- 2 - 



with traces for 28 Septemter and 18 September 1%9. For the period 

 28 September to 8 October (period A) a wind averaging Beaufort Si 

 persisted; for the period 18 September to 28 September (period B) 

 the wind averaged Beaufort /,.. During period A the mixed layer 

 temperature cooled almost 5° F and deepened about 110 feet, sug- 

 gesting the upward mixing of a large amount of cold water into the 

 surface layer from below the thermocline. For period B, however, 

 the thermocline depth remained almost constant and the surface 

 layer temperatiore increased, suggesting little or no mixing across 

 the thermocline. 



Consider that a strong wind (and associated mixing across 

 the thermocline) persists in one section of the ocean, while nearby 

 a weaker wind occurs (causing little or no mixing). The colder 

 water in the surface layer under the stronger wind will alter the 

 density distribution in the surface layer. In response to this new 

 density distribution, a current will occur within the upper ocean layers, 



EVALUATDIG THE WIND MIXING CURRENT 



Assume that the ocean is a two-layer system with constant 

 densities in the upper and lower layers. Strong winds over a portion 

 of the ocean will then cause mixing across the thermocline (boundary) 

 and a region of relatively cold water to be formed in the surface 

 layer of the ocean. Neglecting the other wind effects, such a hori- 

 zontal variation in the density distribution of the ocean surface 

 layer will lead to a current. 



