24 
Table 4 
Daily heat exchange in the snowpack during May (when melting does not occur). 
Depth below NZ p AWE 
snow surface 
(cm) (cm) gcm3 g cm-2 
0-3 3.0 0.51 1.53 
3-21.5 18.5 0.360 6.66 
21.5-23.0 1.5 0.900 1.35 
23.0-25 2.0 0.350 0.70 
25-26 1.0 0.900 0.90 
26-40 14.0 0.206 2.88 
DWE AT AO 2a 
g cm-2 XE cal cm-2 cal cm2 
1.53 10.0 7.6 7.6 
8.19 4.0 13tS 20.9 
9.54 1.6 let 22.0 
10.24 1.4 0.5 22a5 
11.14 1.4 0.6 23.1 
14.02 1.0 1.4 24.5 
*The symbols used at the top of the table are explained in Table 2. 
A higher average density value of 0.338 g 
cm? was obtained by using the vertical core 
sampling method along traverse T-4* on 20 May; 
using this value together with the average depth 
of 32 cm, we obtained an average value of 10.8 
cm water equivalent. 
A density of 0.324 g cm? is obtained by 
averaging the values from the detailed studies 
with those from traverse 4. If we use this value 
together with the average depth of 32 cm, we 
obtain an average water equivalent of 10.4 cm. 
The latter value is consistent with Fig. 12, which 
summarizes all of the 150 values of water equiv- 
alent data from Table 5, and we will use it. 
In summary, we shall use the following 
values for the tundra snow at Prudhoe Bay 
during May 1972: 
Average depth = 32 cm; 
Average density = 0.324 g cm’; 
Average water equivalent = 10.4 cm H20. 
Snow drifting 
Snow depth profiles along three selected 
traverses are plotted in Fig. 13. These traverses 
were either parallel (T-5 and T-6) or perpen- 
dicular (T-9) to the winds (Fig. 1). The road in 
T-5 is nearly perpendicular to the winds, and 
large drifts form adjacent to it. The road in T-6 
makes an oblique angle with the winds, and the 
road in T-9 is nearly parallel with the winds. In 
the latter case no drifting is caused by the road. 
The probe depth data are plotted as if the base 
of the snowpack were a horizontal plane. This is 
not true, of course, and most of the irregularities 
in thickness result from the irregular bottom 
topography; the upper surface is smoother (Fig. 
6b). 
A convenient way to summarize the quan- 
tity of snow in the drifts is to measure their 
cross-sectional areas and to compare them with 
an “average cross-sectional area,’’ obtained by 
(0) 5 10 15 20 25 30 
Water Equivalent, cm 
Fig. 12. Histogram of water equivalents. 
*This is the only traverse in which sufficient density samples (15) were taken away from the 
influence of roads, prior to melting. (See Table 5 and Fig. 1). 
