The team is specialized in the study of the optical properties of aerosols as well as their hygroscopic properties in order to establish a link between these properties and the chemical composition, size and morphology of the particles.

  • Optical properties (in collaboration with LOA, ULille).

The aim is to determine the complex refractive indices for different families of aerosols (volcanic dust, desert dust). The experiment consists in recording the extinction spectra of these particles in the far, medium and near infrared range as well as in the UV-vis. The measurement of the size distribution is also recorded in parallel. From these experimental data, it is possible to invert the spectra to restore a complete set of indices thanks to an optimal estimation method associated with a scattering theory (Mie or CDE for example). These complex refractive indices are intrinsic characteristics of the particles and are necessary to derive the optical quantities commonly used in remote sensing: simple scattering albedo, optical thickness, mass absorption coefficient.

  • Hygroscopic properties

We study the ability of aerosol particles to form cloud droplets. The experiment is centered on the use of a condensation nuclei counter which allows to generate a zone of supersaturation with respect to liquid water in order to generate conditions encountered during cloud formation. The experimental measurements are interpreted by applying the Köhler theory to determine the hygroscopicity parameter, κ, as a function of the chemical composition of the particles (organic, inorganic, internal mixture).

Contact : Denis Petitprez (denis.petitprez()