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 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 (CNsub2.5/sub) was highest during the austral summer, with an average value of 1080.39?±?595.05?cmsup?3/sup, and lowest during the austral winter, with a mean value of 197.26?±?71.71?cmsup?3/sup. 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 iC/i and ik/isubiT/i/sub. The values for iC/i varied from 6.35 to 837.24?cmsup?3/sup, with a mean of 171.48?±?62.00?cmsup?3/sup. The values for ik/isubiT/i/sub ranged from 0.07 to 2.19, with a mean of 0.41?±?0.10. In particular, the ik/isubiT/i/sub 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, iκ/i, 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.