COUPLING BETWEEN SEA AND AIR 403 



is considerably simplified. In the future one may hope to use 

 automatic buoys that continuously register and transmit data on 

 these transfer functions from different areas of the oceans. How- 

 ever, the measuring technique must first be developed further. 

 Other problems, such as the influence of the buoy or of neighboring 

 ships on the turbulent transfer, also must be studied with great 

 care. 



The second step in our attempt to formulate a more nearly 

 complete model of the physical state and dynamics of the ocean 

 is the setup of the appropriate model equations for the interior of 

 the sea. The equations describing the transport of mass, salt, mo- 

 mentum, and heat within the sea are known, but we are in doubt 

 about what values should be used for the turbulent exchange 

 coefficients. These should be known provided the turbulence 

 problem is solved. However, at present one should introduce 

 measured values for these coefficients. Already by means of the 

 present velocity data and the data for temperature and salinity in 

 the oceans one can make reasonable estimates of both the hori- 

 zontal and the vertical exchange coefficients. It must be admitted 

 that this way of including the turbulent transfer mechanism is, 

 from a theoretical point of view, unsatisfactory, but there is hardly 

 any alternative. 



The last step is to couple our interior model to the boundary 

 processes mentioned and try to predict what the interior state and 

 the dynamics of the oceans will be when we apply the measured 

 forces at the sea surface. Here one runs into purely mathematical 

 difficulties, arising from the complicated nonlinear form of the 

 complete model equations. In principle, one could go directly to 

 an electronic computer and try to solve the problem, but it may 

 be better to approach the solution in steps, by a series of suc- 

 cessively more complicated models that allow us to see the physical 

 picture clearly at each stage. 



In spite of all the theoretical difficulties, some advances have 

 already been made on the problem. A model relating the vertically 

 integrated ocean transport to the wind stress acting at the surface 

 has been given by Sverdrup, and has been successful in predicting 

 at least the major features of the ocean currents. The model is 



