Smith 



the temperature structure, but the most striking is on the seaward 

 side of the cyclonic eddy where the 14° C to 18°C isotherms at 650 

 feet exhibit a depth change of 125 feet (Area A, fig. 10). 



Direct current measurements were made in the same manner as 

 in 1964. Square tow patterns for current determinations were sched- 

 uled for the ends of each track leg and for each leg center. The cur- 

 rent pattern at the middle of leg P-Q and point Q were deleted because 

 of equipment failure. The midleg pattern of leg K-M was omitted in 

 order to obtain an uninterrupted digital temperature recording to be 

 used in a separate study. 



Figures 11, 12, and 13 display the circulation referenced to 750 

 feet for depths of 43, 259, and 505 feet, respectively. The 200- and 

 400-foot depth contours of the 25° C isotherm are included in each 

 figure to better show the region of confluence of the counter- rotating 

 eddies. At each depth the converging currents near the center of 

 track leg E-F are the greatest, where the proximity of the two eddies 

 is the smallest. Here currents, referenced to 750 feet, were 1.4, 

 1. 8, and 1. 3 knots at the respective depths. 



As would be expected, the near-surface (43 feet) currents (fig. 

 11) for the general area are the strongest and range from 0. 3 to 1. 4 

 knots. Although it is not conclusive, some evidence of water leaving 

 the main westerly flow west of point C and flowing northward along 

 the west coast of the flow obstruction, as in 1964, can be seen. 

 Figures 11, 12, and 13 present similar circulation patterns, with 

 the velocities decreasing with depth in all areas except one. In the 

 area of eddy convergence, as described by the middle of track legs 

 C-D, E-F, and G-H, the current at 259 feet is greater than that 

 above or below it. It should be pointed out that the current direc- 

 tions for this area at depths 259 and 505 feet are more easterly than 

 that at 43 feet. Transient wind effects may cause the current at 43 

 feet to have a more westerly direction and could effectively reduce 

 the eddy tangential current velocity. 



No current measurements were made near the eddy centers. 

 Hence, speculation on a vortex type is not possible on the basis of 

 variation of tangential velocities with respect to distance from the 

 center. However, the position and the counter-rotation of the eddies 

 resemble Karman vortices in the wake of the island of Hawaii. Sev- 

 eral similar eddies could exist downstream to the west. 



DISCUSSION 



The current in the region of the Hawaiian Islands generally flows 

 toward the west but sometimes has a northerly or southerly com- 

 ponent, dependent basically upon the position of the Eastern North 

 Pacific High (Sverdrup, et al. , 1942). 



409 



