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| Titel |
Simplifying the calculation of light scattering properties for black carbon fractal aggregates |
| VerfasserIn |
A. J. A. Smith, R. G. Grainger |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 15 ; Nr. 14, no. 15 (2014-08-07), S.7825-7836 |
| Datensatznummer |
250118925
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| Publikation (Nr.) |
 copernicus.org/acp-14-7825-2014.pdf |
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| Zusammenfassung |
| Black carbon fractal aggregates have complicated shapes that make the
calculation of their optical properties particularly computationally
expensive. Here, a method is presented to estimate fractal aggregate
light scattering properties by optimising simplified models to full
light scattering calculations. It is found that there are no possible
spherical models (at any size or refractive index) that well represent
the light scattering in the visible or near-thermal infrared. As
such, parameterisations of the light scattering as a function of the
number of aggregate particles is presented as the most pragmatic
choice for modelling distributions of black carbon when the large
computational overheads of rigorous scattering calculations cannot be
justified. This parameterisation can be analytically integrated to
provide light scattering properties for lognormal distributions of
black carbon fractal aggregates and return extinction cross sections
with 0.1% accuracy for typical black carbon size distributions.
Scattering cross sections and the asymmetry parameter can be obtained
to within 3%. |
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