The Global Energy and Water Cycle Experiment (GEWEX) is an international effort developed by the World Climate Research Programme as a coordinated group of activities aimed at improving our understanding and prediction of the role that the water cycle plays in the climate system. As a major contribution to GEWEX, the Canadian Mackenzie GEWEX Study (MAGS) focuses on understanding and modelling the flows of energy and water into and through the atmospheric and hydrological systems of the Mackenzie River basin which yeilds the largest North American source of fresh water discharge into the Arctic Ocean. The Basin itself is subjected to wide climatic fluctuations, and is currently experiencing a warming trend. MAGS necessarily involves coordinated research into many atmospheric, land surface and hydrological issues assosicated with cold climate systems. A network among the Canadian universities, governments, communities and the private secotr is critical to the success of the project to benefit Canada and the international science.

MAGS is also an important Canadian contribution to the Global Water and Energy Cycle Experiment (GEWEX); a major international research project coordinated by the GEWEX Hydro-meteorology Panel (GHP) under the auspices of the World Climate Research Programme (WCRP). The objectives of GEWEX are to:

• measure global hydrological cycle and energy fluxes,
• model the global hydrological cycle and its impact on atmosphere, oceans and land surfaces,
• predict global and regional response of water resources to environmental change,
• advance observing techniques and data management and assimilation systems.

MAGS research is being conducted by a network of Canadian government and university scientists supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), Environment Canada, and other government and industrial partners.