Chapter Four 



LARGE-SCALE FEATURES OF THE 

 NORTH ATLANTIC CIRCULATION 



For more than a century the surface features of the oceans have been 

 crudely determined from literally millions of ship reports sent in to the 

 various naval hydrographic services throughout the world. Since no 

 special effort is made to navigate with precision in the deep ocean, the 

 reported surface currents are not determined with very high precision, but 

 the charts draAvn up from this large source of data give a good over- all 

 view of surface currents. An example of such a compilation is the United 

 States Navy Hydrographic Office Current Atlas (1946). 



SURFACE FEATURES 



A schematic chart of surface currents is shown in fig. 2. The part of the 

 Atlantic on which oiu" attention is focused in this book is the remarkably 

 intense set of currents on the western side of the ocean, along the open 

 coast of North America. People commonly speak of this whole system of 

 currents as the Gulf Stream, even though very little water from the Gulf 

 of Mexico is actually in the Stream. 



Iselin (1936, pp. 73-75) attempted to introduce a well-defined nomen- 

 clature for various parts of the current system of the western North 

 Atlantic. The entire set of western currents was to be called the Gulf 

 Stream System, and the current from Tortugas, in the Florida Straits, to 

 Cape Hatteras was to be called the Florida Current. The old term Gulf 

 Stream was retained for the section of the current between Cape Hatteras 



