New particle formation events observed at King Sejong Station, Antarctic Peninsula – Part 1: Physical characteristics and contribution to cloud condensation nuclei
The physical characteristics of aerosol particles during particle bursts observed at King Sejong Station in the Antarctic Peninsula from March 2009 to December 2016 were analyzed. This study focuses on the seasonal variation in parameters related to particle formation such as the occurrence, formation rate (FR) and growth rate (GR), condensation sink (CS) and source rate of condensable vapor. The number concentrations during new particle formation (NPF) events varied from 1707 to 83 120 cm−3, with an average of 20 649 ± 9290 cm−3, and the duration of the NPF events ranged from 0.6 to 14.4 h, with a mean of 4.6±1.5 h. The NPF event dominantly occurred during austral summer period (∼72 %). The measured mean values of FR and GR of the aerosol particles were 2.79±1.05 cm−3 s−1 and 0.68±0.27 nm h−1, respectively, showing enhanced rates in the summer season. The mean value of FR at King Sejong Station was higher than that at other sites in Antarctica, at 0.002–0.3 cm−3 s−1, while those of growth rates were relatively similar to the results observed by previous studies, at 0.4–4.3 nm h−1. The derived average values of CS and source rate of condensable vapor were (6.04±2.74)×10-3 s−1 and (5.19±3.51)×104 cm−3 s−1, respectively. The contribution of particle formation to cloud condensation nuclei (CCN) concentration was also investigated. The CCN concentration during the NPF period increased by approximately 11 % compared with the background concentration. In addition, the effects of the origin and pathway of air masses on the characteristics of aerosol particles during a NPF event were determined. The FRs were similar regardless of the origin and pathway, whereas the GRs of particles originating from the Antarctic Peninsula and the Bellingshausen Sea, at 0.77±0.25 and 0.76±0.30 nm h−1, respectively, were higher than those of particles originating from the Weddell Sea (0.41±0.15 nm h−1).