河网形态与环境条件的关系

Relationship between river network pattern and environmental condition

在不同自然环境和地质构造的影响下,产生了不同的河网发育模式,从而形成各种河网形态。为了探讨环境条件与河网形态的关系,该文对卫星图片加以分析,以平面拓扑特征为依据划分了3种典型河网形态:羽状河网、叶状河网和枝状河网,并对这3种典型河网形态的Horton比和流域外型参数进行了统计。结果表明,对于不同的大型河网,其分支比、长度比、面积比分别趋向于定值,与环境条件无关,而不同小流域Horton比差异巨大,由此得出了Horton比可以反映小尺度上环境条件所产生影响的结论。

River networks evolved in different ways depending on the environmental and geological conditions, leading to various river network patterns. The relationship between the river patterns and the environmental conditions was analyzed by classifying three typical river network patterns （feather, leave, and branch） based on their planar topological features in satellite images. Statistics are given for the Horton ratios and basin shape parameters for the three patterns. The bifurcation ratios converge to 2, the length ratios to 4, and the area ratios to 4 for large river networks, regardless of the environmental conditions. However, the Horton ratios differed greatly at small scale suggesting that the Horton ratios can be used to reflect the influence of environmental conditions at small scales.