This manuscript compares aerosol size distributions and microphysical property measurements from the Raman lidar BASIL and from aircraft sensors during HyMeX-SOP1. The attention was focused on a measurement session on 02 October 2012, with BASIL measurements revealing the presence of a lower aerosol layer extending up to 3.3 km and an elevated layer with extending from 3.6 km to 4.6 km. Aerosol size distributions and microphysical characteristics were determined from three-wavelength particle backscattering and extinction profile measurements through a retrieval approach based on Tikhonov regularization. A good agreement is found between BASIL retrievals and the microphysical sensors’ measurements for all considered aerosol dimensional and microphysical characteristics. Specifically, BASIL and in-situ volume concentration values are 1-3.5 mm3cm-3 in the lower layer and 2-4 mm3cm-3 in the upper layer. Furthermore, effective radius values from BASIL and the in-situ sensors’ measurements are in the range 0.2-0.6 mm both in the lower and upper layer. Particle size distributions were determined at 2.2, 2.8, 4 and 4.3 km, with again a good agreement between the Raman lidar and the microphysical sensors throughout the considered height interval. These results, in combination with Lagrangian back-trajectory analyses and chemical composition measurements, indicate that aerosols below 3 km were possibly originated by forest fires in North America or by anthropogenic activities in North-Eastern Europe, while aerosols above 3 km were originated over the North Atlantic and presumably include both a marine and an organic component. This interpretation is compatible with the lidar retrieved profiles of particle complex refractive index.
