河川径流情势主成分分析

Principal component analysis of runoff regimes of rivers

为了获得正确、可靠的河川径流情势,有效开发利用河流水能资源,以抚河流域为案例,分析了抚河12个水文站的日均流量、最小日平均流量、最大(小)月平均流量、基流指数、小于或等于年均流量5%的持续天数、大于或等于90 d的日均流量、日均流量标准偏差、年均流量变异系数等10个变量的径流样本主成分,计算了主成分的贡献率、累计贡献率、得分和样本综合得分,评价了抚河干支流径流情势。结果表明:第一主成分反映河川径流的阈值变幅、离散程度和对称状况,第二主成分反映河川径流的基流指数和变异系数,这2个主成分的贡献率依次降低。这些研究成果旨在为河流管理部门了解不同干支流河川径流情势、规划流域水能资源开发方案和维持河流良好水环境等提供技术支持和可靠的数据支撑。

In order to obtain correct and reliable runoff regimes, and to effectively develop and utilize hydropower resources of rivers, using the Fuhe River Basin as an example, we analyzed the principal components involving ten variables of runoff samples from 12 hydrological stations on the Fuhe River. The variables included daily mean flow, minimum daily mean flow, maximum and minimum monthly mean flows, base flow index, number of days during which the streamflow is equal to or lower than 5% of annual mean flow, daily mean flow for a period of 90 days or one exceeding 90 days, standard deviation of daily mean flow, and coefficient of variation of the annual mean flow. We calculated the contribution rates of the principal components, the cumulative contribution rates, and scores of samples and their comprehensive scores, and evaluated the runoff regimes of the main stream and tributaries of the river. The results show that the first principal component reflects the threshold value range of runoff, discrete degree, and symmetry conditions;the second principal component reflects the base flow index and the coefficient of variation of runoff, and the contribution rates of the two principal components decrease successively. These research results can provide river management departments with technical support and a reliable data basis for understanding runoff regimes of different main streams and tributaries, planning programs for development of hydropower resources in river basins, and maintaining a healthy water environment for rivers.