Applicability And Application Of PREC/L Reanalysis Of Precipitation Data In Shiyang River Basin

There is a shortage of water resources in the western region of China,and the development and utilization of water resources is extremely urgent.This paper takes the Shiyang River Basin in the western region as the research area,with complex terrain and sparse distribution of meteorological and hydrological stations.Firstly,the applicability of PREC/L reanalysis precipitation data in Shiyang River Basin is analyzed.Then,VIC hydrological model simulation is optimized as supplementary data of measured precipitation data,and then the stone sheep are studied under the scenario of increasing precipitation at different monthly and daily scales.The response of river basin runoff provides a theoretical basis for optimizing the effect of artificial precipitation.The main contents and research results of the thesis are as follows:(1)In order to evaluate the applicability of PREC/L reanalysis of precipitation data in the Shiyang River Basin,based on the measured precipitation data of the basin site,the regional applicability analysis and correction of the PREC/L reanalysis precipitation data were carried out.The results show that the PREC/L reanalysis of precipitation data in the annual,spring,summer,autumn and winter scales of the multi-year mean and measured precipitation deviation,deviation rate and other indicators performed well,the deviation rate does not exceed 20%.On the spatial scale,the precipitation data of PREC/L reanalysis is consistent with the distribution of measured precipitation,and the precipitation decreases gradually from the south to the north of the basin,but there is a large deviation between the measured precipitation in the southern part of Yongchang station and the northern part of Minqin station..After comprehensively considering multiple factors such as DEM and terrain,the Shiyang River Basin is divided into five regions for linear correction of the PREC/L reanalysis data.The consistency of the corrected reanalysis precipitation and the measured precipitation spatial distribution is improved.Moreover,the deviation rate from the measured precipitation is reduced,which indicates that the reanalysis of precipitation data can be used as a powerful complement to the basin precipitation observation data after verification and correction.(2)Using the corrected high-resolution PREC/L to re-analyze the precipitation data as the supplementary data of the precipitation of the meteorological site,and improve the simulation effect of the constructed VIC hydrological model.The Nash coefficient on the regular internal-day scale of the 2015-2016 rate is calculated to be 0.58,and the relative error is 11.23%.The Nash coefficient during the 2016-2017 verification period is 0.6,and the relative error is 11.15%.The constructed VIC hydrological model is applicable to the Shiyang River Basin,and the PREC/L reanalysis data can effectively improve the lack of precipitation data and uneven spatial distribution in the basin.(3)Through the constructed VIC hydrological model,select two characteristic points 1 and 2 near the Wushaoling site,and design the precipitation variation scenarios of 63 kinds of monthly scales and 3 kinds of daily scales,and analyze the Shiyang River under these scenarios.The response of the basin runoff.The results show that when the precipitation is increased by 20% in one month,the rainfall in the feature point 2 in August has the greatest response to runoff;when the rain increases in two months,the rain increases in the July and August of the feature point 2.The response of runoff is the most obvious;when the precipitation is increased for three months at the same time,the rain increases at the same time in August of feature point 1 and July and August of feature point 2,and the response to runoff is the largest;During the monthly precipitation,the rain increases in July and August of feature point 1 and July and August of feature point 2,and the response to runoff is the largest.When the precipitation is increased for five months,at feature point 1,In July and August,and in July and August of feature point 2,simultaneous rainfall increased the response to runoff.On the daily time scale,the increase in rainfall on the day of the largest monthly rainfall has the greatest impact on the change of runoff outlet flow in the basin,indicating that increasing the daily precipitation in different time periods has different responses to runoff.Can provide a theoretical basis for optimizing artificial precipitation.