Variations of constituents of individual sea-salt particles at Syowa station, Antarctica

Abstract. Unusual aerosol enhancement is often observed at Syowa Station, Antarctica, during winter and spring. Simultaneous aerosol measurements near the surface and in the upper atmosphere were conducted twice using a ground-based optical particle counter, a balloon-borne optical particle counter, and micropulse lidar (MPL) in August and September 2012. During 13–15 August, aerosol enhancement occurred immediately after a storm condition. A high backscatter ratio and high aerosol concentrations were observed from the surface to ca. 2.5 km over Syowa Station. Clouds appeared occasionally at the top of the aerosol-enhanced layer during the episode. Aerosol enhancement was terminated on 15 August by strong winds from a cyclone's approach. In the second case, on 5–7 September, aerosol number concentrations in Dp > 0.3 μm near the surface reached > 104 L−1 at about 15:00 UT (Universal Time) on 5 September despite calm wind conditions, whereas MPL measurement exhibited aerosols were enhanced at about 04:00 UT at 1000–1500 m above Syowa Station. The aerosol enhancement occurred near the surface to ca. 4 km. In both cases, air masses with high aerosol enhancement below 2.5–3 km were transported mostly from the boundary layer over the sea-ice area. In addition, air masses at 3–4 km in the second case came from the boundary layer over the open-sea area. This air mass history strongly suggests that dispersion of sea-salt particles from the sea-ice surface contributes considerably to aerosol enhancement in the lower free troposphere (about 3 km) and that the release of sea-salt particles from the ocean surface engenders high aerosol concentrations in the free troposphere (3–4 km). Continuous MPL measurements indicate that high aerosol enhancement occurred mostly in surface–lower free troposphere (3 km) during the period July–September.

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Simultaneous aerosol measurements of unusual aerosol enhancement in troposphere over Syowa Station, Antarctica

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-26269-2013 ◽

2013 ◽

Vol 13 (10) ◽

pp. 26269-26303

Author(s):

K. Hara ◽

M. Hayashi ◽

M. Yabuki ◽

M. Shiobara ◽

C. Nishita-Hara

Keyword(s):

Boundary Layer ◽

Sea Ice ◽

Sea Salt ◽

Free Troposphere ◽

Syowa Station ◽

Particle Counter ◽

Air Masses ◽

Optical Particle Counter ◽

Strong Winds ◽

Storm Condition

Abstract. Unusual aerosol enhancement is often observed at Syowa Station, Antarctica during winter through spring. Simultaneous aerosol measurements near the surface and in the upper atmosphere were conducted twice using a ground-based optical particle counter, a balloon-borne optical particle counter, and micro-pulse LIDAR (MPL) in August and September 2012. During 13–15 August, aerosol enhancement occurred immediately after a storm condition. A high backscatter ratio and aerosol concentrations were observed from the surface to ca. 2.5 km over Syowa Station. Clouds appeared occasionally at the top of aerosol-enhanced layer during the episode. Aerosol enhancement was terminated on 15 August by strong winds caused by a cyclone's approach. In the second case on 5–7 September, aerosol number concentrations in Dp > 0.3 μm near the surface reached > 104 L−1 at about 15:00 UT on 5 September in spite of calm wind conditions, whereas MPL measurement exhibited aerosols were enhanced at about 04:00 UT at 1000–1500 m above Syowa Station. The aerosol enhancement occurred near the surface–ca. 4 km. In both cases, air masses with high aerosol enhancement below 2.5–3 km were transported mostly from the boundary layer over the sea-ice area. In addition, air masses at 3–4 km in the second case came from the boundary layer over the open-sea area. This air mass history strongly suggests that dispersion of sea-salt particles from the sea-ice surface contributes considerably to the aerosol enhancement in the lower free troposphere (about 3 km) and that the release of sea-salt particles from the ocean surface engenders high aerosol concentrations in the free troposphere (3–4 km).

