Modelling lidar-relevant optical properties of complex mineral dust aerosols

By J. Gasteiger, M. Wiegner, S. Groß, Volker Freudenthaler, C. Toledano, M. Tesche, K. Kandler. 2011

154 citations recorded by the source corpus.

We model lidar-relevant optical properties of mineral dust aerosols and compare the modelling results with optical properties derived from lidar measurements during the SAMUM field campaigns. The Discrete Dipole Approximation is used for optical modelling of single particles. For modelling of ensemble properties, the desert aerosol type of the OPAC aerosol dataset is extended by mixtures of absorbing and non-absorbing irregularly shaped mineral dust particles. Absorbing and non-absorbing particles are mixed to mimic the natural mineralogical inhomogeneity of dust particles. A sensitivity study reveals that the mineralogical inhomogeneity is critical for the lidar ratio at short wavelengths; it has to be considered for agreement with the observed wavelength dependence of the lidar ratio. The amount of particles with low aspect ratios (about 1.4 and lower) affects the lidar ratio at any lidar wavelength; their amount has to be low for agreement with SAMUM observations. Irregularly shaped dust particles with typical refractive indices, in general, have higher linear depolarization ratios than corresponding spheroids, and improve the agreement with the observations.

Subfields: Atmospheric Science, Earth-Surface Processes, Global and Planetary Change

View Paper: https://www.semanticscholar.org/paper/82c7c9e72ac8138f0889f88e395bb7ad0b917714

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Citations in the corpus

Depolarization and lidar ratios at 355, 532, and 1064 nm and microphysical properties of aged tropospheric and stratospheric Canadian wildfire smoke (2018, methodology): “The larger the particles for a given wavelength, the larger the linear depolarization ratio (Gasteiger et al., 2011).”
Observations of the spectral dependence of linear particle depolarization ratio of aerosols using NASA Langley airborne High Spectral Resolution Lidar (2015, methodology): “In a theoretical treatment of a particular measurement case, Gasteiger et al. (2011) modeled the particle depolarization ratio at multiple wavelengths using size distributions and refractive indices appropriate for SAMUM measurements, using mixtures of various irregular shapes to represent the dust…”
Aerosol classification from airborne HSRL and comparisons with the CALIPSO vertical feature mask (2013, background): “Observations of intermediate depolarization are frequently assumed to reflect a mixture of pure dust with other aerosol types (e.g., Sugimoto and Lee, 2006; Tesche et al., 2009; Gasteiger et al., 2011; Groß et al., 2011).”
Optical properties of long-range transported Saharan dust over Barbados as measured by dual-wavelength depolarization Raman lidar measurements (2015, background): “But as the optical properties are related to the microphysical properties like particle size, particle shape and chemical composition (Gasteiger et al., 2011b, a), aerosol aging, mixing and modification during transport can have an impact on the lidar derived optical properties, as well as on their…”
Potential of polarization/Raman lidar to separate fine dust, coarse dust, maritime, and anthropogenic aerosol profiles (2017, methodology): “…on fine dust depolarization ratios became available and can be used in the POLIPHON methodology which was based before on a few laboratory measurements of fine and coarse-dust-dominated linear25 depolarization ratios (Sakai et al., 2010) and simulation studies by Gasteiger et al. (2011).”
The automated multiwavelength Raman polarization and water-vapor lidar PollyXT: The neXT generation (2016, background): “The interpretation of the backscatterrelated Ångström exponents is complicated by the fact that dust particles are irregularly shaped and shape-related optical effects are different for different wavelengths (Gasteiger et al., 2011).”