ON THE EVOLUTION PROCESS OF LONG WAVES IN THE BAROTROPIC ATMOSPHERE

In this paper the evolution process of disturbances superimpased on a barotropic non-uniform (curvilinear in particular) basic current are investigated.The previous workt1 is generalized by means of general treatment both for the longwaves superimposed on basic current with ultra-long waves and the medium or short waves superimposed on basic current with long waves.The main results are as follows:when the wavelength of small trough or ridge is enlarged,it's amplitude increases and the disturbance develops.In opposite case,i.e.when the wavelength shortens,its amplitude decreases and the disturbence is damped.As a small and short wave has changed into a long wave,the abovementioned laws become clearer,i.e.the wavelength of developing (damping) longwave increases (decreases) more rapidly.These results might be used to explain some observations of evolution processes of trough and ridge in the real atmosphere.Besides,the evolution of disturbance is determined completely its structure,especially by the direction of its axis and its relative position in the basic current.In northern hemisphere,the axis of the developing disturbance is directed NE-SW-ly to the north of the jet stream,and NW-SE-ly to the south of it;while the axis of the damping disturbance is directed NE-SW-ly to the south of the jet stream and NW-SE-ly north of it.These results are in good agreement with the theory of angular transport as well as synoptic experience.