I am wondering if it is possible to upscale methane flux from static chamber measurements to ecosystem scale without Eddy Covariance tower data. Any help/ guidance would be highly appreciated. Thanks a lot
If you have a map of the vegetation communities within your study area (that you have measured fluxes from using chambers), you could do an area-weighted mean upscaling of the flux measurements. We did similar in our study here for comparison with measurements with EC tower.
Davidson, S.J., Santos, M.J., Sloan, V.L., Reuss-Schmidt, K., Phoenix, G.K., Oechel, W.C. and Zona, D., (2017) Upscaling CH4 Fluxes Using High-Resolution Imagery in Arctic Tundra Ecosystems, Remote Sensing, 9(12), 1227; https://doi.org/10.3390/rs9121227
In wetlands, methane fluxes often vary between different plant assemblages. If this was true at your site, you could use static chambers to measure methane fluxes in each of the plant assemblages. Then, you would multiply the per-meter-squared flux rate from a particular plant assemblage (measured using chambers) by the area of that vegetation assemblage in the ecosystem (determined through field surveys and/or remote sensing) to give the total methane flux from a particular plant assemblage. Summing the total methane flux from each assemblage would then give an ecosystem-scale flux.
I have seen multiple papers that have taken this approach; here is one such study (Morozumi et al. 2019. https://doi.org/10.1080/16000889.2019.1581004).
If methane fluxes varied as a function of some other environmental condition (for example, elevation, soil moisture), you would use the same general approach. Instead of vegetation assemblages to guide your deployment of chambers, you would deploy them across the full range of environmental conditions (for example, from lowest to highest elevation, or wettest to driest soil), then use the resulting methane flux vs. environmental condition relationship to scale from chambers up to the ecosystem.
Thanks a lot for a detailed explanation Scott J Davidson Scott C. Neubauer
It is very useful.
Dear Ruchita, you may find this paper useful too:
Budishchev, A., Mi, Y., Van Huissteden, J., Belelli-Marchesini, L., Schaepman-Strub, G., Parmentier, F. J. W., ... & Dolman, A. J. (2014). Evaluation of a plot-scale methane emission model using eddy covariance observations and footprint modelling. Biogeosciences, 11(17), 4651-4664.
doi:10.5194/bgd-11-3927-2014.