An ANR B2C project thesis by Johannes Heuser
Le jury de thèse se composait de :
Romain CEOLATO, Ingénieur de recherche, ONERA (rapporteur)
Athanasios NENES, Professeur, Ecole Polytechnique Fédérale de Lausanne (rapporteur)
Cyrielle DENJEAN, Chargée de recherche, CNRM (examinatrice)
Daniela MELONI, Chargée de recherche, ENEA (examinatrice)
Denis PETITPREZ, Professeur, Université de Lille/PC2A (examinateur)
Bénédicte PICQUET-VARRAULT, Professeure, UPEC, LISA (présidente du jury)
Jean-François DOUSSIN, Directeur de recherche, CNRS, LISA (directeur de thèse)
Claudia DI BIAGIO, Chargée de recherche, CNRS, LISA (encadrante de thèse)
Martin GYSEL-BEER, Chercheur, PSI (membre invité)
The aim of this thesis work is to provide new measurements and descriptions of the physical, chemical and optical properties of soot and its BC (black carbon) and BrC (brown carbon) fractions, in order to improve their representation in climate models and remote sensing algorithms. The aim is to advance understanding and description of the variability of soot properties 1) during emission, for variable combustion conditions, and 2) during ageing in the atmosphere, in particular due to internal mixing with organic and inorganic compounds forming a coating on the soot surface. In order to carry out a mechanistic study of soot properties, a coherent set of experiments was set up using the CESAM (Chambre Expérimentale de Simulation Atmosphérique Multiphasique) atmospheric simulation chamber and a propane-based soot generator.
Photo de groupe avec Johannes Heuser et le jury de thèse. (de gauche à droite : D. Meloni, B. Picquet-Varrault, C. Di Biagio, J. Heuser, J. F. Doussin, M. Gysel-Beer, R. Ceolato, C. Denjean, A. Nenes, D. Petitprez).
Experiments were deployed to determine key optical parameters used in modeling and remote sensing, such as absorption, extinction and scattering cross sections (MAC, MEC, MSC), simple scattering albedo (SSA), and complex refractive index (CRI). The properties of soot from different combustion conditions were used to establish a generalized relationship between MAC and the chemical composition of freshly emitted particles. Optical calculations based on two descriptions of particle morphology were performed to determine the CRI of soot and discuss the usability and relevance of the data for different hypotheses of shape representations.
Soot aerosols were subjected to various simulated atmospheric aging processes to determine the effects of aging on their absorption capacity and physico-chemical properties. In particular, the formation of a coating and the increase in absorption due to this internal mixing were studied for two precursors and coating processes. This made it possible to study the relationship between increased absorption, particle ageing and coating thickness, of interest throughout the soot life cycle.
(Gauche) Johannes Heuser pendant la lecture du serment en présence de son jury. (Droite) Visite de la chambre CESAM par les membres du jury.
This thesis is funded by the B2C project “Constraining the direct radiative effect of black carbon and brown carbon on climate: an innovative experimental study of their spectral optical properties” financed by the French National Research Agency (contract ANR-19-CE01-0024-01).
This work was also funded by the TNA activity of the European Union's Horizon 2020 research and innovation program through the EUROCHAMP-2020 infrastructure activity under grant agreement no. 730997. It was also supported by the DIM Qi² and the Région Paris Ile-de-France, and by the GDR SUIE of the CNRS.
Publications
Heuser, J., Di Biagio, C., Yon, J., Cazaunau, M., Bergé, A., Pangui, E., Zanatta, M., Renzi, L., Marinoni, A., Inomata, S., Yu, C., Bernardoni, V., Chevaillier, S., Ferry, D., Laj, P., Maillé, M., Massabò, D., Mazzei, F., Noyalet, G., Tanimoto, H., Temime-Roussel, B., Vecchi, R., Vernocchi, V., Formenti, P., Picquet-Varrault, B., and Doussin, J.-F.: Spectral optical properties of soot: laboratory investigation of propane flame particles and their link to composition, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2024-2381, 2024.