Application of Stochastic System Theory for Rainfall Runoff Analysis

通过流域蓄泄非线性关系的时空变化参数的变化，研究了小流域洪水径流过程。采用随机系统理论中的参数辨识方法，主要研究成果如下：1.利用随机系统理论对状态空间进行参数论证。时变库容参数的变化与沟道径流代表的坡面上快速流的产生密切相关，通过识别这些变化可以反推平均流应力。提出了一种模型，该模型用库容SC来处理以贯通流为主时和以沟流为代表的快速流为主时流域蓄水与流量的关系。结果表明，仅用雨量和流量资料就可以用非线性滤波的方法来估计SC。文中还给出了利用SC进行参数辨识的方法。阐明径流模型参数的空间变异性是集总问题的重要研究内容。

Studies are made on flood runoff processes in small mountainous basin through variation in timespace-varying parameters of the nonlinear relationship between basin storage and dischage. An identification method of the parameters is used by the stochastic system theory.The results are summarized as follows:1. Parameter argumentation is utilized in state space formulation by using stochashic system theory.2. The variations of time-varying storage parameters are closely related to the generation of fast flowe on a hillslope as represented by gully runoffs,and it is possible to inversely estimate the average flow-ststes by identification of the variations.3. A model,in which storage Sc is used to join the ralationship between basin storage and discharge when throughflows predominate and that when fast flows (represented by gully flow) predominate,is introduced. It is shown that Sc can be estimated by nonlinear filtering with only rainfall and discharge data. The method of identifying the parameters using Sc are also shown.4. It is important for lumping problem to clarify space variations of runoff model parameters.