One-Dimensional Simulation of the Thermal Structure of Urban Atmosphere

In order to make clear the thermal structure of the atmosphere in urban area, one-dimensional numerical simulation is performed. Paticular attention is paid to the effects of condition of the earth surface, aerosol and artificial heat release. The results indicate that the temperature in urban area is generally higher than that in rural one and that the inversion layer near the earth surface in the urban area disappears at night in the winter season due to surface roughness and artificial heat. The considerable difference is formed in temperature in rural and urban areas for several hours before and after sunset. Aerosol has much effect in the daytime and the maximum effect of the diameter is found in the case when the diameter nearly equal to the wavelength of the visible light.