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Light scattering by particles with small-scale surface roughness: comparison of four classes of model geometries

Författare och institution:
Michael Kahnert (Institutionen för rymd- och geovetenskap); Timo Nousiainen (-); Manu Anna Thomas (-); Jani Tyynelä (-)
Publicerad i:
Journal of Quantitative Spectroscopy and Radiative Transfer, 113 ( 18 ) s. 2356–2367
ISSN:
0022-4073
Publikationstyp:
Artikel, refereegranskad vetenskaplig
Publiceringsår:
2012
Språk:
engelska
Fulltextlänk:
Fulltextlänk (lokalt arkiv):
Sammanfattning (abstract):
We compare four different model geometries for particles with small-scale surface roughness. The geometries are based on regular and stochastic surface perturbations, as well as on 2D- and 3D-roughness models. We further compare T-matrix and discrete dipole computations. Particle size parameters of 5 and 50 are considered, as well as refractive indices of 1.6 + 0.0005i and 3 +0.1i. The effect of small-scale surface roughness on the intensity and polarisation of the scattered light strongly depends on the size parameter and refractive index. In general, 2D surface roughness models predict stronger effects than 3D models. Stochastic surface roughness models tend to predict the strongest depolarising effects, while regular surface roughness models can have a stronger effect on the angular distribution of the scattered intensity. Computations with the discrete dipole approximation only cover a limited range of size parameters. T-matrix computations allow us to significantly extend that range, but at the price of restricting the model particles to symmetric surface perturbations with small amplitudes.
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
NATURVETENSKAP ->
Fysik ->
Atom- och molekylfysik och optik ->
Optik
NATURVETENSKAP ->
Fysik ->
Astronomi, astrofysik och kosmologi ->
Astronomi
NATURVETENSKAP ->
Geovetenskap och miljövetenskap ->
Meteorologi och atmosfärforskning
Nyckelord:
Scattering, Aerosols, T-matrix, Surface roughness, Mineral dust, Lidar
Chalmers fundament:
Grundläggande vetenskaper
Postens nummer:
167678
Posten skapad:
2012-12-13 11:37
Posten ändrad:
2013-02-05 11:00

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