Microscopic observations of core-shell particle structure and implications for atmospheric aerosol remote sensing

International audience Tropospheric aerosols play an important role in atmospheric chemistry, Earth’s radiative budget, and climate.After their generation, aerosols can suffer ageing processes and alter their physicochemical properties. Anaccurate accounting for these processes requires observations of the aerosol properties on different temporaland spatial scales. The current work is dedicated to: (i) study of physicochemical properties and mixing state ofindividual particles by means of analytical scanning and transmission electron microscopy for aerosolscollected during episodes of elevated aerosol loading; (ii) analysis of the effect of microphysical properties onoptical characteristics as measured and retrieved by remote sensing; and (iii) investigation of possibleparameterization of aerosol composition and core-shell structure in remote sensing algorithms. The workpresents observations conducted in northern France and western Africa (Senegal) as part of Labex CaPPAproject and SHADOW field campaigns. It includes simultaneous analyses of collected individual particles’composition and structure, remote sensing and in situ observations of urban/industrial, Saharan dust andbiomass burning particles near the surface and at different altitudes. A series of numerical simulations devotedto an analysis of the sensitivity of remote sensing observations to aerosol mixing state is conducted. Insights ona possible parameterization of aerosol core-shell structure in retrieval algorithms are finally presented.