Asymmetry of Jet Streams Formed under Nonlinear Geostrophic Adjustment in Shallow Water

Abstract

The process of geostrophic adjustment in a rotating layer of shallow water is considered. For initial distributions of the fluid depth in the form of a step and a localized rectangle, this process results in the formation of an isolated jet stream and a system of two counter jet streams, respectively. This paper studies the structural features of these flows, which is related to the nonlinearity of the adjustment process. The main feature for an isolated jet stream is the horizontal asymmetry of its velocity profile. For a system of two opposing flows, a mirror asymmetry is characteristic, which is caused by the sign dependence of the amplitude of the initial depth perturbation. The velocity of flows with a negative sign (depression) always exceeds the velocity with a positive sign (elevation).