A nonlinear model representing only the first baroclinic mode shows a remarkable ability to simulate observed features of the Somali Current system during the southwest monsoon. These features include the strength of the current and its highly nonlinear horizontal structure, a succession of warm and cold eddies just east of the main current, and appropriate patterns of upwelling. The response to the wind along the coast is rapid with large changes occurring in a period of a week. The maximum upwelling occurs near the coast northwest of the warm eddies where the Somali Current separates from the coast, forming the northern branch of an eddy. Associated with this upwelling, sharp cold tongues extend up to 500 km offshore separating the warm eddies. The eddies tend to stall as they move northward from the equatorial region. A comparison of open- and closedbasin solutions of the model equations demonstrates that the upwelling, the strength of the current and the eddies, and the movement of these features along the coast are very sensitive to the strength and distribution of the wind stress and to the boundary conditions. However, the basic structure is not. (The low-level jet is modelled on one of the wind patterns used.)

Simulation of the Somali Current system requires high resolution both longshore and offshore. Here, Δy = 20 km (longstream), and Δx = 6 km near the boundary to 192 km in the interior to cover a 5000 × 5000 km region with a grid of 250 × 61 points per variable.