At Prudhoe, the mean maximum values for 
July in excess of 10°C are significantly greater 
than would have been estimated using only data 
from the immediate coastal stations at Barrow 
and Barter Island. 
The steepness of the summer temperature 
gradient from the Arctic coastline inland is 
illustrated in Table 5. Summer data from two 
stations, Point McIntyre on the coast and a 
location approximately 16 km south of Dead- 
horse, are incorporated to provide continuity. 
Considering a total distance of approximately 
144 km from Point McIntyre south to Happy 
Valley, the increase of total thaw season degree- 
days is 5 degree (°C) days per kilometer 
proceeding inland. The temperature gradient 
may also be characterized by July temperature 
differences. Based on the data given in Table 4, 
an average increase of July mean temperature 
away from the coast is 5.9°C (100 km)'. Some 
comparable data are available inland of Barrow. 
Temperature data obtained in 1966 by Johnson 
and Kelley at Meade River, 120 km south of 
Barrow, showed a 6.5°C difference from Barrow 
(North Meadow Lake) temperatures for the 
month of July. This gives an inland temperature 
increase of 5.4°C (100 km)', almost identical 
to the rate determined for the Point MclIntyre- 
Happy Valley gradient. Also based on the Meade 
River data, a total thaw season degree-day gradi- 
ent of 3.9°C km’! was calculated, about one 
degree C less than indicated for the Point 
McIntyre-Happy Valley gradient. Climatic gradi- 
ents have also been observed from Barrow south- 
ward by Clebsch and Shanks (1968). Increases 
for rainfall, evaporation, and evapotranspiration 
were observed between Barrow and their study 
site 55 km inland. Temperature observations 
were limited to weekly maximum and minimum 
values in that study, and are not directly com- 
parable to the above analysis. All of the other 
Table 5 
Annual thaw/freeze degree-day (°C) accumulations 
1970-1973 
Summer 1970/ 
Winter 1970-71 
Summer 1971/ 
Winter 1971-72 
295/4891 
Summer 1972/ 
Winter 1972-73 
320/4496 
273/5417 
Barrow 
Barter Island 372/5520 352/5063 402/4585 
Prudhoe 529/5739 564/5469 617/4835 
Happy Valley 890/5331 1020/5081 956/5372 
Degree-days (°C) 
4 4 so 4 == L “+ 4 n 
Mi-eAG, (Min TUDE TU, AS aa OMLIN amb aaa 
Month 
Fig. 2. Freeze-thaw regimes for principal 
North Slope stations. 
parameters measured, however, clearly indicated 
increased warmth and moisture gradients toward 
the inland study site. These are important gradi- 
ents for many types of environmental phenome- 
na and should be considered in any study uti- 
lizing coastal temperature data to represent con- 
ditions some distance from the coast. 
Fig. 2 illustrates the annual freeze-thaw 
regimes for the principal North Slope stations 
for the period of similar record. The similarity 
of the freeze season, the increased warmth, and 
greater temperature amplitude of inland loca- 
tions discussed above can be observed. 
Precipitation 
It is difficult to assess the variation of 
precipitation regimes as was done with air tem- 
peratures because precipitation values show 
greater fluctuations and were not obtained at all 
stations. The only long-term records, Barrow 
and Barter Island, indicate that Barter Island 
receives considerably more summer precipitation 
than Barrow (Table 6). The only available sum- 
mer precipitation data for Prudhoe Bay are from 
1971 (Kane and Carlson) since Biome observa- 
tions were considered anomolous. The monthly 
totals are low compared to other stations on the 
North Slope. Summer precipitation amounts 
appear to increase inland as evidenced by partial 
records for Happy Valley, and as previously 
indicated by Clebsch and Shanks (1968) for the 
Barrow area. 
