Ill 



simulates a large gyral, but the introduction and removal of 

 water is restricted to only part of the bay. 



The April subsurface temperature distribution was more 

 indicative of water motion than that in the upper layers (Fig. 

 49). In this month there was an indication of a divergence 

 opposite Playa del Rey where the isotherms showed a flow 

 entering from the west to within three miles of shore and 

 then diverging to the north and south (Fig. 50). Both of 

 the slopes parallel to the shore were strong and continuous, 

 and likely developed dominant flows out of the bay in the two 

 directions. The subsurface topography in February showed an 

 almost completely different pattern from the surface water 

 (Fig. 51). There was a similar packing of the isotherms in 

 the central part of the bay which may have resulted in a 

 shoreward transport, but the general motion was then to the 

 north following the warmer mass of water near shore (Fig. 52). 

 This is not an uncommon feature of the water in the bay, and 

 certainly must indicate the immediate reaction of the upper- 

 most water layers to specific meteorologic conditions. 



The thermal pattern for March 21, 1956 shows the only 

 temperature distribution that departs from that normal to 

 the winter (Fig. 53). This is also the only clear cut case 

 where any data show the introduction of water from the south 

 into the bay and the escape of water to the north. The flat 

 gradient offshore would allow drift toward the east to with- 

 in two miles of shore where the strong northerly flow was 

 present. Drift cards released on this day all landed to the 

 north of their point of origin, confirming this pattern. This 



