Abstract
Considering the latent heat of water vapour, the vertical instability is; where T1' is the equivalent temperature obtained from the data of aerological observations, T2' the equivalent temperature when the previous stratum attains the state of equilibrium, and p0 the surface pressure. The author calculated this vertical instability at the time of the approach of tropical storms and investigated the distribution of the instability. It was found that there are greater vertical instabilities in the external region of storm and in the direction of the motion. In view of the above fact, we may conclude that Margules' vertical instability indicates the tendency of the energy release.