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

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-7555-2011 ◽

2011 ◽

Vol 11 (3) ◽

pp. 7555-7591 ◽

Cited By ~ 2

Author(s):

K. Hara ◽

K. Osada ◽

C. Nishita-Hara ◽

T. Yamanouchi

Keyword(s):

Seasonal Variations ◽

Fine Particles ◽

Austral Summer ◽

Sea Salt ◽

Coarse Particles ◽

Free Troposphere ◽

Syowa Station ◽

Air Masses ◽

Antarctic Expedition ◽

The Antarctic

Abstract. Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica during the 46th Japanese Antarctic expedition (2005–2006). The CN concentration reached a maximum in the summer, although the number concentrations of fine particles (Dp > 0.3 μm) and coarse particles (Dp > 2.0 μm) increased during the winter-spring. The 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, where the number concentrations in fine and coarse modes were remarkably lower. The frequent appearance of higher CN concentrations in the free troposphere relative to continuous aerosol measurements at the ground strongly suggests that new particle formation is more likely to occur in the lower free troposphere in Antarctic regions. Seasonal variations of size distribution of fine-coarse particles show that the contribution of the coarse mode was greater in the winter-spring than in summer because of the dominance of sea-salt particles in the winter-spring. The number concentrations of fine and coarse particles were high in air masses from the ocean and mid-latitudes. Particularly, aerosol enhancement was observed not only in the boundary layer but also in the lower free troposphere during and immediately after Antarctic haze events occurring in May, July, and September.

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Variations of constituents of individual sea-salt particles at Syowa station, Antarctica

Tellus B ◽

10.1111/j.1600-0889.2005.00142.x ◽

2005 ◽

Vol 57 (3) ◽

pp. 230-246 ◽

Cited By ~ 23

Author(s):

KEIICHIRO HARA ◽

KAZUO OSADA ◽

MIZUKA KIDO ◽

KATSUJI MATSUNAGA ◽

YASUNOBU IWASAKA ◽

...

Keyword(s):

Sea Salt ◽

Syowa Station

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Tethered balloon-borne aerosol measurements: seasonal and vertical variations of aerosol constituents over Syowa Station, Antarctica

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-8153-2013 ◽

2013 ◽

Vol 13 (3) ◽

pp. 8153-8211

Author(s):

K. Hara ◽

K. Osada ◽

T. Yamanouchi

Keyword(s):

Boundary Layer ◽

Relative Abundance ◽

Lower Troposphere ◽

Sea Salt ◽

Heterogeneous Reactions ◽

Aerosol Sampling ◽

Free Troposphere ◽

Tethered Balloon ◽

Syowa Station ◽

Salt Fractionation

Abstract. Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica during the 46th Japanese Antarctic expedition (2005–2006). Direct aerosol sampling was operated from near the surface to the lower free troposphere (approximately 2500 m) using a balloon-borne aerosol impactor. Individual aerosol particles were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Seasonal and vertical features of aerosol constituents and their mixing states were investigated. Results show that sulfate particles were dominant in the boundary layer and lower free troposphere in the summer, whereas sea-salt particles were dominant during winter–spring. Minerals, MgSO4, and sulfate containing K were identified as minor aerosol constituents in both boundary layer and free troposphere over Syowa Station. Although sea-salt particles were dominant during winter–spring, the relative abundance of sulfate particles increased in the boundary layer when air masses fell from the free troposphere over the Antarctic coast and continent. Sea-salt particles were modified considerably through heterogeneous reactions with SO42−, CH3SO3−, and their precursors during the summer, and were modified slightly through heterogeneous reactions with NO3− and its precursors. During winter–spring, sea-salt modification was insignificant, particularly in the cases of high relative abundance of sea-salt particles and higher number concentrations. In August, NO3− and its precursors contributed greatly to sea-salt modification over Syowa Station. Because of the occurrence of sea-salt fractionation on sea-ice, Mg-rich sea-salt particles were identified during April–November. In contrast, Mg-free sea-salt particles and slightly Mg-rich sea-salt particles co-existed in the lower troposphere during summer. Thereby, Mg separation can proceed by sea-salt fractionation during summer in Antarctic regions.

