街区尺度屋顶绿化热效应及其与城市形态结构之间的关系  

Thermal effects of block-scale roof greening and their relationships with urban geometry

作　　者：姜之点 彭立华 杨小山[1,2] 姚灵烨 朱春磊 JIANG Zhidian;PENG Lihua;YANG Xiaoshan;YAO Lingye;ZHU Chunlei(School of Architecture,Nanjing Tech University,Nanjing 211816,China;Laboratory of Green Building and Eco ;city,Nanjing Tech University,Nanjing 211816,China)

机构地区：[1]南京工业大学建筑学院,南京211816 [2]南京工业大学绿色建筑与生态城市实验室,南京211816

出　　处：《生态学报》2018年第19期7120-7134,共15页Acta Ecologica Sinica

基　　金：国家自然科学青年基金项目(41401179;51408303);江苏省自然科学基金项目(BK20140941;BK20161547)

摘　　要：研究探讨大面积屋顶绿化如何改善城市冠层内部三维空间的热环境,改善效果与城市形态结构之间存在的关系。基于三维小气候模型ENVI-met 4.2,开展街区尺度屋顶绿化热效应研究。在南京市选择具有不同形态结构特征的8个典型样区,每个样区设置2种朝向(街道与主导风向平行或相交)、3种屋顶绿化情景(传统光屋顶、简易型绿化、复合型绿化),共对48种情景进行了微气候模拟与分析。结果表明,街区尺度屋顶绿化产生的"冷岛"可从屋面扩散到地面空间,缓解城市冠层热岛效应。白天14:00时,8个样区屋顶1.5 m高处的降温强度最高可达0.64℃,样区平均降温强度最大值为0.44℃;地面1.5 m高处的降温最大值为0.55℃,样区平均降温强度最大值为0.25℃。建筑高度、高宽比、容积率与屋面、地面降温强度之间均存在显著负相关关系;建筑密度与屋面降温强度显著正相关,但与地面降温强度之间无显著相关性。总的来说,紧凑低层建筑区和开敞低层建筑区实施屋顶绿化后产生的降温效应明显高于紧凑和开敞高层建筑区;建筑高度和密度相同时,街道走向与主导风向呈45°夹角比与主导风向平行具有更高的降温强度。研究结果能够促进对亚热带城市地区建筑-植被-大气相互关系的深入认识,并为屋顶绿化实践提供指导。Many studies reported that green roofs can notably alleviate roof-level surface and air temperatures, cutting building cooling loads and energy consumption. However, few studies have explored how large-scale roof greening affects the three-dixnensional thermal environment of the urban canopy layer and how green-roof thermal performance correlates with urban geometry. This research investigated the block-scale green-roof thermal performance and its relationships with urban geometry factors by applying the three-dimensional microelimate model ENVI-met 4.2 in Nanjing City. Eight study plots with distinguished urban forms in conjunction with two orientations and three roof greening options generated a total of 48 scenarios for ENVI-met modeling and analysis. Results suggested that block-scale roof greening not only cooled the roof-level ambient atmosphere, but could ameliorate the ground-level mieroclimate. At 14：00 during the day, the air temperature reduction at 1.5 m height above the roof surface could reach 0.64 ℃ with an average reduction of 0.44℃. The maximum and average air temperature reductions at 1.5 m height above the ground were 0.55 ℃ and 0.25 ℃, respectively. Building height, height-to-width ratio, and floor area ratio had significant negative correlations with both the roof and ground level thermal effects. Building density was positively related with roof-level thermal effects, but had no significant correlation with ground-level thermal effects. Overall, compact low-rise and open low-rise building areas exhibited much higher cooling effects than compact and open high-rise building areas. Study sites with S-N orientation had better thermal performance than SW-NE orientated sites. These findings can deepen our understanding of building-vegetation-climate interactions in urban areas and provide a reference for roof greening practice in humid subtropical cities.

关 键 词：屋顶绿化 热效应 城市形态结构 局地气候区 

分 类 号：TU985.12[建筑科学—城市规划与设计] X16[环境科学与工程—环境科学]