On the Upper Disturbances in the Westerlies whose Mean Circulation have Longitudinal Wind Gradient

Abstract

The theoretical studies of the disturbances in the westerlies have, so far, been based on the longitudinally uniform current taken as mean circulation. The problem of the disturbances in the jet stream (max. westerlies) which has eastward wind gradient is especially taken up in this paper, and the analytic solution of Laplaces' equation was given under the assumption that, as Platzman did, every motion has constant absolute vorticity and their perturbation is irrotational.
As the first approximation of the solution, it was proved that the wave length of the perturbation is in agreement with the Rossby's result and the amplitude increases eastward, that is, in the direction of the decrease of zonal (sectional) index (the Namias' emperical law).