摘要
[背景]城市热岛效应对人体健康产生显著的负面影响。城市绿地能够有效改善城市热环境,提高人体热舒适度。[目的]探究植被配置结构的温湿效应及对人体热舒适度的影响,以期为城市预备地景观规划提供参考,预防并减少城市热岛效应对城市居民健康的影响。[方法]以合肥某高校预备地为研究对象,选取晴朗无云且无极端天气的夏季典型气象日进行实地监测,以实测数据进行ENVI-met软件数值模拟精度验证。基于垂直和水平的视角对植被配置结构方案进行量化界定,根据植被配置类型(草地、灌木+草地、乔木+草地、乔木+灌木+草地)、种植布局(列植、均匀点植)及种植密度[植物间高宽比(ART)分别为0.75、1.13、1.50、2.25]三个方面建立9个模拟方案,定量对植被配置结构方案的降温增湿效应及人体热舒适度(生理等效温度,PET)进行评价。[结果]所有模拟方案的降温增湿效果的变化趋势较为一致,基本上呈现先升后降的变化趋势。方案八(乔木+草地,ART=2.25,均匀点植)的降温增湿效果最优,降温指标较最差的方案一最大差值达1.36℃,增湿6.29%。方案九(乔木+灌木+草地,ART=2.25,均匀点植)的人体热舒适度最优,PET值为35.37℃。不同植被配置类型对热舒适度的改善效果由强到弱的顺序为乔灌草结构(方案九)>乔草结构(方案八)>灌草结构(方案二)>草地结构(方案一);15∶00时,乔灌草结构(方案九)的PET值较草地结构方案(方案一)下降了7.44℃。乔木间种植密度越大,模拟方案与原始方案的温度和相对湿度的差值就越高。在控制相同绿量的情况下,在植被种植稀疏时,均匀点植展现出更优的人体舒适度,但方案三(乔木+草地,ART=0.75,均匀点植)与方案五(乔木+草地,ART=1.5,列植)PET值相差仅0.15℃;当种植密集时,列植则更有利于风的流通,更有效降低场地温度,方案七(乔木+草地,ART=2.25,列植)比方案四(乔木+草地,ART=1.13,均匀点植)PET值低0.87℃。[结论]城市绿地在夏季降温增湿效应明显,均匀点植的乔草结构(ART=2.25)对热环境降温增湿效果最明显,均匀点植的乔灌草结构方案下人体舒适度最优。植被配置结构优化对于减少城市热岛效应,提高人体热舒适性和促进居民健康有重要意义。
[Background]The urban heat island effect has a significant negative impact on human health.Urban green space can effectively improve the urban thermal environment while enhancing human thermal comfort.[Objective]To investigate the effects of vegetation configuration structure on temperature and humidity and on human thermal comfort,with a view to providing reference for the landscape planning of urban reserve,preventing and reducing the impact of urban heat island effect on the health of urban residents.[Methods]The study was carried out on a typical clear and cloudless summer day without extreme weather in a university reserve area in Hefei.The numerical simulation accuracy of ENVI-met software was verified by measured data.Based on the quantitative definition of vegetation configuration structure scheme from vertical and horizontal perspectives,nine simulation scenarios were established based on three aspects including vegetation configuration type(grass,shrub+grass,tree+grass,tree+shrub+grass),planting layout(column planting,uniform spot planting),and planting density[the aspect ratio of trees(ART)between plants was 0.75,1.13,1.50,and 2.25,respectively]to quantitatively evaluate the cooling and humidifying effects and human thermal comfort[physiological equivalent temperature(PET)]of the vegetation configurations.[Results]The change trends of the cooling and humidifying effects of all the simulated scenarios were consistent,basically first increasing and then decreasing.Among all the simulated scenarios,the cooling and humidifying effects of scenario 8(tree+grass,ART=2.25,uniform spot planting)were the best,with the greatest cooling of 1.36℃and humidification of 6.29%in comparison to the worst scenario 1 in the reserve area.The human thermal comfort of scenario 9(tree+shrub+grass,ART=2.25,uniform spot planting)was the best,with the PET of 35.37℃.The order of improvement effect of different vegetation configurations on thermal comfort from strong to weak was tree+shrub+grass structure(scenario 9)>tree+grass structure(scenario 8)>shrub+grass structure(scenario 2)>grass structure(scenario 1).At 15:00,the PET value of tree+shrub+grass structure(scenario 9)decreased by 7.44℃in comparison to that of grass structure(scenario 1).The higher the planting density among trees,the higher the difference in temperature and relative humidity between the simulated and the original scenarios.In case of holding the same amount of greenery,uniform spot planting showed better human comfort when the vegetation was planted sparsely,but the difference between the PET value of scenario 3(tree+grass,ART=0.75,uniform spot planting)and scenario 5(tree+grass,ART=1.5,column planting)was only 0.15℃;when the vegetation was planted densely,column planting was more favorable to wind circulation and more effective in reducing the temperature of the site,with a lower PET value of 0.87℃for scenario 7(tree+grass,ART=2.25,column planting)than for scenario 4(tree+grass,ART=1.13,uniform spot planting).[Conclusion]Urban green space has obvious cooling and humidifying effects in summer.The human comfort of tree+shrub+grass structure with uniform spot planting is optimal,and the cooling and humidifying effects of tree+grass structure with uniform spot planting are the most obvious.The optimization of vegetation configuration structure is crucial for reducing urban heat island,improving human thermal comfort,and promoting residents’health.
作者
董冬
邰宇
罗毅
张五四
顾康康
DONG Dong;TAI Yu;LUO Yi;ZHANG Wusi;GU Kangkang(School of Architecture and Planning,Anhui Jianzhu University,Hefei,Anhui 230601,China;Anhui Institute of Land Spatial Planning and Ecology,Anhui Jianzhu University,Hefei,Anhui 230601,China;Tongcheng Natural Resources and Planning Bureau,Anqing,Anhui 231400,China)
出处
《环境与职业医学》
CAS
CSCD
北大核心
2023年第8期900-909,共10页
Journal of Environmental and Occupational Medicine
基金
安徽省自然科学基金项目(2008085QC132)
安徽省高等学校科学研究重点项目(2022AH050244)
安徽建筑大学科研项目(2020-RK12,2020QDZ26)。
关键词
植被配置结构
降温增湿效应
人体热舒适性
微气候
vegetation configuration structure
cooling and humidifying effect
human thermal comfort
microclimate