The Mackenzie GEWEX Study: A Contribution to Cold Region Atmospheric and Hydrologic Sciences

The Mackenzie GEWEX Study (MAGS) is a collaborative study with the goals of understanding and modeling the high-latitude energy and water cycles, and improving our ability to assess the changes to the water resources of northern Canada that arise from climate variability and anthropogenic climate change. The Mackenzie River Basin (MRB) was selected for a comprehensive study as it possesses many of the environmental attributes of the northern circumpolar region, offers an excellent natural laboratory for studying cold region processes, and experiences significant climate warming and large climate variability. The Basin exhibits an annual negative heat balance, low annual mean temperature and a large positive water balance that promotes large river flow, notably during the spring snowmelt period. High topography of the Western Cordillera and low relief of the central and eastern Basin exert a strong influence on the pattern of atmospheric circulation, and on the advective heat and moisture fluxes. Numerous lakes and extensive wetlands affect surface energy and water balances through evaporation enhancement. Snow, ice (river and lake), and frost are major land surface features molded by the cold climate, and they in turn have strong feedbacks to the atmospheric and hydrologic processes. One major research challenge was to piece together the energy and water budgets given limited data of reliable quality. Through the decade-long MAGS research, this challenge was met in part by intensive studies in select regions within the MRB, the use of remote sensing information and ground observations, and the development and employment of models at various scales. This book is a compilation of the knowledge gained which is equally applicable to other cold regions in the world.