There is general agreement now among oceanographers that the large ocean currents are essentially maintained by the stress exerted by planetary wind systems on ocean surfaces. Therefore it is of primary importance for oceanography to know the distribution of the wind stress on oceans and its variation in time.
Palmén, Erik. 1955. "On the exchange of momentum between the atmosphere, the oceans and the solid earth." Journal of Marine Research 14, (4). https://elischolar.library.yale.edu/journal_of_marine_research/857