Influence of Local Topography, Soils, and Vegetation on Microclimate and Hydrology at a High Arctic Site, Ellesmere Island, Canada

Influence of topography, soils, and vegetation on the microclimate and hydrology of four slopes and a plateau site located within a 1-km2 area in the continuous permafrost zone of Arctic Canada was studied. The field season covered two summers with contrasting climatic conditions. During the warm, dry summer (1990), the between-slope differences in radiation, and air and ground temperatures were exaggerated, while during the cloudy summer (1989), diffuse rather than direct solar radiation prevailed and the differential heating between slopes was reduced. Ground thaw increased in the warm summer, but maximum thaw depth at any site was also affected strongly by vegetation and soil characteristics, the latter being controlled by local geology and geomorphic processes. Precipitation on slopes can be influenced by wind and snow accumulation is modified by the local topography such as slope concavities. Snow ablation was largely accomplished through radiation melt so that the albedo changes were important. Meltwater runoff was maintained only downslope of deep snowbanks, and only the lower slopes experienced continuous saturation or groundwater flow. The spatial pattern of snow accumulation, frost table configuration, and surface or groundwater flows tend to recur annually, indicating the long-term influence of topography, soils, and vegetation on hydrologic processes at the local scale. Such studies linking the spatial and temporal variability of environmental attributes on energy and water flow improve our understanding of landscape ecology in northern environments and are useful when point observations are scaled up to match the dimensions of regional climate models.