ABSTRACT
In 1948 Henry Stommel, in the seminal paper entitled “The Western Intensification of Wind-driven Ocean Currents,” see [1], proposed a simple model for the Gulf Stream based on the fundamental equations of geophysical fluid dynamics. In that paper Stommel concentrated on isolating the parameters that lead to the generation of boundary layers on the western boundaries of large basins in the northern hemisphere, reminiscent of the Gulf and Kuroshio Streams. Stommel showed that the variations of the Coriolis parameter f with latitude are primarily responsible for the formation of boundary layers in wind-driven circulations. Specifically, in the Stommel model the only forces present are the ones due to Coriolis, the wind stress, and an additional frictional force whose presence, albeit somewhat artificial, is intended to help with writing down a well-posed boundary value problem for a second order PDE for the stream function of the flow. A relatively careful derivation of this model will be one of the main features of this chapter.
