Geoscience Reference
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Siberian Islands, about half the surface is occupied by ice caps and the rest by polar
desert (Golubchikov,
1996
).
Figure 2.12
shows its extent based on vegetation crite-
ria. Conventional climate data are inadequate for mapping its distribution attributed
to the general lack of evaporation data and the inappropriateness of standard cli-
matic classification criteria for the Arctic (Bovis and Barry,
1974
).
In the polar deserts, mean annual temperatures are quite low and only exceed the
freezing point in one or two summer months. Mean winter month temperatures are
typically −30 to −35°C, while means of the warmest month, July, are typically 1 to
5°C. The fairly low summer maxima, while partly a function of latitude, are also
attributed to persistent multiyear sea ice along the northern coasts of Greenland and
the Canadian Arctic Archipelago, and around many of the Siberian islands. Areas in
the continental interior of the Arctic and subarctic can have similar (or even lower)
winter air temperatures than polar desert, but July mean temperatures are consider-
ably higher, yielding a pronounced annual temperature range.
Polar desert climates have been described for Peary Land, north Greenland
(Putnins,
1969
), Ellesmere Island (Lotz and Sagar,
1963
; Barry and Jackson,
1969
;
Alt et al.,
2000
), Devon Island (Courtin and Labine,
1977
), the northern Taymyr
Peninsula and the Siberian Arctic Islands (Korotkevich,
1972
). The areas in Peary
Land and the Canadian Arctic Archipelago are characterized by high continentality
with monthly mean temperatures in the winter months of −30°C or below and July
values of 4-5°C. In Severnaya Zemlya, mean annual air temperatures are −13 to
−16°C. Means for winter months of −28 to −33°C compare to those of around 1°C
during summer months. Even in July, frost is recorded on eighteen days. Climatic
differences between coastal weather stations and inland sites like Lake Hazen and
Tanquary Fiord on Ellesmere Island have been pointed out by Jackson (
1959b
) and
Barry and Jackson (
1969
). Based on six years of data, B. Alt et al. (
2000
) show that
mean July temperatures average 3°C higher in the interior of the Fosheim Peninsula
at Hot Weather Creek than at Eureka on the coast. In winter, inland temperatures are
1.5-3.5°C lower than at the coast.
Especially striking are variations in the frequency of extreme minimum tempera-
tures. On Ellesmere Island, the frequency of minima below −45°C during February
1950-1960 was 21 percent at Eureka but less than 2 percent at Alert (Hagglund and
Thompson,
1964
). These are both coastal sites. By comparison, Lake Hazen, an
inland site, recorded minima of −45°C or below on all but three days in December
1957 (Jackson,
1959a
). In some inland areas, summer conditions are surprisingly
mild. Remarkably for the latitude, there are sixty-five frost-free days at Tanquary
Fiord (81.4°N, 71.9°W) and seventy at Brónlunds Fiord on Greenland (82°N,
30.5°W). One could conceivably grow lettuce! Over the 1989-1993 period, the
melt season (days with mean temperatures above freezing) at Eureka ranged from
seventy-two to ninety-five days. At Hot Weather Creek, the corresponding values
are seventy-four to ninety-six days (Alt et al.,
2000
).
As the preceding results imply, topoclimates and microclimates are strongly
developed in many polar desert areas. It is not uncommon for the local topography
to give rise to foehn conditions and resulting spells of high summer temperatures.
Air temperatures of 18°C have been recorded under these conditions on the eastern
