90 THE NAVY OCEAN SCIENCE PROGRAM 



OCEAN DYNAMICS 



From the scientific point of view, the ocean is an exceedingly 

 complex system. Sophisticated hydrodynamic theory, aided by 

 our newly acquired ability to handle nonlinear equations using 

 computer techniques, has produced a series of mathematical mod- 

 els proposing to reduce the complex motions to order. Theoretical 

 development is currently limited by the unavailability of experi- 

 mental results to test theories, and to evaluate key parameters 

 that influence the mathematical models. First-order experiments, 

 in the last two or three years, have gathered preliminary evi- 

 dence on the nature of some dominant modes of motion, and have 

 pointed clearly to logical methods for attacking the larger 

 problem. We have gained reasonable assurance that instru- 

 mental techniques can be evolved to bring observation and theory 

 into fruitful interplay and make a substantial improvement in 

 our understanding. Thus, we have an obvious point of departure 

 for a major scientific effort. 



The pattern of research into circulation' and internal-wave 

 problems on the one hand, and underwater sound transmission 

 on the other, suggests increasing interactions among these 

 programs. It is diflicult to conjecture the exact form this inter- 

 action may take, but the periods of some sound-transmission 

 fluctuations correspond to periods of internal waves to be ex- 

 pected in the same area. Even rather subtle features of the 

 water structure have long been known to affect sound mea- 

 surably, and the doppler shifts to be expected in sound trans- 

 mitted through ciirrents, if properly observed, might provide 

 useful information about the currents themselves. The begin- 

 nings of such cooperative investigations are underway or in 

 prospect. 



AIR-SEA INTERACTION 



The exchange of energy and material across the air-sea inter- 

 face embraces a large variety of studies. One part of these 

 studies is concerned with the prediction of the growth and decay 

 of wind waves. This aspect has progressed well in recent years, 



