# Why is ocean surface velocity around 3% of wind velocity?

Many introductory level textbooks suggest that, as a rule of thumb, the velocity of the ocean surface is around 3% the wind velocity at 10 meters above the sea surface.

For instance, Ocean Circulation by the Open University Press, page 39:

Another useful empirical observation is that the surface current speed is typically 3% of the wind speed, so that a 10 m/s wind might be expected to give rise to a surface current of about 0.3 m/s

What are the mechanisms that result in this ratio? How universal is this relationship?

• Haven't seen that before, unless it refers to wave-induced drift rather than Eulerian current. Can you reference some particular titles and/or quote a paragraph? – milancurcic Dec 15 '14 at 22:58