Abstract
A special three-dimensional solution of similarity type is given for a meridionally closed ocean with dynamic according to Stommel's classical transport model, and with the density determined by three-dimensional advection and vertical diffusion. The boundary current exhibits a rapidly varying scale depth; this depth becomes zero at a critical latitude where the current must separate. The solution requires an upwelling everywhere, to be balanced by abyssal sources of water and a deep circulation, as described by Stommel and Arons. It is proposed that a more general similarity form may be useful in future analytical as well as numerical studies of the ocean circulation.