IMPACT OF CLIMATIC FACTORS ON TURNOFF OF THE HUANGHE RIVER

In recent years, Turnoff of the Huanghe River has gained much concern. It has been argued that the turnoff of the Huanghe River results from complex reasons including natural and man made factors. Among the natural factors, impact of climatic factors is more important and more direct. Therefore, this paper analyzes the impact of climatic factors on the turnoff of Huanghe River by employing empirical data. Temperature and rainfall data set from 1951 to 1999 of nearly 100 stations in the Huanghe River valley are used to calculate the amount of area rainfall over upstream, midstream and downstream area respectively by the Tasin polygonal method. Based on the calculating result, climatic characteristics in terms of temperature and rainfall within 50 years along the Huanghe River valley are analyzed. Almost 40 sites data of temperature and rainfall from 1920～1999 in the Huanghe River valley are used to discuss the impact of temperature and rainfall on the turnoff of Huanghe River. The conclusion is that from 1922 to 1932, higher temperature and less rainfall directly resulted in the low water of Huanghe River valley. While in recent two or three decades, apart from climate factors, influence from human activities, such as over development, unreasonable using of water resources and destroy of eco environment of the Huanghe River, is growing more evidently, whose negative impact on the turnoff of Huanghe River should be concerned a lot.