耦合不确定性的山洪灾害风险预警方法及应用

Coupled uncertainty of flash flood forecasting method and its application

山洪灾害风险预警过程中各组分(数据、水文模拟、预警方法)的不确定性对山洪风险预警不确定性的影响机制尚不明确,缺乏定量组合分析理论与方法。本文提出了一种针对山洪灾害风险预警的耦合不确定性分析方法。该方法基于水文模型模拟及动态量临界雨量进行山洪灾害风险预警,并对预警过程中降水输入、水文模拟及山洪预警方法的不确定性及其组合不确定性进行分析。在福建闽江下游流域的应用结果表明,降水输入、水文模型径流模拟、临界雨量量化方法所导致的不确定性占总体不确定性的36%、24%及40%。在耦合不确定分析下,不同风险等级(Ⅳ、Ⅲ、Ⅱ、Ⅰ四个风险等级)对应的山洪灾害的发生概率平均分别为58%、65%、79%、81%。本研究发展的不确定性分析方法对于精准预报及科学防灾抗洪有着重要的实践意义。

Uncertainty in each forecasting component,such as driving data,hydrological simulation,and early warning method,imposes an impact on the uncertainty of flash flood risk early warning,but its mechanism is not well understood yet and the theory and method for a quantitative combination analysis are lacking.This study develops a coupled uncertainty analysis method for flash flood early warning based on hydrological model simulations,formulates a dynamic critical rainfall index,and applies both to an analysis of the lower reaches of the Min River in Fujian Province.The results show the uncertainties caused by precipitation input,runoff simulation,and critical rainfall quantification account for 36%,24%and 40%of the total uncertainty,respectively.Under a coupled uncertainty analysis,the average probabilities of flash flood disasters at risk levels IV,III,II and I are 58%,65%,79%and 81%,respectively.This new analysis method is of great significance in practical flash flood warming and disaster prevention.