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Internal Waves . Internal waves that may develop currents 

 are generally of tidal period. In an internal wave, one or 

 more density surfaces at intermediate depths remain level, 

 however, and the slopes that result above or below a level 

 surface are in opposite directions. The corresponding currents 

 are in opposite directions and if internal waves of different 

 periods are present simultaneously, a complicated pattern of 

 currents results. This is especially true in shelf waters 

 where shoaling conditions may cause the breaking and re- 

 development of a multitude of internal waves with several 

 differing periods. It is recognized that temperature patterns 

 in Santa Monica Bay may be frequently complicated by this 

 feature of the subsurface water motion. 



The Temperature Distribution and Currents 



Steady State Conditions 



Along the Malibu coast and in the southern part of the 

 bay adjacent to the Palos Verdes Hills, cool water units are 

 nearly always present. The temperature differential between 

 the water nearshore at Malibu and that offshore is generally 

 not great and the occurrence here of this water pattern is 

 attributed to upwelling. At the present state of knowledge 

 concerning the existence of cooler water nearshore, it is 

 impossible to determine whether the occurrence along Malibu 

 represents an upward displacement of subsurface water, or a 

 continuously rising flow associated with upwelling or diver- 

 gence. Either is possible, but because of the wind patterns 

 in the area, it is more likely that an intermittent upward 



