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

摘要

Seasonal variability in the physical characteristics of aerosol particlessampled from the King Sejong Station in the Antarctic Peninsula wasinvestigated over the period between March 2009 and February 2015. Clearseasonal cycles for the total particle concentration (CN) were observed. Themean monthly concentration of particles larger than 2.5 nm (CN) washighest during the austral summer, with an average value of1080.39 ± 595.05 cm, and lowest during the austral winter, witha mean value of 197.26 ± 71.71 cm. The seasonal patterns in theconcentrations of cloud condensation nuclei (CCN) and CN coincide, with bothconcentrations being at a minimum in winter and maximum in summer. Themeasured CCN spectra were approximated by fitting a power-law functionrelating the number of CCN for a given supersaturation (SS) to each SS value,with fitting coefficients and . The values for varied from6.35 to 837.24 cm, with a mean of 171.48 ± 62.00 cm.The values for ranged from 0.07 to 2.19, with a mean of0.41 ± 0.10. In particular, the values during the australsummer were higher than those during the winter, indicating that aerosolparticles are more sensitive to SS changes during summer. Furthermore, theannual mean hygroscopicity parameter, , was estimated as0.15 ± 0.05, for a SS of 0.4 %. The effects of the origin andpathway travelled by the air mass on the physical characteristics of theaerosol particles were also determined. The modal diameter of aerosolparticles originating in the South Pacific Ocean showed a seasonal variationvarying from 0.023 µm in winter to 0.034 µm in summer forthe Aitken mode, and from 0.086 µm in winter to 0.109 µmin summer for the accumulation mode.