干旱区枯季径流频率线型优选及参数估计方法初探

Research on Optimization Selection of Dry Season Runoff Frequency Distribution Curve Type and Parameter Estimation Methods

目前,对枯水径流的分析和预测工作都还比较薄弱,尤其在西北干旱地区。枯水径流在水力发电、农业灌溉以及城市工业和生活供水等方面都有重要的意义。采用PPCC检验方法对我国常用的5种水文频率分布线型进行检验,确定适合乌鲁木齐河流域的最优线型为皮尔逊Ⅲ型;以参数、设计值的不偏性和有效性为评价标准,对4种主要的P?Ⅲ型分布参数估计方法:矩法、适线法、权函数法及线性矩法,进行统计试验综合比较研究,确定线性矩法为P?Ⅲ型分布较优的参数估计方法。

At present, the analysis and forecast work of dry season runoff is still relatively weak, especially in the northwest arid region. Researching on it has important significance in hydropower, agricultural irrigation and water supply for urban industry and res idential living, etc. In this paper, the PPCC test methods is used to test 5 kinds of hydrological frequency distribution curve type which are commonly used in China and it is determined that the P-Ⅲ type is the best fit curve type for Urumqi River Basin. Then, the effectiveness and non-hiased criteria of the parameters and the design value are taken as evaluating standard to comprehensively and statistically compare the 4 major estimation methods of P-Ⅲ type distribution parameter, namely the moment method, the fitting method, the weight function method and the line of the moment method. In the end, the parameter estimation method is determined as the more fitting method for the optimum distribution of P-Ⅲ type.