564 EIGHTH PACIFIC SCIENCE CONGRESS 



tense upwelling can be seen in the belt within O.bDh from the coast-line 

 and the stream-lines go down gradiially outside the wind zone. This 

 means that beyond the wind zone there occurs the process of sinking. 



The fact that the expressions for the velocity components all in- 

 clude sin (f, in the denominator shows that the lower the latitude the 

 more intense will be the process of upwelling. Perhaps the strong 

 upwelling off the Peruvian coast may be ascribed to this theoretical 

 result. 



It will be interesting and useful to compute the magnitude of the 

 off-shore currents and the velocity of upwelling from the stream-function 

 given by (36) and to compare them with the values formerly estimated 

 fi'om various sources. 



It is of coiu-se not easy to estimate the magnitude of the coefficients 

 of mixing. The vertical mixing coefficient may be estimated at some- 

 thing like 1000 c.g.s. If we adopt this value, Dy is about 162 meters 

 for a latitude of 30° N. To estimate Ai, is even more difficult. But 

 actual oceanographic observations show that A^JA^ — W' approximately. 

 This means that D^ is just about 1000 times as large as Z),., or 162 kilo- 

 meters. Furthermore, we do not know much about the width of the 

 coastal wind belt. In this computation, the author tentatively assumed 

 L — 2.0944 X Dh that is, about twice as large as Dj,; or at 339 kilo- 

 meters. 



It will be still more difficult to estimate the wind velocity of the 

 northwesterlies prevailing off the coast of Southern California in the 

 earlier summer months. The author took t = 1 c.g.s. This corre- 

 sponds to a wind velocity between 5 and 6 m/s. If we consider the 

 upwelling off the coast of southern California and take o?) = 30° N, 

 we have 



-^~- — = 2.37 X 105 sec-i 

 pw sm i> 



From the table we can compute the average velocity between the surface 

 and the layer 0.21>v deep by 



liTT A^ 045 



= 2.37 X 105 x^^ = 3.35 cm/sec (offshore) 



pw sin </j Az 0.2Z>v 



This is the maximum velocity of the offshore current in che layer be- 

 tween the surface and the 32.4 meters level. 



The maximum vertical velocity can be estimated in a similar way, 

 viz., at 



