作为流域山坡单元离散控制参数的河网阈值

Drainage area threshold as a parameter for controlling spatial hillslope discretization in basins

对于基于山坡单元的GBHM模型,河网阈值的选取决定了模型模拟时的流域离散精度。该文以流域地形地貌分析为基础,提出了一种基于多重分形的河网阈值联合优选SD-MF法,该法首先根据传统方法确定河网阈值的选取范围,然后利用多重分形选取阈值范围内的相对最优值。SD-MF法在密云水库以上潮河流域及白河流域的应用结果表明:2个流域恰当的河网阈值均为0.675 km2,为流域GBHM模型的构建奠定了基础。

The drainage area threshold controls the resolution of the basin discretization when the hillslope-based GBHM （geomorphology-based hydrological model） model is used for hydrological simulations. This paper describes a multi-fractal method based on analyses of the river slope and the drainage density developed from analyses of the geomorphologieal properties of various basins. In this method, the drainage area threshold is first determined by traditional methods, then the relative optimal scope is determined using the multi-fractal method. The results applied to the Chao and Bai River basins of the upper Miyun Reservoir show that appropriate drainage area thresholds for both basins are 0. 675 km^2 for use in the watershed GBHM model.