Disregarding the thickness of the ice in the denominator of this formula in view of its small- 

 ness as compared with the thickness of the layer from which the ice was formed, and also consid- 

 ering the ratio of densities of ice and water as 0. 9, we get 



^^^ 0.9 iS-Si)i (4) 



z 



and 



1.1 ZAS 



I 



If the salinity of ice is taken as 0, we get the simpler formulas 



(5) 



AS = 2:^, (6) 



2 



By analogous reasoning we find that increase in the salinity of the layer during evaporation 

 will be 



^^- 2 ' (8) 



where s as before is the thickness of the uniform layer of salinity S and a is the height of the 

 evaporated layer. 



For water, whose salinity is greater than 24.7 o/oo, the temperature of maximum density is 

 lower than the freezing point, and therefore for such water the specific volume will decrease, to- 

 gether with a temperature drop to the freezing point. In a particular case with low salinities and 

 low temperatures, it may be shown conversely that a certain temperature rise is required to reduce 

 the specific volume. 



Thus, in the general case (S > 24. 7 o/oo) a certain amount of heat must be removed from the 

 examined layer in order to decrease the specific volume. Referring this quantity of heat to 1 cm^ 

 of the sea surface, considering the specific heat of water as unity and measuring the thickness of 

 the layer in meters, we get 



^^ - TooT ' (9) 



where A t is the drop in temperature of a layer s meters thick 



and AQ is the amount of heat in g/cal removed from 1 cm^ of the sea surface. 



Let us assume that at the initial moment we have two layers with corresponding temperatures 

 ±1 and t2. salinities S-^ and 52, specific volumes a.^ and Og' ^^'^ layer heights si and S2- -Actu- 

 ally, from what has been said above, after complete mixing of these layers, the total thickness of 

 the mixed layers will he s-^ 2 ~ ^1 "*" ^2' while the total specific volume will be equal to the specific 

 volume of the lower layer, i.e. , a-^ 2 ~0'2' 



71 



