TURBULENT TRANSPORT 



339 



example the Gulf Stream fragment region, and here caution must 

 be exercised in interpreting the average condition. 



The ideahzations of the North Atlantic density field and surface 

 circulation given in Fig. 1 may amuse, but certainly will not shock, 

 the practical oceanographer. He has become enured to the struggling 

 theoretician and even will accept as a rough picture the two-layer 

 ocean shown in pole to equator section on the right of this figure. 

 The wind stress, r, is responsible for driving the hot Th surface 

 layer south and west to form a strong boundary current which sweeps 

 north to mix with cold Tc northern waters. However, not a single 

 symbol or a single line on this drawing should be accepted except 

 as a very crude integral of a fluid process. 



Fig. 1. An idealized North Atlantic Ocean. 



Isolating Several Turbulent Processes 



The vector r is given as a number and a direction, yet it stands 

 for the fascinating process by which a turbulent wind transfers 

 momentum through the wave-whipped surface to generate a net 

 mass transport at right angles to r. The temperature Th hides 

 much of marine meteorology. If we understood the complicated 

 turbulent processes of evaporation and cumulus convection over 

 the tropical oceans, we might be able to predict Tn. It is the basic 

 quantity defining the energy source for atmospheric motions and 

 for the thermal circulations of the sea. The temperature Tc is the 

 consequence of both energy radiation to space and turbulent con- 

 vection into cold winter winds. Complicated as it is, the Tc process 



