The Three-dimensional Temperature Distribution and its Variation in Time 107 



1000 2000 3000 WOO 5000 km 



SOOOlm ' 



Fig. 48. Formation of a tongue-shaped distribution in a property of sea water by advection 



and mixing (turbulence). 



zooo 



3000 



iWGO 



5000 km 



5000 hm 



Fig. 48a. Tongue form produced by turbulent mixing at constant flow velocity shown in a 



cross-section (tongue of i'-content for a steady current, which attains a constant ^-content 



in its total cross-section when it enters into a second water type.) 



case corresponds to the conditions present in the spreading of a current of water of 

 high saHnity penetrating into a body of water of lower salinity. 



In the horizontal and vertical distribution of the temperature and saHnity over a 

 large space in the ocean there are often found cases wheie the isolines have a tongue- 

 form. This distribution allows the numerical determination of the relationship be- 

 tween the exchange and the velocity of the flow, that is, of the quantity Ajpu provided 

 that this is imposed by exchange processes. Such calculations are fairly numerous: 

 they have been made, for instance, by Defant (1936) for the subantarctic intermediate 

 current and for the Antarctic bottom current in the South Atlantic (AJpu =-- 1 — 10 

 which for u = 1-5 cm/sec gives A^ as about 0-5-10 gcm-\sec-^); by Montgomery 

 (1939) for the equatorial counter current in the Atlantic (maximum value for A^ 

 0-4 g cm-Vsec-\ for Ay 4 x 10^ g cm-Vsec-^ by Sverdrup and Fleming (1941) 

 for the coastal water off California at 200 and 400 m depths {AJp = 2x10*' cm^/sec) 

 and by Seiwell for the distribution of temperature and salinity in the Caribbean 

 Sea {AJp larger than 1C« cm^/sec). Recently Defant (1955) in an investigation of the 



