Attribution Analysis Of Runoff Variation In Zhanghe River Basin Based On Budyko Framework

Due to the influence of environmental change,the runoff of Zhang River Basin shows a downward trend in the past 60 years.The environmental change mainly includes two aspects of climate and human activities.Quantitative assessment of the impact rate of climate change and human activities on runoff plays an important role in planning and managing the planning and allocation of water resources in Zhang River Basin.In this paper,the runoff evolution characteristics of five hydrological stations in Zhang River Basin are analyzed by various methods;a potential evapotranspiration estimation model suitable for Zhang River Basin is constructed by comparing and analyzing the existing potential evapotranspiration estimation models;and based on various forms of empirical formulas under Budyko framework,the impact rate of climate change and human activities on runoff change in Zhang River Basin is quantitatively evaluated.The main results are as follows:(1)The annual runoff change trend of the five hydrological stations in Zhang River Basin is basically the same,with a significant downward trend and obvious mutation characteristics;the annual runoff reduction rate of Qingzhang river basin is greater than that of Zhuozhang River;on the tributaries of Qingzhang River and Zhuozhang River,the decreasing rate of runoff increases with the increase of confluence area;the year of abrupt runoff is determined as 1978 The research period is divided into base period(1959-1978)and change period(1979-2017).(2)Compared with PM,the results of Hargreaves model based on radiation have the least error;the average relative humidity is an important factor affecting the potential evapotranspiration;the highest temperature,the lowest average relative humidity and the maximum sunshine hours are obtained in the confluence area of Liujiazhuang station,which leads to the maximum potential evapotranspiration of Liujiazhuang station;compared with Zhuozhang River,Qingzhang river has the highest potential evapotranspiration,The results show that the potential evapotranspiration of Qingzhang river is higher than that of Zhuozhang River due to high temperature,low relative humidity and large sunshine hours.The annual average temperature of Zhang River Basin increases,and the potential evapotranspiration has a decreasing trend,which leads to the phenomenon of "Evaporation Paradox".(3)The results obtained by the cumulative slope rate method are consistent with those obtained by the Budyko framework method,which proves that the calculation results based on the Budyko framework are reliable.It can be concluded that: in Zhanghe River Basin,human activities play a leading role in runoff reduction,among which the most important is affected by the change of underlying surface.Specifically,the runoff reduction in Zhanghe River Basin is mainly caused by the change of underlying surface,the impact of climate change on runoff is mainly caused by the change of precipitation,and the potential evapotranspiration has little impact on the runoff change of Zhanghe River Basin,and has a negative impact;with the increase of basin area,the impact of human activities on runoff change increases,and the impact of climate change decreases.