79 An Adjusted Boxplot for Outlying Rainfall Observations

The main aim of this paper is to present a new method of detecting outliers in skewed rainfall observations based on an adjusted boxplot. The proposed adjusted boxplot adopts the medcouple to modify the classic method that often erroneously declares many points as outliers when data are skewed. The medcouple make the adjusted boxplot not only find skewness, but also is insensitive to outliers.. Synthetic data are given to test the performance of the roposed method. The results illustrate that the proposed method can be used as a fast and automatic outlier detection tool for skewed rainfall observations.