PRELIMINARY ANALYSIS ON THE STRUCTURE AND INTENSITY OF CONCENTRIC DOUBLE-EYE TYPHOONS

Typhoon eye, one of the most outstanding features in the evolution of typhoon, has various complex configurations: circular, elliptic, oval, square, polygonal, or irregular shapes. It is very interesting to note that some typhoons show the concentric double-eyes encircled with two concentric cloud towers.The concentric double-eye structure and intensity of typhoons are investigated and discussed by using reconnaissance aircraft data, radar echo photos and satellite images, 76 double-eye typhoons were observed during 1949－1983. The results indicate that the concentric double-eye structure, generally appearing in intense typhoons over the northwestern Pacific Ocean, is closely related to typhoon’s intensity. This kind of structure has apparent characteristics in geographical and seasonal distributions.Based on the observational data, an idealized structure model for the concentric double-eye typhoons is proposed.