Application Of TRMM Rainfall Products In Runoff Simulation Of Ganjiang River Basin

The global water cycle cannot be separated from the important link of rainfall,which directly affects human production and life.However,strong rainfall can lead to a series of natural disasters such as mountain torrents and debris flows,and also has a significant impact on agriculture.Therefore,we need to study rainfall,grasp its rules,and timely predict various rainfall information to minimize losses when dangerous disasters occur,This makes the study of rainfall of important practical significance.Rainfall is an important input link for hydrological analysis and simulation of a hydrological model.Although traditional rainfall stations have accurate data,their spatial distribution is insufficient,and the distribution of rainfall stations worldwide is not perfect.Due to geographical and environmental factors,the conditions for building traditional rainfall stations in many regions are not satisfied,and there is no way to obtain accurate rainfall data,which has become a major problem for water conservancy workers,But with humans being able to observe satellite precipitation from space,there are solutions to this puzzling problem.The satellite precipitation observation system is also the only scheme currently able to understand changes in global rainfall data,and has important advantages in spatial rainfall distribution.The TRMM satellite was jointly developed,designed,and launched by the National Aeronautics and Space Administration of the United States and the National Space Development Agency of Japan.The satellite was launched in Japan in November1997.In August 2001,the orbit height of the TRMM satellite was raised from 350 km to 402.5 km,providing global observation data from 50 ° north latitude to 50 ° south latitude;This has provided reference data for regions worldwide that lack rainfall data.However,current TRMM satellite rainfall data still have some potential observation errors and cannot be directly used in hydrological analysis.Therefore,how to effectively utilize TRMM satellite rainfall data is an important research topic for water conservancy workers.Taking Ganjiang River basin as the research area,this paper studies the TRMM 3B42 RT V7 satellite data and the ground measured rainfall data,discusses the fusion method of the measured rainfall data and the satellite rainfall data,compares the effect of runoff simulation before and after the fusion,and obtains a method of how to improve the accuracy of rainfall data in hydrological simulation.The main research contents and relevant conclusions of this paper are as follows:(1)Taking the Ganjiang River Basin as the research area,the accuracy evaluation and runoff simulation research of TRMM satellite rainfall data were conducted.Based on the comparison of measured rainfall data,it was found that there were quantitative errors in satellite rainfall data when rainfall intensity was greater than 40mm/d and less than 1mm/d,and accuracy correction was needed.(2)The TOPMODEL hydrological model is driven by satellite rainfall data and measured rainfall data to simulate runoff.The results show that the simulation results of satellite rainfall data are not as good as the measured data.The Nash efficiency coefficient of runoff simulation is 0.736,and the Nash efficiency coefficient of measured rainfall-runoff simulation is 0.812.There are problems with the accuracy of satellite data,but it has certain utilization value.(3)In order to correct the error of satellite rainfall data,the advantages of high precision of ground rainfall stations at single point and the satellite data can well reflect the overall rainfall distribution of the basin as well as the error of satellite data in special rainfall are used,and the fusion method of Tyson polygon and area-weighted rainfall calculation is reasonably used;Using the fused rainfall data to drive the hydrological model for runoff simulation,the results show that the overall simulation curve is more consistent with the measured runoff,with a Nash efficiency coefficient of 0.863;The fused rainfall data is significantly improved in runoff simulation and the simulation accuracy is improved.This method of correcting rainfall data has good application effect in Ganjiang River basin.