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| Titel |
Long-range transport of giant particles in Asian dust identified by physical, mineralogical, and meteorological analysis |
| VerfasserIn |
G. Y. Jeong, J. Y. Kim, J. Seo, G. M. Kim, H. C. Jin, Y. Chun |
| 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. 1 ; Nr. 14, no. 1 (2014-01-15), S.505-521 |
| Datensatznummer |
250118266
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| Publikation (Nr.) |
 copernicus.org/acp-14-505-2014.pdf |
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| Zusammenfassung |
| Giant particles transported over long distances are generally of limited
concern in atmospheric studies due to their low number concentrations in
mineral dust and possible local origin. However, they can play an important
role in regional circulation of earth materials due to their enormous volume
concentration. Asian dust laden with giant particles was observed in Korea on
31 March 2012, after a migration of about 2000 km across the Yellow Sea from
the Gobi Desert. Scanning electron microscopy (SEM) revealed that 20% of
the particles exceeded 10 μm in equivalent sphere diameter, with a
maximum of 60 μm. The median diameter from the number distribution
was 5.7 μm, which was larger than the diameters recorded of 2.5 and
2.9 μm in Asian dust storms in 2010 and 2011, respectively, and was
consistent with independent optical particle counter data. Giant particles
(>10 μm) contributed about 89% of the volume of the
dust in the 2012 storm. Illite–smectite series clay minerals were the major
mineral group followed by quartz, plagioclase, K-feldspar, and calcite. The
total phyllosilicate content was ~52%. The direct long-range
transport of giant particles was confirmed by calcite nanofibers closely
associated with clays in a submicron scale identified by high-resolution SEM
and transmission electron microscopy. Since giant particles consisted of clay
agglomerates and clay-coated quartz, feldspars, and micas, the mineral
composition varied little throughout the fine (<5 μm),
coarse (5–10 μm), giant-S (10–20 μm), and giant-L
(>20 μm) size bins. Analysis of the synoptic
conditions of the 2012 dust event and its migration indicated that the
mid-tropospheric strong wind belt directly stretching to Korea induced rapid
transport of the dust, delivering giant particles. Giant dust particles with
high settling velocity would be the major input into the terrestrial and
marine sedimentary and ecological systems of East Asia and the western
Pacific. Analysis of ancient aeolian deposits in Korea suggested the common
deposition of giant particles from Asian dust through the late Quaternary
Period. The roles of giant particles should be reviewed with regard to
regional circulation of mineral particles and nutrients. |
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