Retrievals of aerosol microphysical parameters from a combination of airborne HSRL and ground-based elastic lidars during DISCOVER-AQ: Preliminary results

Knowledge about the physical and optical properties of aerosols is of fundamental importance when assessing the effects of such particles in the global radiation budget. Multi-spectral aerosol optical depth (AOD) is retrieved globally on a daily basis from satellites such as MODIS and also from AERONET. The retrieval of microphysical properties of aerosols such as size distribution and complex refractive index of refraction has been performed operationally in the framework of AERONET. However, retrievals based on inversion of multi-spectral radiance measurements are representative of the entire atmospheric column and therefore do not provide information on the vertical distribution of aerosols in the atmosphere. Retrievals of the microphysical parameters of aerosols from multi-spectral lidar measurements have been demonstrated in the last decade but almost exclusively in the framework of the European lidar network and with lidar systems specifically engineered to the type of measurements needed for the retrievals. In this work we show preliminary results obtained from the retrievals of multi-platform/multi-wavelength lidar data during the DISCOVER-AQ campaign that took place in the Baltimore-Washington corridor during July 2011. We utilize combined measurements from NASA Langley's airborne HSRL system and a ground based elastic lidar to obtain the so called 3+2 set of backscatter and extinction coefficients needed to retrieve the microphysical parameters. We compare results with ground-based AERONET and airborne in-situ measurements of effective radius, single scattering albedo, complex index of refraction, angstrom exponent and volume and surface-area concentrations.