title: Can simple particle shapes be used to model scalar optical properties of an ensemble of wavelength-sized particles with complex shapes?
abstract: We compute the scalar optical properties of size-shape distributions of wavelength-sized randomly oriented homogeneous particles with different nonaxially symmetric geometries and investigate how well they can be modeled with a simple spherical, spheroidal, or cylindrical particle model. We find that a spherical particle model can be used to determine the extinction and scattering cross sections, the single-scattering albedo, and the asymmetry parameter with an error of less than 2%, whereas the extinction-to-backscatter ratio Reb is reproduced only with an error of 9%. The cylindrical and spheroidal particle models yield slightly improved results for Reb that deviate from those obtained for the complex particle ensemble by 7% and 5%, respectively. Large discrepancies between results of the different models are observed for the linear depolarization ratio, thus indicating limitations of models based on simple particle shapes.
authors.affiliation: Deportment of Physics, University of Bergen, Norway. Michael.Kahnert@fi.uib.no
authors.forename: F Michael
authors.initials: FM
authors.lastname: Kahnert
authors.forename: Jakob J
authors.initials: JJ
authors.lastname: Stamnes
authors.forename: Knut
authors.initials: K
authors.lastname: Stamnes
mesh_terms: D008962:Models, Theoretical; D055095:Optics and Photonics