中文摘要：

把握径流波动规律、对径流演变趋势做出准确判断,是当前水文学研究的有益课题。综合考虑径流序列演变的时变性、随机性和非线性特点,引入R/S分析法及其时变Hurst指数,并以黄河干流为例,深刻描述了径流时间序列演变过程的持久性测度。计算结果表明：黄河干流径流时间序列在时间和空间分布上具有分形特征,径流演变存在状态持续性及其内在的周期循环长度,从而为河川径流的非线性和复杂性研究提供了新的研究视角和实证结论。

英文摘要：

To grasp the rule and the skeleton of the runoff fluctuation thus to estimate its trend truly is an available task in the field of hydrology currently. Based on R/S theory and its time - change exponent which named Hurst, Taking the main stream of the Yellow River as a case, comprehensively considering the characteristics of time - change, randomcity and non - linearity of the runoff time series, persistence measure in the process of the runoff evolution were described. It was found that the runoff time series of the Yellow River is of fractal, in which existing the state durative and the cycle during runoff fluctuation. Thereby a new angle of views and demonstration resuits were provided for workin~ over the nonlinearity and the comDlexitv of the river runaff.