An eddy covariance system for measuring evaporative fluxes in the Quesnel river basin, British Columbia

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The anthropogenic emission of greenhouse gases such as carbon dioxide and methane has caused global surface air temperatures to rise by about 0.6°C during the past century.  This trend is expected to accelerate in the next century as greenhouse gas emissions intensify.  Some of the greatest environmental changes will be in high-latitude and high altitude regions where the surface energy budget is highly sensitive to modifications in snow and ice covers.  Global warming will therefore have significant repercussions on the water budget of northern mountainous watersheds such as the Quesnel River Basin (QRB) of British Columbia (BC). The Quesnel River drains an area of 11,500 square kilometres of variable (mountainous to flat) terrain at a mean elevation of 1400 m, and it encompasses some of the wettest and driest areas of BC's interior. Although future precipitation is likely to increase owing to the enhanced capacity of the atmosphere to hold water vapour at warmer temperatures, it is unknown how the additional input of freshwater will be partitioned after falling on the land surface. The goals of my research program are to obtain and maintain a long-term climatology of water budget terms for the QRB and to explore the effects of climate variability and change on water fluxes including evaporation. This proposal seeks funding for an eddy covariance system that will measure 3-dimensional fluctutations in wind speed and water vapour from which the evaporative flux will be deduced. This system will complement the existing and developing observational network in the QRB and provide critical data for the validation of numerical simulations of the QRB water cycle. A good understanding of the role of climate variability and change on the QRB water budget is critical since it is a major tributary of the Fraser River, constitutes a major spawning area for Pacific salmon, and supports active logging, agricultural, and tourism industries, among other commercial activities.