On the following subject: High Resolution Modelling of Aerosol Dynamics in the Mediterranean Coastal Zone.
Composition of the Jury
Rapporteurs
Marie-Noelle Bouin - (CNRM -Météo-France)
Umberto Rizza (CNR ISAC)
Examiners
Marc Mallet (CNRM)
Malik Chami (Sorbonne University)
Alexander Van Eijk (TNO)
Directors
Jacques Piazzola - University Professor (University of Toulon - Mediterranean Institute of Oceanography)
Pierre Sagaut - University Professor (Aix-Marseille University - M2P2)
Summary
Marine aerosols, generated by wind-wave interaction processes, are a major component of natural aerosols and play an important role in the planet's radiation balance. For this reason, a better understanding of the properties and atmospheric dynamics of these particles is a major challenge in the context of climate change, but also in terms of their interactions with atmospheric pollutants and the transport of large quantities of organic matter, which will have an impact on air quality, particularly in coastal regions. This thesis work was devoted to the development of a detailed model of the atmospheric dynamics of these aerosols in coastal areas, with the aim of gaining a better understanding of the intrusion and local atmospheric variations of marine aerosol concentrations in these spatially limited areas. To do this, an LES version of the MESO-NH model, in which a specific formulation of the marine aerosol source function developed in the MIO laboratory was introduced, was implemented over the Toulon coastal region. The numerical simulations were compared with experimental data acquired on board the ship Atalante during the MIRAMER research campaign. The ability of the numerical model to predict variations in aerosol concentration as a function of different local wind directions was assessed. The results provided a better understanding of the impact of the geographical configuration of the coastline on aerosol dynamics, and demonstrated the contribution and limitations of the high-resolution modelling used. The latter relate in particular to the limitations of the meteorological model in rendering localised turbulent structures, which need to be better described for accurate aerosol modelling, particularly in the land-sea transition zone. This work has also made it possible to improve the source function of aerosols from wave breaking for short fetches thanks to specific work on the wave slope.