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Macke, A., and M.I. Mishchenko, 1996: Applicability of regular particle shapes in light scattering calculations for atmospheric ice particles. Appl. Opt., 35, 4291-4296.
We ascertain the usefulness of simple ice particle geometries for modeling the intensity distribution of light scattering by atmospheric ice particles. To this end, similarities and differences in light scattering by axis-equivalent, regular and distorted hexagonal cylindric, ellipsoidal, and circular cylindric ice particles are reported. All results pertain to particles with sizes much larger than a wavelength and are based on the geometric optics approximation. At a non-absorbing wavelength of 550 nm, ellipsoids (circular cylinders) have much (slightly) larger asymmetry parameter g than regular hexagonal cylinders. However, our computations show that only random distortion of the crystal shape leads to a closer agreement with g-values as small as 0.7 as derived from some remote sensing data analysis. This may suggest that scattering by regular particle shapes is not necessarily representative of real atmospheric ice crystals at non-absorbing wavelengths. On the other hand, if real ice particles happen to be hexagonal, they may be approximated by circular cylinders at absorbing wavelengths.
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