Daily variation of aerosols of marine and continental origin in the surface air over a small island, Okushiri, in the Japan Sea

Daily aerosol samples were collected for 6 months from 25 November 1984 at Okushiri Island in the Japan Sea. The samples were analyzed for aluminum (an indicator of mineral aerosol) and sodium (an indicator of sea salt aerosol), and the following results and conclusions were obtained. The atmospheric concentration of aluminum was higher in spring than winter, while the concentration of sodium in winter decreased toward spring. The concentration of sodium was positively correlated with westerly wind force but the concentration of aluminum was not correlated with the wind force. According to a harmonic analysis of the observed data, the Concentration of aluminum showed a 4-day periodicity, but we could not find any remarkable periodicity for sodium. These results suggest that the mineral aerosols in the surface air over the Japan Sea were transported across a long distance, probably from the arid regions of the Asian continent with continental air masses changing its direction gradually, and that a large amount of sea salt aerosol is produced in the Japan Sea during the winter monsoon and transported directly to the coastal area along the Japan Sea.