Canada

Hydrology

An understanding of the linkages between atmospheric-terrestrial and hydrologic processes is required before ramifications of future global changes to arctic environments can be assessed. Part of this study focussed on understanding the present-day spatial and temporal variability of topography, pedology and botany in relation to the local microclimatology and hydrology of a High Arctic site. Fieldwork (1989-1993) at Hot Weather Creek, Ellesmere Island, N.W.T. revealed the direct (i.e., radiation, temperature), recurrent i.e., (ground thaw, snow cover) and long-term patterns (e.g. soils, vegetation) arising within a small area (1km$sp2$). This study also indicted the importance of radiation as the driving force behind snowmelt patterns, ground thaw and soil moisture. Subsequently, much emphases was placed on the development and testing of a solar radiation model which employs summer field camp data (twice-daily air temperature and cloud information). The successful performance of this model especially when averaged over a four-day period suggests it utility in other areas of the Arctic where similar input data are available. The radiation model was employed within a surface energy balance model which similarly uses limited field camp data (twice-daily temperature, wind and cloud data) obtained at a point. The testing of this model with measured net radiation from both level and sloping surfaces with varying surface conditions, suggest that it is possible to use limited input data from a point to calculate surface energy fluxes (Q*, $rm Qsb{e}, Qsb{h}, Qsb{s})$ for a range of sites. The surface energy balance model was used to simulate melt and evaporation for a small, continuous permafrost basin (Heather Creek, N.W.T.) during two contrasting summer seasons (1989-cool/wet and 1990-warm/dry). Model performance at the basin scale was assessed in a simple water balance framework with both years showing simulated long-term storage of less than 20% of total precipitation input. Hypothetical alterations in atmospheric and terrestial impacts of +/- 10% revealed that slight changes in aerosols, cloud amount and temperature have more affect on basin hydrological processes (melt, evaporation and storage) than slight changes in surface conditions (e.g. resistance, albedo). This study will be of interest to northern scientists wishing to better understand both the present-day linkages between atmosphere-terrestrial and hydrological processes and future global impacts.

AAGNN13695