Smith 



Patter n 



Fig. 1 - (a) Cutaway view o£ ducted current meter, 

 (b) Current meters mounted on thermistor chain, 

 and (c) Tow pattern for current determinations 



through the meter will always be opposite the direction of the ship's 

 travel. Summarizing current measurement considerations: C4 at 

 750 feet will give the ship's speed over the ground, and the ship's 

 speed is always much greater than the current speed; and the eddy 

 center is an area of possible error. 



CRUISE 29, 1964 



In this cruise, two types of measurements were used to define 

 the eddy boundaries: water properties (internal temperature struc- 

 ture and surface density distribution) and relative currents. In the 

 area south of Oahu, a cyclonic eddy 125 miles in diameter, centered 

 70 miles off the west coast of the island of Hawaii, was located. 



The average depths of the 25 C and 23 C isotherms were con- 

 toured after low- pass filtering the detailed analog temperature 

 records (figs. 2 and 3). The doming apparent in the temperature 

 structure is indicative of counterclockwise eddy rotation in the 

 northern hemisphere. The eddy appears somewhat elliptical in 

 shape in both figures. The 25° C depth contours show a trough or 

 possibly a parisitic eddy near shore (fig. 2). This feature is not 

 present at the depths of the 23° C isotherm (fig. 3). The tempera- 

 ture structure for the leg that passes nearest the eddy center (leg 

 H to I) is shown in figure 4. The dome in the structure is obvious. 



398 



