Measurements of Aerosol Size and Microphysical Properties: A Comparison Between Raman Lidar and Airborne Sensors
Paolo Di Girolamo, Benedetto De Rosa, Donato Summa, Noemi Franco, Igor Veselovskii
Abstract
Abstract This manuscript compares measurements of aerosol size distributions and microphysical properties retrieved from the Raman lidar BASIL with those obtained from a series of aircraft sensors during HyMeX‐SOP1. The attention is 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 extending from 3.6 to 4.6 km. Aerosol size distribution and microphysical properties are determined from multi‐wavelength particle backscattering and extinction profile measurements through a retrieval approach based on Tikhonov regularization. A good agreement is found between BASIL and the microphysical sensors' measurements for all considered aerosol size and microphysical properties. Specifically, BASIL and in‐situ volume concentration values are in the range 2–5 μm 3 cm −3 in the lower layer and in the range 1–3.5 μm 3 cm −3 in the upper layer. Values of the effective radius values from BASIL and the in‐situ sensors are in the range 0.2–0.6 μm in both the lower and upper layer. Aerosol size distributions are determined at 2.2, 2.8, 4 and 4.3 km, with a good agreement between the Raman lidar and the microphysical sensors at all considered heights. We combined these size and microphysical results with Lagrangian back‐trajectory analyses and chemical composition measurements. From this combination of datasets we conclude that aerosol particles below 3 km were probably originated by wildfires in North America and/or by anthropogenic activities in North‐Eastern Europe, while aerosols above 3 km were also probably originated by wildfires in North America.