The Variation of General Circulation in the Barotropic Atmosphere

Abstract

With a closed system of prognostic equations, which govern the time change of zonal mean flow, of merdional eddy transport of westerly momentum and of kinetic energy of disturbance, the variation of general circulation in the barotropic nondivergent atmosphere is discussed, including a physical interpretation of barotropic instability.
There are three fundamental types in the motion of jet stream: first is the one ex pected in the barotropically unstable state where the jet stream is sharp and corresponds to the phenomenon such as splitting ; second is expected in the barotropically stable state where the jet stream is flat and the motion is mainly affected by the latitudinal distribution of kinetic energy of the disturbance; the third is characterized by the alternate oc currence of the first and the second.
Results of tentative prediction of zonal mean flow are shown.