Wind speeds are relatively low off southern California. Speeds of 6-1 1 m/sec during 

 the summer (Fig. 57) occur between 10 and 20 percent of the time in the nearshore area and 

 up to 40 percent of the time west of San Clemente Island. In winter, the frequencies of near- 

 shore winds of 6-10 m/sec increase to 20 percent while those of offshore winds remain near- 

 ly the same. Winds of > 18 m/sec are increasingly frequent in winter, occurring about 1 to 

 3 percent of the time off the Channel Islands and less than 0.5 percent in the nearshore areas 

 (Fig. 54). Winds of < 3 m/sec occur about 30 percent of the time in winter and summer in 

 the Channel Island areas and about 50 to 60 percent of the time in the nearshore environ- 

 ment (33°-34°N). 



The mixed layer* depth, given in Figs. 58 and 59, are relatively shallow in the near- 

 shore areas and increase in a westerly direction. During summer the mixed depth is very 

 shallow (about 6 meters) in the inshore areas; in winter this depth increases to 18 meters in- 

 shore, to about 24 meters off San Clemente Island, and to about 60 meters to the southwest 

 (30°N,120°W). 



Figures 60 through 7 1 give monthly prevailing current direction and mean current 

 speed. Currents south of 32° 30'N are generally south at 20 to 25 cm/sec. North of this, 

 the currents are more variable in speed and direction. The prevailing nearshore currents are 

 also 20 to 25 cm/sec. Currents in the Channel Island areas are more variable in direction in- 

 cluding some westerly and northerly currents varying between 20 and 36 cm/sec on average. 

 During fall and early winter the prevailing currents change to predominately a north to 

 northwest direction (Davidson Current) with speed averaging 20 to 25 cm/sec. A high north- 

 westerly current approximating 50 cm/sec off Santa Catalina is observed in December (Fig. 

 71). In January, near coastal currents are variable and in the spring the prevailing direction 

 is south to southeast with speeds averaging from 20 to 30 cm/sec. Other current studies of 

 the southern Cahfornia area include CALCOFI, Ref. 47; Scripps Institute of Oceanography, 

 Ref. 48; and the Oceanographic Survey of the Santa Barbara Channel Oil Spill, Ref. 49. 



Specific Phase 1 site selections in the southern California area were made using the 

 following criteria. 



1 . Locate within the 500-fathom (915-meter) contour to make mooring costs as 

 economical as possible and still test the deep water OFEF concept. 



2. Remain outside shipping and submarine transit lanes and common pleasure- 

 boating areas. 



3. Be within 32 kilometers (2-hour transit) of scientific and logistic support due to 

 the frequent observation and measurement requirements of the Phase 1 fanns. 



*The layer in which wind-mixing occurs and Iwlow wliich the therniocline begins. The mixed layer is usually a! a very low 

 nutrient concentration due to phytoplanktonic utilization in this zone. 



90 



