Abstract
Thermal characteristics of urban space in TOKYO and OSAKA were investigated with thermal infrared images through weather satellites, weather observed data on the ground and LANDSAT data. Thermal infrared images and weather data were obtained in the midday of summer and in the early morning of winter. After the comparison of the ground surface and atmospheric temperature and the multiple regression analysis between the occupancy ratio of each type of urban space and the ground surface and atmospheric temperature around the weather monitoring station, some characteristics were found. 1. Both of the ground surface and atmospheric temperature in the areas with many tall buildings are lower than other type of urban area in the midday of summer. This agrees with OKE's "negative heat island". 2. Both of the ground surface and atmospheric temperature in the lower and densely built up areas are highest in the midday of summer. In the early morning of winter the ground surface temperature in the areas with many tall buildings is high. 3. Correlation is found between ground surface temperature and the constitution of urban space. Correlation coefficient is so much high in the early morning of winter. Correlation between atmospheric temperature and the constitution of urban space is lower than that of ground surface temperature because of instability of atmosphere and uncertainty of solar radiation and wind velocity. 4. Water suface temperature is low in the midday of summer and is high in the early morning of winter because of large heat capacity of water. Accordingly water covered area contributes to the mitigation of urban climate. As thermal characteristics of area with many tall buildings are similar to that of water covered area, research of heat capacity of urban space is needed hereafter. Ground surface temperature mentined above is black body temperature calculated from the input energy to weather satellite's sensor (TIROS/NOAA AVHRR).
