Abstract

A typhoon usually develops from an unstructured cloud cluster. In general, the more axis-symmetry a typhoon cloud pattern is, the stronger the typhoon intensity could be. This study analyzes the MTSAT_IR1 image data of severe typhoon Jangmi during the period from tropical depression to severe typhoon stage. The gradient of the gray values in the MTSAT_IR1 image is calculated from the horizontal and vertical derivatives by using Sobel’s template. Then, the deviation angle of each gradient vector relative to a radial line extending from typhoon eye is calculated. The results show that the deviation angle distribution become approaching Gaussian distribution when the intensity of typhoon increase from tropical depression to severe typhoon period, and the structures of cloud cluster will become more axis-symmetry to the center of typhoon.