89 



Seasonal Distribution 



Winter , The winter season, i.e., those months when cold 

 water is characteristic of the nearshore area, begins in 

 November and ends in May. Within three miles of the Santa 

 Monica-Red ondo shoreline the gradient current is toward the 

 south, although its velocity and direction along any part of 

 the coast varies considerably. The nearshore area, where the 

 least motion results from thermal gradients, is in the central 

 part of the bay between Playa del Rey and Manhattan Beach. 

 Here flat isothermal surfaces are common and when thermal 

 slopes occur, they are gentle. Thus, currents due to winds 

 and tides are more effective and the semi-diurnal tidal 

 oscillations are frequently the dominant motion in a north and 

 south direction. There are also conditions when the extent 

 of the upwelling along the Malibu shore may be so great that 

 a cold tongue of water projects to the south causing an 

 easterly flowing current opposite the Santa Monica-Venice 

 shoreline. 



The spatial distribution of the Surface Unit on November 

 23, 1955 exemplifies many of the conditions characteristic of 

 this season (Fig. 31). The 58°F temperature surface inter- 

 sects sea level nearshore north of Malibu and is within 15 

 feet of the sea surface off Palos Verdes. Offshore it deepens 

 to a maximum depth of 96 feet over the edge of the shelf. Any 

 currents generated by the isothermal slopes must be toward 

 shore off Santa Monica, Playa del Rey, and Red ondo, and south 

 out of the bay opposite the Palos Verdes Hills. Southerly 

 drift is likely negligible or non-existent due to the gently 



