Geoscience Reference
In-Depth Information
8.5
Mountains and Uplands
Mountains and uplands in the Arctic exert both local and regional modifications on
climate. Mountains and plateaus, many containing glaciers and ice caps, are found
in the eastern section of the Canadian Arctic Archipelago (Baffin, Devon, Ellesmere,
and Axel Heiberg islands), coastal east and west Greenland, Scandinavia, the western
Eurasian Arctic islands (Svalbard, Novaya Zemlya), and on the mainland in Alaska,
the Urals of Russia, and northeastern Siberia (
Chapter 2
). The Ural Mountains (up
to 1885 m) run north-south and form the conventional boundary between European
and Asian Russia. They have a number of small glaciers, mostly in cirques. The
Brooks Range forms the true Arctic mountains of Alaska. Orientated nearly east-
west, they rise to 1,500-3,000 m and have small glaciers like the McCall.
The literature on upland and mountain climates in the Arctic is fairly extensive.
Major field programs have been conducted on the Barnes and Penney ice caps on
Baffin Island (Orvig,
1954
), Franz-Josef Land (Krenke,
1961
), Meighen Island (Alt,
1975
), Devon Island (Holmgren,
1971
) Axel Heiburg Island (Müller and Roskin-
Sharlin,
1967
), and other regions. These have provided detailed information on sur-
face energy budgets and meteorological conditions. Upland, mountain, and ice cap
climates are quite diverse, but can be broadly characterized in terms of the com-
bined effects of elevation, the high albedo of snow and ice surfaces and the influ-
ence of summer melt on depressing surface air temperatures.
The last effect is a good example of local climate modification. For example,
Bradley and Serreze (
1987
) examined the cooling effect of a small (roughly 5 km
2
)
ice cap on northeast Ellesmere Island based on data collected during the summer of
1982. Meteorological stations were maintained over the middle of the ice cap and
on a tundra surface (polar desert) several kilometers away at very nearly the same
elevation. At 150 cm above the surface, they measured a cooling effect of the ice cap
(with respect to the tundra site) ranging from 0.5 to 1.4°C. The cooling effect was
larger very near the surface (15 cm), ranging from 1.5 to 2.5°C. Surface melt over the
ice cap associated with the cooling effect was teamed with a persistent near surface
temperature inversion, such that the sensible heat flux was directed downward while
it was upward over the tundra location. During snow-free conditions, the albedo at
the tundra site of about 0.10 compared with ice cap values from 0.4 to 0.7.
Regarding regional influences, while katabatic winds associated with Arctic ice
caps are not nearly as well expressed as over Greenland, they can certainly be pre-
sent, such as on and around the large Devon ice cap. By contrast, the Brooks Range
is known to play an important role in the regional circulation in winter when it gives
rise to a westerly “barrier wind” as a result of the thermal wind component that
results from the cold air trapped at low levels north of the range (Barry,
2008
, 135).
Summer influences of the Brooks Range on the Arctic frontal zone were examined
in
Chapter 4
.
Several recent studies (Golubchikov,
1996
; Shahgedanova,
2002
; Glazovsky,
2003
)
document the characteristics and variety of mountain and upland conditions in the
Eurasian Arctic. The Urals extend some 3,000 km southward from the Arctic coast.
