TABLE 44. THE THERMAL CONDUCTIVITY OF SNOW AS A FUNCTION 

 OF ITS DENSITY (MULTIPLIED BY 10*) 



Density of snow 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 



Thermal conductivity . . 1 3 6 11 18 24 33 43 54 



As we see with high snow densities, thermal conductivity computed according to Abel's for- 

 mula is very close to the thermal conductivity of ice determined by direct measurements. 



The coefficients of temperature conductivity and thermal conductivity are related to each 

 other by the formula 



where a is the coefficient of temperature conductivity, 

 fe is the coefficient of thermal conductivity, 

 c is the specific heat, 

 6 is the density. 



For water, the turbulent coefficients of temperature conductivity and thermal conductivity, 

 determined generally very approximately, can in practice be considered equal to each other 

 numerically (not in size) since both the specific heat and the density of sea water are very near to 

 unity. 



For pure ice it can be seen from table 43 that the coefficient of temperature conductivity is 

 numerically more than twice the coefficient of thermal conductivity. For sea ice, the coefficient 

 of temperature conductivity depends to a great extent on an extremely changing specific heat. 



LITERATURE: 1, 62, 73, 104. 



Section 65. Density as a Function of Temperature and Salinity 



As we have seen, natural ice is not a homogenous body, but a porous one, the cells and capil- 

 laries of which are filled with brine, silt, and air. Some of these cells are completely isolated 

 from each other, others communicate freely both with each other and with the external water and 

 air. This condition makes the concept of density when applied to natural ice extremely conditional. 

 In any case when we speak of the density of ice , we must relate this concept to sufficiently large 

 volumes of it in order to obtain an average value. 



The density of pure ice which has no air bubbles at 0° equals 0. 9176 g/cm^. Therefore, its 

 specific volume is equal to 1. 0898 cm3 /gram. Inasmuch as the specific volume of pure water at 

 0° is equal to 1.00013, consequently, during ice formation, the specific volume increases approxi- 

 mately 9 per cent. 



During changes in temperature, the density of pure ice changes insignificantly. Actually, the 

 coefficient of volumetric thermo-expansion of pure ice within the temperature limits of 0° to -20° 

 is approximately 



/3 =0.000165. 



162 



