Towards Regional CO2 Flux Estimates for North America From Inverse Modeling

The two-way nested TM5 transport model is used to estimate sources and sinks of CO2 on a regional scale over North America. This study uses a 80x80km grid scale over the US, a 250x150km grid over North America, and a 600x400km grid over the rest of the world. This setup balances the need for high spatial resolution, computational efficiency, and retaining information from remote areas. We focus on quantifying the model's seasonal and diurnal rectifier, the feasibility of solving for weekly grid-based CO2 fluxes, and the incorporation of vertical profiles from aircraft measurements in the inversion . The huge computational burden of this problem are tackled with the adjoint of the TM5 model, and a newly developed Kalman filter assimilation technique. The aim is to produce regional scale, weekly CO2 fluxes that are optimally consistent with the NOAA CMDL measurement, and can be used to answer both scientific and policy driven questions.