基于ENVI-met的道路绿地微气候效应模拟与分析研究

SIMULATION AND ANALYSIS OF MICROCLIMATE EFFECT OF ROAD GREENBELT BASED ON ENVI-MET

道路是城市的骨架,处于城市形象的五大要素之首。道路绿化诞生之初即源于人们对道路环境的需求,道路绿化是改善道路微气候条件的重要策略。因而,合理地进行道路绿地规划设计,使其生态效益最大化,具有重要的理论和实践意义。论文以城市道路空间微气候为研究对象,运用城市微气候模拟软件ENVI-met,选取1.5 m人行高度的温度、相对湿度、PM2.5浓度作为微气候指标要素,模拟不同道路绿地率、道路绿带断面形式对道路空间微气候的影响,结果表明:第一,增加道路绿地率能改善城市道路微气候效应,起到降温增湿、消减人行道PM2.5浓度的作用;第二,相同绿地率情况下,道路绿带断面设计的绿带数越多,道路绿化降温增湿效果越好。40%绿地率的四板五带式效果最佳,对比无绿化道路温度降低率约为11%,湿度增长率约43%;第三,道路绿带断面设计形式影响了PM2.5浓度在道路空间的分布,导致机动车道PM2.5浓度增加,人行道PM2.5浓度减少,40%绿地率的两板三带式对人行道PM2.5浓度消减效果最佳,对比无绿化道路增减率最大提高了27%。

As the skeleton of the city, the road is the most significant one among the five elements of the city image. Road greening originated from people’s demand for road environment and is an important strategy to improve road microclimate conditions. Therefore, it is of great theoretical and practical significance to carry out road green space planning and design rationally to maximize its ecological benefits. This paper takes urban road space microclimate as the research object, using ENVI-met, a urban microclimate model software and selecting 1.5 m high temperature, the relative humidity, concentration of PM2.5 as indicator factors of micro climate to simulate the influence of different road greenbelts rate and road Green Belt sections on the microclimate of road space. The results show that:(1) Increasing the road green rate can improve the microclimate effect of urban roads, playing a role in cooling and humidifying, and reducing the PM2.5 concentration of sidewalks;(2) at the same green rate, the more complex form cross section of road green belt is designed, the better effect of cooling and humidifying road green belt plays. Section type of the four boards and five belts has the best effect. Compared with the non-greening road, the temperature reduction rate is approximately 11% and the humidity growth rate is approximately 43%.(3) the cross-section form of road greenbelt designed influences the distribution of particles in road space, leading to PM2.5 concentration increased in motor roads and decreased in pavements. Section type of two board three zones has the best effect in reducing PM2.5 concentration. Compared to no green road, the maximum growth rate increased by 27%.