1996 Fiscal Year Final Research Report Summary
The role of Rossby waves in decaying turbulent motion on a rotating sphere : an insight on zonal wind distributions of planetary atmospheres.
| Project/Area Number |
07640566
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Meteorology/Physical oceanography/Hydrology
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| Research Institution | University of Tokyo |
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Principal Investigator |
HAYASHI Yoshi-Yuki University of Tokyo, Graduate School of Mathematical Science, Associated Professor, 大学院・数理科学研究科, 助教授 (20180979)
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| Co-Investigator(Kenkyū-buntansha) |
YAMADA Michio University of Tokyo, Graduate School of Mathematical Sciences, Professor, 大学院・数理科学研究科, 教授 (90166736)
TAKEHIRO Shinichi Kyushu University, Department of Earth and Planetary Sciences, Research Associat, 理学部, 助手 (30274426)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Rossby waves / Spherical motion / non-divergent fluid / turbulence / planetary atmospheres / wave mean-flow acceleration / super rotation / general circulation of atmospheres |
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| Research Abstract |
The purpose of this study was to investigate the behavior oftwo-dimensional non-divergent flow on a rotating spherical shell. We expected to obtain some insight on the distribution of zonal flowsobserved in the real earth and/or planetary atmospheres. Our purpose also contained, in the mean time, developing a suitable computation and/or information environment for pursuing our scientific object.
The experiment of developing common software resources and environment between the groups of University Tokyo and Kyushu University via Internet revealed several fatal issues to be improved in our program structures. There were heavy overhead problems in our developed software resources. The activity aiming at developing a structured software including high dimensional models, that is, the shallow water model and three dimensional spherical convection model, finished with not very satisfying stage. However, the collaboration experiment via Internet was carried out with good performance, partly o
… More
wing to the eatablishment of SINET.The computer communication between the workstations of Tokyo and Kyushu presented good environment for destant collaboration.
The two-dimensional spherical experiment with numerical method verified that the scenario in which Rossby waves are absorbed in the higher latitudes and deposit eastward angular momentum there was acceptable. The weak non-linear experiments in which the non-linear terms were restricted only to the zonal acceleration due to weak interaction confirmed that the acceleration mechanism was that described by weak non-linear theory. However, we couold not produce very convincing example where a wave packet was absorbed by the critical latitude as was expected by WKB theory. The resolution used in the experiment seemed to be insufficient in obtaining such results.
The three dimentional spherical experiments showed that the equatorial zonal acceleration obtained by thermal convection is also explained by the dynamics of Rossby waves which emerge from the two dimensional constraint forced by the spherical geometry. We succeeded in classifying the east-west acceleration due to convective motion by the use of Rossby waves existing there. Less
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