Year‐round record of size‐segregated aerosol composition in central Antarctica (Concordia station): Implications for the degree of fractionation of sea‐salt particles

Abstract

[1] The origin of sea-salt aerosol that reaches the high Antarctic plateau and is trapped in snow and ice cores remains still unclear. In particular, the respective role of emissions from the open ocean versus those from the sea-ice surface is not yet quantified. To progress on this question, the composition of bulk and size-segregated aerosol was studied in 2006 at the Concordia station (75°S, 123°E) located on the high Antarctic plateau. A depletion of sulfate relative to sodium with respect to the seawater composition is observed on sea-salt aerosol reaching Concordia from April to September. That suggests that in winter, when the sea-salt atmospheric load reaches a maximum, emissions from the sea-ice surface significantly contribute to the sea-salt budget of inland Antarctica.

Modelling the physical multiphase interactions of HNO<sub>3</sub> between snow and air on the Antarctic Plateau (Dome C) and coast (Halley)

“…NaNO 3 , Dasgupta et al, 2007) and, therefore, decreases the ratio of gaseous HNO 3 and the total atmospheric nitrate. At Dome C, the atmospheric sea salt aerosol concentration in late winter or early spring can be up to a factor of 4 larger than the annual mean (∼ 5 ng m −3 , Legrand et al, 2016) due to the large sea ice extent (Jourdain et al, 2008). Therefore, using the total measured atmospheric nitrate as gaseous HNO 3 for constraining the models might lead to an overestimate of ] in snow at Dome C, especially in early summer.…”

Seasonally resolved ice core records from West Antarctica indicate a sea ice source of sea‐salt aerosol and a biomass burning source of ammonium

“…The prevalence of the sea ice source of sea-salt aerosol versus the open ocean source remains the subject of ongoing research, however [e.g. Abram et al, 2013;Hara et al, 2012;Jourdain et al, 2008;Spolaor et al, 2013;Wolff et al, 2003], and whether the potential sea ice source is dominated by windblown frost flowers or blowing snow is also uncertain [Abram et al, 2013;Yang et al, 2008].…”

“…Much of the research on long-term trends in atmospheric aerosol content in Antarctica has come from snow pit and ice core measurements near coastal research stations [Weller et al, 2011;Wolff et al, 2008] or highelevation deep drilling sites [De Angelis et al, 1987;Jourdain et al, 2008;Weller and Wagenbach, 2007]. While these records are important for detailed studies that are difficult in remote locations and for long-term paleoclimate reconstructions, they generally are unable to provide subannually resolved records that are also outside of the local influence of the marine boundary layer.…”

High summertime aerosol organic functional group concentrations from marine and seabird sources at Ross Island, Antarctica, during AWARE

“…Consistent with this seasonal difference in particle number concentrations, most summertime non-sea salt sulfate mass concentrations were at least 5 times higher than winter concentrations (Jourdain and Legrand, 2002;Weller and Wagenbach, 2007;Udisti et al, 2012;Legrand et al, 2017a;Asmi et al, 2018), likely because of the contributions from biogenic DMS emissions from the surrounding Southern Ocean. However, most sea salt aerosols had wintertime maximum concentrations with more than 2 times more Na + mass concentrations in winter than summer (Parungo et al, 1981;Wagenbach et al, 1998;Jourdain and Legrand, 2002;Weller and Wagenbach, 2007;Jourdain et al, 2008;Udisti et al, 2012;Legrand et al, 2017a, b;Asmi et al, 2018).…”