基于分形和R/S分析的渭河干流径流变化特征研究

Analysis of runoff variation characteristics in the mainstream of Weihe River based on fractal theory and R/S analysis method

  • 摘要: 变化环境下日益突出的水资源供需矛盾对流域水资源管理提出更高要求。通过分析流域径流量变化特征,揭示流域水资源演变趋势,为流域水资源合理开发利用提供依据。以渭河流域为研究区域,采用Mann-Kendall非参数检验、分形理论和R/S等方法分析渭河干流6个典型水文站1956—2015年径流时空变化特征、持续性及两者之间的关系。结果表明:渭河干流各站点的月径流量均呈减少趋势,从上游到下游,月径流量减少趋势的显著性越来越弱,呈显著性减少趋势的月份越来越少。渭河干流各站点的月径流深Hurst指数均大于0.5,即未来与历史变化情况呈正相关性,各站点未来月径流量将呈持续减少趋势。汛期分维数大于非汛期,上游月径流分维数小于下游,中游月径流分维数最大。分维数越大,径流过程变化越复杂,河流调节能力越差,表明渭河干流在汛期和中游径流量调节能力相对较差。Hurst指数与分形维数之间有着显著负相关性,即径流量越复杂,分维数越大,Hurst指数越小。研究结果可为流域水资源科学调度提供依据,有利于促进流域内水资源严格管理。

     

    Abstract: The increasingly prominent contradiction between supply and demand of water resources under the changing environment has put forward higher requirements for the development and utilization of water resources in the river basin. By analyzing the characteristics of the runoff change in the basin, the evolution trend of the water resources in the watershed is revealed, which provides a scientific basis for the rational development and utilization of the water resources in the drainage basin. Taking the Weihe River basin (WRB) as the research area, the spatial and temporal variation characteristics, continuity and their relationships of the runoff measured at the six typical hydrological stations located along the mainstream of the WRB from 1956 to 2015 are analyzed by the methods of the fractal theory, Mann-Kendall non-parametric test and R/S analysis. The research results show that the monthly runoff measured by all hydrological stations in the Weihe River mainstream has decreasing trends. The significant decreasing trends of the monthly runoff become weaker, and the number of month with significant decreasing trends becomes less and less from the upstream to the downstream of the WRB. The Hurst index of the monthly runoff depth for all stations in the mainstream of the WRB is greater than 0.5. The results show that the future trends are positively correlated with those of the past, indicating that the monthly runoff will continue to decrease in the future. The fractal dimensions of the runoff during the flood season are larger than those of the non-flood season. The monthly runoff fractal dimensions of the upstream are smaller than those of the downstream, and the monthly runoff fractal dimensions in the middle reaches are the largest. The larger runoff fractal dimension represents the more complex runoff process and the worse regulation ability of the river. It is found that the adjustment ability of the runoff during the flood season in the middle reaches of the WRB mainstream is relatively poor. The Hurst index is significantly negatively correlated to the fractal dimension of the monthly runoff. That is, the more complex the runoff changes, the larger the fractal dimension and the smaller the Hurst index. The results can provide a basis for scientific operation of the water resources in the watershed and facilitate the strict management of the water resources in the basin.

     

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