Assessing net ecosystem carbon exchange of U S terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations

Journal Article · Sat Jan 01 00:00:00 EST 2011 · Agricultural and Forest Meteorology

OSTI ID:1015080

Zhuang, Qianlai ^[1]; Law, Beverly E ^[2]; Baldocchi, Dennis ^[3]; Ma, Siyan ^[3]; Chen, Jiquan ^[4]; Richardson, Andrew ^[5]; Melillo, Jerry ^[6]; Davis, Ken J ^[7]; Hollinger, D ^[8]; Wharton, Sonia ^[9]; Falk, Matthias ^[9]; Paw, U Kyaw Tha ^[9]; Oren, Ram ^[10]; Katulk, Gabriel G ^[10]; Noormets, Asko ^[11]; Fischer, Marc ^[12]; Verma, Shashi ^[13]; Suyker, A E ^[14]; Cook, David R ^[15]; Sun, G ^[8] ; McNulty, Steven G ^[8]; Wofsy, Steve ^[5]; Bolstad, Paul V ^[16]; Burns, Sean ^[17]; Monson, Russell K ^[17]; Curtis, Peter ^[18]; Drake, Bert G ^[19]; Foster, David R ^[5]; Gu, Lianhong ^[20]; Hadley, Julian L ^[5]; Litvak, Marcy ^[21]; Martin, Timothy A ^[22]; Matamala, Roser ^[15]; Meyers, Tilden ^[23]; Oechel, Walter C ^[24]; Schmid, H P ^[25]; Scott, Russell L ^[26]; Torn, Margaret S ^[12]

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1. Purdue University
2. Oregon State University
3. University of California, Berkeley
4. University of Toledo, Toledo, OH
5. Harvard University
6. Marine Biological Laboratory
7. Pennsylvania State University
8. USDA Forest Service
9. University of California, Davis
10. Duke University
11. North Carolina State University
12. Lawrence Berkeley National Laboratory (LBNL)
13. University of Nebraska
14. University of Nebraska, Lincoln
15. Argonne National Laboratory (ANL)
16. University of Minnesota
17. University of Colorado, Boulder
18. Ohio State University, The, Columbus
19. Smithsonian Environmental Research Center, Edgewater, MD
20. ORNL
21. University of New Mexico, Albuquerque
22. University of Florida, Gainesville
23. NOAA, Oak Ridge, TN
24. San Diego State University
25. Indiana University
26. USDA ARS

More 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.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge National Environmental Research Park
• Sponsoring Organization: USDOE
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1015080
• Journal Information: Agricultural and Forest Meteorology, Vol. 151, Issue 1; ISSN 0168-1923
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CARBON
CARBON CYCLE
CARBON DIOXIDE
CARBON SINKS
CLIMATIC CHANGE
DISTRIBUTION
DISTURBANCES
DROUGHTS
ECOSYSTEMS
FORESTS
HURRICANES
RESOLUTION
SATELLITES
SAVANNAS
TERRESTRIAL ECOSYSTEMS