Precipitation Runoff Trend In The Source Region Of The Yellow River Under Future Climate Change

Climate change and human activities have led to a series of changes in the hydrological process.The Yellow River source region is an important part of the Yellow River Basin and one of the important water source conservation areas.Therefore,studying the future climate trend changes in the source region of the Yellow River and its impact on runoff have important practical significance for the management,planning and development of future water resources in the Yellow River source region.This paper uses the SWAT hydrological model as a tool to firstly use the measured meteorological data from 7 stations of Hongyuan,Maqu,Maduo,Ruoergai,Jiuzhi,Dari and Henan to simulate historical runoff and judge the applicability of the SWAT model in the Yellow River source region.The results show that the simulated values of monthly runoff in the source region of the Yellow River are in good agreement with the measured values.The Nash efficiency coefficient(NSE)and relative error(Re)in the calibration period(1975-2000)are 0.81 and-0.004,and the NSE and Re in the Verification period(2001-2012)are 0.8 and 0.058,the result indicate that the SWAT model can well simulate the monthly runoff in the source region of the Yellow River,and has good applicability in this area.Then,the accuracy and correction of the precipitation and temperature data of the CMIP5 CMCC-CM model are carried out,and the future trend changes of the corrected precipitation and temperature are analyzed.The results show that the future precipitation shows a decreasing trend and the future temperature shows an upward trend.Finally,the future precipitation and temperature data are input into the well-defined SWAT model to predict the future runoff of the Yellow River source region,and the trend change analysis is carried out.The results show that the future runoff of the Tangnaihai station in the Yellow River source region shows a decreasing trend and benchmark.Compared with the period(1971-2010),in 2011 to 2050,the RCP4.5 series predicted runoff reduction by 1.6% and the RCP8.5 series predicted runoff decreased by 3.7%.In 2051 to 2090,the RCP4.5 series predicted runoff reduction 0.3%,RCP8.5 series runoff reduced by 29.2%.In summary,the SWAT model has good applicability in the source region of the Yellow River.The future precipitation in the Yellow River source region is reduced,the temperature is rising,and the runoff is reduced.The results of this study can provide reference for future water resources management and planning in the region.