Geoscience Reference
In-Depth Information
lowlands of the New Siberian Islands (L.S. Berg, cited by Golubchikov,
1996
) and
in Tanquary Fiord, Ellesmere Island (Barry and Jackson,
1969
). Extremes of around
28°C reported from the interior of Wrangel Island (Golubchikov,
1996
) may arise
from occasional warm air incursions from the Siberian lowlands combined with
foehn subsidence.
Precipitation in polar desert areas is low and occurs mainly as snow. On Ellesmere
Island, mean daily precipitation on summer days with measurable amounts is
between 0.8 and 1.5 mm with maximum falls typically around 4-8 mm at Eureka
(Alt et al.,
2000
). On rare occasions, summer precipitation can be associated with
convective storms. Annual precipitation is typically 100-300 mm. Winter snow
depths are generally around 200-400 mm but highly variable. Exposed parts of the
surface may be blown free of snow for most of the winter. In other areas, drifting
may result in a fairly deep snowpack. Where drifting is especially pronounced and
in sheltered areas, snow can linger through the summer.
8.2.2
An Example - Resolute Bay, NWT
Resolute Bay (Cornwallis Island, Canadian Arctic Archipelago) is typical of a polar
desert location.
Figure 8.7
summarizes this site's mean annual cycles of surface air
temperature, precipitation, cloud cover, and downward solar radiation. Mean tem-
perature ranges from a low of about −33°C in February to 4°C in July. Precipitation
exhibits a pronounced August maximum of about 33 mm, compared to winter-
month precipitation totals of less than 5 mm. Note that these are raw station pre-
cipitation totals with no adjustments for wind-induced gauge undercatch and trace
amounts. This contrasts with the spatial fields of precipitation in
Figure 6.3
, which
contain bias adjustments and are also heavily smoothed through the interpolation
procedures. Even assuming that bias adjustments would double estimated winter
precipitation, the winter aridity at this site is clear.
Winter-month cloud cover (the average percent of the celestial dome covered by
cloud) is only about 40 percent, fostering longwave losses to space which contribute
to low temperatures. Cloudiness increases through spring and summer to a maxi-
mum of more than 80 percent in August and September. The annual cycle is only in
rough accord with that of precipitation. Note the sharp rise in cloud cover between
April and May when low-level Arctic stratus begins to dominate. The daily average
solar radiation in June is about 280 W m
−2
.
8.3
Maritime Arctic
8.3.1
Characteristics
The major characteristics of the maritime Arctic are extensive cloudiness, high
humidity and a small range in annual temperature. Such climatic conditions are best
developed in the Atlantic sector of the Arctic, such as Svalbard (
Figure 8.8
) and
Iceland. On Jan Mayen, Svalbard, the mean temperature is near −7°C in February
