流域汇流的概率论体系探讨

基于统计物理学观点,给出了净雨过程和流域出口断面流量过程的概率论解释。在此基础上,应用概率论中随机变数函数分布的理论导出了卷积公式,获得了不同于Rodriguez-Iturbe等对流域瞬时单位线所作的概率解释,且前提条件更为明确。证明了流域瞬时单位线的一阶原点矩、流域滞时和平均流域汇流时间是完全等价的,从而为计算平均流域汇流时间提供了一个概念明晰、操作简便的计算方法。给出了两个应用概率论方法确定流域瞬时单位线的方法,其中之一是笔者提出的。

Study of mechanism of watershed concentration flow based on probability theory

Based on view of the probability theory, probability explanations of net tainfall process over watershed and discharge hydrograph of watershed outlet are given. On the basis of these, the convolution integral equation is derived by theory of distributed function of random variate in probability theory, and probability meaning of the instantaneous unit hydrograph (IUH) of watershed is again obtained under obviouser conditions. Equivalent relationship among first order moment about the origin of IUH of watershed, lag time of watershed and average concentration flow time of watershed is proved, and a computational method of average concentration flow time of watershed is given. Finally, two methods of determining the IUH of watershed are presented by means of probability theory.