MAJOR CURRENTS OFF THE WEST COASTS OF 

 NORTH AM) SOUTH AMERICA 



Introduction 



The descriptions of eight principal currents in this report are 

 based mainly on data obtained by direct methods in regions from the 

 Bering Sea to Cape Horn. Except for the Peru and Cape Horn Currents, 

 surface flows appear to be ill defined and exhibit characteristic 

 variability. 



The usual graphic presentation of ocean currents is, at best, 

 a static picture. The surface of the ocean is in constant motion, 

 the movement being exceedingly variable in some regions and relatively 

 constant in others. The currents described in this report are those 

 vhere the movement within specified boundaries exhibits a permanent 

 or seasonal flow. The regions beyond the boundaries of the currents 

 are those where flows, frequently considered part of the prevailing 

 current, are less defined, described from insufficient data, mainly 

 tidal, under the influence of winds or river discharge, or variable 

 and turning. The bo^mdarieE indicate gradual change between zones of 

 wore persistent flow and zones of less stable or weaker flow. 



The approximate boundaries and the main body of each current 

 shown are based on ship drift observations and direct measurements 

 by instrument, which describe the two main features of the current, 

 namely, direction and speed. Dynamic topography presentations are 

 mentioned or shown only where they might prove of interest by 

 comparison with results of direct measurements. 



