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Assessing net ecosystem carbon exchange of U.S. terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observationsAuthor(s): Jingfeng Xiaoa; Qianlai Zhuang; Beverly E. Law; Dennis D. Baldocchi; Jiquan Chen; al. et.
Source: Agricultural and Forest Meteorology 151:60–69
Publication Series: Scientific Journal (JRNL)
PDF: View PDF (1.64 MB)
DescriptionMore accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a carbon sink, the size, distribution, and interannual variability of this sink remain uncertain. Here we report a terrestrial carbon sink in the conterminous U.S. at 0.63 pg C yr−1 with the majority of the sink in regions dominated by evergreen and deciduous forests and savannas. This estimate is based on our continuous estimates of net ecosystem carbon exchange (NEE) with high spatial (1 km) and temporal (8-day) resolutions derived from NEE measurements from eddy covariance flux towers and wall-to-wall satellite observations from Moderate Resolution Imaging Spectroradiometer (MODIS). We find that the U.S. terrestrial ecosystems could offset a maximum of 40% of the fossil-fuel carbon emissions. Our results show that the U.S. terrestrial carbon sink varied between 0.51 and 0.70 pg C yr−1 over the period 2001–2006. The dominant sources of interannual variation of the carbon sink included extreme climate events and disturbances. Droughts in 2002 and 2006 reduced the U.S. carbon sink by ∼20% relative to a normal year. Disturbances including wildfires and hurricanes reduced carbon uptake or resulted in carbon release at regional scales. Our results provide an alternative, independent, and novel constraint to the U.S. terrestrial carbon sink.
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CitationXiaoa, Jingfeng; Zhuang, Qianlai; Law, Beverly E.; Baldocchi, Dennis D.; Chen, Jiquan; et. al. 2011. Assessing net ecosystem carbon exchange of U.S. terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations. Agricultural and Forest Meteorology 151:60–69.
KeywordsNet ecosystem carbon exchange, Eddy covariance, MODIS, Carbon sink, U.S., Interannual variability, Drought, Disturbance
- Data-driven diagnostics of terrestrial carbon dynamics over North America
- A continuous measure of gross primary production for the conterminous United States derived from MODIS and AmeriFlux data
- Estimation of net ecosystem carbon exchange for the conterminous United States by combining MODIS and AmeriFlux data
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