Methane emissions from an oil sands tailings pond: a quantitative comparison of fluxes derived by different methods

Abstract. Tailings ponds in the Alberta oil sands region are significant sources of fugitive emissions methane to atmosphere, but detailed knowledge on spatial and temporal variabilities is lacking due limitations methods deployed under current regulatory compliance monitoring programs. To develop more robust representative for quantifying emissions, three micrometeorological flux (eddy covariance, gradient, inverse dispersion) were applied along with traditional chambers determine fluxes over a 5-week period. Eddy covariance measurements provided benchmark. A method presented directly calculate stability-corrected eddy diffusivities that can be vertical gas profiles gradient estimation. Gradient shown agree within 18 %, while dispersion model estimates 30 % lower. Fluxes have only minor diurnal cycle (15 variability) weakly dependent wind speed, air, water surface temperatures. Flux underestimated by 64 this particular campaign. The results show larger footprint together high resolution measurement may result pond greenhouse emissions.