OCEAN CURRENTS 



173 



the Faroes and thence to Iceland 



which runs from Scotland to 

 and Greenland. The iso- 

 therms of 5, 10, 15, and 

 20 show a downward 

 curve between 25 and 35 

 north and south latitudes, 

 whereas in the equatorial 

 regions they lie quite near 

 the surface. To account 

 for the temperature distri- 

 bution warm and cold ver- 

 tical currents are shown 

 in the diagram, upwardly- 

 directed cold currents in 

 the equatorial region, 

 and downwardly-directed 

 warm currents in the 

 temperate regions. 



The regions in which 

 the isothermal lines bend 

 upwards towards the sur- 

 facq are precisely the 

 central regions of the 

 great circular currents 

 e.g., between 25 and 35 

 N. Lat. 



The influence of den- 

 sity on vertical circulation 

 is naturally most im- 

 portant. 



As an example of the 

 drift of water due to differ- 

 ences in salinity let us take FIG. 33. TEMPERATURE SECTION OF 



,, ,n ( TV/r j- f THE ATLANTIC ALONG 30 W. LONG. 



the outflow of Mediter- , G g CHOTT ) 



ranean water into the 



North Atlantic. At depths of 1,000 metres (547 fathoms) 



