3种频率曲线参数统计方法的应用分析

根据江西省永修县1950～2009年的年最大日降雨量资料,分别采用矩法、权函数法、概率权重矩法等3种参数统计方法,计算出年最大日降雨量频率,并以频率曲线与经验点据的拟合情况,来评估3种方法计算结果的偏差.结果表明,矩法估计的频率曲线与经验点据拟合较差,由矩法估计的参数及由此所得的频率曲线总是系统偏小;概率权重矩法估计的频率曲线较之经验点据,其上部略偏低,拟合欠佳;权函数法改善了频率曲线和经验点据间的拟合,取得了良好的效果,但仅适用于连续系列.比较分析结果也说明我国主要采用适线法估计频率曲线的统计参数是有统计学理论根据的.

Analysis of the parameter statistical method of three frequency curves

Based on the annual maximum daily rainfall data in Yongxiu county from 1950 to 2009,the freguency of annual maximum daily rainfall is calculated by the moment method,the weight function method and the probability weight moment method.And according to the fit condition between frequency curve and empirical point data,the deviation of three methods is estimated.The results show that the parameter and frequency curve by the moment method have system deviation,its fit between frequenc ycurve and empirical point data is bad.The probability weight moment method like this.The fit of the weight function method is good but it is only suitable for continous series.At last,the results proved to estimate satistical parameter of frequency curve by the curve-fitting method is right.