42 
Table 10 
Observations of radiation temperatures of various surfaces at 
Prudhoe Bay, 1972 and 1973. 
Time Surface Cloud Cloud 
Day A.D.T. Temp. Surface Type Temp. Type 
1972 
08.22 2135 6.4 Grass -35.0 Ci 10/10 
2135 8.9 Puddle -35.0 Ci 10/10 
08.23 15.30 10.0 Grass No meas. AsCi 10/10 
09.20 14.22 0.2 Melting snow = 516 FsSt 10/10 
14.22 0.9 Mud, dark brown =1526 FsSt 10/10 
14.22 1.6 Gravel - 5.6 FsSt 10/10 
15.30 - 0.3 Sea ice OES FsSt 10/10 
15.30 0.4 Sand = 3:3 FsSt 10/10 
15.30 - 0.6 Snow =e Oro FsSt 10/10 
15.30 - 0.9 Sea water = Bis} FsSt 10/10 
20.25 - 2.1 Snow grass - 74 FsSt 10/10 
09.21 15.45 - 4.6 Snow on top of pingo - Cs 2/10 
15.45 1.2 Soil on top of pingo = Cs 2/10 
15.45 - 2.6 Snow on slope facing sun ~ Cs 2/10 
15.45 7.9 Soil on slope facing sun — Cs 2/10 
15.45 - 6.6 Snow on shaded slope — Cs 2/10 
15.45 = 16511 Soil on shaded slope = Cs 2/10 
21.00 -10.6 Snow grass = Cs 2/10 
1973 
06.06 13.45 2.4 Water logged tundra 2.6 St 10/10 
13.45 49 Small puddles 2.6 St 10/10 
07.15 15.03 7.9 Wet tundra 0.9 St 10/10 
09.06 22.00 3.5 Lake No meas. St 10/10 
Drizzle 
22.00 1.4 Gravel No meas. St 10/10 
Drizzle 
09.07 09.50 3.5 Lake - 3.6 St 10/10 
09.50 2.6 Gravel - 3.6 St 10/10 
10.11 14.02 3.6 Snow - 5.6 St 10/10 
14.02 0.0 Slush at the bottom 
of the snow cover 
Visual observations in connection with occa- 
sional helicopter flights on 4 and 5 June 1973 
did not indicate that the breakup on the coast 
was later than it was a few tens of kilometers 
inland. In the Prudhoe Bay area a slight advance- 
ment of the breakup could be observed, how- 
ever. Earth Resources Technology Satellite 
(ERTS) images of Prudhoe Bay on 27 May 1973 
also indicated that the breakup in the coastal 
zone was not much influenced by distance to 
the shore. On the other hand, the influence of 
natural and man-made dust was quite obvious in 
the satellite data (Holmgren et al. 1975). 
Another feature of the surface characteris- 
tics during breakup is the large spatial and 
temporal variability of the surface temperatures. 
Table 10 gives radiation temperatures of various 
surfaces as measured by a Barnes thermal radio- 
meter with a field of view of about 2° and 
sensitive to radiation within the 8-14 um band. 
The values in Table 10 represent averages of a 
few readings for each surface type. In the in- 
