The three-dimensional water body of the survey region, extending 

 down to 600 m. , can be separated into the surface layer and two inter- 

 mediate layers. The upper intermediate layer is centered about the 

 salinity maximum, corresponding approximately with the 24. 5 sigma-t 

 surface (see fig. 22 for typical temperature-salinity diagrams). The 

 lower layer is centered about the salinity minimum, corresponding 

 approximately with the 26. 5 sigma-t surface. The distribution of mass 

 in each is associated with a current pattern and these patterns, when 

 added vectorially, give the net surface circulation. Thus figures 8 and 

 9, the geopotential topographies at 300 m. relative to the 600-m. level 

 ajid the geopotential topography at the surface relative to the 300-m. 

 level, illustrate the relative flow pattern of the lower intermediate layer 

 and the upper intermediate layer (including the surface layer), respec- 

 tively. These, when added, give the surface circulation relative to the 

 600-m. level (fig. 5). 



Bathythermograph Data 



Figure 10 represents the vertical bathythermograph temperature 

 distribution oriented in sections from north to south along the lines of 

 stations. At this stage of analysis little additional information can be 

 obtained from these figures, and they are included as a record only. 

 The counterclockwise vortex is clearly indicated by the rising isotherms 

 between stations 12 and 15. 



Summary of Cruise 



The survey data obtained on cruise 17 of the Hugh M. Smith 

 represent typical summer conditions with normal trade wind weather 

 prevailing. The counterclockwise vortex west of Hawaii was found on 

 previous cruises, which have been discussed by McGary (1956). Two 

 circulation systems were emphasized, the lower intermediate which is 

 associated with the salinity minimum and the upper intermediate which 

 is associated with the salinity maximum. The former consisted of 

 westerly-setting currents north of the islaund chain which showed the 

 effect of the islajid barrier. The latter indicated southerly-setting 

 currents impinging on the island chain which were deflected to the 

 southeast by the island group from Oahu to Maui. On the leeward side 

 the upper intermediate circulation was dominated by the counterclock- 

 wise vortex. The results of these two systems, together with the sur- 

 face distribution of nnass, is a rather compliccited net surface pattern 

 as shown by the geopotential topography (fig. 5). 



10 



