THE MERIDIONAL TRANSPORT OF KINETIC ENERGY IN THE ATMOSPHERE

Abstract

The meridional transport of kinetic energy in a flow pattern composed of an arbitrary mean zonal current and a cellular or wave perturbation flow is studied. It is found that the meridional transport of kinetic energy in such a system is mainly determined by the profile of the mean zonal velocity and the orientation of the trough and ridge lines of the system. The rate of the northward geostrophic transport of kinetic energy across a characteristic length or a latitudinal circle is shown to be approximated by the product of the mean velocity of the zonal current and the rate of the poleward transport of westerly momentum. The magnitude of the rate of the northward transport of kinetic energy is estimated (for the month of January 1949) from geostrophic winds. It is found that intense meridional transport of kinetic energy takes place in the layer between 100 and 300 mb. The greatest northward flux of kinetic energy, and its greatest meridional convergence and divergence, occur in the vicinity of the westerly jet center. The magnitude of the rate of the meridional transport of existing kinetic energy is compared with that of the work done by the pressure force. It is found that in the lower latitudes the mean rate of the meridional transport of existing kinetic energy is of the same order of magnitude as that of the work done by the pressure force, whereas in the middle and higher latitudes the former is of lower order of magnitude than the latter.