路面温度对城市热岛的影响

分析了城市热岛形成的主要原因,指出城市下垫面特性、城市大气污染和城市人工热源是城市热岛形成的主要影响因素。通过试验数据和数学计算论证了路面温度对城市大气温度的影响。介绍了太阳辐射、云层状况、大气相对湿度、风速、降水等环境因素对路面温度的影响,并利用数据、公式和图表重点讨论了路面反照率、路面湿度等路面特性因素对城市路面温度的影响。根据路面反照率与路面温度的数值关系,提出通过铺装水泥混凝土路面或碎石封层的方式提高路面反照率,缓解大城市热岛效应;根据路面湿度与路面温度的关系,提出通过增加透水性路面面积,缓解大城市热岛效应。

Influence of Pavement Temperature on Urban Heat Island

The main causes of urban heat island formation including underlying surface features,air pollution and artificial heat sources were analyzed.The effect of pavement temperature on air temperature was elucidated.A brief introduction of environmental factors influencing on pavement temperature such as solar radiation,cloud layer,relative humidity of atmosphere,wind speed and precipitation was involved.Pavement characteristics which effect on pavement temperature such as albedo and pavement humidity were discussed.A semi-quantitative connection between albedo of pavements and its effect on the diurnal variation of air temperature in large cities was presented.The time dependence of the pavement temperature was measured and calculated,and a formula to approximate the reduction of the peak air temperature by higher pavements' albedo was presented and compared favorably with simulations.The results indicate that the urban heat island effect can be reduced by increasing albedo of pavements such as cement concrete paving and chip-seal resurfacing,or enlarging the area of porous asphalt pavements according to the relationship between humidity and temperature of pavement.