594 EIGHTH PACIFIC SCIENCE CONGRESS 



fills a previously existing gap in the information for the central area. 

 The relatively flat dynamic topography is especially sensitive to transient 

 conditions and experimental error. Nevertheless, the topographies con- 

 sistently show a weak northeasterly circulation at 5 cm/sec or less, part 

 of which is deflected southward off Vancouver Island to continue along 

 the coast past 45° North. This circulation pattern is consistent with 

 previous work in the adjoining areas, and with the assumed divergence 

 of the Aleutian Current beginning well offshore around 45° North. 



The G.E.K. has been shown to measure apparent currents which 

 rotate in direction and fluctuate in intensity. The peak flows are of 

 the order of 20-35 cm/sec which is several times greater than the net 

 flows. The rotations contain semidiurnal and inertial constituents, the 

 latter predominating. 



A time study in direct measurement of currents on Cobb Sea- 

 mount, 270 miles offshore, has been compared with a similar time study 

 with the G.E.K. in the adjoining deep water. Harmonic analysis of the 

 North and East components of velocity has produced amplitudes of 

 7-11 cm/sec for the semidiurnal constituents. The differences could be 

 almost completely accounted for by the change in phase of the moon 

 during the period of the measurements. The amplitudes of the inertial 

 constituent were 9 and 13 cm/sec in one case and 22.5 cm/sec in the 

 other, a difference ascribed to an abrupt change in wind velocity. 

 AnotL»;r time study with the G.E.K. showed similar results, but smaller 

 amplitudes. The combined results suggest that the currents being mea- 

 sured by the G.E.K. are real. This conclusion is supported by the pub- 

 lished results of current measurements at several deep-sea anchor stations 

 which show similar variations. 



The net currents obtained by averaging the G.E.K. results show 

 little correspondence with those indicated by dynamic topographies. The 

 former probably represent short-term surface currents due to the wind, 

 whereas the dynamic topographies represent integrated effects over 

 longer periods. 



m conclusion, it is suggested that progress in the interpretation 

 of currents in this area requires a better insight into the cause and 

 nature of the transient currents. The G.E.K. should be useful in these 

 studies, but must be further evaluated in terms of direct measurements. 



Literature Cited 



Defant, a. 1932. "Die Gezeiten und innem Gezeitenwellen des Atlantischen 

 Ozeans," Wiss. Ergebn. der Deutschen Atlnnt. Expedit. auf dem 'Meteor' 

 1925-1927 7 Teil I. 



