【作者】 张俊；

【导师】 郭晓华；

【作者基本信息】 长江大学 ， 风景园林， 2022， 硕士

【摘要】 城市化给人们生活带来便利的同时也带来了一系列的环境问题,其中以热岛效应最为显著。现有研究表明,城市公园作为城市规划设计的重要组成部分,对缓解城市热岛效应具有重要意义。关于公园降温方面采用的研究方法可分为遥感反演、实地测量和数值模拟,研究内容主要体现在研究公园整体面积、形态及内部个别组分对降温的影响,但由于城市公园内部及周边环境复杂多样,影响因素千差万别,研究结论间存在较大差异,尚不能有效指导公园建设。数值模拟技术可控制研究对象的影响因素,因而近年来尤为受到关注,其中以代表性软件ENVI-met最为突出,据统计已有超过一半的城市微气候模拟研究使用ENVI-met模型。ENVI-met内置植物模块,可通过调整绿地内部空间布局从而设置多样化场景,并通过对比各情景内的布局观测微气候的响应特征,在现今绿地规划已由增量向存量转化的背景下成为风景园林学者研究室外微气候的主要手段。目前ENVI-met运用于公园降温的研究主要集中在对公园局部组分的优化验证上,对公园内部组分占比及布局形式的研究尚未涉及。本研究在武汉市现有公园建设规划框架下,选取已建成公园作为主要研究样本,探讨公园降温的优化建议。首先,分析现有公园内部组分及前人研究成果,总结归纳出绿地、水体及硬质组分的4种占比比例及16种布局形式;其次,选取后襄河公园为建模蓝本,进行ENVI-met验证;之后,通过ENVI-met软件建立64组案例模拟,对比分析不同组分占比及布局形式下公园温度分布情况;最后,结合E NVI-met模型数据,依据公园内部平均温度、温度极值及公园外降温面积等指标探讨公园组分占比及布局形式对降温效应的影响规律,并以此提出优化建议。研究分析发现:1、公园组分的占比变化会导致公园内部降温存在显著差异(1)绿地组分在公园内部降温效应中占据主导作用,绿地组分占比减少,公园内最低温度区间面积随之减小;(2)公园内部水体占比为30%,绿地组分占比为49%,硬质组分占比为21%时,公园内部降温情况最好,且受组分布局形式变化的影响最小。2、公园组分布局形式的选择对公园内部降温效应的影响显著(1)硬质组分集中布置或布置在公园中间时,会给公园降温带来显著消极影响,分散布置时可减弱这种消极影响;(2)水体组分集中布置或呈环状布置时,降温情况良好,与分散布置时相比公园平均温度可优化0.56℃;(3)硬质组分可与水体组分随风向相互作用,能够有效缓解硬质组分给公园降温带来的消极影响,在综合平均温度上可优化0.31℃。3、公园对外部降温情况受到组分占比布局形式的双重影响(1)公园对外部环境的降温情况分为两种。与公园边缘直接相接触的降温区域,是公园内部降温能力的溢出表现,其降温情况与公园内部降温情况一致;与公园边缘没有直接相接触的降温区域是公园对外部环境的降温能力体现,其降温情况受到外部环境的影响;(2)组分占比上,公园内部水体占比为40%,绿地组分占比为42%,硬质组分占比为18%,此时公园对外部环境的降温情况最好;(3)布局形式上,水体组分布置在公园边缘或公园中心位置时,公园对外部环境的降温能力较强;在公园对外部环境的降温作用中,水体组分与硬质组分共同发挥作用;绿地组分分散布置或均匀布置在公园最外层时,公园对外部环境的降温能力较弱,降温面积最小。研究以数值模拟工具实现了公园内部绿地、水体及硬质组分不同占比及布局形式之间的搭配,得出了公园内部组分的最适占比及布局形式之间的降温优劣性,以弥补对公园降温效应的研究不足,为现阶段公园优化建设提供理论建议。更多还原

