Abstract
Abstract. Seasonal variability in the physical characteristics of aerosol particles sampled from the King Sejong Station in the Antarctic Peninsula was investigated over the period between March 2009 and February 2015. Clear seasonal cycles for the total particle concentration (CN) were observed. The mean monthly concentration of particles larger than 2.5 nm (CN2.5) was highest during the austral summer, with an average value of 1080.39 ± 595.05 cm−3, and lowest during the austral winter, with a mean value of 197.26 ± 71.71 cm−3. The seasonal patterns in the concentrations of cloud condensation nuclei (CCN) and CN coincide, with both concentrations being at a minimum in winter and maximum in summer. The measured CCN spectra were approximated by fitting a power-law function relating the number of CCN for a given supersaturation (SS) to each SS value, with fitting coefficients C and kT. The values for C varied from 6.35 to 837.24 cm−3, with a mean of 171.48 ± 62.00 cm−3. The values for kT ranged from 0.07 to 2.19, with a mean of 0.41 ± 0.10. In particular, the kT values during the austral summer were higher than those during the winter, indicating that aerosol particles are more sensitive to SS changes during summer. Furthermore, the annual mean hygroscopicity parameter, κ, was estimated as 0.15 ± 0.05, for a SS of 0.4 %. The effects of the origin and pathway travelled by the air mass on the physical characteristics of the aerosol particles were also determined. The modal diameter of aerosol particles originating in the South Pacific Ocean showed a seasonal variation varying from 0.023 µm in winter to 0.034 µm in summer for the Aitken mode, and from 0.086 µm in winter to 0.109 µm in summer for the accumulation mode.
Highlights
Aerosol particles in the atmosphere are either emitted directly from various natural and anthropogenic sources or produced by gas-to-particle conversion processes
King Sejong Station is located on the Barton Peninsula of King George Island, which has a population density higher than other regions in Antarctica due to the research activities conducted on eight permanent on-site stations
No clear annual trends for temperature were observed during the 6-year period due to a relatively short observation period
Summary
Aerosol particles in the atmosphere are either emitted directly from various natural and anthropogenic sources (primary aerosol particles) or produced by gas-to-particle conversion processes (secondary aerosol particles). These particles influence the local and global climates directly by scattering and absorbing radiation and indirectly by acting as cloud condensation nuclei (CCN) or ice nuclei (IPCC, 2013). Because there are less anthropogenic emission sources in Antarctica, it is a suitable place to study the formation and growth processes of natural aerosol particles. For these reasons, monitoring the physical properties of aerosol parti-
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