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Optical and Chemical Properties of Atmospheric Aerosols at Amami Oshima and Fukue Islands in Japan in Spring, 2001

2013; The Meteorological Society of Japan; Volume: 91; Issue: 1 Linguagem: Inglês

10.2151/jmsj.2013-104

2186-9057

Sachio Ohta, Naoto Murao, Sadamu Yamagata,

Atmospheric aerosols and clouds

The optical and chemical properties of atmospheric aerosols were determined from the ground-based measurements at Amami Oshima in April 2001 during the Asian Atmospheric Particle Environmental Change Studies (APEX) campaign and at Fukue Island in March 2001. At Amami Oshima from April 10 to 16, an aerosol event was observed in which the volume scattering coefficient and sulfate concentration of fine particles increased conspicuously. At the former term of the aerosol event, the single scattering albedo reached 0.98. At the latter term of the event, on the other hand, it was 0.80-0.90 and the concentrations of elemental carbon, aluminum, and zinc increased by a factor of several to ten times compared with the rest of the observation terms. Using chemical and backward trajectory analyses, it was established that the transparent aerosols, rich in sulfate, were converted from sulfur dioxide gas emitted by the Miyake Island volcano at the former term of the aerosol event, while the turbid and absorptive aerosols were anthropogenic aerosols appearing together with Asian yellow dust from continental China at the latter term of the event. The measurements at Fukue Island showed that the volume scattering coefficients as well as the concentrations of sulfate, elemental carbon, aluminum, and zinc were higher than those at Amami Oshima, while the single scattering albedo was relatively low. This study elucidates that in spring, large amounts of anthropogenic particles are frequently transported together with Asian yellow dust from inland continental China to the Pacific Ocean, and that the single scattering albedo and the ratio of organic to elemental carbons are approximately 0.80-0.85 and 1, respectively, over the north-western Pacific Ocean.