Year-round study of the optical properties of airborne dust in Antarctica.

OPTAIR is a multidisciplinary project to study the optical properties of airborne particles at Concordia Station, on the East Antarctic plateau, to assess the relationship among the optical properties of dust suspended in air and deposited by the snow. A permanent instrument based on the Single Particle Extinction and Scattering (SPES) method specifically designed and realized in Milan has been installed in November 2018. It continuously produces time resolved data providing several optical properties for each particle, aiming to feed the models describing radiation transfer through the Earth's atmosphere, an open issue for what concerns the effects of dust. Data show evidence of important changes of the optical properties of dust across the year, with a relevant fraction of particles accumulated during short bursts lasting a few hours. This shows the need of time resolved information about the optical properties of dust to infer the effective impact of dust on radiative transfer.