| Project/Area Number |
07458122
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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 |
Environmental dynamic analysis
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| Research Institution | Osaka University |
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Principal Investigator |
YAMAGUCHI Katsuhito Faculty of Eng., Osaka University, Professor, 工学部, 教授 (90029166)
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| Co-Investigator(Kenkyū-buntansha) |
KONDO Akira Faculty of Eng., Osaka University, Assistant Professor, 工学部, 助手 (20215445)
KAGA Akikazu Faculty of Eng., Osaka University, Associated Professor, 工学部, 助教授 (90029265)
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| Project Period (FY) |
1995 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥6,400,000 (Direct Cost: ¥6,400,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Keywords | urban canopy / sky view factor / heat island / radiation / Monte Carlo method / 都市キャノピ / 短波放射 / 長波放射 / 大気境界層 / 蒸発 / 都市気候 / 水分ポテンシャル / 風洞実験 / 数値シミュレーション / 蒸発効率 / 飽和透水係数 / 建物表面積密度関数 |
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| Research Abstract |
The averaged minimum temperature in August at Osaka City is rising about 2 degrees in 100 years. It can be considered that the cause induced heat island phenomenon is the increase of energy consumption and the alteration of the ground surface. In this study, we simulated the influence of the building configration on the wind velocity and potential temperature within the urban canopy layr, using one dimensional atmospheric boundary layr model. It assumed that the building of the same size had been regularly arranged in the shape of a lattice within the urban canopy, and the shortwave radiation and long wave radiation fluxes in the urban canopy were independently estimated correctly by the photon tracking method based on the Monte Carlo method. When a fraction of an area covered with the buildings (eta) increased or the urban canopy height (h_c) became high, it was found that the shortwave radiation flux which the ground surface receives at the daytime decreases, and the long wave radiation flux emitted to the sky decreases at the night time. Next, the heat budget equation model on the building and ground surface, and one dimensional atmospheric boundary layr model were combined, and the temperature and the wind velocity distribution in the urban canopy were predicted. When eta increased or h_c became high, the wind velocity in the urban canopy decreased, and the potential temperature rise at the daytime became small and the potential temperature fall at the night time became also small. It became clear by these results that the increase of eta and the rise of h_c are one of the causes of the heat island phenomenon.
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