College of Landscape Architecture, Beijing Forestry University, Beijing 100083, China; School of Landscape Architecture, Zhejiang A & F University, Hangzhou 311300, China.
College of Landscape Architecture, Beijing Forestry University, Beijing 100083, China.
Sci Total Environ. 2018 May 1;622-623:882-891. doi: 10.1016/j.scitotenv.2017.11.327. Epub 2017 Dec 13.
Green areas in the city can greatly improve the outdoor thermal environment, as well as mitigate the urban heat island effect by reducing summer air temperature. In a context of climate change, with the expected increase in temperature and intensity of heat waves, cooling by green areas is set to become increasingly important. In this study, field observations were carried out to investigate the thermal performance of a large urban vegetated park and its influence on thermal environment of the surrounding urban areas in Beijing, China. Measurements were conducted along a selected path during three summer days with clear skies and light winds by mobile traverses. The results showed that the park was cooler than the surrounding urban areas both during the daytime and at night. The mean air temperature differences between the park and the surrounding areas were in the range of 0.6-2.8°C at different times, with a maximum of 4.8°C observed at midnight. The results also found that as the distance from the park border increased, the ambient air temperature exhibited a gradually increasing trend. This indicated the park has a cooling effect on the urban environments adjacent to the park, and this cooling effect extended approximately 1.4km from the park boundary. The air temperature variations also depended strongly on the land cover characterizing the immediate environment of the measurement sites. Increasing the percent vegetation cover could significantly decrease air temperature, while the increase of percent impervious surface area would significantly increase it.
城市中的绿色区域可以极大地改善室外热环境，并通过降低夏季空气温度来减轻城市热岛效应。在气候变化的背景下，随着温度和热浪强度的预期增加，绿色区域的降温作用将变得越来越重要。本研究通过移动遍历在三个晴朗微风的夏季日进行了实地观测，以调查中国北京一个大型城市植被公园的热性能及其对周围城市热环境的影响。结果表明，公园在白天和夜间都比周围城市地区凉爽。公园和周围地区之间的平均空气温度差异在不同时间的范围内为 0.6-2.8°C，午夜时最大差值为 4.8°C。结果还发现，随着与公园边界的距离增加，环境空气温度呈现逐渐增加的趋势。这表明公园对毗邻公园的城市环境具有冷却作用，这种冷却作用从公园边界延伸约 1.4 公里。空气温度的变化也强烈依赖于测量点周围环境的土地覆盖特征。增加植被覆盖率可显著降低空气温度，而增加不透水面面积则会显著增加空气温度。
