| Project/Area Number |
63540310
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
気象・海洋・陸水学
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| Research Institution | 東京水産大学 |
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Principal Investigator |
SUDO Hideo Tokyo Univ. Fisher., Faculty of Fisheries, Professor, 水産学部, 教授 (50150298)
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| Project Period (FY) |
1988 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1990: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1989: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1988: ¥600,000 (Direct Cost: ¥600,000)
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| Keywords | Sea Surface Salinity / Japan Sea Proper Water / Heat Flux / Fresh Water Flux / Density Inversion / Geostrophic Transport / 表層混合層 / 日本海表層水 / 対馬暖流 |
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| Research Abstract |
Monthly means charts of temperature, salinity and density at the sea surface and their differences between sea surface and 10 m depth are constructed for the area north of 33'N and east of 127'E from available historical data. In late autumn to winter a density inversion of about 0.1 kg m^<-3> frequently occurs in the greater part except near the coast and west of the northern Japan. The density difference between sea surface and 10 m depends primarily upon the salinity difference and shows a regular annual cycle as well as the sea surface salinity in the Tsushima Warm Current area of the southwestern part of the sea. A high surface density of 27.30 kg m^<-3> or more with a high salinity of 34.05 or more is occasionally shown north of 40'N, west of 138'E in winter ; it is close to the density of the upper portion of the Japan Sea Proper Water and its mixed layer extends to a depth of 500 m. Geostrophic transports for hydrographic sections in the Japan Sea show that there must be a level of no motion at a depth of about 1000 m or more. Heat flux estimated as geostrophic advection varies greatly according to choice of level of no motion, while there is practically no difference between heat flux from the sea surface to 1000 m and that to the sea bottom. The net heat flux for the water column is considered to be outward in the southern part of the sea in spring and summer. Large-scale fresh water flux is not significant except for the southern part in summer to autumn.
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