Applicability Of Imerg Satellite Precipitation Data In Runoff Simulation In Karst Area

Precipitation is the foundation of hydrological research.Improving the accuracy of precipitation measurement is great for flood forecasting,water resources utilization,and water ecological management.The paper takes the IMERG satellite precipitation data as the research object,and performs GDA correction and accuracy evaluation on the original IMERG data.On this basis,took the original and corrected IMERG data apply in runoff simulation.The main work and research results are as follows:(1)Comparing the original and corrected IMERG data with the ground station data respectively,the overall results show that the original IMERG-early,IMERG-late and IMERG-final data have low accuracy on short time scales,and the spatial and temporal distribution of precipitation has a certain deviation compared with the ground data;The corrected IMERG-early,IMERG-late and IMERG-final data have better accuracy indicators on each time scale,which can better describe the temporal and spatial distribution of ground precipitation data.(2)Substituting the original and corrected IMERG data into the HEC-HMS flood model.The results show that the qualified rate of the simulated IMERG data simulation flood is only 5.56%,and the simulation result is below the C level;the qualified IMERG data simulates the flood pass rate.It is 66.67%and the simulation result is C level.The results show that the original IMERG data can not be directly applied to flood simulation,and the corrected IMERG data has relatively good performance in flood simulation,and has certain potential in improving flood simulation accuracy.(3)Substituting the original and corrected IMERG data into the SWAT model,and simulating the daily and monthly runoff process.The results show that the daily and monthly runoff simulated by the original IMERG data are all“unqualified”grades,and the simulation effect is poor;the daily runoff of the corrected IMERG data simulation is“qualified”grade,and the simulated monthly runoff is "good," grade.The results show that the original IMERG data can not be directly applied to long-term runoff simulation,and the corrected IMERG data has certain applicability in long-term continuous runoff simulation.