CGRG Bibliography of Canadian Geomorphology
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Author : Burn, C.; and Zhang, Y.
Date : 2010.
Title : Permafrost and climate change at Illisarvik, Mackenzie delta region, western Arctic coast, Canada.
Publication : CMOS-CGU Ottawa 2010. 44th Annual CMOS Congress, 36th Annual Scientific Meeting of CGU, 3rd Joint CMOS-CGU Congress. May 31-June 4, 2010. Ottawa, Ontario.
Issue :
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Abstract
Canada’s western Arctic has experienced greater atmospheric warming since 1970 than most other areas of the country, with the rate of increase in mean annual air temperature being 0.77ºC/decade. There is an air temperature record for the Mackenzie delta area since 1926, but before 1970 there was only slight warming. In 1974, J. R. Mackay published a baseline map of permafrost temperatures in the area, which were 1º – 3ºC lower than present measurements of annual mean ground temperature. At Herschel Island, 100 km west of the delta, the temperature profile in permafrost has been reconciled with climate warming during the 20th century using a numerical simulation. Illisarvik is a long-term field site for permafrost investigations on Richards Island, established by J. R. Mackay in 1978. In 2006 and 2008 we drilled bore holes to 50- and 53-m depth, at sites in undisturbed tundra, cased the holes with one-inch steel pipe, and installed temperature cables with thermistors spaced at 5 m intervals in the casing. These sites have provided temperature profiles of identical gradient, but offset by about 0.4ºC. The profiles decrease in temperature with depth, indicating recent warming of the ground. The temperatures at 20-m depth are -7.1ºC and -6.8ºC, over 1ºC warmer than data from 1970; at the surface the increase is close to 3ºC. We have reproduced the temperature profile at the site with a similar numerical simulation as for Herschel Island, but with the warming concentrated in the last 40 years. The simulation was calibrated against deep temperature records available for the area and a regional heat flux of 0.05 Wm-2. The thermal conductivity of the sand formations in the area, which extend below 100 m depth, is relatively high. The simulation indicates the thermal regime has been disturbed from equilibrium to about 100-m depth.
Bibliography of Canadian Geomorphology