Note on Yoshida's (1955) theory of coastal upwelling

Coastal upwelling is commonly explained on the basis of Ekman's [1905] theory. At some distance from the coast, where the effects of the coastal boundary are negligible, the Ekman transport of surface water normal to the coast is given by ((1))where Tn is mass transport through unit width vertical surface parallel to the coastline, τp is the component of the wind stress parallel to the coastline, and ƒ is the Coriolis parameter. The transport is directed 90° to the right of the wind in the northern hemisphere. Along the coast of northern California, Oregon, and Washington, which runs approximately north-south, northerly winds transport the surface water offshore, necessitating replacement inshore by upwelling.