Spectral particle absorption coefficients, single scattering albedos and imaginary parts of refractive indices from ground based in situ measurements at Cape Verde Island during SAMUM-2

Article English OPEN
Müller, T. ; Schladitz, A. ; kandler, K. ; Wiedensohler, A. (2011)

During the SAMUM-2 experiment, spectral absorption coefficients, single scattering albedos and imaginary parts of refractive indices of mineral dust particles were investigated at the Cape Verde Islands. Main absorbing constituents of airborne samples were mineral dust and soot. PM10 spectral absorption coefficients were measured using a Spectral Optical Absorption Photometer (SOAP) covering the wavelength range from 300 to 960 nm with a resolution of 25 nm. From SOAP, also information on the particle scattering coefficients could be retrieved. Spectral single scattering albedos were obtained in the wavelength range from 350 to 960 nm. Imaginary parts of the refractive index were inferred from measured particle number size distributions and absorption coefficients using Mie scattering theory. Imaginary parts for a dust case were 0.012, 0.0047 and 0.0019 at the wavelengths 450, 550 and 950 nm, respectively, and the single scattering albedos were 0.91, 0.96 and 0.98 at the same wavelengths. During a marine case, the imaginary parts of the refractive indices were 0.0045, 0.0040 and 0.0036 and single scattering albedos were 0.93, 0.95 and 0.96 at the wavelengths given above.DOI: 10.1111/j.1600-0889.2011.00572.x
  • References (52)
    52 references, page 1 of 6

    Anderson, T. L., Covert, D. S., Marshall, S. F., Laucks, M. L., Charlson, R. J., and co-authors. 1996. Performance characteristics of a highsensitivity, three-wavelength, total scatter/backscatter nephelometer. J. Atmos. Oceanic Technol. 13, 967-986.

    Anderson, T. L. and Ogren, J. A. 1998. Determining aerosol radiative properties using the TSI 3563 integrating nephelometer. Aerosol Sci. Tech. 29, 57-69.

    Ångstro¨m, A. 1929. On the atmospheric transmission of Sun radiation and on dust in the air. Geogr. Anal. 12, 155-156.

    Ansmann, A., Petzold, A., Kandler, K., Tegen, I., Wendisch, M., and coauthors. 2011. Saharan Mineral Dust Experiments SAMUM-1 and SAMUM-2: What have we learned? Tellus 63B, this issue.

    Arnott, W. P., Hamasha, K., Moosmu¨ller, H., Sheridan, P. J. and Ogren, J. A. 2005. Towards aerosol light-absorption measurements with a 7- wavelength Aethalometer: evaluation with a photoacoustic instrument and 3-wavelength nephelometer. Aerosol Sci. Tech. 39, 17-29.

    Bergstrom, R. W., Russell, P. B. and Hignett, P. 2002. Wavelength dependence of the absorption of black carbon particles: predictions and results from the TARFOX experiment and implications for the aerosol single scattering albedo. J. Atmos. Sci. 59, 567-577.

    Birmili, W., Stratmann, F. and Wiedensohler, A. 1999. Design of a DMA-based size spectrometer for a large particle size range and stable operation. J. Aerosol Sci. 30, 549-553.

    Birmili, W., Schepanski, K., Ansmann, A., Spindler, G., Tegen, I., and co-authors. 2008. A case of extreme particulate matter concentrations over Central Europe caused by dust emitted over the southern Ukraine. Atmos. Chem. Phys. 8, 997-1016.

    Bohren, C. F. 1987. Multiple-scattering of light and some of its observable consequences. Am. J. Phys. 55, 524-533.

    Bond, T. C., T. L. Anderson, et al. 1999. Calibration and intercomparison of filter-based measurements of visible light absorption by aerosols. Aerosol Science and Technology 30, 582-600.

  • Similar Research Results (3)
  • Metrics
    2
    views in OpenAIRE
    0
    views in local repository
    0
    downloads in local repository
Share - Bookmark