Modelling Seasonal and Annual Variability of Carbon Fluxes in a Large Boreal Hydroelectric Reservoir
Weifeng Wang, McGill University, Department of Geography, and Global Environmental and Climate Change Centre, Montreal, QC, Canada, Youngil Kim, Oregon State University, Forest Ecosystems and Society, Corvallis, OR, United States, Nigel T Roulet, McGill University, Department of Geography, Montreal, QC, Canada, Ian B Strachan, McGill University, Department of Natural Resource Sciences, Montreal, QC, Canada and Alain Tremblay, Hydro-Québec, Environment Production, Montreal, QC, Canada
Contact First Author: Weifeng Wang; wang.weifeng@njfu.edu.cn
Previously Published Material: The content was presented in the AGU fall meeting, but we have more solid simulation results and new findings.
English Abstract:
Greenhouse gas emissions from hydroelectric reservoirs have attracted much attention over the past decades. To quantify CO2 emissions from reservoir surfaces we intergrate a lake carbon model, modified from the Hanson Lake Carbon Model, a newly developed 1-dimension thermal stratification model, and a terrestrial biogeochemistry model (DNDC: DeNitrification-DeComposition) that simulates vegetation litter and soil organic carbon dynamics under flooded conditions. We evaluated CO2 emissions simulated by the newly developed FAQ (Flooded AQuatic)-DNDC model using observed fluxes from an eddy covariance tower in an ~600 km2 boreal hydroelectric reservoir, Eastmain-1, in northern Quebec, Canada, for the period of 2007-2012. Simulated annual CO2 emissions generally matched the observed fluxes. The model captures well the seasonal pattern of CO2 flux from the reservoir surface, although the simulated peak emission in spring are overestimated compared to the observations. Sensitivity analysis shows that the amounts of dissolved organic carbon (DOC) input rarely affect CO2 emissions but greatly influences the DOC concentration in water column. Our analysis also suggests that warming changes the temporal pattern and magnitude of CO2 emissions. Future research on mechanisms of CO2 evasions through ice is necessary for reliable simulation for seasonal ice covered aquatic ecosystems.
