Infrasonic Precursor of Tropical Cyclone

Intense infrasonic emission was observed prior to the birth of a tropical cyclone [1]. It is connected apparently with instability of atmospheric layers in cyclone area. There are different mechanisms of this effect. Stratified compression flow is unstable [2], providing amplification of its potential component. Cooling of air in upward convection flow makes water vapor supersaturated. This is a nonequilibrium state of fluid where effect of instability can be developed [3]. The equation of infrasonic propagation in such a medium is developed and its solutions are obtained. Corresponding analyses makes it possible to clarify some aspects of cyclone infrasonic precursor.