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

Abstract

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 winterspring. 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 winterspring 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.

Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice

“…This inverse relationship between pressure and aerosol number concentration suggests an association with the passage of cyclones, a pattern consistent with previous studies (e.g. Ito, 1989;Hara, 2004;Hara et al, 2011b). Given that the previously presented back trajectory analysis suggested an AFT source region for the aerosol, it is reasonable to suggest that cyclones provide an accelerated pathway for air-mass subsidence from the AFT to the surface where measurement occurs.…”

“…Numerous studies have previously observed enhanced aerosol number concentrations in the AFT (e.g. Ito et al, 1986;Osada et al, 2006;Hara et al, 2011b), and even more have suggested it as the dominant source region of Antarctic aerosol (Ito, 1989(Ito, , 1993(Ito, , 1995Virkkula et al, 2009;Asmi et al, 2010;Järvinen et al, 2013;Koponen et al, 2003). We speculate that the absence of signs of growth in the data presented in this study could be a result of condensational growth halting, possibly due to exhaustion of the precursor source, prior to reaching the measurement location.…”

Characterization of the inter-annual, seasonal, and diurnal variations of condensation particle concentrations at Neumayer, Antarctica

“…Typical CP concentrations observed at South Pole were lower by a factor of around two compared to coastal NM, reflecting less efficient transport of the largely marine biogenic CP source (photo-oxidation of algae derived precursor dimethylsulfide, DMS, to nss-SO 2− 4 and MS aerosol; see discussion below) to the Antarctic Plateau. Year-round observation available from Antarctic coastal sites Mawson (67 • 36 S, 62 • 53 E) and Syowa (69 • 00 S, 39 • 35 E), showed CP concentrations comparable to NM (Gras, 1993;Ito, 1985;Hara et al, 2011a). Note that due to exceedingly strong and perpetual katabatic winds and low sea salt aerosol concentrations, Mawson has a somewhat continental character (Gras, 1993) which seems, however, not to be reflected in CP concentrations typically observed at this site.…”

Seasonal variations in physical characteristics of aerosol particles at the King Sejong Station, Antarctic Peninsula

“…Over time aerosol particles measurements have been conducted at various research stations in Antarctica, notably Aboa (Koponen et al, 2003;Virkkula et al, 2007;Kyrö et al, 2013), Amundsen-Scott (Arimoto et al, 2004;Park et al, 2004), Concordia (Järvinen et al, 2013), Halley (Rankin and Wolff, 2003;Roscoe et al, 2015), Kohnen (Weller and Wagenbach, 2007;Hara et al, 2010), Maitri (Pant et al, 2011), Mawson (Gras, 1993), McMurdo (Hansen et al, 2001;Mazzera et al, 2001), Neumayer , Syowa (Ito, 1985;Hara et al, 2011b), andTroll (Fiebig et al, 2014). Antarctic aerosol particles have been investigated regarding their size distribution (Koponen et al, 2003;Belosi et al, 2012), optical properties (Shaw, 1980;Tomasi et al, 2007;Weller and Lampert, 2008), chemical composition (Virkkula et al, 2006;Weller and Wagenbach, 2007;Asmi et al, 2010;Hara et al, 2011a), and mass concentration (Mazzera et al, 2001;Mishra et al, 2004).…”

“…Antarctic aerosol particles have been investigated regarding their size distribution (Koponen et al, 2003;Belosi et al, 2012), optical properties (Shaw, 1980;Tomasi et al, 2007;Weller and Lampert, 2008), chemical composition (Virkkula et al, 2006;Weller and Wagenbach, 2007;Asmi et al, 2010;Hara et al, 2011a), and mass concentration (Mazzera et al, 2001;Mishra et al, 2004). Other studies have also focused on aerosol transport in the upper atmosphere (Hara et al, 2011b) and new particle formation (Järvinen et al, 2013;Kyrö et al, 2013;Weller et al, 2015). Although various studies have been performed in Antarctica, research on the seasonal variations of CN, CCN, and the size distribution of aerosol particles has not been considered in the Antarctic Peninsula.…”