Comparative Analysis Of Calculation Method Based On Multi-source Rainfall In Jiangxi Basin

Surface rainfall is widely used in water conservancy industry.It is a basic product for water conservancy work.Because of the abundance of precipitation data and the variety of calculation methods,it is very important to select a suitable data and calculation method which can improve the accuracy of business work and reduce the workload.In this paper,the surface rainfall is integrated into GIS,using the characteristics of GIS,the production of the bottom rainfall map,the calculation and drawing of the surface rainfall.Through three precipitation data and three calculation methods,the surface rainfall results of the 4 precipitation processes are compared and analyzed,in which the Tyson polygon and arithmetic mean method are used for meteorological and hydrological data.The grid averaging method is used for the three source fusion precipitation data,and the gap between each other is found by comparison.The calculation of Tyson polygon and the subbasin division of a watershed by GIS are used to calculate the area and surface rainfall in Jiangxi province.The results are as follows:(1)using the 4 rainstorm precipitation process of 2015-2016 years,the two precipitation process is analyzed in detail,which shows that the precipitation distribution and the magnitude of precipitation have obvious systematic differences under different influence systems.(2)for the data of meteorological stations and hydrological stations,the results of Tyson polygon and arithmetic mean of the two data are found to be in good agreement with the Tyson polygon method and arithmetic mean method.Among the statistical results of hydrological data,only the error of the individual sub area is more than2-3mm,and the rest are around 1mm.Therefore,the more dense the site is,the closer the two methods are.(3)the 9 sub units divided by 3 types of rainfall estimation results have systematic differences.The results of the three source fusion data and the meteorological data and hydrological data show that in the rainfall above the rainfall level,the hydrological data compared with the three source fusion precipitation data is small,and the meteorological data compared with the three source fusion precipitation data are large.The average precipitation results of the three kinds of data are averaged,and the three source fusion precipitation is larger than the three,and the meteorological data and hydrological data are smaller than those of the three.Whenthe control area of each weather station exceeds 2000km2,the result of the arithmetic average method is much less than that of the Tyson polygon method.When the control area of each hydrological station exceeds 50km2,the result of the arithmetic average method is much less than that of the Tyson polygon method.The results of this study can provide reference for real-time operation of flood forecasting and accurate forecast of basin surface rainfall,and provide a reliable reference for water resources scientific research,flood control scheduling and water storage power generation.