Dependence of Aerosol Extinction Measurements Using a Camera Based Lidar on Various Aerosol Phase Functions.

A camera-based lidar (CLidar) is used to study nighttime aerosol extinction profiles in San Salvador, Bahamas. A CCD camera with wide-angle view is placed several hundred meters away from a vertically transmitted laser to capture the entire beam from ground to zenith. The CCD signal consisting of both aerosol and molecular side scattering is normalized at a region free of aerosol to a model of molecular scattering to remove the molecular component. Each scattering altitude is calculated from the system geometry. To convert the aerosol single angle scatter to aerosol extinction, an aerosol phase function and a single scattering albedo must be used. Aerosol phase functions from AERONET data in regions close to San Salvador and CALIPSO model phase functions are employed to calculate aerosol extinction. Measurements from two different days exhibit spatial and temporal distributions of boundary layer aerosols which differ based on the variation of phase functions selected.