Seasonal variations and vertical features of aerosol particles in the Antarctic troposphere
Seasonal variations and vertical features of aerosol particles in the Antarctic troposphere
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DOI：
10.5194/acp-11-5471-2011
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发表时间：
2011-06
影响因子：
6.3
通讯作者：
K. Hara;K. Osada;C. Nishita-Hara;T. Yamanouchi
中科院分区：
文献类型：
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作者：
K. Hara;K. Osada;C. Nishita-Hara;T. Yamanouchi
摘要。日本第46次南极考察（2005-2006年）在南极的Syowa站进行了系留气球气溶胶测量。CN浓度在夏季达到最大值，而细颗粒（D p >0.3 μm）和粗颗粒（D p >2.0 μm）的浓度在冬春季节有所增加。近地表（地表- 500 m） CN浓度为30 ~ 2200 cm−3，低层自由对流层（大气- 1500 m） CN浓度为7 ~ 7250 cm−3。在南方夏季，自由对流层下部常观测到较高的CN浓度，其中细模态和粗模态的数量浓度显著较低。相对于地面连续气溶胶测量，自由对流层中CN浓度的频繁出现强烈表明，新的粒子形成更有可能发生在南极地区较低的自由对流层中。细颗粒-粗颗粒粒度分布的季节变化表明，由于海盐颗粒在冬春季占主导地位，冬春季对粗颗粒的贡献大于夏季。来自海洋和中纬度地区的气团中细颗粒和粗颗粒的数量浓度较高。特别是，在5月、7月和9月的南极雾霾事件发生期间和之后，不仅在边界层中观测到气溶胶增强，而且在对流层低层自由层中也观测到气溶胶增强。
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 ( D p >0.3 μm) and coarse particles ( D p >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.