一种降雨异常值探测的新方法

A new method for detection of abnormal rainfall data

经典箱形图运用到有偏数据时,常常将超过触须区间的有偏数据错误地判断为异常值。为适应降雨数据这类偏态数据的异常值探测,引入偏态的抗差描述参数,对经典箱形图法进行偏态改造,从而使新的触须区间可更准确地描述数据分布。将改造箱形图与经典箱形图分别应用到无异常值和有异常值两种情况,其结果显示改造箱形图能更适应有偏数据,探测风险明显减小,同时探测效果有保证。

When classical box-plot is applied to the biased data, the biased data over the whisker intervals are often judged to be the abnormal values. In order to detect those abnormal values of such biased data from rainfall data, the skewness parameter of robust description is introduced to improve the classical box-plot for the skewness, and then the data distribution can be more correctly described with the new whisker intervals. Both the improved and classical box-plots are applied to the situations with or without the abnormal data and the result shows that the improved one can be more adaptable to the biased data with a significant decrease of the detection risk, while the detecting effect can be ensured as well.