Smith 



TOO - 



200 



? 300 



400 - 



500 -^ 



600 



700 



Fig. 5 - Temperature structure between points R and S 

 (Figs. 2 and 3) 10-1/2 days after points H to I were re- 

 corded. Dashed line shows better symmetry and mi- 

 gration from east to west of the eddy. 



of the dome apex from east to west during the elapsed timie. From 

 the east-to-west change in position of the average depth of isotherms, 

 it appears that the eddy moved in a westerly direction at the rate of 

 0. 6 mile per day during the period of observation. This rate of 

 migration is quite slow when compared to that of a cyclonic eddy, 50 

 miles in diameter and southeast of Oahu, which moved westward in 

 1963 at about 7 miles per day (Barkley, et al. , 1965). 



Another method was used to study the eddy. Surface water 

 samples and bucket thermometer temperatures were taken at inter- 

 vals that varied from one to six hours, dependent upon the position 

 in the track. The eddy position as derived from the surface density 

 ((^t) distribution (fig. 6) agrees well with the position derived from 

 the isotherm depth contours. Upwelling of dense water at the eddy 

 center is clearly demonstrated, and the direction of eddy rotation 

 can be established. In the northern hemisphere, the light water is 

 to the right of the observer when facing the direction of flow (Sverd- 

 rup, et al. , 1942). 



402 



