Oil Spreading on the Sea

winds and currents, and the second of the increase in area of the oil due to the tendency of the oil to spread in calm water. The drift due to wind may be estimated by arg uin g that the turbulent­ shear-stress law at the water interface is approximately the same in both the air and the water. If the wind velocity some distance (usually 10 meters) above the water surface is U, then the turbulent stress is