Accession Number : ADA132889

Title :   Measurements of Optical Properties of Particulates in an Arid Region.

Descriptive Note : Final rept. 15 Mar 82-30 Apr 83,


Personal Author(s) : Reagan,John A

PDF Url : ADA132889

Report Date : 31 Aug 1983

Pagination or Media Count : 25

Abstract : Aerosol extinction profiles and aerosol extinction-to-back-scatter ratio, S(a), values have been determined for numerous days over the period May, 1979 to May, 1982 in Tucson, AZ via slant-path lidar measurements. These results have been analyzed to obtain a model aerosol extinction profile and a model S(a) value. The model extinction profile is characterized by rapidly, nearly linearly decreasing extinction through a 3km mixing layer (decreasing from 0.018/km at 200 m to 0.003/km at 3km), and a much more slowly decreasing extinction above the mixing layer. The mixing layer optical depth is about 0.04, and the optical depth to the maximum observation height (19km) is about 0.07. The inverse variance weighted S(a) value is about 25, and the majority of the S(a) determinations fell between 20 and 35. A limited number of cooperative lidar and balloon-borne cascade impactor measurements were also made to investigate aerosol size distribution and refractive index properties and their effects on the lidar observations. Impactor measurements yielded size distributions that were generally similar in shape, the distributions being perturbed Junge types with a dominance of coarse mode particles causing a bulge in the distributions in the large particle range.

Descriptors :   *Earth atmosphere, *Aerosols, *Optical radar, *Light transmission, Arid land, Optical properties, Extinction, Backscattering, Particulates, particle size, Optical data, Remote detectors, Ratios, Refractive index, Air, Mixing, Data acquisition, Altitude, Atmospheric scattering, Light scattering, Range(Distance), Profiles, Arizona, Atmosphere models, Statistical distributions

Subject Categories : Meteorology
      Optical Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE