Seasonal variations and vertical features of aerosol particles in the Antarctic troposphere

Tethered balloon-borne aerosol measurements were carried out at Syowa Station, Antarctica during the 46th Japanese Antarctic Research Expedition. CN concentration had a maximum in the summer, whereas the number concentrations of fine particles (D_p>0.3 μm) and coarse particles (D_p>2.0 μm) inc...

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Bibliographic Details
Main Authors: Keiichiro Hara, Kazuo Osada, Chiharu Nishita-Hara, Takashi Yamanouchi, Masahiko Hayashi
Format: Article in Journal/Newspaper
Language:English
Japanese
Published: National Institute of Polar Research 2010
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Online Access:https://doi.org/10.15094/00009582
https://doaj.org/article/3fc6141ee6344dbfbcf7319083581750
Description
Summary:Tethered balloon-borne aerosol measurements were carried out at Syowa Station, Antarctica during the 46th Japanese Antarctic Research Expedition. CN concentration had a maximum in the summer, whereas the number concentrations of fine particles (D_p>0.3 μm) and coarse particles (D_p>2.0 μm) increased during the winter-spring. The range of CN concentration was 30-2200 cm^<-3> near the surface (surface-500 m) and 7-7250 cm^<-3> in the lower free troposphere (>1500 m). During the austral summer, higher CN concentration was often observed in the lower free troposphere. Frequent appearance of higher CN concentration in the free troposphere relative to the surface measurements strongly suggests that new particle formation in the Antarctic regions occurs in the lower free troposphere. Single particle analysis indicated that most of the aerosol particles during the winter were composed of Mg-enriched sea-salt particles originated from sea-salt fractionation on the sea-ice and their modified particles by NO_3^<-> and SO_4^<2->. This suggests that sea-salt fractionation on sea-ice and modification of sea-salt particles were affected greatly by aerosol hygroscopicity during the winter. Antarctic haze layer was observed not only in the boundary layer but also in the lower free troposphere.