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Observations of Giant Sea-Salt Particles over the Ocean From Tokyo to Syowa Station, Antarctica

Journal of the Meteorological Society of Japan Ser II ◽

10.2151/jmsj1965.48.4_377 ◽

1970 ◽

Vol 48 (4) ◽

pp. 377-380 ◽

Cited By ~ 2

Author(s):

Katsuhiro Kikuchi ◽

Shogo Yaura

Keyword(s):

Sea Salt ◽

Syowa Station

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-5471-2011 ◽

2011 ◽

Vol 11 (11) ◽

pp. 5471-5484 ◽

Cited By ~ 26

Author(s):

K. Hara ◽

K. Osada ◽

C. Nishita-Hara ◽

T. Yamanouchi

Keyword(s):

Seasonal Variations ◽

Fine Particles ◽

Austral Summer ◽

Sea Salt ◽

Coarse Particles ◽

Free Troposphere ◽

Syowa Station ◽

Air Masses ◽

Antarctic Expedition ◽

The Antarctic

Abstract. Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica during the 46th Japanese Antarctic expedition (2005–2006). The CN concentration reached a maximum in the summer, although the number concentrations of fine particles (Dp>0.3 μm) and coarse particles (Dp>2.0 μm) increased during the winter–spring. The 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, where the number concentrations in fine and coarse modes were remarkably lower. The frequent appearance of higher CN concentrations in the free troposphere relative to continuous aerosol measurements at the ground strongly suggests that new particle formation is more likely to occur in the lower free troposphere in Antarctic regions. Seasonal variations of size distribution of fine-coarse particles show that the contribution of the coarse mode was greater in the winter–spring than in summer because of the dominance of sea-salt particles in the winter–spring. The number concentrations of fine and coarse particles were high in air masses from the ocean and mid-latitudes. Particularly, aerosol enhancement was observed not only in the boundary layer, but also in the lower free troposphere during and immediately after Antarctic haze events occurring in May, July and September.

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Tethered balloon-borne aerosol measurements: seasonal and vertical variations of aerosol constituents over Syowa Station, Antarctica

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-9119-2013 ◽

2013 ◽

Vol 13 (17) ◽

pp. 9119-9139 ◽

Cited By ~ 24

Author(s):

K. Hara ◽

K. Osada ◽

T. Yamanouchi

Keyword(s):

Boundary Layer ◽

Relative Abundance ◽

Lower Troposphere ◽

Sea Salt ◽

Heterogeneous Reactions ◽

Aerosol Sampling ◽

Free Troposphere ◽

Tethered Balloon ◽

Syowa Station ◽

Salt Fractionation

Abstract. Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica, during the 46th Japanese Antarctic expedition (2005–2006). Direct aerosol sampling was operated from near the surface to the lower free troposphere (approximately 2500 m) using a balloon-borne aerosol impactor. Individual aerosol particles were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Seasonal and vertical features of aerosol constituents and their mixing states were investigated. Results show that sulfate particles were predominant in the boundary layer and lower free troposphere in summer, whereas sea-salt particles were predominant during winter through spring. Minerals, MgSO4, and sulfate containing K were identified as minor aerosol constituents in both boundary layer and free troposphere over Syowa Station. Although sea-salt particles were predominant during winter through spring, the relative abundance of sulfate particles increased in the boundary layer when air masses fell from the free troposphere over the Antarctic coast and continent. Sea-salt particles were modified considerably through heterogeneous reactions with SO42− CH3SO3− and their precursors during summer, and were modified slightly through heterogeneous reactions with NO3− and its precursors. During winter through spring, sea-salt modification was insignificant, particularly in the cases of high relative abundance of sea-salt particles and higher number concentrations. In August, NO3− and its precursors contributed greatly to sea-salt modification over Syowa Station. Because of the occurrence of sea-salt fractionation on sea ice, Mg-rich sea-salt particles were identified during the months of April through November. In contrast, Mg-free sea-salt particles and slightly Mg-rich sea-salt particles coexisted in the lower troposphere during summer. Thereby, Mg separation can proceed by sea-salt fractionation during summer in Antarctic regions.

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