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, F. J. W., Sachs, T., Rinne, J., Zona, D., Oechel, W., Tagesson, T., Jackowicz-Korczyński, M., Aurela, M.
• Format: Text
• Language: English
• Published: 2018
• Subjects: Arctic; Merra; Global warming; Tundra
• Online Access: https://doi.org/10.5194/bg-11-1961-2014; https://www.biogeosciences.net/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 (CO 2 ) and methane (CH 4 ) 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 CO 2 and CH 4 fluxes over pan-Arctic eddy covariance (EC) flux tower sites. The TCF model estimates GPP, CO 2 and CH 4 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 CO 2 and CH 4 records, with corresponding RMSE uncertainties of ≤ 1.3 g C m −2 d −1 (CO 2 ) and 18.2 mg C m −2 d −1 (CH 4 ). Although the estimated annual CH 4 emissions were small (< 18 g C m −2 yr −1 ) relative to R eco (> 180 g C m −2 yr −1 ), they reduced the across-site NECB by 23% and contributed to a global warming potential of approximately 165 ± 128 g CO 2 eq m −2 yr −1 when considered over a 100 year time span. This model evaluation indicates a strong potential for using the TCF model approach to document landscape-scale variability in CO 2 and CH 4 fluxes, and to estimate the NECB for northern peatland and tundra ecosystems.