洪水预报误差在河道演算中的传递分析

考虑入流过程洪水预报误差的随机性,基于Nash汇流理论建立了河道洪水演算的随机模型,在预报误差近似独立且服从正态分布时,推导了出流过程的计算公式和方差函数,定义了洪水预报误差随机性的传递函数,分析了洪水预报误差的随机性在河道洪水演算过程中的传递特征。实例应用结果表明,上游入流的洪水预报误差经过河槽调蓄或经由Nash汇流模型演算后,其不确定性会大为降低。同时,根据建立的河道洪水演算随机模型,还可以确定出流过程的置信区间,从而为估计河道防洪控制断面可能出现的风险提供理论依据。

Stochastic Transfers of Inflow Forecast Errors in River Flood Routing

A stochastic river flood routing model based Nash flow concentration theory was built in consideration of the stochastic inflow forecast errors. The downstream outflow process and its variance function were deduced under the assumption of independently and identically normally distributed errors. The uncertainty of the outflow caused by the stochastic inflow forecast errors was characterized by the stochastic transfer function. Case study shows that the uncertainty of the outflow decreases after the river flow routing or via the calculation of Nash flow routing model. Confidence intervals of the forecast can also be determined by the proposed stochastic model, which may provide scientific evidence for estimating of the risk of flood control section.