The northern Great Plains extend well into Canada to a latitude of about 52°N. Contrary to the perception of the plains as monotonous, this region has a varied topography and earth history. Bedrock uplands stood in the path of Pleistocene ice sheets. These unglaciated bedrock plateaus rise to the highest elevations in the Canadian interior. The glacial landscapes include large ice-thrust moraines, the limits of the last glaciation, extensive outwash and lake deposits, and meltwater channels up to 3 km wide and more than 100 m deep.
Postglacial landforms include active sand dunes, and a valley network featuring badlands and landslides. The most distinctive characteristic, however, is the dry climate and extreme variations in weather. Resistance of the landscape to climatic events and change is lacking where vegetation is sparse and substrata are poorly consolidated. The postglacial response of surface processes to climatic variability and change has varied significantly among the landscapes that comprise the southern Canadian Interior Plains. Thus future impacts of climatic change may be largely confined to sensitive landscapes among vast areas that are largely geomorphically inert.
The Canadian Climate Centre's general circulation model predicts that, with increased CO2 concentrations, the largest rise in mean surface temperature in southern Canada will occur in the Interior Plains. Furthermore, southwestern Saskatchewan and southeastern Alberta--the Palliser Triangle--is the only major subhumid region of Canada. Therefore the Geological Survey of Canada initiated the Palliser Triangle Global Change Project to examine the response of earth surface processes to climatic change and variability.
The modeling and mapping of potential changes in surface process, or landscape sensitivity, require a large digital geographic database, as the degree of sensitivity will vary across this large diverse region. The basic spatial units are derived from digital maps of soil, climate, topography, surficial geology, land cover and hydrography, according to salient landscape parameters (e.g. soil and topographic variables) that control geomorphic response to climate. The GIS then is used to couple models of the surface processes with the geographic database. Most models, like the processes themselves, operate at local scales. Therefore a theoretical framework is required to the link the properties of slopes and streams to regional landscape parameter. Only then can sensitivity be expressed in terms and units that are valid at a regional scale.
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