The Effect of Ground Pavement on the Urban Thermal Environment

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First, constructing experimental pavements with various materials, such as asphalt, concrete, macadam, and sand, the energy budget components at the surface, solar radiation, atmospheric radiation, backward infared radiation, temperature distribution inside the pavement was measured, together with those at the bare soil. It was found that the sensible heat transport amounted up to 350W/m2 about 14:00 on the asphalt surface, whereas 150W/m2 with the concrete surface and the bare soil. This high emission from the asphalt surface is due to the high temperature, 60 to 70 C, which was 20 degrees higher than that of the atmosphere.The infrared emission from the surface exceeds the atmospheric radiation by 200W/m2, which was also very high. The atmospheric radiation flux model was developed to estimate how much percentage of this emission excess is absorbed by the atmosphere. The results show that, accumulated within 500m from the ground, there is about 80W/m2 excess of absorption compared with the emission of the air in case of the asphalt. This is also very high compared with anthropogenic heat emission, which is about 10-20W/m2 in average.This high absorption rate was confirmed with field experiment by raising infrared radio meter.