Table 1. --Average surface temperatures, salinities, and densities in 

 the quadrants of the survey region. H. M. Smith cruise 17 



Density distribution 



The surface density of sea water is a function of the independent 

 variables tennperature and salinity. Their relative importance can be 

 judged when one considers that the change of surface density in the 

 Hawaiian Islands region due to a 0. 3 /oo salinity decrease is apjroxi- 

 mately equivalent to a 1.6 F. temperature increase. Thus, changes in 

 salinity as shown in table 1 are not negligible in their effect on the density. 



Figure 4 shows the surface density distribution in units of sigma-t 

 with contour intervals of 0. 1. When compared with figures 2 and 3, it 

 indicates that the main features of temperature and salinity had an addi- 

 tive effect upon the density distribution; that is, whenever the temperature 

 was low, the salinity was high, and conversely low salinities corresponded 

 with high temperatures. 



Average surface sigma-t values are listed in table 1, 



The lowest 

 The 



densities occurred on station 1 and off the west shore of Hawaii, 

 densest water was found in a region centered at 20 N. , 157 15'W. asso- 

 ciated with the counterclockwise vortex. The average density increased 

 from south to north and from west t<o east. 



Surface circulation 



It is not always easy or desirable to make direct current 

 measurements in order to obtain the circulatory pattern of a region. 



