Presentation
The French MicroCarb mission will be launched in 2025 to provide scientific information on the carbon cycle. The instrument is designed to provide estimates of the column-average dry-air mole fraction of atmospheric carbon dioxide (XCO2). MicroCarb builds on a high spectral resolution infrared grating spectrometer aboard a microsatellite with four spectral bands: O2@0.76mm, O2@1.27mm, weak CO2@1.60 mm and strong CO2@2.04 mm, absorption bands. The main acquisition modes (nadir over lands and in the glint direction over oceans) will enable a spatial resolution of about 5×8 km2. Other acquisition modes are planned to focus the observations specific regions of interest.
The operational processing chain to retrieve XCO2 from the reflected radiance measurements will rely on a full physics radiative transfer model (4A-OP) inversion based on optimal estimation with the 4ARTIC software (Prototyped and operated by CNES, developed by Thalès Service). SATINV contributes to this algorithmic development by testing the estimation performances of 4ARTIC on actual radiance measurement made by the OCO-2 instrument (with three spectral bands common to MicroCarb).
In parallel, we are developing a computationally efficient AI-based retrieval method using neural networks, and trained on actual L1 radiance spectra and XCO2 products from the CAMS (Copernicus Atmosphere Monitoring Service) global atmospheric inversions.
