历史洪水不确定性对洪水频率计算成果的影响

Influence of Uncertainty from Large Historical Flood Upon Frequency Analysis

历史洪水在洪水频率计算中起到了重要作用。估计的历史洪水数量及其重现期均存在不确定性(与真值偏离),以统计试验法研究了不确定性对洪水频率计算成果的定量影响。结果表明:在多数情况下,即使历史洪水存在不确定性,但积极作用是主要的;在历史洪水存在不确定性情况下,以概率权重矩法估计的参数稳健性优于优化适线法。

Large historical flood discharges can play an important role in hydrologic frequency analysis. However their magnitude and recurrence interval must be estimated and they suffer from a serious uncertainty. Such uncertainties ought to be taken into account in frequency analysis. The study on influence of uncertainty upon frequency analysis has been conducted by using a statistical experimental method. The results indicate that although estimated magnitude and recurrence interval of large historical flood discharges are involved in uncertainties, their positive role may be significant in most cases. Moreover, under the situation of uncertainties in large historical flood, the quantities estimated by probability weighted moments may be more robust than those by a optimal curve fitting method.