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| Titel |
Effects of dust particle internal structure on light scattering |
| VerfasserIn |
O. Kemppinen, T. Nousiainen, G. Y. Jeong |
| 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 ; 15, no. 20 ; Nr. 15, no. 20 (2015-10-28), S.12011-12027 |
| Datensatznummer |
250120129
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| Publikation (Nr.) |
 copernicus.org/acp-15-12011-2015.pdf |
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| Zusammenfassung |
| There is a large variety of internal structures inside atmospheric dust
particles, making them inherently inhomogeneous. Such structures may have
a large effect on ground-level and atmospheric radiation. So far, dust
particle internal structures and their effect on the light scattering
properties have proved to be hard to quantify, in part due to challenges in
obtaining information about these structures. Recently, internal structures
of individual dust particles were revealed through focused ion beam milling
and analyzed. Here, we perform a sensitivity study to evaluate the optical
impacts of some of the typical internal structures revealed. To obtain
suitable model particles, the first step is to generate inhomogeneous
particles with varying internal structures by using an algorithm that is
based on three-dimensional Voronoi tessellation. The parameters for the
particle generation are obtained from studies of real-world Asian dust
particles. The second step is to generate homogeneous versions of the
generated particles by using an effective-medium approximation, for
comparison. Third, light scattering by both versions of these particles is
simulated with discrete dipole approximation code. This allows us to see how
different internal structures affect light scattering, and how important it
is to account for these structures explicitly. Further, this allows us to
estimate the potential inaccuracies caused by using only homogeneous model
particles for atmospheric studies and remote-sensing measurements. The
results show that the effects vary greatly between different kinds of
internal structures and single-scattering quantity considered, but for most
structure types the effects are overall notable. Most significantly, hematite
inclusions in particles impact light scattering heavily. Furthermore,
internal pores and hematite-rich coating both affect some form of light
scattering noticeably. Based on this work, it seems that it is exceedingly
important that the effects of dust particle internal structures on light
scattering are accounted for in a wide variety of applications. |
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