Turbidity over the Indian Ocean

• Main Authors: Matsubara, Kouji, Ohata, Tetsuo, Kawaguchi, Sadao
• Language: English
• Published: 1983
• Subjects: Indian; Syowa Station; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/record/1501/files/KJ00000012134.pdf

P(論文) Atmospheric turbidity measurements were carried out over the Indian Ocean by a sunphotometer (λ=368,500,675,778,862nm) during the voyage from Tokyo to Syowa Station, in the period of November through December 1979 and also from Syowa Station to Port Luis in the period of February through March 1981. In the region between 17°N and 67°S, the highest value of aerosol optical thickness (λ=500nm) was 0.175 observed in the east end of the Indian Ocean close to the northwest coast of Australia, and the lowest value was in the region south of 20°S in the Indian Ocean. The aerosol optical thickness in the low turbidity condition depends on the wind speed, whereas in the high turbidity condition the dependency is not clear. The aerosol volume of large particles (0.5≤r≤7μm) determined from the spectral extinction coefficient of the aerosol optical thickness gradually decreases from north to south. On the other hand, aerosol volume of small particles (0.03≤r≤0.5μm) showed a maximum, contributing to the total volume appreciably, in the oceanic region between 10°and 20°S where the highest value of aerosol optical thickness was observed. departmental bulletin paper