由流路长度分布律和坡度分布律确定地貌单位线

Study of determining geomorphologic unit hydrograph by means of probability density functions of path length and slop

根据Rodriguez Iturbe等和Gupta等导得的流域瞬时单位线即为雨滴汇流时间分布密度的结论,基于雨滴汇流时间等于其流路长度与其速度之商的基本关系式,提出了应用概率论理论建立由雨滴的流路长度分布律和速度分布律确定流域瞬时单位线的方法,并提出了由坡度分布律转换成速度分布律的原理和方法,以及由数字高程模型(DEM)自动获取雨滴流路长度分布律和坡度分布律的方法。此外,还应用最大信息熵原理给出了坡度分布密度的解析表达式。实例表明,作为一种新的毋须通过实测降雨径流资料确定流域单位线的方法,具有进一步研究和推广应用的前景。

The instantaneous unit hydrograph (IUH) was interpreted as the probability density function (PDF) of water drop travel time in the basin by RodriguezIturbe et al and Gupat et alAs the water drop travel time in the basin equals to proportionality of the water drop path length to its velocity, a new method for determining IUH is suggested by means of the PDFs of path length and velocity of water drop based on law of the probability theory The PDF of the water drop path length can be viewed as the width function, and the PDF of water drop velocity is transformed by the PDF of slop Otherwise, the analytical equation of slop PDF is derived by the principle of maximization information entropy Technical support of the new method is of the digital elevation model The example watershed given in this paper is located at Hubei province, China, and the simulation accuracy is satisfactory