校园行道树对夏季室外行人热舒适的影响研究

道路绿地作为城市绿地的重要组成部分,在缓解城市热岛和改善行人热舒适等方面起着重要作用。通过监测大学校园内7种典型行道树树荫和阳光下的空气温度(T_a)、相对湿度(RH)、风速(V_a)、黑球温度(T_g)和太阳辐射(G)等气象参数以及行道树的叶表面温度(T_(1s),运用通用热气候指数(Universal Thermal Climate Index,UTCI)分析不同行道树对道路空间热环境的影响和行人热舒适的改善效果。结论如下:1)行道树改善道路空间行人热舒适作用明显,对T_a和平均辐射温度(Mean Radiant Temperature,T_(mrt)降低能力最强的树种分别为悬铃木和银杏;2)天空可视因子(Sky View Factor,SVF)是影响道路空间行人热舒适的主要因素;3)T_(1s)与UTCI呈强线性正相关(R~2=0.8083),夏季T_(1s)越高,道路空间行人热舒适度越差。研究结果从室外热舒适评价的角度为行道树设计提供了理论基础和量化指导。

Effects of Avenue Trees on Human OutdoorThermal Comfort during Summer on Campus

As a significant part of green space, avenue treesplay an important role in relieving urban heat island effects andimproving pedestrians'' thermal comfort. This study conducted onsitemeteorological measurements, including air temperature (Ta),relative humidity (RH), wind speed (Va), globe temperature (Tg )and solar radiation (G) in the tree shade and sunlight, and the leafsurface temperature (Tls) of seven avenues on campus. UniversalThermal Climate Index (UTCI) was used to identify the effect ofavenue trees on outdoor thermal environment and pedestrians''thermal comfort. The results indicated that: 1) Avenue trees actedas an important role in improving pedestrians'' thermal comfort.Tree species with the highest reduction of Ta and mean radianttemperature (Tmrt) were Platanus acerifolia and Gingo biloba ; 2) SkyView Factor (SVF) was the main factor affecting outdoor thermalcomfort under street spaces; 3) Tls was positively linearly correlatedwith UTCI (R2= 0.8083), and the human outdoor thermal comfortdecreased with the summer Tls increasement. The findings couldprovide a theoretical basis and design guidance for street treesdesign based on outdoor thermal comfort evaluation.