Tropical Cyclone Convection Structure Evolution During Rapid Intensification Using Himawari-8 Satellite

The tropical cyclone (TC) convective structure evolution during rapid intensification (RI) process were explored by using the differenced infrared and water vapor imagery (IRWV) from Himwari-8 satellite in the western North Pacific. The radial and azimuthal profiles and the morphological features were extracted from 1-hour interval images and several key patterns and the rules considering the location, shapes, and magnitude of the IRWV were identified through the whole RI process. The results show that the development and maintenance of a good spin structure of the negative IRWV were crucial for TC intensification. The RI-onset periods were normally connected with the sudden change of IRWV and the inward movement to the inner-core area. The pinhole eye features were normally a sign of continue RI, while the sudden decrease of IRWV area or the appearance of symmetric central overcast features indicates the ending of RI process.