| Project/Area Number |
12440123
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | HOKKAIDO UNIVERSITY |
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Principal Investigator |
HAYASHI Yoshiyuki Hokkaido Univ., Grad. School of Sci., Pro., 大学院・理学研究科, 教授 (20180979)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIOKA Keiichi Tokyo Univ., Grad. School of Math. Sci., Asso. Pro., 大学院・数理科学研究科, 助教授 (90292804)
ISHIWATARI Masaki Hokkaido Univ., Grad. School of Environmental Earth Sci., Asso. Inst., 大学院・地球環境科学研究科, 助手 (90271692)
TANIMOTO Youichi Hokkaido Univ., Grad. School of Environmental Earth Sci., Asso. Pro., 大学院・地球環境科学研究科, 助教授 (00291568)
ODAKA Masatsugu Hokkaido Univ., Grad. School of Sci., Asso. Inst., 大学院・理学研究科, 助手 (60344462)
NAKAJIMA Kensuke Kyoto Univ., Grad. School of Sci., Asso. Inst., 理学部, 助手 (10192668)
沼口 敦 北海道大学, 大学院・地球環境科学研究科, 助教授 (30237797)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥7,900,000 (Direct Cost: ¥7,900,000)
Fiscal Year 2002: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2001: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 2000: ¥3,400,000 (Direct Cost: ¥3,400,000)
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| Keywords | Tropical precipitation pattern / Aqua-planet experiments / Response to warm SST area / Matsuno-Gill pattern / GCM / Ensemble experiments / Water vapor divergence / convergence / Multi-dimensional data analysis / 赤道ケルビン波 / 赤道ロスビー波 / かんばつ |
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| Research Abstract |
For the purpose of investigating the embedded dynamical structures in the varieties of distributions of precipitation activities and atmospheric circulations generated in response to the inhomogeneity of the sea surface temperature (SST) distribution, we have performed numerical experiments by the use of a general circulation model (GCM) uder the aqua-planet condition where all the surface is covered with the ocean, and we developed software tools for these experiments. Our major results are summarized in the following three points.
Firstly, for the purpose of examining the causality of the atmospheric response to a warm SST anomaly placed at the equator, an ensemble switch-on experiment is conducted to reduce the transient noise caused by both individual small scale convective activities and large scale intraseasonal variabilities. It is demonstrated that, to the east of the warm SST area, precipitation increases because of the equatorial surface frictional convergence associated with
… More
the Kelvin wave like response, while to the west of the warm SST area, precipitation decreases because of the equatorial surface frictional divergence associated with the Rossby wave like structure.
Secondly, for the sake of efficient analyses of the massive data produced by aqua planet experiments, a data structure for multi-dimensional large-size data is designed and a library, gtoo14 Fortran90 library, is developed for handling the data with the proposed structure. Numerical data are stored in netCDF files so that data is independent of machine architecture and is transparent through network. The data structure is summarized as gtoo14 netCDF convention, which is a convention of metadata including information for visualization.
Thirdly, a series of preliminary aqua-planet experiments are performed to investigate the precipitation responses to various SST distributions. For the cases with two warm SST areas placed at the equator, it is shown that the resonses can be recognized by the equatorial wave theory. For the cases with sinusoidal SST anomaly at the equator, there emerges a locality of the appearances of estward propagating precipitation structures and westward propagating precipitation structures. For the cases with a warm SST area in the off-equatorial region, there appears a band of precipitation which can be recognized as subtropical convergence zone. Less
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