Study On Runoff Change And Attribution Of Tumen River Based On SWAT Model

With the influence of global warming,the dynamic change of water heat balance and the change of underlying surface caused by human activities,the hydrological cycle process of the basin is inevitably affected.Tumen River Basin is located at the junction of China,North Korea and Russia.It is an important international river in China.It is an important support area and a new fulcrum of maritime strategy in the implementation of the "the Belt and Road" strategy.It is of great significance to carry out hydrological research on the basin,explore the dynamic changes of water cycle in the basin,and realize the rational and sustainable development and efficient utilization of water resources.Based on the climate data of 14 meteorological stations in the study area and the surrounding area and the runoff data of the hydrological station nearest to the estuary,in combination with land use change and soil data,this study establishes a SWAT model suitable for the hydrological study of Tumen River Basin,explores the attribution analysis of the runoff change in Tumen River Basin,and quantitatively analyzes the influence amount and contribution rate of each influencing factor to the runoff change.The main conclusions of the study are:(1)The runoff in the study area decreased significantly from 1988 to 2011,and there was a sudden change in 2002.Based on this,the base period(1988-2001)and the sudden change period(2002-2011)were divided.Among the relevant climate factors,the precipitation and relative humidity have a significant downward trend,the sunshine hours and potential evapotranspiration have a significant upward trend,and the time and time of the mutation point are similar to the runoff,and other factors have no significant changes.(2)From 1988 to 2011,the change trend and sudden change time of climate factors such as annual average daily precipitation and annual average sunshine hours of Tumen River showed high correlation and consistency with runoff change characteristics.The underlying surface condition in the study area is stable and has no obvious impact on the runoff change.The decrease of precipitation has a significant positive effect on the runoff change,while the increase of sunshine hours has a negative effect on the runoff change.The coupling effect of the three factors has a significant positive effect on the change of runoff;In addition,other factors have a certain negative effect on the change of runoff.(3)The accuracy of SWAT model constructed in this study is within the confidence interval of the study,which indicates that it can better simulate the hydrological situation of Tumen River Basin.Through scenario setting,the separation of precipitation,sunshine hours,land use and the coupling effect of the three is realized.The research results show that the contribution rate of sunshine hours change to runoff reduction is 18%;The contribution rate of precipitation change to runoff increment is 99%;The contribution rate of land use change to runoff reduction is 1%;The contribution rate of coupling effect to runoff reduction is 95%,which indicates that the influence of precipitation on runoff is decreased under the interaction of other factors;The contribution rate of other factors to the runoff of Tumen River is-4%.