湿热地区垂直绿化对城市街区微气候影响机理及其优化配置研究

Vertical greenery systems (VGSs) on building walls are considered as a potentially effective way of green and low carbon building technologies to improve the building indoor and outdoor environment and mitigate urban heat island (UHI) effect. VGSs on building envelopes can reduce wall temperatures through evapotranspiration, shading effect, wind barrier effect, insulating capacity and low solar absorbance of plants and substrates. A lack of quantitative research on the outdoor microclimate effects and influence mechanisms of vertical greenery systems at the building and city scales creates a knowledge gap that limits the understanding of this significant aspect in VGS science. This empirical experiment will study the microclimate characteristics, radiation and energy balance, meteorological index, vegetation and substrate characteristics of vertical greening on the building envelopes in hot and humid regions, and will focus on the influencing factors and influence mechanisms of outdoor microclimate effect of vertical greenery systems using a new method and software technology in environmental physics and plant ecology. This study will use ENVI-met, a city microclimate simulation software, to simulate the outdoor microclimate of building envelopes in the experimental area, correct the parameters rightly, and verify the validity of ENVI-met model by comparing with experimental data. Then the present study will use this software to simulate the outdoor microclimate of urban blocks with several simulation scenarios of building scenes and planting design of VGSs, and study the effects of VGSs on the alleviating the UHI effect. The outdoor microclimate of VGSs on the building environment and urban blocks in hot and humid regions in this study can provide more knowledge on the understanding of this significant aspect of VG science on landscape ecology, and lay the foundation for exploring the scientific application of urban greening. It also provides important theoretical significance and engineering practical value.

垂直绿化系统通过蒸散效应、遮阴效应、防风效应、隔热效应和植物对太阳能吸收作用，有效改善建筑室内外热环境和缓解城市热岛效应，是园林绿地和低碳绿色建筑的重要类型。但是垂直绿化对城市街区的微气候效应与影响机理尚待阐明。本项目拟借助环境物理学与植物生态学的方法和技术，通过现场实测研究垂直绿化的建筑室外微气候特征、辐射能量平衡、气象指标、植物和基质指标，揭示微气候效应的影响因素和作用机理。并运用城市微气候模拟软件ENVI-met建立实况热环境模拟模型并校正参数，将数值模拟和实测匹配度验证，确定软件模拟可以替代实测。再利用此软件进行不同建筑物和绿化配置的布局模式下垂直绿化对城市街区微气候的数值模拟研究，阐明垂直绿化对城市热岛效应的缓解效果。本项目前期基础扎实，将阐明湿热地区垂直绿化对建筑外立面和城市街区的微气候效应，丰富园林绿地的景观生态理论，为优化应用配置提供应用基础，具有重要的研究意义和应用价值。

垂直绿化系统集建筑、植物、材料为一体，不仅可以显著提高高密度城市建筑环境的空间利用率，而且可以降温增湿，提升室外热环境舒适度。因此，作为调节城市微气候环境和缓解热岛效应最有潜力的绿化方式之一，迅速在全球高密度城市得到广泛应用。本项目借助环境物理学与植物生态学的方法和技术，通过现场实测研究垂直绿化系统的建筑室外微气候特征、辐射能量平衡、气象指标、植物和基质指标，深入探索垂直绿化系统的微气候效应的影响因素和作用机理。并基于缩尺尺度外场实验，现场监测并分析垂直绿化系统在不同街谷高宽比和不同绿化率配置条件下模拟街谷的热环境特征、风环境特征和辐射影响的时空变化，指出垂直绿化系统对城市街谷的调节作用受垂直绿化系统植物状况和不同街谷形态等多方面影响，对在高密度街区的垂直绿化系统的应用提供科学依据。最后，运用城市微气候模拟软件ENVI-met模拟工具构建城市垂直绿化街区微气候模型，使其作为湿热地区城市微气候研究的有效预测工具，揭示垂直绿化在不同建筑物参数的布局模式下城市街区热环境的数值模拟研究，阐明垂直绿化对城市热岛效应的缓解效果，优化其生态景观配置。本项目科学全阐明湿热地区垂直绿化系统对建筑环境和城市街区的微气候效应，研究成果丰富园林绿地的景观生态理论，为优化应用配置和改善城市生态环境提供理论依据和实践指导，具有重要的研究意义和应用价值。