Air temperature variation with time and thermally evaluated atmospheric conditions correlated with land use change in urban areas of Japan

The trends and variations in air temperature from 1987 to 2004 correlated with land use patterns in urban areas of Japan were studied in terms of urban heat islands. The air temperatures seemed to show an increasing trend; however, the differences were statistically insignificant due to the large variation and short survey period. The large increase rate of the air temperature was observed in the spring. The increasing rate of the air temperature at nighttime was larger than that during the daytime. The land use pattern was analysed using land use data prepared by the National Land Agency of Japan, and changes in land use were numerically explained by applying the thermal property parameter (c −1 ρ −1 κ −1/2 ). The relationship between the air temperature variation after sunset and the thermal property parameter was examined, and the air temperature variation after sunset was accounted for by the thermal property parameter.