西部北太平洋亜寒帯海域における酸性海霧の発生要因

• Main Author: 植松, 光夫
• Format: Article in Journal/Newspaper
• Language: Japanese
• Published: 北海道大学低温科学研究所
• Subjects: 400; Arctic; Pacific; Phytoplankton; Subarctic
• Online Access: http://hdl.handle.net/2115/45163

西部北太平洋亜寒帯域は霧の多発する海域である. 海霧のpHは2.8-5.5と酸性を示し, 粒径分布は陸上の霧の一山型とは異なり, 霧粒の直径は7.0μmと27.5μmにピークを持つ二山型であった. エアロゾルと海霧のイオン成分の比較から, 硝酸イオンを含む粗大粒子が, 霧によって選択的に除去される事を明らかにした. これは大気経由の人為起源窒素化合物が海霧により海洋へ供給され, 海洋生態系へ影響を与えていることを示唆する. Chemical and physical properties of sea fog over the sub-arctic North Pacific regions were determined. The mean size distribution of liquid water content (LWC) of sea fog indicated two peaks, which was different from the common single modal spectra of terrestrial fog. The mean pH values of fog water ranged from 2.8 to 5.5 over the investigated regions. Nitrate existed as coarse particles acts as condensation nuclei (CN) of sea fog droplets. These results suggest that sea fog over the subarctic North Pacific is one of important scavengers of natural and anthropogenic substances transported from the Asian continent and atmospheric nitrogen deposition to the marine environment may stimulate phytoplankton growth.