690 



The Stratospheric Circulation 



There is no current here which can be continuously followed through carrying water 

 in large quantities to the south. Probably only very weak spreading and mixing 

 processes operate here in variable direction. The deep sea circulation of the Western 

 Trough is thus dominant and sets the basic pattern for the whole of the South Atlantic 

 oceanic space. 



Table 155. Mean values of the meridional water transport in the total space of the 

 South Atlantic Ocean {between 5° S. and 35° S.) given in units 10^ m^ sec ^ 



9. The Effects of the Subtropical Adjacent Seas on the Deep Sea Circulation. 



Analysis of series measurements in mid-latitudes of the eastern North Atlantic 

 led already at an early stage to the recognition of a warm highly saline water type with 

 little oxygen content, the principal characteristics of which point towards the Straits of 

 Gibraltar which can therefore be considered as effects on the waters of the Atlantic, 

 of the water flowing out of the European Mediterranean. The significance of "Mediter- 

 ranean water" in the Atlantic deep-sea circulation was first pointed out by Jacobsen 

 (1929). 



A detailed investigation and review of the phenomenon was then given by WiJST 

 (1936) in the "Meteor" Report; he termed this water type "upper North Atlantic 

 Deep Water". It is characterized by its high salinity which is in sharp contrast to the 

 Antarctic intermediate water above it. Off Spain the core layer can be found at about 

 1000-1250 m and lowers down towards the equator reaching a depth of 2000 m 

 between 10° S. and 20° S. From the salinity distribution in the core layer it is immediately 

 obvious (see Fig. 329) that the spread takes its origin from the waters off Spain, and 

 that it obtains its high salinity content of 36-4%o or more by way of the Mediterranean 

 water flowing out through the Straits of Gibraltar in the lower layers (p. 529 et seq., 

 see also, pt. I, p. 182). This water sinks to about 1000 m where it finds a corresponding 

 density and then spreads out in a fan-like fashion under the action of turbulence and 

 Coriolis force. Figure 330 impressively shows the great distances to which still an effect 

 of the Mediterranean Water can be traced. It extends northwards past 50° N. and it 

 reaches particularly pronounced directly across the entire Atlantic as far as the Ameri- 

 can coast. Towards the south the last traces can be followed even to the higher 

 latitudes of the Southern Hemisphere. The percentage of Mediterranean water present 

 at any point can be determined from a standard curve for the [rS'J-relationship in the 



