Inasmuch as the amount of brine in sea ice is not great, then from formula (1) we obtained 

 approximately 



It follows from formula (2) that the specific heat of sea ice consists of the specific heat of 

 pure ice and corrections for salinity. This correction is greater the greater the salinity of sea ice 

 and the lower the salinity of the brine. The salinity of the brine is less the higher the temperature 

 of sea ice. 



Formula (2) includes: C . — the specific heat of pure ice and ^j — the heat of fusion of pure 

 ice at a temperature of sea ice equal to t. 



Dickens and Osborne gave the following formula for the specific heat of pure ice at 

 temperatures of -2° to -40°: 



Ci= 0.5057 + 0.001863/. <3) 



They also showed that between 0° and -2° the specific heat of pure ice increases very much 

 and at -0. 06°, it reach 1. 73. This indicates that some internal molecular changes occur in pure 

 ice near the freezing temperature. Phenomena of the same type should, of course, also occur in 

 sea ice. 



As for the melting temperature \ included in formula (2), it is necessary to turn attention to 

 the fact that formation and melting of additional pure ice occurs in the brine of the cells at the 

 temperature of the sea ice itself, i. e. , at very low temperatures. Because of this, we need to use 

 Pearson's formula here which was checked by Petterson, namely: 



X, =80+0.5t, <^) 



where 80 is the heat of fusion of pure ice at 0°, 



T is the temperature of sea ice, 



0. 5 is the difference in the specific heat of water and ice. 



This formula is based on the consideration that in order to form ice, the temperature of the 

 brine should at first be mentally raised to the freezing temperature of pure water, then the melting 

 point of pure ice should be subtracted from it, and then the temperature of the formed ice should 

 be lowered to the initial temperature of the brine. 



The other values entering formula (2), namely: salinity of the brine Sj at a given tempera- 

 ture of the brine t , and the changes in the salinity with a change in the temperature d^^/dr are 

 obtained from table 33. 



Table 39 gives the specific heat of sea ice at different temperatures, and salinity computed 

 by Malmgren, 



As it follows from this table, the specific heat of sea ice at high temperatures and high 

 salinities of the ice can reach large values. Thus, for instance, when t = -2° and Si = 15 o/oo the 

 specific heat of sea ice equals 16. 01 g-cal. Such high specific heat is explained by the fact that with 

 a 1° change in temperature, formation or melting of considerable amounts of pure ice with the 

 accompanying release and absorption of the heat of fusion, occurs In the salt cells. 



152 



