Salinity of the Ocean, its Variation in Oceanic Space and in Time 



111 



Using the above mentioned relationship the quantity Ajpu can be determined 

 numerically for every point more accurately than in the rough calculation made here 

 by deliberately selecting a large water column. 



Table 75. Mean values for Ajpu for transverse sections {normal to the direction of 

 spreading) through the subantarctic intermediate water in the Atlantic 



Table 75 shows that the vertical distribution of A I pu scarcely changes along the 

 entire region of spreading: Al pu is least at the core of the spreading water (on the 

 average 0-82) and rises steadily both above and below with the distance from the core 

 to large values (about 3). If the distance from the core axis is denoted by z, then 

 Alpu=^f(z). 



When / is the Prandtl mixing length 





and therefore 



Az) = 



Pcu 



u dz 



Integrating this equation for constant / from the core (2 

 below the core then, since dujdz is always negative, 



f* u 



/(zyz=-/Mn-, 



0), to a distance b above and 



where Mq and u are the values of u in the core and at a distance b from the core. The 

 value of the left-hand side can be found from Table 75 and this gives, knowing /, 

 the ratio of m/mq as a function of the vertical distribution and ihus also of the quantity 

 AJAq, where A^ and A are the exchange coefficients in the core itself and at a distance 

 b from it. The constancy of / can be tested on the plausible assumption that the velocity 

 of the current within a distance of ±300 m from the core falls to a low value; over a 

 wide region / is almost constant with a value of about 150 cm. The results of the 

 calculation are shown in Fig. 81. The relative distribution of velocity over a trans- 

 verse section has a striking similarity to that distribution found experimentally in 

 turbulent spreading processes in a "jet". This justifies the conclusion that the spread 

 of the subantarctic intermediate water in the Atlantic northwards, along the boundary 

 between the oceanic stratosphere and the troposphere, is very probably a process that 



