吉林省旬降水量的客观分级方法探讨

Discussion on the Objective Classification Method for Ten-day Rainfall of Jilin Province

根据吉林省现行旬降水量等级划分标准和办法,提出了一种基于降水概率分布函数的客观划分办法。该方法引入Z指数变换,将偏态分布的旬降水量序列转换为近于正态分布的Z序列,通过对Z指数的划分反算而得实际降水量的划分结果。该方法既考虑其自身概率分布,又避免了复杂的分布函数参数计算。将该方法的客观标准与现行标准的划分结果进行比较分析,发现前者结果稳定,随机性小,结果更为合理。

Based on the current standard and method to classify the ten-day rainfall of Jilin Province at present, a new method, which is based on the probability distribution function, is presented. In view of the non-normal distribution of ten-day rainfall, Z index transformation is employed. The index can transform the non-normal distribution data into the normal one. The classification result of rainfall is based on classifying the Z index. The results of the new method are more stable and more rational than those of the original method.