On vertical mixing and the energy transfer from the wind to the water

Observations of the vertical mixing in the surface layer of the sea, on small time and space scales, in conditions of fairly strong winds and stably stratified waters, are used, together with relevant oceanographic measurements, to investigate the relation between the wind-generated vertical mixing and the energy transfer from the wind to the water. Only the energy transfer due to the work of the tangential stress is considered, i.e. the wave energy is not included in the considerations. It is found that only a very small part of the energy is consumed by the local vertical mixing. Furthermore, the observations are found to be consistent with expressing the energy transfer as the product of the surface wind stress and the wind-generated surface current. A relation between the vertical momentum transfer and the wind velocity is suggested on the basis of this result.