Transport and convergence of the North Atlantic drift current computed from the average January pressure distribution
According to Montgomery (1936, 1938), one of the important effects of the wind blowing over the sea surface is its production of positive and negative convergence in the drift current, which is essentially limited to a surface homogeneous layer usually less than 50 meters thick. This convergence results from the net transport of the drift current at right angles to the wind, the magnitude of the transport being such that the deflecting force acting on it exactly compensates the wind stress. Of course, this involves the assumption that the drift current has come to equilibrium with the wind. To avoid boundary conditions, this theory should be applied only to the open ocean, away from coast lines and in deep water....
Brooks, Edward M.. 1939. "Transport and convergence of the North Atlantic drift current computed from the average January pressure distribution." Journal of Marine Research 2, (2). https://elischolar.library.yale.edu/journal_of_marine_research/551