Potential of the CarbonSat Mission for Assessing CO2 fluxes at Global and Local Scale
Broquet, Grégoire1; Renault, Emmanuel1; Chevallier, Frédéric1; Bovensman, Heinrich2; Buchwitz, Michael2; Reuter, Max2; Breon, Francois-Marie1; Pillai, Dhanya2; Chimot, Julien3; Vinuessa, Jean-Francois3; Houweling, Sander4

CarbonSat was selected by ESA as a candidate for the 8 Earth Explorer Opportunity (EE8). The mission concept and instrument characteristics are described by Bovensmann et al. (2013, this session). As part of the preparation for the mission, two scientific studies have been funded by ESA; the first one (Buchwitz et al.) analyses the performance of the mission in terms of CO2 and CH4 columns. The other one, LOGOFLUX, analyses the performances in terms of surface fluxes. The imaging capabilities of the instrument make it possible to identify concentration plumes downwind of large emission sources such as cities or fossil-fuel power plants. The concentration gradient is directly related to the emission intensity so that the source intensity may be estimated through inverse transport modelling. There are however several source of uncertainties that are evaluated through the LOGOFLUX study. · Atmospheric transport and in particular the wind speed · Measurement error and biases · Inhomogeneous spatial and temporal distribution of the sources · Impact of sources and sinks outside of the observation domain. · Vertical distribution of the concentration plume As part of LOGOFLUX, several tools have been developed to invert emission factors based on the column concentration measurements. A simple tool is a plume shape model that requires limited information about the atmospheric transport. Another type of tool uses a full description of the atmospheric transport and permits the estimation of the spatial and temporal structure of the source. These tools have been applied on simulated observations of the Paris and Berlin area, as well as an hypothetical power plant. The presentation will quantify these various sources of errors and provide an overall estimate of the CarbonSat capabilities to monitor the anthropogenic sources of CO2. In addition, CarbonSat will generate a huge amount of CO2 column observations, at least one order of magnitude more numerous than current or forthcoming missions. These observations will be used to monitor natural fluxes (sources and sinks) at the global scale. LOGOFLUX will assess the potential of CarbonSat for this objective, in comparison to that offered by the other missions (GOSAT, OCO-2).