Land Use Dataset Accuracy And CFSR Precipitation Data Correction Simulation Of SWAT Model Rainfall Runoff

Precipitation is a key link in the natural water cycle and a key factor in the formation of runoff.Accurate simulation of runoff is of great significance for rational utilization of water resources,flood control and disaster reduction.Researchers often use distributed hydrological models to simulate runoff in river basin,among which SWAT model is widely used.As the basic input data of SWAT model,the accuracy of land use data and precipitation data have some influence on model simulation.However,the lack or incomplete rainfall data caused by terrain barrier,human and material shortages hinders the relevant hydrological simulation researches.The CFSR precipitation data is widely used in hydrological simulation because of its simple acquisition and high resolution,but its applicability in Jinghe upstream basin has not been verified.Therefore,in order to determine the resolution of land use data and the influence of CFSR precipitation data on the model hydrological simulation process and its results,we use different resolution of land use datasets in this paper in the jinghe river basin above the jingchuan hydrological station?China's 1:100,000 land use dataset with a resolution of 105m,Land 1 and China's 1:100,000 land use dataset with a resolution of 1 km,Land 2,and WESTDC land use dataset with a resolution of 1 km,Land 3?and the different precipitation data?CFSR precipitation data before and after the data is corrected and ground rainfall station data?to simulate the monthly runoff of the jingchuan hydrological station during the period of1980-1990.Taking 1980 as the model warm-up period,1981-1986 as the model rate period and 1987-1990 as the model validation period,E_NS and R² were selected as evaluation indexes of model simulation results to analyze and compare runoff simulation results of various SWAT models,and the following main conclusions were drawn:?1?The SWAT model is suitable for the Jinghe upstream basin,and the SWAT model corresponding to the Land 2 data set has better simulation effect than the other two data sets.At the calibration period,the evaluation indexes of simulation results E_NS=0.75,R²=0.76;During the validation period of the model,the evaluation indexes E_NS=0.69,R²=0.77;?2?The resolution of the input land use data mainly affects the division of the hydrological response unit of the model,but has little influence on the hydrological simulation results.In other words,the resolution of the input land use data set is not simply linear with the model simulation results;?3?The resolution of CFSR precipitation data is very low compared with the measured ground rainfall station precipitation.There is an overestimation of the measured monthly precipitation in January-April and November-December,and there is precipitation in the measured monthly precipitation from June to July,that is,the CFSR precipitation data on the monthly scale has overestimated weak precipitation and underestimates the heavy precipitation.?4?The CFSR is used for runoff simulation with low simulation accuracy,and the runoff simulation results are E_NS<0.5 and R²<0.5,which is difficult to meet the needs of runoff simulation.?5?After correcting the CFSR precipitation data by using two CFSR precipitation data correction methods,the data accuracy of the CFSR precipitation data set itself or the model runoff simulation result obtained by driving the SWAT model as the model input data has been greatly improved.The CFSR precipitation data can be used in the upper reaches of the Jinghe river.This study has certain reference value for the selection of similar land use datasets in the upper reaches of the Jinghe river,the correction method of CFSR precipitation data sets and its runoff simulation prediction.