CGRG Bibliography of Canadian Geomorphology
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Author : Endrizzi, S.; Marsh, P.; and Quinton, W.
Date : 2010.
Title : Topographic control on the depth of thaw in a peat covered continuous permafrost site in the arctic tundra and implication on the runoff production.
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
In permafrost dominated, tundra environments a spatially variable thaw depth, when combined with spatially variable water supply, organic soil thickness, and depth variable hydraulic conductivity in organic soils, has a significant impact on the flow of water from uplands to the stream channel, and therefore on stream discharge. The purpose of this work is studying how topography controls the depth of thaw. The study is performed using the hydrologic model GEOtop, which was applied to the Siksik Creek drainage basin located in proximity of the Mackenzie delta, and characterized by a relatively gentle topography (elevation from 0 and 80 m a.s.l. and area of 1 km2). GEOtop is a grid-based model that uses high resolution topographic data from Lidar, for example, and includes a complete surface energy balance scheme that accounts for variations in the turbulent and radiant fluxes. The model also has a complete subsurface heat and water flux scheme that is able to route water and energy both vertically and laterally. Topography affects the spatial variability of the depth of thaw through its control exerted on the surface energy balance and subsurface flow. The latter directly affects soil moisture, and then the thermal conductivity of the peat soil. The results show that the major effect is played by subsurface flow, and the surface energy balance spatial variability has very little effect. In order to understand the processes in environments with more rugged topography, virtual topographies with more accentuated slopes and elevations have been derived from the topography of the Siksik basin. It is shown that as the topography becomes more and more rugged, the controlling effect of the surface energy balance becomes more and more important, but the subsurface flow still remains significant and strongly affects the spatial variability of the depth of thaw.
Bibliography of Canadian Geomorphology