latter is a large circulatory system which extends from approximately 

 21°N. to 27°N. 



Regions of high current velocities (of the order of 1 to 2 knots) 

 are found in the vicinity of stations 44, 42, 50, 58, west of station 12, 

 and elsewhere. Most of these are on the periphery of the vortices men- 

 tioned above. 



Figure 15 also shows that the area north of 27 N. is one of 

 stagnation (no currents) except for a northeasterly drift in its northwest 

 section. 



Geomagnetic Electrokinetograph (GEK) observations 



The GEK (von Arx 1950) observations are plotted on figure 16 

 in which the arrows indicate the direction of flow and numbers the speed 

 in cm. /sec . 



On 33 GEK stations duplicate determinations were made with 

 floated (dotted arrows) and unfloated electrodes in order to determine 

 the validity of the "droop" correction (McGary 1955:8). Figure 16 shows 

 that in many cases there was good agreement between the two methods. 

 For a number of observations, however, the currents obtained by the 

 two methods were 90 or more apart, particularly when the GEK indi- 

 cated low current speeds. 



The GEK data have been presented only as a record, and no 

 detailed analysis in relation with the geostrophic—' currents has been 

 attempted. However, a superficial comparison between the two nnethods 

 of obtaining surface currents shows some resemblance, particularly in 

 regions of high current speed. North of 26 N. , in the region of weak 

 currents, there is little agreement between the two methods. The region 

 south of 24 N. is one of much vortex activity where it is reasonable to 

 expect vortices both of smaller dimensions and shorter life. Here the 

 GEK which measures essentially instantaneous currents, would be ex- 

 pected to deviate from the geostrophic flow. 



Surface temperature, salinity, and density 

 and the surface circulation 



It would be desirable to be able to interpret the flow pattern from 

 the distribution of the surface salinity, temperature, and density. In 

 the lee of the island chain some confirmation of the flow pattern is derived 



5/ ^ 



— Geostrophic currents are those obtained from the geopotential 



topography. 



14 



