is expected to be in magnitude of the surface currents only and not in 

 their direction. 



The salinity distribution is also shown in figure 6 by means of 

 dashed lines (isohalines). A salinity maximum is generally to be found 

 at approximately 100 m. and a minimum at approximately 400 m. The 

 salinity maximum east of station 22 is greater than 35.2 /oo and west 

 of station 14 less than 35. 2 /oo. In the vicinity of the counterclock- 

 wise vortex this salinity structure has broken down with a disappearance 

 of the maximunn, which now occurs as a pocket at the surface. 



A better over -all picture of the circulation can be obtained from 

 the bathymetric charts of sigma-t surfaces. Figure 7 shows a series 

 of charts for the depths of the 26. 5, 26. 0, 25. 5, 25. 0, 24. 5, and 24. 

 sigma-t surfaces which will convey to some degree the three-dimensional 

 changes in the distribution of mass associated with the circulation. The 

 dashed lines indicate the salinity distribution on the sigma-t surfaces. 

 However, due to the complexity of the circulation and to lack of detail 

 and precision, the usefulness of salinity as a tracer is considerably 

 impaired, so the flow pattern will be deduced from the isobaths. 



According to the 26.5 and 26.0 sigma-t surfaces, the direction 

 of flow north of the island chain is fronn east to west and the deflecting 

 effect of the islands of Hawaii and the group from Maui to Oahu is 

 apparent. The 25.5 and 25.0 sigma-t surfaces indicate a general 

 change of direction to the northeast in the same region. Finally the 

 24.5 and 24.0 sigma-t surfaces show a southeasterly drift on the wind- 

 ward side except north of Kauai and Kauai Channel, where the flow is 

 from the north. 



South of the islajid chain the flow on the 26. 5 sigma-t surface is 

 generally toward the northwest. The position of the counterclockwise 

 vortex is clearly indicated by the 380-m. isobath. The other surfaces 

 show that the vortex features become increasingly dominant toward the 

 surface. In the survey region south of Kauai the northerly component 

 of flow prevails up to the 24.0 sigma-t surface. 



In figure 7 the layers which are identified by constant sigma-t 

 values can be considered as independent current systems which, when 

 added together, produce the net surface current. This, essentially, is 

 done in dynannic calculations, using isobaric rather than sigma-t 

 reference surfaces. 



