• Kosuke IGARI, Field Study for Inhomogeneity of the Thermal Environment due to the Difference in Structure within the City2014: .

Abstract


By changing the scale to be evaluated, the thermal environment of the city shows different characteristics. Urban geometry and land use are one of the factors producing inhomogeneity of the thermal environment in the scale of the city, and it is particularly apparent in commercial and residential areas due to differences in a, structure, etc. However, it is generally difficult to investigate influence of temperature due to the differences in block structures and land usage and, in particular, few studies have investigated and compared commercial areas with residential areas. Shibuya, Tokyo consists of commercial area, residential area, and large green area, and they are adjacent to each other. Therefore, this study clarified the influence of the structures of the city on temperature by in-situ observations, and the importance of the distinction of the commercial area and the residential area. We conducted themeteorological observation and taking thermal image from 3 August, 2014 to 5 August, 2014. It was revealed that the commercial area had a higher temperature than the residential area, but at night times, this was reversed. In daytime, while the surface temperature of the buildings did not differ, the roadside temperature of the commercial area was higher than the residential area. It was thought that these are caused by heat insulating pavement structure in commercial areas, the length and frequency of the shade time due to the difference in height of the buildings, and the strength of the heat movement caused by the wind due to differences in the width of the road and in the occupation area of the buildings. On the other hand, at night, the difference in roadside temperature at the commercial area and residential area could not be seen. However, it is thought that the commercial area had a higher temperature than the residential area because of artificial anthropogenic heat and heat storage effect by many high buildings in the commercial area. Furthermore, it is revealed that ground inversion layer does not develop and it is difficult to develop radiative cooling in the commercial area. It is thought that these greatly affect the formation of the heat spot in the commercial area and promote the development of the nocturnal heat island. It could be concluded that when evaluating urban thermal environment, commercial areas and residential areas should be distinguished because they have different characteristics in thermal environment.

Keywords: urban structure, urban geometry, land use, observation