HR: 11:05h
AN: A51H-04    [PDF]
TI: Global Carbon Fluxes Based on Global CO$_{2}$ and Carbon Isotope Measurements
AU: * Bruhwiler, L M
EM: lori.bruhwiler@noaa.gov
AF: NOAA Climate Monitoring and Diagnostics Laboratory, 325 Broadway R/CG1, Boulder, CO 80305 United States
AU: Michalak, A M
EM: anna.michalak@noaa.gov
AF: NOAA Climate Monitoring and Diagnostics Laboratory, 325 Broadway R/CG1, Boulder, CO 80305 United States
AU: Miller, J B
EM: john.b.miller@noaa.gov
AF: INSTAAR, University of Colorado, Boulder, CO 80309 United States
AU: Peters, W
EM: wouter.peters@noaa.gov
AF: CIRES, University of Colorado, Boulder, CO 80309 United States
AU: Tans, P
EM: pieter.tans@noaa.gov
AF: NOAA Climate Monitoring and Diagnostics Laboratory, 325 Broadway R/CG1, Boulder, CO 80305 United States
AB: Obtaining detailed and accurate estimates of carbon fluxes is of considerable scientific and political importance, and using isotopic information can help constrain these fluxes. For example, measurements of the carbon isotope ratio of CO$_{2}$ ($\delta^{13}$C) helps resolve longitudinal structure in carbon fluxes by constraining the land-sea partitioning of regional carbon fluxes. In this study, we improve on past efforts to use $\delta^{13}$C measurements to further constrain CO$_{2}$ fluxes in several important ways. First, we use more observations of $\delta^{13}$C than have been used in the past. There are now 51 stations from which regular measurements of $\delta^{13}$C are available. Secondly, we use a monthly resolution time-dependent inversion technique, which allows us to make maximal use of the atmospheric $\delta^{13}$C data. Specifically, we take advantage of the information contained in the seasonal cycles of CO$_{2}$ and $\delta^{13}$C, not just the annual mean values. Although we use the best possible estimates of the terrestrial isotopic signatures and isotopic disequilibrium terms, there is significant uncertainty associated with these terms, and we will address the ways in which their uncertainty limits the ability of $\delta^{13}$C to add useful information to the inversion. In this presentation, we will also introduce the technique that we use for atmospheric inversions, a fixed-lag Kalman smoother. This technique offers computational efficiency while also having the advantage of propagating covariance forward in time.
DE: 0312 Air/sea constituent fluxes (3339, 4504)
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting