Heat storage of pavement and its effect on the lower atmosphere

Heat flux at the air/ground interface was observed and analysed for various pavement materials on summer days. The surface temperature, heat storage and its subsequent emission to the atmosphere were significantly greater for asphalt than for concrete or bare soil. At the maximum, asphalt pavement emitted an additional 150 W m(-2) in infrared radiation and 200 W m- 2 in sensible transport compared to a bare soil surface. Analyses based on a parallel layers model of the atmosphere indicated that most of the infrared radiation from the ground was absorbed within 200 in of the lower atmosphere, affecting air temperature near the ground. With large difference between air and ground surface temperature at noon, the rate of infrared absorption by the lower atmosphere over asphalt pavement was greater by 60 W m(-2) than that over the soil surface or concrete pavement a figure comparable to the absorption by turbulent transport.