1987 Fiscal Year Final Research Report Summary
Variabilities of Ocean and Atmosphere Circulations in the tropics
| Project/Area Number |
61302024
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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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, 応用力学研究所, 助教授 (50091400)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEUCHI KENSUKE Faculty of Science, Hokkaido University, 理学部, 助教授 (00107450)
SUGINOHARA NOBUO Faculty of Science, Tokyo University, 理学部, 助教授 (50090519)
YASUNARI TETSUZO Institute of Geoscience, Tsukuba University, 地球科学系, 講師 (80115956)
SUMI AKIMASA Faculty of Science, Tokyo University, 理学部, 助教授 (10179294)
MATSUNO TAROH Faculty of Science, Tokyo University, 理学部, 教授 (40037172)
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| Project Period (FY) |
1986 – 1987
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| Keywords | EL Nino / Southern Oscillation / ENSO / Rossby wave / Kelvin wave / 30-50 Day Oscillations / Monsoon / 大気海洋結合モデル |
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| Research Abstract |
In a wide variety of global climate changes, there is a strong interannual signal which has devastating effects on various human activities. This signal is now called ENSO by use of an acronym coined after EL Nino and the Southern developing more complete numerical models for further understanding and future forecasting of ENSO.
The oceanography group, after completing a three-dimensoinal Pacific Ocean model, has shown that the structures of equatorial currents are very sensitive to magnitudes of vertical viscosity and diffusivity. In addition, the model run with real winds from 1969 through 1984 has demonstrated that the warm water piled up in the northwestern Pacific one year prior to the ENSO year progresses along the equatorial wave-guide during the initial stages of ENSO events. This suggests some important roles played by the atmospheric intraseasonal disturbances during the onset phase of ENSO.
The meteorology group hhas shown, by analyzing global data sets of the years from 1964 through 1981, that the eastward propagation of sea-level pressure and zonal wind anomalies from the Indian Ocean toward the eastern Pacific is a fundamental nature of ENSO. In order to understand the roles played by intraseasonal disturbances, the modelling group has tried to simulate the disturbances by use of the atmospheric general circulation model(AGCM). The extremely successful result is now stimulating similar studies almost all over the world.
The air-sea interaction group has classified posible mechanisms of ENSO into three categories and has derived a necessary comdition for instability of the coupled system. It has also developed a process-oriented air-sea coupled model which is able to simulate te global features of the 1982/83 and 1986/87 ENSO events in a quite reasonable fashion.
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