The Low-Level Jet as a Western Boundary Current

Abstract

The low-level jet which flows across the equator and up the Somali coast is considered as a western boundary current of the East African mountain chain. The jet is assumed to be forced by the low-level divergence in the subtropical high pressure belt of the Southern Hemisphere and convergence in the monsoon trough. A simple model with this type of forcing is proposed and analytic and numerical solutions obtained. These appear to be in reasonable agreement with observation. The sensitivity of the model jet to spatial variation in the forcing, temporal changes in the intensity of the low-level convergence, and nonlinearity are examined.