Quantification of aerosol type vertical profiles from real airborne multiwavelength lidar observations using the AEROTYPro/GRASP approach

Aerosols are solid and liquid particles present in the atmosphere and play a crucial role in atmospheric composition. They are emitted from natural sources, such as mineral dust, sea spray, biogenic emissions, and volcanic eruptions, as well as anthropogenic sources, including traffic, industrial processes, and biomass burning. The presence of aerosols in the atmosphere can have detrimental effects on air quality, and thereby, human health; however, accurately quantifying these effects remains challenging due to the complexity of the processes involved in the interaction between aerosols and clouds. To better understand and simplify the complexity of aerosol composition, it is necessary to discriminate them into distinct types.

Recent spaceborne lidar, called Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) platform, provided profiles of qualitative identification of the main aerosol type on a global scale. To address these limitations and to provide more insights, we have developed an innovative retrieval approach called AEROTYPro/GRASP (Aerosol Type Profiling/Generalized Retrieval of Atmosphere and Surface Properties) to discriminate the fractions of five types, such as Smoke, Continental, Oceanic, Dust, and Urban Polluted, using three wavelengths (355 nm, 532 nm, and 1064 nm).

In this study, we apply the AEROTYPro/GRASP retrieval approach to discriminate the aerosol concentration vertical profiles for Smoke, Continental, Oceanic, Dust, and Urban polluted using the real airborne lidar measurements, such as backscatter, extinction, and depolarization, obtained from the second-generation NASA Langley Research Center (LaRC), High Spectral Resolution Lidar-2 (HSRL-2) lidar. In addition, the AEROTYPro/GRASP retrieval approach provides the bulk optical and microphysical properties, including aerosol optical depth, single scattering albedo, lidar ratio, absorbing aerosol optical depth, and effective radius. We further evaluated the retrieval approach on several airborne lidar flight transects.