Thermal effect of the greens on the urban living environment

草地热环境物理特征：对不同地表材料、不同大小的草地进行了热环境测量。白天，所有地面材料的温度都在向上下降到200厘米；这一垂直温度分布表明热流上升或空气变暖。另一方面，夜间草地上的温度在上升，而沥青路面上的温度像白天一样下降。这表明草地表面在夜间起到了冷源的作用。在两个较大的草地表面测量了水平温度分布。中心部的温度低于外围。这一趋势在夜间更为显著，导致最大差异超过1度。综合考虑市区多个沥青路面停车场，推荐绿色停车场或地下停车场绿地覆盖作为缓解城市暖化的有效城市环境设计。热指标评价室外热环境：在裸露地面的树荫下和沥青路面的阳光下进行主观实验。虽然气温和相对湿度差异不大，但两个暴露空间的地球温度和地面温度以及总太阳辐射有很大差异。体温感与舒适感高度相关。全球温度、热带夏季指数和标准有效温度与温感相关性较高，其中前两项相关性也较好。这表明，考虑到易于测量，全球温度是评价室外热环境的一个有用的指标。

Physical characteristics of thermal environment over the grasses :Measurements of thermal environment over the grass with various sizes were conducted, compared with different ground surface materials. The temperature was decreasing upward to 200cm over all kinds of surface materials in the day ; this vertical temperature profile indicates upward heat flow or warming the air. On the other hand, the temperature was increasing over the grasses at night, while it was decreasing over the asphalt like in the day. This suggests that the grass surface acts as the cool source at night. Horizontal temperature distribution was measured over two large grass surfaces. Temperature was lower at the central part than in the peripherials. This tendency was more remarkable at night, resulting in the maximum differential over 1 degree. Considering a number of asphalt-paved parking lots in the urban area, these results lead to recommendation of the green parking lots or the green coverages by undergrounding parking lots as effectual urban environmental design for mitigating the urban warming.Evaluation of outdoor thermal environment by thermal indices :Subjective experiments were conducted in the treeshade on the bare ground and in the sunshine on the asphalt pavement. There was great difference in globe temperature and ground surface temperature as well as general solar radiation between the two exposure spaces, though little difference in air temperature and relative humidity. Temperature sensation has high correlation with comfort sensation. Thermal indices that show high correlation with temperature sensation are Globe Temperature, Tropical Summer Index, and Standard Effective Temperature, among which the former two have similarly good correlation. This indicates that globe temperature is a useful index for evaluating outdoor thermal environment, considering easy measurement.