泾、洛河水系与径流过程的分形特征及相互关系研究

Fractal Characteristics of Channel System and Runoff Process and the Correlation between Jinghe River and Luohe River

为明确水系形态与径流过程之间的分形关系,以渭河支流泾河与北洛河为例,运用盒维数计算其水系的分维数,判断流域地貌发育阶段;借助Arc GIS软件计算分析泾河张家山站、北洛河状头站的年、月、汛期径流序列分维数,揭示不同时间尺度径流过程的分形特征与水系分形的变化与相互关系。研究发现:两河均处于流水地貌发育壮年期,流域侵蚀作用仍比较强烈;泾河水系分维数与张家山站的汛期径流序列的分维数最接近,显示水系形态主要受汛期(6-9月)径流影响;北洛河水系分维数与状头站年径流序列分维数接近,故北洛河水系形态主要由年径流塑造;8月径流对泾、北洛河河网水系的塑造作用比其他月份大。研究可为河道侵蚀防治提供参考,并进一步深化分形理论在河流水文研究方面的应用。

In order to ensure the fractal relation between the shape of channel system and runoff series, two branches of Weihe River, Jinghe River and North Luohe River are taken as examples in this paper, their channel system＇s fractal dimension has been calculated by using the box dimension method, then the basin landform development stage is judged. With the aid of the ArcGIS, this paper analyzes the fractal dimension of the annual runoff process, the monthly runoff process and the flood season runoff process of Zhangjiashan Station, Jinghe River, and Zhuangtou Station, Luohe River, and, looking for the changing feather on fraetal characteristics of different time runoff series and of the channel system＇s fractal change, thus seek for the relation between them. Result shows that, Jinghe River, and Luohe River all stay at the mature stage of the basin landform development, basins＇erosion is still very intensive. Channel system＇s fractal dimension of the Jinghe River is mostly close to the fractal dimension of flood season runoff series of Zhangjiashan Station, it means that river network shape mainly made by flood season （June to September） runoff process. The channel system＇s fractal dimension of the Luohe River is mostly close to the fractal dimension of annual runoff series of Zhuangtou Station. It is clear that river network shape is mainly made by annual runoff process. Compared to other months, August runoff series have the strongest function on channel network＇s making. The research may provide a reference for watercourse erosion prevention and controlling, and can also deepen the application of fractal theory on the river hydrology research.