论文部分内容阅读
采用Pettitt法和里海哈林法(Lee-Heghinian)检验了流量年际变化中的突变现象,所得到的突变点将宁蒙河段年径流过程划分为三个阶段,即:1969年前;1969年-1986年;1986年以后。分析了三个阶段洪水过程的各自特点,结果显示:1969年前洪水峰型相对多尖瘦,常为多峰型;1969年-1986年洪水过程的特点和前一时期相比,洪水峰型变胖,多为单峰型。1986年以后主要为中小洪水,中小洪水矮胖,洪峰低,历时长。从气候变化、支流来水、灌溉引水、水利工程影响等四个方面分析了洪水变化的原因,发现人类活动(水库修建、灌溉引水)是造成宁蒙河段洪水年内、年际变化的主要原因。气候变化在一定程度上减少了宁蒙河段的来水量,支流对宁蒙河段水量变化影响微弱。
Pettitt method and Lee-Heghinian method were used to test the abrupt changes in the interannual variation of the flow rate. The obtained abrupt change points divided the annual runoff in the Ningmeng reach into three stages, that is, before 1969, 1969 Year - 1986; after 1986. The characteristics of the flood process in the three stages are analyzed. The results show that the peak shape of the flood before 1969 is relatively thin and often multi-peak type. Compared with the previous flood period, the characteristics of the flood peak Fat, mostly unimodal. After 1986, mainly small and medium-sized floods, small and medium-sized floods plump, low peak, lasted a long time. The causes of flood changes are analyzed from the aspects of climate change, tributary flow, irrigation and diversion, and the impact of water conservancy projects. It is found that human activities (reservoir construction and irrigation and diversion) are the main causes for the year-on-year and inter-annual variations of floods in Ningmeng reach . Climate change reduced water inflow to Ningmeng reach to a certain extent, and tributary impact on water volume change in Ningmeng reach was weak.