基于部分概率权重矩的P-Ⅲ分布参数估计方法

在洪水频率分布参数估计中,根据部分概率权重矩（PPWM）和无限区间积分原理,推导了PPWM的皮尔逊三型分布(P-Ⅲ)参数估计公式,并用Monte Carlo试验验证了估计量的统计特性。以陕北地区枣园、吴旗、黄陵3个水文站的年最大洪峰流量系列为例,建立了PPWM的P-Ⅲ分布。结果表明,低删失样本的PPWM在高分位数估计方面有效性良好,适用于洪水频率分布参数估计。

Estimation methods of P-III distribution parameter based on partial probability weighted moments

The parameter estimation formula of Pearson III (P-III) distribution is derived according to PPWM (Partial Probability Weighted Moments) and infinite interval integral principle, and the statistical properties of estimated parameters were verified by Monte Carlo test. The P-III distribution of PPWM is established by using annual maximum flood peak series of Zaoyuan, Wuqi and Huangling Hydrological Stations . The results indicate that the method of PPWM from lower bound censored samples is still effective in high quantiles estimation, which is feasible for the estimation of flood frequency distribution parameters.