Biomass burning aerosol optical properties and applications to remote sensing – BIODARS

The main objective of the BIODARS project is to study the impact of the optical properties of biomass burning aerosols obtained from laboratory measurements on the improvement of the characterization and monitoring of fires by remote sensing. Indeed, fires are recognized as one of the main sources of absorbing aerosols, making them a key parameter of atmospheric chemistry and radiation balance. However, their great chemical and microphysical diversity make them one of the most poorly known types of aerosols and therefore difficult to monitor and quantify. The ambition of the BIODARS project is therefore based first on the laboratory determination of the optical properties, in particular the complex refractive indices (CRI) over a wide spectral range (from far infrared to UV) of aerosols resulting from the combustion of fuels representative of different forests often impacted by mega-fires. Measuring the CRI in such a large spectral window is a challenge and represents a real advance in the determination of optical properties (AOD, SSA, etc.) necessary for remote sensing retrievals. The methodology for determining the CRI has already been successfully applied by our group on mineral dust and volcanic ash, including for aerosols absorbing in the near infrared. In this project, it is planned to apply this approach to aerosols produced by combustion under controlled conditions, as well as to aerosols collected during forest fires. Then we will establish their chemical and morphological composition, as well as the state of mixture in order to best establish the link between physical, chemical and optical properties. Finally, we will study the contribution of this new information for remote sensing (ground-based and satellite) to their spatial and temporal monitoring and their physicochemical characterization.