Using directional data method for analysis on typhoon movement and its probability distribution features

In many scientific fields such as meteorology, biology, geography, oceanography and astronomy, the angle value is very important, for example, wind directions, and the directions on which animals and birds migrate.This kind of data is called as directional data.In some problems, it is not expressed as "angle" value, such as month by month mean temperature, however, it can be changed into a directional data through some transformations.The statistical method of directional data means that the methods of mathematical statistics are used in the treatment of directional data.In this way, data are considered as the points on two-dimensional cycle or higher dimensional sphere.Therefore, this method can also be called statistics on sphere.Because of its own characteristical feature, the statistics of directional data much differ from common statistics.Up to now, research work in this field has just started in China.In this paper, a statistical study on typhoon moving directions after their formation over the China Sea and the Western Pacific by use of the directional data method is reviewed.