【Abstract】 Urbanization brings convenience to people’s life,but also brings a series of environmental problems,among which the heat island effect is the most significant.Existing studies show that urban parks as an important part of urban planning and design,play an important role in alleviating urban heat island effect.The research methods about park cooling can be divided into remote sensing inversion,field measurement and numerical simulation,the research content mainly reflects in the whole research park area,shape and internal individual components to the cooling influence,but due to the surrounding environment inside the city park is complicated,the influencing factors vary greatly,there is a big difference between research conclusion,cannot be effectively guide the construction of the park.Numerical simulation technology can control the influencing factors of the research object,so it has attracted particular attention in recent years,among which ENVI-met,the representative software,is the most prominent.According to statistics,ENVI-met model has been used in more than half of urban microclimate simulation studies.ENVI-met has a built-in plant module,which can set up diversified scenes by adjusting the internal space layout of green space,and observe the response characteristics of microclimate by comparing the layout of each scene.It has become the main means for landscape architecture scholars to study outdoor microclimate under the background that green space planning has been transformed from increment to stock.At present,the research on the application of ENVI-met in park cooling mainly focuses on the optimization and verification of local components of the park,while the research on the proportion and layout form of internal components of the park has not been involved.Under the framework of existing park construction planning in Wuhan,this study selected established parks as the main research samples to discuss the optimization suggestions of park cooling.Firstly,analyze the existing internal components of the park and the previous research results,and summarize 4 kinds of proportion and 16 kinds of layout forms of green space,water body and hard components.Secondly,houxianghe Park was selected as the modeling model for ENVI-met verification.After that,64 groups of cases were simulated by ENVI-met software to compare and analyze the temperature distribution of the park under different composition ratios and layout forms.Finally,based on the ENVI-met model data,the influence of park composition proportion and layout form on the cooling effect was discussed according to the average temperature inside the park,the temperature extreme value and the cooling area outside the park,and the optimization suggestions were put forward.Research analysis found that:1.Changes in the proportion of park components will lead to significant differences in the temperature drop inside the park(1)Green space component played a leading role in the cooling effect inside the park,and the minimum temperature area in the park decreased as the proportion of green space component decreased;(2)When the proportion of water in the park is 30%,the proportion of green space is 49%,and the proportion of hard components is 21%,the cooling in the park is the best,and the least affected by the changes in the component layout form.2.The composition layout of the park has a significant influence on the cooling effect inside the park(1)If the hard components are arranged centrally or in the middle of the park,it will have a significant negative effect on the cooling of the park,and the negative effect can be weakened when the hard components are dispersed;(2)When the water component is concentrated or circular,the temperature situation is good,and the average temperature of the park can be optimized by 0.56℃ compared with the dispersed layout.(3)Hard components can interact with water components in the wind direction,which can effectively alleviate the negative impact of hard components on the cooling of the park.The comprehensive average temperature can be optimized by 0.31℃.3.The external cooling of the park is doubly affected by the composition proportion layout(1)The cooling of the park to the external environment can be divided into two types.The cooling area directly in contact with the edge of the park is the overflow performance of the cooling capacity inside the park,and its cooling situation is consistent with the cooling situation inside the park.The cooling area without direct contact with the edge of the park is the embodiment of the cooling ability of the park to the external environment,and its cooling situation is affected by the external environment.(2)In terms of the proportion of components,the proportion of water in the park is40%,the proportion of green space is 42%,and the proportion of hard components is18%.At this time,the cooling of the park to the external environment is the best;(3)In the form of layout,when the water component is located at the edge of the park or the center of the park,the park has a strong cooling ability to the external environment;in the cooling effect of the park on the external environment,water components and hard components play a role together.When green space components are distributed or uniformly arranged in the outermost layer of the park,the cooling capacity of the park to the external environment is weak and the cooling area is the smallest.Research with numerical simulation tools to implement within the park green space,water,and rigid component selection and layout of different forms,obtained the optimal proportion of the cooling between the park internal components and the layout form,to make up for the research of the park cooling effect,provide theoretical suggestions for the current park optimization construction.更多还原