129 



A rather exceptional pattern occurred on the 10th of 

 August; a pattern which was never repeated during the remainder 

 of the survey. A large flat-surfaced gyral of warm water ex- 

 tended over the northern shelf with rather steep thermal slopes 

 along the east and southern borders. A similar flat gyral, 

 but of cold water extended over the southern shelf. Water 

 motion generated by this pattern would be out the center of 

 the bay directly opposite Hyperion. Wind drift would, of 

 course, be dominant over most of the bay and with a strong 

 west wind, the flow in the central portion would likely be 

 negligible . 



The upper temperature topography on August 24 had no 

 thermal slopes of any magnitude. Nevertheless, upwelling is 

 still present in the north and isolated but definitive warm 

 areas occurred in the nearshore zone. In contrast, the sub- 

 surface topography was more complex and showed a definite 

 trend of water motion to the south. There was a pattern 

 directly seaward from Hyperion similar to that noted on 

 August 18. In this pattern, however, the thermal slopes were 

 more pronounced, although not as continuous; and in the absence 

 of movement by the wind, it is more likely that a seaward flow 

 existed. 



The Surface Water Unit topography was similar on September 

 8 and 16, 1955, in that any water motion that did occur from 

 temperature slopes was from the southwest into the Bay (Figs. 

 64 and 65). The thermal slope in the offshore area on the 8th 

 was more pronounced than on the 16th, so it is presumed that 

 wind drift was less a factor of importance on the earlier date. 



