and the prediction is unstable.It can be seen that the research results can provide effective guidance for the selection of regional methods for parameter-free regional parameters.(4)Based on the above research results,this paper establishes a short-term hydrological forecasting research system for data-free areas coupled with TRMM satellite rainfall,and for the first time in the ungauged basins hydrological forecasting application semidistributed The TOPMODEL model,and comparative analysis of the TOPMODEL model and the Xinanjiang model in the no-data area forecast effect.The results show that the accuracy of hydrological prediction of TOPMODEL model is significantly higher than that of Xin'anjiang model,and the simulation results are more stable,which is more suitable for hydrological forecasting in the ungauged basins.