Constraints on CO2 flux emissions: reconstructions of in-situ measurements from Lagrangian stochastic inversion

Uncertainties in the CO2 fluxes introduce significant limitations for the validation of emission mitigation policies and the understanding of processes in carbon cycle science. We have performed diffusive Lagrangian reconstructions of in-situ CO2 data in order to obtain constraints of CO2 fluxes. Data has been collected during the CONTRAIL campaign and from the Tsukuba tower, nearby the CO2 emission hot spot of the Tokyo Bay Area. Advective transport based on analyzed meteorological winds is characterized by the transition probability function estimated with the proportion (or mixing ratio) of trajectories having been in contact with the PBL in the emission region within a designated period of time. This allows sensitivity studies as well as direct comparison with observations via the reconstruction of the volume mixing ratio of CO2. Sensitivity to different simplified boundary layer representations, turbulent mixing representations and meteorological fields is firstly studied. We are employing the WRF-Chem model for the calculation of high-resolution meteorological data products as well as Eulerian reconstruction of the CO2 observations. The properties of Lagrangian and Eulerian transport will be discussed.