Transport of mineral and anthropogenic aerosols during a Kosa event over East Asia

Abstract

A quantitative appraisal of the formation processes and distribution of mineral aerosols internally mixed with anthropogenic substances is necessary for estimating the aerosol radiative forcing, especially over the North Pacific region. A large‐scale Kosa (“Yellow Dust”) phenomenon associated with the movement of a low‐pressure system was observed at Nagasaki, about 1000 km east of the Asian continent in the spring of 1996. During the Kosa period (April 16–17), fine sulfur particles appeared first, and after 12 hours, a major plume of large mineral particles reached Nagasaki, which was detected and measured by the single‐particle analysis with sampling intervals of 2 hours. The results demonstrate that Asian dust storms are occasionally capable of transporting mineral and anthropogenic particles in separate air masses from the source regions via the marginal seas to the western North Pacific. We note that it takes a certain time to admix the different air masses containing various types of aerosols along their transport paths from the Asian continent to remote marine atmosphere. The interactions of mineral particles with anthropogenic substances predominantly take place within the marine boundary layer toward the east over the North Pacific.