Ekman Layer
D1. Physical and chemical oceanography and marine meteorologyDefinition
Surface or bottom layer where wind or bottom friction transfers momentum.
The Ekman layer is the surface (or bottom) layer in which wind stress (or bottom friction) is balanced by the Coriolis force, producing the Ekman spiral. Its thickness scales as sqrt(2 Az / f), where Az is the turbulent eddy viscosity, and runs from tens to about a hundred meters in the open ocean. Above it the wind drives the layer; below it the interior flow is geostrophic.