Retrievals of aerosol single scattering albedo by multiwavelength lidar measurements: evaluations with nasa langley hsrl-2 during discover-aq field campaigns Pérez Ramírez, Daniel Whiteman, D.N Veselovskii, I Colarco, P Korenski, M da Silva, A This work focuses on the study and evaluation of the retrievals of aerosol complex refractive index (m = m r + im i ) and single scattering albedo (SSA) from the inversion of multi-wavelength lidar measurements, particularly of three backscattering coefficients (β) at 355, 532 and 1064 nm and two extinction coefficients (α) at 355 and 532 nm, typically known as the stand-alone 3β + 2α lidar inversion. The focus is on the well-known regularization technique for spherical particles. It is well known that constraints in the range of refractive indices allowed in the inversion are essential, both for the real (m r ) and imaginary (m i ) parts, due to the under-de- termined nature of the problem. Usually these constraints are fixed for a given set of inversions. Using a large database of AERONET retrievals, correlations between retrieved m r and mi are observed and those correlations together with results from the GOCART model are used to define optimized, case-dependent, constraints in the stand-alone 3β + 2α lidar inversion. For each inversion performed, the optimized constraints are computed from the 3β + 2α data using a-priori information of extinction-to-backscattered ratio (LR) and the Angstrom exponent computed with α at 355 and 532 nm. The stand-alone 3β + 2α lidar inversion with optimized, case-dependent, constraints is applied to airborne NASA LaRC HSRL-2 experimental measurements during DISCOVER-AQ. The optimized constraints selected from the measured 3β + 2α are compared with the typing classification based on additional multiwavelength depolarization measurements, showing consistency between aerosol size and ab- sorption range and aerosol typing. Evaluations of the SSA retrieved by the stand-alone 3β + 2α lidar inversion with optimized constraints are done by comparisons with correlative airborne in-situ measured SSA. The agreement between both methodologies is satisfactory for most aerosol types as differences are within the uncertainties of each methodology. 2023-11-17T07:55:10Z 2023-11-17T07:55:10Z 2019 journal article Published version: Remote Sensing of Environment 222 (2019) 144–164 https://hdl.handle.net/10481/85745 https://doi.org/10.1016/j.rse.2018.12.022 eng info:eu-repo/grantAgreement/EC/H2020/MSC GRASP-ACE 778349 http://creativecommons.org/licenses/by-nd/4.0/ open access Attribution-NoDerivatives 4.0 Internacional Elsevier