Introduction to translation of V. W. Ekman’s “Outline of a Unified Ocean Current Theory”

Vagn Walfrid Ekman’s classical paper on the “spiral” (Ekman, 1905) is well known to the oceanographers, but his other contributions to the theory of the general oceanic circulation, several of which were written in German and Swedish, have escaped notice even of some experts in this field. The paper “Über Horizontalzirkulation bei windezeugten Meeresströmungen” (Ekman, 1923) gives, for the first time, a complete formulation of the problem of the steady wind-driven circulation in a homogeneous sea, when variable topography, bottom friction, and the βeffect are included. The final equation, when written in terms of a transport stream function, takes essentially the same form as the model equations of the oceanic circulation given later by Stommel¹ (1948), which lead to the explanation of the westward intensification of ocean currents.

Stommel, H. 1948. The westward intensification of wind driven ocean currents. Trans. Amer. Geophys. Un., 29, no. 2