| Project/Area Number |
63460046
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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 | Kyushu University |
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Principal Investigator |
YAMAGATA Toshio Research Institute for Applied Mechanics, Kyushu University, Associate Professor, 応用力学研究所, 助教授 (50091400)
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| Co-Investigator(Kenkyū-buntansha) |
UMATANI Shinichirou Research Institute for Applied Mechanics, Kyushu University, Research Associate, 応用力学研究所, 助手 (30112353)
蒲地 政文 九州大学, 応用力学研究所, 助手 (70169613)
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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 |
¥6,800,000 (Direct Cost: ¥6,800,000)
Fiscal Year 1990: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1989: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1988: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | Gcm / Costa Rica Dome / Mindanao Dome / Itcz / Monsoon / ENSO現象 / エル・ニ-ニョ / アジア・モンス-ン / ミンダナオ・ド-ム / コスタ・リカ・ド-ム / 季節風 / 黒潮 / コスタ・リカ・ドーム / IG力学 / PG渦 / TG渦 / 熱帯収束帯(ITCZ) / ENSO |
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| Research Abstract |
We have investigated temporal and spatial variabilities of the ocean circulation in the Pacific using a high resolution general circulation model (GCM) forced by the observed winds with idealized surface heat fluxes. The following are major conclusions from the numerical simulations.
(1) The Costa Rica Dome with a cyclonic circulation grows rapidly in late spring and matures in summer and early fall in accord with the northward migration of the ITCZ. In winter strong northerns converging the southernmost ITCZ excite warm anticyclonic warm eddies, which erode the Costa Rica Dome. The Costa Rica Dome can be maintained by the winds with the cyclonic curl in summer only when the embryo of a cyclonic eddy is preconditioned in winter and early spring.
(2) The Mindanao Dome evolves in late fall off the Philippine coast due to local upwellinhs when a positive curl associated witn the northeast Asian winter monsoon increases over the region. After reaching a maximum in winter it begins to decay in spring due to an intrusion of downwelling long Rossby waves excited in winter by the northeast trade winds farther eastward near 160 -E, as well as a retreat of the local positive wind stress curl. The seasonal variation of the model Mindanao Dome is almost perfectly determined by the change of the wind field in the western Pacific west of the date line.
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