Basic Principles of the General Oceanic Circulation 



559 



when the counter current is more strongly developed this only occurs between 50° W., 

 10° N. and 60° W., 14° N. From here a combined current runs in a westerly direction 

 towards the West Indies throughout the whole year; this is the source for the surface 

 currents in the West Indies and therefore also for the Gulf Stream (Dietrich, 1937 b; 

 1939), which is in agreement with the results of Brooks (1930, see also, Shaw and 

 Hepwort, 1910) showing that the fluctuations in the south-east trade winds are more 

 closely connected with water and air temperatures in Western Europe than are those 

 of the north-east trade winds. 



The Equatorial Counter Current lies between the two equatorial currents. Table 147 

 presents its position in different seasons. During almost the whole of the year it is 

 divided into two parts; the "western" counter current weak and not very broad, 

 found particularly during the first winter months and the "eastern" counter 

 current which is present all the year round. Only in the summer months do they 

 join, thereby forming a mighty counter current. The origin of this lies west of 50° W., 

 near the American coast, its width covers the area between 10° and 3° N. showing 

 considerable speed and constancy. During the period of its greatest extent the central 

 area of the current is characterized by a convergence region towards which water 

 flows from both sides. An attempt has been made by Schumacher (1940) to show 

 a connection between the temporary interruptions in the counter current above the 

 mid-Atlantic Ridge and the topography of the rise. 



Table 147. Extent of the Equatorial Counter Current in the Atlantic Ocean 

 (according to Schumacher) 



* Starts presumably farther north-west,** with interruptions. 



Northern Hemisphere. The combined equatorial currents enter the Caribbean Sea 

 between the Antilles and spread over almost its entire width as the Caribbean Current; 

 this flows almost due west with its greatest velocities in the southern part. In some 

 months large vortices are formed off" the coast of Costa Rica, Panama and Colombia. 



