| Project/Area Number |
19K21561
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| Project/Area Number (Other) |
18H06499 (2018)
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Multi-year Fund (2019)
Single-year Grants (2018) |
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| Review Section |
1101:Environmental analyses and evaluation, environmental conservation measure and related fields
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| Research Institution | Nagoya University |
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Principal Investigator |
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| Project Period (FY) |
2018-08-24 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Keywords | 海霧 / 沈着 / イオウ / 安定同位体 |
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| Outline of Research at the Start |
北海道東部太平洋沿岸をはじめに、世界各地の海霧多発地域では時にpH３前後の酸性霧が観測される。一般に霧は大気汚染物質である人為由来の硫酸や硝酸により酸性化するが、海霧が生じる気流は大洋を経る場合が多く、人為汚染物質はほぼ含まないと推定される。そこで海霧に含まれる硫黄安定同位体比を測定して海洋由来であることを確認し、さらに道東で観測される霧のpHの日変化を説明するため窒素安定同位体比を測定して人為由来の貢献を明らかにする。
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| Outline of Final Research Achievements |
The object of this research was to determine the source of chemical contents in sea-fog at the Pacific coast of eastern Hokkaido, Japan, through the analysis of stable isotope of sulfur.
Results on lichens that were collected at three sites commonly indicated decline with exponential function along transect from coastline to inland. Values were converged into around 5 permil at all inland sites, and it indicates the major source of the deposited sulfur would be rainwater. On the other hand, values at coastline were commonly higher than its in inland. Fog is mainly occupied by advection sea-fog in this region, and additionally there are no large city nor large factory around each transect. Then the major source of deposited sulfur would be ocean along the Pacific coast of eastern Hokkaido, although its degree were different among area. Order among its value in coastline was partly disagree with the inclination of frequency of fog day from east to west along the Pacific coast in Hokkaido.
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| Academic Significance and Societal Importance of the Research Achievements |
これまでの研究では、時折観測される北西太平洋の酸性海霧は、東アジアの人為負荷源から輸送されたSOxやNOxに由来するとされてきた。しかし北海道の内陸部では天水がイオウの起源であり、長距離輸送された人為由来のイオウが北西太平洋に広範囲に沈着しているという従来の説を覆すものである。
東アジアがSOxやNOxの大規模な排出源であることは疑いないが、その輸送過程や沈着範囲を明らかにする上で、本研究は海洋、つまり自然由来のイオウの循環の過程の一端を明らかにした。
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