One-dimensional simulation of the thermal structure of urban atmospheres

In order to elucidate the thermal structure of the atmosphere in urban areas, a one-dimensional numerical simulation is performed. Particular attention is paid to the effects of the earth surface condition, aerosols and artificial heat release. The results indicate that the temperature in urban areas is generally higher than in rural areas and that the inversion layer near the earth surface in urban areas disappears at night in the winter season due to surface roughness and artificial heat release. A considerable temperature difference is formed in rural and urban areas for several hours before and after sunset. Aerosols have a great effect in daytime and the maximum effect of the aerosol diameter is found for the case of the diameter nearly equalling the wavelength of visible light.