57 



that at some times its lower range is affected by the intro- 

 duction of deeper cooler water. For example, the lower tem- 

 peratures in July 1955 could represent an intrusion of slope 

 water over the edge of the shelf. 



The subsurface water in October 1955 was similar to that 

 in July 1956, as was that representative of August 1956. On 

 the other hand, the Subsurface Water Unit in April 1956 was 

 more closely related to that in the summer of 1955. 

 August 1955 



The water units and their temperatures for August 1955 

 are shown in Figure 18. As in the previous months, definite 

 surface and subsurface units were defined. The Surface Water 

 Unit was composed of an intermediate or transitional subunit, 

 and an offshore surface subunit. The latter was under the 

 inshore surface water in some places, and in others was 

 apparently missing either because of mixing, or because of 

 replacement by the inshore water unit. 



In the inshore area of Redondo Canyon, the intermediate 

 water subunit was apparently absent and the Subsurface Water 

 Unit lay directly below the offshore surface subunit. This 

 may have been due to the exclusion of the intermediate water 

 nearshore followed by a subsequent flow of the upper surface 

 water directly over the deeper water in the canyon. The 

 sharp thermocline in this area may then have been the result 

 of shear between the surface and subsurface units. 



The surface layer, including the intermediate or transi- 

 tional subunit, varied in temperature from 55° to 71°F. The 

 subsurface water varied from 51° to 54°F. The surface unit 



