HR: 13:40h
AN: A42D-01    [PDF]
TI: Changes in Gross and Net CO2 Fluxes Over the Last two Decades Deduced from CO2, 13C, and 18O Atmospheric Measurements
AU: * ciais, p
EM: ciais@lsce.saclay.cea.fr
AF: LSCE CEA-CNRS, bat 709 CE Orme des Merisiers, Gif sur Yvette, 91191 France
AU: Peylin, P
EM: peylin@lsce.saclay.cea.fr
AF: LSCE CEA-CNRS, bat 709 CE Orme des Merisiers, Gif sur Yvette, 91191 France
AU: cuntz, m
EM: cuntz@lsce.saclay.cea.fr
AF: LSCE CEA-CNRS, bat 709 CE Orme des Merisiers, Gif sur Yvette, 91191 France
AU: Miller, J B
EM: John.B.Miller@noaa.gov
AF: NOAA CMDL, 325 Broadway, Boulder, CO 80305 United States
AU: Miller, J B
EM: John.B.Miller@noaa.gov
AF: INSTAAR, 1560 30th street, Boulder, CO 80309 United States
AU: Miller, J W
EM: jwhite@colorado.edu
AF: INSTAAR, 1560 30th street, Boulder, CO 80309 United States
AU: francey, r
EM: rjf@dar.csiro.au
AF: CSIRO DAR, Aspendale Victoria, Aspendale, 3195 Australia
AU: rayner, p
EM: ray060@dar.csiro.au
AF: CSIRO DAR, Aspendale Victoria, Aspendale, 3195 Australia
AB: Year-to-year fluctuations in the growth rate of atmospheric CO2 are largely contributed by the effects of climate variability on terrestrial CO2 fluxes. High precision atmospheric 13C time series can be used in so called "double deconvolutions" to separate land from oceans fluxes. But 13C data alone provide almost no information on the interannual variability of the gross fluxes (Photosynthesis, Ecosystem Respiration, Combustion) controlling the carbon balance of terrestrial ecosystems. We used records of 18O in CO2 in addition to 13C and CO2 from the CMDL and CSIRO global air sampling networks, which span over the past two decades into a bayesian 'triple deconvolution". This method allows to infer year-to-year variations in photosynthesis and respiration at the hemispheric level, given additional a priori knowledge of the variability in isotopic fractionations and disequilibrium terms. The magnitude of the changes in gross CO2 fluxes that are required to explain the variability of the 18O signal will be compared to the magnitude of changes in the net fluxes.
DE: 0330 Geochemical cycles
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting