5. THE Y mP CCMPCNENT 



According to Ekman (1905), the direction of the wind current 

 at the surface is 45*^ to the right of the wind in the Northern 

 Hemisphere and this angle increases with depth. Recent inves- 

 tigations reveal that the deflection is more nearly 12-20 degrees, 

 being larger and more irregular at the lower wind speeds (possibly 

 because of the increased importance of other components) and 

 smaller at higher wind speeds. As the surface wind is about the 

 same angle to the left o. the geostrophic wind, it is assumed herein 

 that the direction of the wind current is the direction of the geostrophic 

 wind . 



Numerous empirical studies have indicated use of a single factor 

 to relate surface current speed to wind speed. The formula of 

 Vv itting (190S) appears to agree well with available data and further 

 allows approximate incorporation of mass transport by waves in a 

 simple expression: 



V * ^^3 V \ (4) 



where \V is the mean geostrophic wind speed for a 24-hour period. 



g 



In the present work it is assumed that the current is relatively 

 uniform and unidirectional in the turbulent mixed layer down to the 

 thermocline (or about 200 meters). The mass transport of the waves, 

 however, would modify this picture as it decreases exponentially 

 with depth (Masch 1962). Therefore, if W is in meters/sec and 



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