Journal cover Journal topic
Atmospheric Measurement Techniques An interactive open-access journal of the European Geosciences Union

Journal metrics

  • IF value: 3.089 IF 3.089
  • IF 5-year<br/> value: 3.700 IF 5-year
    3.700
  • CiteScore<br/> value: 3.59 CiteScore
    3.59
  • SNIP value: 1.273 SNIP 1.273
  • SJR value: 2.026 SJR 2.026
  • IPP value: 3.082 IPP 3.082
  • h5-index value: 45 h5-index 45
Atmos. Meas. Tech., 10, 2923-2939, 2017
https://doi.org/10.5194/amt-10-2923-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
15 Aug 2017
Aethalometer multiple scattering correction Cref for mineral dust aerosols
Claudia Di Biagio1, Paola Formenti1, Mathieu Cazaunau1, Edouard Pangui1, Nicolas Marchand2, and Jean-François Doussin1 1Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), UMR 7583, CNRS, Université Paris Est Créteil et Université Paris Diderot, Institut Pierre et Simon Laplace, Créteil, France
2Aix Marseille Univ., CNRS, LCE, Marseille, France
Abstract. In this study we provide a first estimate of the Aethalometer multiple scattering correction Cref for mineral dust aerosols. Cref is an empirical constant used to correct the aerosol absorption coefficient measurements for the multiple scattering artefact of the Aethalometer; i.e. the filter fibres on which aerosols are deposited scatter light and this is miscounted as absorption. The Cref at 450 and 660 nm was obtained from the direct comparison of Aethalometer data (Magee Sci. AE31) with (i) the absorption coefficient calculated as the difference between the extinction and scattering coefficients measured by a Cavity Attenuated Phase Shift Extinction analyser (CAPS PMex) and a nephelometer respectively at 450 nm and (ii) the absorption coefficient from a MAAP (Multi-Angle Absorption Photometer) at 660 nm. Measurements were performed on seven dust aerosol samples generated in the laboratory by the mechanical shaking of natural parent soils issued from different source regions worldwide. The single scattering albedo (SSA) at 450 and 660 nm and the size distribution of the aerosols were also measured.

Cref for mineral dust varies between 1.81 and 2.56 for a SSA of 0.85–0.96 at 450 nm and between 1.75 and 2.28 for a SSA of 0.98–0.99 at 660 nm. The calculated mean for dust is 2.09 (±0.22) at 450 nm and 1.92 (±0.17) at 660 nm. With this new Cref the dust absorption coefficient by the Aethalometer is about 2 % (450 nm) and 11 % (660 nm) higher than that obtained by using Cref  =  2.14 at both 450 and 660 nm, as usually assumed in the literature. This difference induces a change of up to 3 % in the dust SSA at 660 nm. The Cref seems to be independent of the fine and coarse particle size fractions, and so the obtained Cref can be applied to dust both close to sources and following transport. Additional experiments performed with pure kaolinite minerals and polluted ambient aerosols indicate Cref of 2.49 (±0.02) and 2.32 (±0.01) at 450 and 660 nm (SSA  =  0.96–0.97) for kaolinite, and Cref of 2.32 (±0.36) at 450 nm and 2.32 (±0.35) at 660 nm for pollution aerosols (SSA  =  0.62–0.87 at 450 nm and 0.42–0.76 at 660 nm).


Citation: Di Biagio, C., Formenti, P., Cazaunau, M., Pangui, E., Marchand, N., and Doussin, J.-F.: Aethalometer multiple scattering correction Cref for mineral dust aerosols, Atmos. Meas. Tech., 10, 2923-2939, https://doi.org/10.5194/amt-10-2923-2017, 2017.
Publications Copernicus
Download
Short summary
Mineral dust is one of the most abundant aerosol species at the global scale and an accurate estimation of its absorption at solar wavelengths is crucial to assess its impact on climate. In this work we provide an estimate of the Aethalometer multiple scattering correction for mineral dust aerosols at 450 and 660 nm. Our results suggest that the use of an optimized correction factor can lead to up to 11 % higher absorption coefficient and to 3 % higher single scattering albedo for mineral dust.
Mineral dust is one of the most abundant aerosol species at the global scale and an accurate...
Share