Заголовок: Absorption and Scattering Properties of Dust Clouds at 10.5-μm
Автор: Bruce C.W.; Kalinowski D.; Ashmore D.R.
Аннотация: Mass-density-normalized absorption and extinction coefficients for arid region soil-based dust were measured at a wavelength of 10.5 μm using photoacoustical techniques, short-path transmissometry, and aerosol dosimetry. An environmental chamber incorporating strong circulation, as well as the various aerosol sampling systems, was specifically designed for aerosol size distributions with particles as large as 40 μm in radius. The mass extinction coefficient was found to be 0.22 m2/g, while the single scattering albedo, determined from the absorption and extinction coefficients, was 0.5. Calculations of these properties were based on two approaches: analyses of size distributions from photomicrographs of filter samples and analyses of the results obtained using a mixed-medium settling theory. In both cases, Mie theory was applied despite the clearly irregular particle forms. Agreement was close to the measured value for both approaches. The expected overestimation of the optical properties for the former model did not occur. Larger particles in this range are included because of their relevance to arid region dust clouds.
