Developing a 14C-Based Fossil Fuel CO2 Emissions Estimation Capability for CarbonTracker

The goal of this project is to develop the tools necessary to use the information from the expanded 14C measurement programs within the context of the CarbonTracker assimilation and inversion framework in order to improve estimates of terrestrial biospheric CO2 exchange (and their uncertainties) over the U.S. A limited number of new 14C observations at the U.S. boundaries as needed to better define the CarbonTracker representation of the 14C �??background�?� against which regional scale depletions (i.e., fossil fuel CO2 enhancements) occur are also proposed. The focus of the development effort is on improving flux retrievals over North America, but these tools will be suitable for implementation in other regions or at the global scale within the CarbonTracker framework. Ultimately, the combination of a 14C-enabled�?� CarbonTracker data assimilation and inversion framework and recommended increases in the density of 14CO2 observations can be used for estimation of fossil fuel emissions at national, regional and, possibly, state levels for independent verification of bottom-up inventories.