YAMAGATA Sadamu Hokkaido Univ., Fac.of Eng., Instr., 工学部, 助手 (80220242)
HAGA Tetsuya Hokkaido Univ., Fac.of Eng., Instr., 工学部, 助手 (00113605)
MURAO Naoto Hokkaido Univ., Fac.of Eng., Assoc.Pro., 工学部, 助教授 (00190869)
|Budget Amount *help
¥6,800,000 (Direct Cost: ¥6,800,000)
Fiscal Year 1996: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1995: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1994: ¥3,500,000 (Direct Cost: ¥3,500,000)
An increase of atmospheric concentrations of anthropogenic aerosols with human activities suppresses the global warming. The suppresion, however, depends strongly on absorptivity of the aerosols in solar wavelengths region. It is, thus, important to determine the global distribution of the absorptivity of atmospheric aerosols. In the study, we measured monthly mean atmospheric concentration of total mass and chemical components of the aerosols from May 1995 through October 1996 at Cape Hedo, northern edge of Okinawa island, Japan, and chemically characterized the aerosols by using the measurement results.
We found that Okinawa aerosol consisted of elemental carbon, organics, sulfate, nitrate, ammonium, chloride, sea-salt cations and soil particles. Total mass concentration of the Okinawa aerosol was 3-11 mug/m^3 less than 2mum in diameter. In spring a large amount of anthropogenic sulfate, organic and elemental carbon particles were transported in addition to Yellow sands from Continental China. In summer, on the other hand, the atmospheric concentration of the total particulate mass was low, but the ratio of vanadium, nickel and cupper contents to the total mass were high, which indicated that the anthropogenic aerosols were distributed over the western Pacific Ocean.
Based on the chemical characterization, we calculated a single scattering albedo of the Okinawa aerosol. It was 0.95 in summer, 0.90 in winter and 0.92 in annual average. It means that the western Pacific maritime aerosol around Okinawa has little absorptivity and capability of suppressing the global warming due to the increase.