中文摘要：

提出一种考虑误差异分布的概率预报方法：根据实测及预报洪水信息,估计不同量级洪水预报误差的概率分布,推导了以预报值为条件的流量分布函数,实现洪水概率预报。以淮河王家坝断面为对象,采用经验预报模型对1996—2007年10场洪水进行预报并分析误差规律,发现不同量级洪水预报误差的均值差异显著,即误差具有异分布特征。为此,构建误差均值与预报值之间的函数关系,建立以预报流量为条件的误差概率分布。在此基础上,对2008年2场洪水进行概率预报,结果表明基于误差异分布的洪水概率预报模型简单实用;若以概率分布期望值作为定值预报,相较于经验预报结果,精度更高。

英文摘要：

A probabilistic flood forecasting method considering the heterogeneity in error distributions of deterministic predictions is presented.In this method,error distributions of different flood magnitudes are constructed using their observed values and model forecasting values（MFVs） and their probabilistic distribution functions（PDFs） conditional on the MFVs are derived; then,by using these PDFs a probabilistic flood forecasting is achieved.In its application to the Wangjiaba station in the Huai River basin,an empirical model was adopted in deterministic flood predictions of the ten flood events occurring in the period of 1996-2007,and variations in the relative errors of the deterministic predictions were examined.This analysis revealed that the means of PDFs of these relative errors differ significantly between different flood magnitudes.To consider such heterogeneity of error distributions,we can construct a functional relationship of the mean value of the relative errors versus their corresponding MFVs,and derive error distributions conditional on the MFVs.This new method was verified by using the data of two floods occurring in 2008.Results show that the probabilistic method is simple and practical and it can give more accurate forecasts than the empirical model when the means of PDFs of discharges are used as deterministic predictions.