Some Studies on Typhoons of 1949 and 1950

摘要

This investigation on the detailed structure of a typhoon is based on the typhoon reconnaissance flight reports furnished by the 2143 d Air Weather Wing.Part one begins with a study of the eye of typhoon. Changes in the size of the typhoon eye have close connection with the life stages of the storm. The elongated shape of the eye changes according to the tilt of the center axis, and deepening of the storm occurs when the eye is open to west, and filling occurs when open to east.The intention of this report is to point out some true features of tropical storms by means of many inflight reports of the typhoons which occurred in the Southwest Pacific during the years 1949-1950.Most of what we know about typhoons is obtained from surface observations or from time sequence data of upper air soundings when the typhoons approached Japan, and, in most cases, for those in mature stage or having changed to extratropical cyclones.In this study, I have adopted the next four stages of the storm defined by W. F. Macdonald.1. Formative stage.... From its formation to typhoon intensity. (Energy accumulating.)2. Immature stage.... From typhoon intensity to maximum intensity. (Energy rapidly accumulates and concentrates at the center.)3. Mature stage.... From maximum intensity till it meets with a front, draws in a stable air mass or passes over a land area. (No energy accumulation, and energy diverges outward.)4. Decay stage.... The typhoon rapidly weakens or becomes an extratropical cyclone. (Energy dissipates or is transferred to frontal wave energy.)These stages are convenient to show the distribution and accumulation of energy. In the following, the sizes and shapes of the eye are not those observed at the earth's surface, but they are from inflight observations in the eye or from images on the radar scope.