A Study on the Urban Thermal Environment Obtained through One-Dimensional Urban Canopy Model

Abstract

The thermal environment was investigated with one-dimensional urban canopy model. In the model, the arrangement of buildings in several ‘km’ square, which corresponds to one horizontal grid in the meteorological mesoscale model, is simply parameterized with the mean width of the buildings, mean width of the roads and distribution of the height of the buildings. Averaged sensible heat flux from the roof, wall and road is separately estimated through heat balance equation over each surface. Anthropogenic heat sources are able to be distributed at each level. When all the building height was 33 m and both width of the buildings and roads were 30m, the air temperature at 3 m high rose by 1 K during afternoon to evening. When narrower roads were used, the temperature increased more in the daytime, but decreased at night. The temperature rise near the surface was greater with buildings than that without buildings, and also greater in case that the heat sources were located near the surface than located near the top of the buildings, when actual daily variation of the anthropogenic heat near Tokyo station was given.