Aerosol properties and associated regional meteorology during winter pollution event at Gosan climate observatory, Korea

This paper describes aerosol optical and physical properties and the corresponding meteorological analysis during a winter-time fine aerosol event at a regional background station, Gosan, in Korea. Spatio-temporal distributions of air pollutants over Northeast Asia during winter are governed by continental outflows; however, winter is the highest in magnitude (9.5 ± 8.7 Mm−1) of aerosol absorption coefficient (σa) among other seasons and the second highest in magnitude (105.3 ± 104.8 Mm−1) of aerosol scattering coefficient (σs) after spring at the Gosan site. Values for σs and σa at Gosan during the winter polluted period (WPP; January 3 to 10, 2008) were recorded as 238.97 ± 123.85 and 18.42 ± 8.49 Mm−1, respectively, which were approximately 5 times greater than those during the winter clean period (WCP; January 13 to 16, 2008) of this study. An ensemble analysis of the OMI aerosol index, wind vectors and background trajectories during the WPP reveals that a slow-moving anticyclonic system, preceded by a frontal system, brought heavy aerosol loading from the Asian continent to the Gosan site. Space-based lidar CALIOP observations support the presence of heavy loadings of aerosol and pollutant plumes over the Yellow sea, before arriving at the Gosan.