1992 Fiscal Year Final Research Report Summary
Unified Hydrological Study on Climate Mitigation Effects in Soil-Plant-Atmosphere
| Project/Area Number |
03452207
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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 |
Hydraulic engineering
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
HINO Mikio Tokyo Institute of Tech., Dept. of Civil Eng., Professor, 工学部, 教授 (30016323)
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| Co-Investigator(Kenkyū-buntansha) |
KANDA M Tokyo Institute of Tech., Dept. of Civil Eng., Research Associate, 工学部, 助手 (90234161)
NADAOKA K Tokyo Institute of Tech., Dept. of Civil Eng., Associate Professor, 工学部, 助教授 (70164481)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Heat island / Urban Meteorology / LES model of plant / Honami (Plant waving) / Vegetation effect / Climate mitigation / Latent heat / Computer simulation |
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| Research Abstract |
1. AIMS: Urban areas in the world are continuing to grow in size and height, Owing to the accumulation of heat in the urban by the low conductivity of heat and high heat capacity of concrete and asphalt used for buildings and road pavement, enclosure of air mass and heat within street canyon and also by the reduction of green and aquatic areas (lake, ponds and coastal zone), cities are becoming the so-called "heat islands".
To compute the turbulent air flow within plant canopies, the LES (Large Eddy Simulation) concept to model numerically the turbulent flow has been extended to include the effect of leaves and branches of plant. In order to estimate the effects of vegetation on the urban climate mitigation, an LES model has been developed taking the three spheres of soil-plant-air as a united entity.
2. RESULT: (1) Turblent flows within and above plant layer are simulated by the newly developed LES model. (2) Large eddies are produced at the interface between plant layer and air flow, which contribute significantly to the exchanges of heat and mass between the layers. (3) The thermal environment around the Royal Palace is simulated. Highway roads around the area act as a source of thermal plumes, while the green area of the place and ponds around it has a considerable effect in mitigating the urban climate. (4) Row of roadside trees has the effect to reduce the temperature within street canyon as much as 10 degrees compared with the situation without them.
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