| Project/Area Number |
62460045
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 | The University of Tokyo |
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Principal Investigator |
NAGATA Yutaka Geophysical Institute Professor, 理学部, 教授 (80011493)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1989: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1988: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1987: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Circumpolar Current / oceanic front / Syowa Station / interannual variation of oceanic condition / Interannual variation of sea level / seasonal variation of sea level / sea level rise in winter / sea ice / 南極還流 / 海面水位 / 南極環流 |
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| Research Abstract |
The Antarctic ocean plays important role in the global climate system as all of the worlds oceans are connected through it. The Japanese activities in the southern oceans are relatively high.
There are accumulation over 20 years period of the data from oceanographic observations conducted on board of Japanese icebreakers and from sea level observation at Syowa Station. The purpose of this investigation is to clarify the structures of the circumpolar currents and their seasonal and interannual variations by using these data. The structures of the oceanic fronts which give boundaries of currents were investigated, and the interannual variations of their positions were analyzed. The results reveal several long-term variations. But the detailed analysis shows that some of them should be interpreted as the spatial variation due to the change of ship course year by year or as the change of frontal structure rather than as the interannual variation. In order to check the nature of obtained ling-term variations, seasonal and interannual change of sea level at Syowa Station were analyzed. It is found that the sea level is highest in mid-winter and lowest in mid-summer. The amplitude of this seasonal variation is very variable year by year. This phenomenon would be explained only by oceanic change including its salinity. The relation between oceanic condition and gee level change is not clear in the present stage, but the results indicate that sea level change gives good information on oceanic variabilities. The seasonal and interannual change of the ice cover were also investigated.
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