A satellite data driven biophysical modeling approach for estimating northern peatland and tundra CO2 and CH4 fluxes

• Published in: Biogeosciences
• Main Authors: Watts, J. D., Kimball, J. S., Parmentier, Frans-Jan, Sachs, T., Rinne, J., Zona, D., Oechel, W., Tagesson, T., Jackowicz-Korczynski, Marcin, Aurela, M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus GmbH 2014
• Subjects: Physical Geography; Arctic; Merra; Global warming; Tundra
• Online Access: https://lup.lub.lu.se/record/4496091; https://doi.org/10.5194/bg-11-1961-2014

The northern terrestrial net ecosystem carbon balance (NECB) is contingent on inputs from vegetation gross primary productivity (GPP) to offset the ecosystem respiration (R-eco) of carbon dioxide (CO2) and methane (CH4) emissions, but an effective framework to monitor the regional Arctic NECB is lacking. We modified a terrestrial carbon flux (TCF) model developed for satellite remote sensing applications to evaluate wetland CO2 and CH4 fluxes over pan-Arctic eddy covariance (EC) flux tower sites. The TCF model estimates GPP, CO2 and CH4 emissions using in situ or remote sensing and reanalysis-based climate data as inputs. The TCF model simulations using in situ data explained >70% of the r(2) variability in the 8 day cumulative EC measured fluxes. Model simulations using coarser satellite (MODIS) and reanalysis (MERRA) Records accounted for approximately 69% and 75% of the respective r(2) variability in the tower CO2 and CH4 records, with corresponding RMSE uncertainties of <= 1.3 gCm(-2) d(-1) (CO2) and 18.2 mg Cm-2 d(-1) (CH4). Although the estimated annual CH4 emissions were small (<18 gCm(-2) yr(-1)) relative to R-eco (>180 gCm(-2) yr(-1)), they reduced the across-site NECB by 23% and contributed to a global warming potential of approximately 165 +/- 128 gCO(2)eqm(-2) yr(-1) when considered over a 100 year time span. This model evaluation indi-cates a strong potential for using the TCF model approach to document landscape-scale variability in CO2 and CH4 fluxes, and to estimate the NECB for northern peatland and tundra ecosystems.