中文摘要：

水文频率分析计算过程中，水文极值样本系列容量一般都较小、代表性不高，使得水文设计值估计具有不确定性。利用Bootstrap方法，研究样本抽样不确定性对水文设计值的影响。与传统水文频率分析方法相比，基于Bootstrap方法不仅可提供设计值的点估计和区间估计，同时能够对设计值的不确定性进行定量评价。此外，基于Bootstrap技术，结合矩法、权函数法及线性矩法，设置3套方案，分析了该方法在不同参数估计方法间的有效性。以南通市1970-2011年共42年的年降雨量数据资料为例，对所提方法进行实例应用分析，结果表明，从期望设计值、90％置信区间及最终设计值角度而言，基于所提方法的设计成果受参数估计方法的选取影响不大，且可回避规范中日值诺莫图通用性较差及误差显著问题。

英文摘要：

A common problem in hydrologic frequency analysis is that the sample size is often too small to adequately represent the statistical property of an entire population. Uncertainties can thus be introduced during the determination of design hydrologic characteristics. In this paper, a new method based on Bootstrap is used to estimate the influence of sample uncertainties on the design characteristics. Compared to conventional approaches, the new method provides not only point estimates and interval estimation for the design characteristics, but also a quantitative evaluation of un- certainties associated with hydrological frequency analysis. In addition, combing with the Bootstrap technique, three schemes are established for assessing the effectiveness of the new method when using different parameter estimation ap- proaches. The schemes are the moment method, the weight function method and the linear-moment method. The Nan- tong annual rainfall data from 1970 to 2011 is used to validate the new method. The result shows that with the new method, the selection of different parameter estimation approaches will have an insignificant impact on the determina- tion of design hydrologic characteristics. This is from the point of view of the expected value, 90% confidence inter- vals and the final design characteristics. The new method can also deal with the limitation of the B value.