An Analysis of the Typhoon Eye Formation

Abstract

The process of the eye formation was analyzed using the hourly infrared radiometer measurement from the Geostationary Meteorological Satellite (GMS) for two typhoons in September, 1990. Typhoon Flo (T9019) showed typical development with the formation of a clear eye. While Typhoon Ed (T9018) did not have a clear eye but finally had a banding-type eye. For both typhoons, the eye first appeared not at the central part but at the edge of a convective cloud, as the deep convective cloud cyclonically circumscribed the warm region. This eye did not continue to be observed from the infrared (IR) data, alternatively appeared and disappeared. Disappearance of the eye is thought to be caused by the cirrus cloud. The rapid developing of T9019 was recognized after the completion of a clear eye with subsiding. The typhoons had the axis-asymmetric structures in the intensifying stage. And the hourly change of the cloud features were unexpectedly conspicuous for the both typhoons.