On the wind-driven circulation in an ocean with bottom topography

Abstract

The influence of bottom topography on the wind-driven ocean circulation is investi gated for a homogeneous, β-plane model with an imposed, steady wind stress curl. The linear model studied by Munk (1950) and the non-linear model studied by Carrier & Robinson (1962) are special cases as is the simple model proposed by Warren (1963) foi the description of Gulf Stream meanders. Although the effects of density stratification are neglected, inertial and frictional effects are included and solutions determined for various kinds of topography.

Simple analytic models are examined and found to be useful in describing limited regions of the ocean basin. In particular the concept of an interior regime, in which nonlinear and frictional terms are unimportant, can be extended to the case of variable depth. In regions of strong inertial flow over topography, the simple meander model investigated by Rossby (1940) has some success in predicting the path of the stream. In both models the importance of isopleths of constant F/H, where F is the Coriolis parameter and H is the depth, is demonstrated by showing that there is a strong tendency for streamlines to follow or meander about such curves. Complete numerical solutions are found for the finite difference vorticity equation by an efficient relaxation scheme developed for this purpose. Results show that the response of the ocean may be strongly controlled by the shape of the ocean bottom and that such gross features of the ocean circulation as Gulf Stream separation, meandering, and variable transport may be related to topograpic effects.