Geoscience Reference
In-Depth Information
Figure 2.16. Percentage coverage of inland water (freshwater lakes and marshes) (from
Bonan, 1995 , by permission of AMS).
Slave Lake (28,500 km 2 ) are by far the largest and both exceed 400 m in depth.
By contrast, Lake Netilling on Baffin Island is just more than 5,000 km 2 and Lake
Hazen on Ellesmere Island (81.5°N, 70°W) is 540 km 2 . In Finnish Lapland, the
largest is Lake Inari (69°N, 27.5°E) at more than 1,000 km 2 . There are few major
lakes in the Russian Arctic. Lake Taymyr (74°N, 74°E) has an area of about 4,500
km 2 . In the tundra areas of western Siberia and the Taymyr Peninsula, lakes are
typically smaller than 0.3 km 2 , with a few larger than 50 km 2 . Here they represent
2-5 percent of the surface (Ananjeva, 2000 ); but in the coastal plain of northern
Alaska, so-called thaw lakes form about 40 percent of the surface. In Greenland,
the Arctic islands, and the mountains of Alaska and the Yukon (Post and Mayo,
1971 ), there are many ice-dammed lakes. Many of them periodically drain and sub-
sequently refill. Hence they are ephemeral features of the landscape.
2.3
Basic Climatic Elements
2.3.1
Snow Cover
Most of the Arctic land and perennial sea ice surface has a snow cover for at least
6-8 months of the year. For a number of reasons snow cover is a key climatic var-
iable: (1) its high albedo (reflectivity in solar wavelengths), typically 0.80 to 0.90
for new snow; (2) the insulating effect it has on the underlying tundra or sea ice;
and (3) its role in storing precipitation over terrestrial regions, which is released as
river discharge during spring and summer. As we have already seen, this impacts
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