1992 Fiscal Year Final Research Report Summary
A New Finding of Large-Scale Ocean Eddy in the Antarctic
| Project/Area Number |
03452059
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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 | Hokkaido University |
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Principal Investigator |
WAKATSUCHI Masaaki Institute of Low Temperature Science Hokkaido University, Professor, 低温科学研究所, 教授 (60002101)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIYOSHI Yasushi Water Research Institute, Nagoya University, Associate Professor, 大気水圈科学研究所, 助教授 (40142749)
OHSHIMA Kay Ichiro Institute of Low Temperature Science Hokkaido University. Research Associate, 低温科学研究所, 助手 (30185251)
TAKEUCHI Kensuke Institute of Low Temperature Science Hokkaido University, Professor, 低温科学研究所, 教授 (00107450)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Ocean Eddy / Antarctic Divergence / Atmosphere-Sea Ice-Oean Interaction / Sea Ice Cover / Upwelling / Polynya / Antarctic Bottom Water formation / Remote Sensing |
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| Research Abstract |
An oceanic structure of the Antarctic Divergence in the Indian Ocean sector was clarifiedon the basis of analysis of hydrographic data and drifting buoy data for Japanese cruises.
The Antarctic Divergence is composed of a street of several cyclonic eddies with the orders of about 500 km in zonal length and about 200 km in meridional length. Part of the eastward flowing antarctic circumpolar Current meanders in the boundary regions between the eddies. The major factor which governs the formation and maintenance of the cyclonic eddies is the advection of two different kinds of waters into shallow and deep layrs of the eddy regions. The warm, saline circumpolar Deep Water advects into the shallow layr as upwelling whereas a cold and dense, coastal water advects into the deep layr as sinking along a relatively shallow ridge slope. The eddy formation recurs year after year though their locations slightly change ; the existence of ridges extending northward from the continental shelf region approximately governs the eddy formation in the selective locations. We found from geostrophical flow patterns and salinity distributions that a water exchange between coastal and offshore regions occurs through the circulation with both the eddies and the CDW meanders ; this also causes the meridional exchanges of heat and salt.
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