20 
It is instructive to attempt to calculate 
temperature variations and heat exchange in the 
snow which result from the daily energy fluxes 
at the surface. Difficulties lie in the uncertain 
values for the thermal diffusivity of tundra snow 
and the fact that air convection may play a 
significant role in the snow (Trabant and Benson 
1972). Published thermal diffusivity values for 
snow vary widely. This is mainly because of the 
variability in snow itself; it is reasonable to 
expect variations in diffusivity values by a factor 
of 2 or more in a typical tundra snowpack. A 
useful summary of thermal data for snow was 
provided by Hansen (1951), and from it we find 
diffusivity values suitable for tundra snow rang- 
ing between 0.0030 and 0.0050 cm? sec’!. 
However, Sorge (1935) found a higher range of 
value for the packed snow of the Greenland Ice 
Sheet. His values would be especially appro- 
priate for the wind packed layers on the tundra. 
Thus, it is reasonable for us to use the range 
from 0.0030 to 0.0060 cm? sec’'. 
Table 2 
Water equivalent and “‘cold content’’ summary of data plotted in Figs. 7 and 9. 
The water equivalent is calculated by integrating the depth-density profile. The ‘cold 
content” is a measure of the amount of heat required to raise the snow to the 
melting point. 
A general summary of the data is as follows: 
Reference Total depth 
Fig. 7 47 
Fig. 9a i 7/ 
Fig. 9b 36.5 
Fig. 9c 35 
Fig. 9d 42 
Fig. 9e 46 
Average 
Density 
gcm3 
0.266 
0.345 
0.329 
0.307 
0.285 
0.324 
The detailed summary of each profile is tabulated below with the columns labeled as follows: 
h = height above soil surface 
Ah = height interval 
p = snow density 
AWE = water equivalent of height interval, Ah 
DWE = cumulative water equivalent of snow from bottom to height Ah 
(Note the units of AWE and DWE can also be thought of as the height of a column of water, i.e., (cm HO) 
c = Specific heat of ice 
AT = Difference between measured snow temperature and 0°C 
AO = Heat required to raise the temperature of the given increment of snow to OG: 
AQ= (AWE) xcx AT 
DO = Sum of AQ values 
Total Water Total Cold 
Equivalent Content 
cm HzO cal cm“? 
12.51 102 
40.45 161 
12.03 34 
10.75 34 
11.97 63 
14.92 87 
(cm) 
(cm) 
(gcm) 
(g cm?) 
(gem?) 
(cal g! ca ) 
(°C) 
(cal cm 2) 
(cal cm?) 
