OCEAN TEMPEBATUBES 



399 



spending ocean current produced, Ekman (1905, p. 42) concluded that 



.0127 



the surface velocity V would be approximately 

 D would have the approximate value 



meters 



h and that 



(175) 



where h is the wind velocity in meters per second. Thus for a wind 

 velocity of ten miles per hour (5.1 meters per second) and at the 



Fig. 16. Components of the water velocity U' and V perpendicular and 

 parallel respectively to the wind, and the velocity of V c in a direction perpen- 

 dicular to the coast. 



76X51 

 latitude 35 D would equal ' = 51 meters, and for a velocity 



V sin <f> 

 of fifteen miles per hour D would equal 75 meters. Solving equation 



(174) for fj. 2 gives 



2 = in 000729 )D 2 



IT* 7T* 



which equals 217 in c. g. s. units, when D equals 7500 cm. and 

 <f> equals 35. 



The relation of vertical velocity to depth will now be deduced from 

 the results of Ekman 's theory. 



Let V make an angle A with the coast (fig. 16) and U' the angle 

 (90-)- A) with the coast, then the velocity perpendicular to the 

 coast is, from equations (172) and (173), 



F'sin A + Z/'sin (90 -f A) = V c 



