|Budget Amount *help
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
Expanded urban area tends to make thermal environment worse in summer time, i.e.unbearably hot summer. The high temperature in urban area is usually caused by the change of urban surface type, e.g.from forest to paved road and buildings, except for extremely concentrated area such as the central Tokyo where the waste heat due to dense energy use may raise temperature directly. Thus mitigation of the high temperature through introduction of vegetation into urban area should be a promising way. The vegetation could also reduce air pollution by absorbing the pollutants. In this study we have developed urban canopy model for prediction of the effects of vegetation and buildings, with a variety of heights, on temperature, wind, and air pollution.
The model parameterizes effects of subgrid-scale buildings and vegetation on the tansfer of momentum, heat, moisture, and air pollutants within canopy and between canopy and upper layrs, and accounts for LAI (Leaf Area Index) of buildings and vegetation, plant's availability of water in soil, heat storage of the buildings, and response of vegetation and buildings to short and long radiation. A series of sensitivity test was carried out on the model performance by changing area ratio of buildings and vegetation within a grid cell, and reasonable results were obtained on the model, e.g.the model well reproduced reduction of daily maximum temperature due to vegetation under continued sunny days, indicating the vegetation can utilize water in deep soil layr for evaporation even under dry surface soil condition. Absorption of air pollutant by vegetation was also evaluated using the model.