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| Titel |
Size-segregated fluxes of mineral dust from a desert area of northern China by eddy covariance |
| VerfasserIn |
G. Fratini, P. Ciccioli, A. Febo, A. Forgione, R. Valentini |
| 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 ; 7, no. 11 ; Nr. 7, no. 11 (2007-06-08), S.2839-2854 |
| Datensatznummer |
250005035
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| Publikation (Nr.) |
 copernicus.org/acp-7-2839-2007.pdf |
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| Zusammenfassung |
| Mineral dust emission accounts for a substantial portion of particles
present in the troposphere. It is emitted mostly from desert areas, mainly
through intense storm episodes. The aim of this work was to quantify
size-segregated fluxes of mineral dust particles emitted during storm events
occurring in desert areas of northern China (Alashan desert, Inner
Mongolia), known to act as one of the strongest sources of mineral dust
particles in the Asian continent. Long-range transport of mineral dust
emitted in this area is responsible for the high particle concentrations
reached in densely populated areas, including the city of Beijing. Based on
a theoretical analysis, an eddy covariance system was built to get
size-segregated fluxes of mineral dust particles with optical diameters
ranging between 0.26 and 7.00 µm. The system was optimised to measure
fluxes under intense storm event conditions. It was tested in two sites
located in the Chinese portion of the Gobi desert. During the field
campaign, an intense wind erosion event, classified as a "weak dust
storm", was recorded in one of them. Data obtained during this event
indicate that particle number fluxes were dominated by the finer fraction,
whereas in terms of mass, coarser particle accounted for the largest
portion. It was found that during the storm event, ratios of size-segregated
particle mass fluxes remained substantially constant and a simple
parameterization of particle emission from total mass fluxes was possible. A
strong correlation was also found between particle mass fluxes and the
friction velocity. This relationship is extremely useful to investigate
mechanisms of particle formation by wind erosion. |
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