station 23 has all but disappeared, whereas that at station 1 has retained 

 a strength similar to that which it showed in the upper layer. Thus the 

 two systems added together give a generally intensified surface flow rela- 

 tive to the 1,000-m. level. 



So far the complex current pattern has given no infornnation about 

 any net circulation through the survey region. To gain an understanding 

 of this the dynamic heights of figures 15, 20, and 21 were averaged in 

 each of the four sections of the survey region and north of 24 N. in the 

 exploratory region. These averages are shown in table 3 below. 



Table 3. --Average dynamic heights in the quadreints of the survey region 



This shows that there is a westerly drift of the lower intermediate water 

 mass in the northern portion of the cruise area. In the main survey re- 

 gion there appears to be a slight southwesterly drift. The surface circu- 

 lation relative to the 300-m. level shows a drift, slightly stronger than 

 the intermediate, setting southeast. These two combine to give a net 

 southeasterly surface drift relative to 1, 000 m. along the island chain 

 and little net flow in the northern section of the survey region. 



Further interesting information can be obtained from an analysis 

 of the salinity minimum. This was suggested by the characteristic shape 

 of temperature salinity diagrams, some of which are shown in figure 22. 

 At station 5, for example, the temperature, salinity, depth, and sigma-t 

 of the salinity minimum are 5.3 C. , 33. 97 /oo, 620 m. , and 26. 8 respec- 

 tively. At station 62 these same variables are 11.3 C, 34.18 /oo, 270 m., 

 and 26. 1. These are the extreme values, the former representing a type 

 of water found in the northern section of the cruise area, and the latter a 

 type found in latitudes south of the island of Hawaii. Values between these 

 extremes are found throughout the remainder of the survey area. Some of 

 the curves also indicate a double minimum, such as at stations 61 and 64 



16 



