水文频率计算中统计参数的不确定性

UNCERTAINTY OF STATISTICAL PARAMETERS IN HYDROLOGICAL FREQUENCY COMPUTATION

采用资源生成的方法，在指定总体为Γ分布的情况下，模拟多个水文系列，用优选搜索法，计算系列长度为２０、５０和１００时的统计参数。分析结果表明，在同一条件下，统计参数有一定的变化幅度，即表现出它们的不确定性程度。实际工作中，所掌握的仅是较短期的水文系列，含有较大的不确定性，对系列的代表性分析和结果的合理性检查，十分重要。

Under the situation where the specific population is gamma distribution,a lot of hydrological series are simulated by data generation technique.The optimized search method is used to calculate the statistical parameters of these series,in which sample sizes of 20,50 and 100 are selected.On the same conditions,the estimated values of statistical parameters are of a certain domain,showing that there are some uncertainties in the parameter estimation and the higher uncertainty the smaller sample size.In practice,there may be higher uncertatinty due to shorter data series.Thus,it is very important to analyze the representation of data series and rationality of results.