城市表面温度与建筑类型关系探讨——以苏州市和张家港市为例

通过遥感影像热红外波段制作亮温图,揭示苏州和张家港两城市的地面温度情况,将城市建筑物按亮温等级划分为高温、较高温、中温等几个类型,发现城市中大型建筑体和建筑物密集群是引起城市热岛效应的主要推手。针对这些建筑物与场地的节能改造、余热利用以及绿化建设是减轻城市热岛效应,改善城市热环境质量的关键措施,今后城市规划应该避免将引起城市明显升温的建筑物和场地置于城市主建成区。     

Measurement of thermal environment in Kyoto city and its prediction by CFD simulation

In the summer of 2002, measurements were simultaneously performed to investigate the characteristics of heat flow in urban areas at three locations in Kyoto city: (1) a commercial urban area mixed with low-rise traditional residential buildings that represents the urban area of Kyoto; (2) a university campus area with lots of green zones; and (3) a plaza covered with a concrete slab which was used as a reference point of measurement. Heat flux of boundary layer over the three locations and the surface temperatures of building walls and streets were measured to investigate the urban thermal environment. For the analysis, a new simulation code was developed by combining unsteady state heat conduction of building walls and grounds, radiation heat exchange between them, and airflow by computational fluid dynamics (CFD). By using this code, the thermal environment of the urban areas such as air temperature, humidity, wind velocity, and boundary layer heat flux was predicted and compared with the measured results. It was found that this model could predict the real thermal environment of the urban area. Using this code, the effect of additional green on roofs and grounds can be investigated in order to mitigate urban heat island and to improve urban thermal environment at the street level.     

Numerical simulation of the thermal environment of urban street canyon and a design strategy

The thermal environment of urban street canyons is closely related to design factors. By establishing a dynamic model of street canyons numerical simulations of temperature fields for typical street canyons are conducted. Through numerical analysis the influence of the most common variables related to environment in China’s urban residential quarters is compared and contrasted. Environmental factors include the height-width ratio of the street canyon, ground paving materials, canyon directions, and facades of buildings on canyon sides. Simulation results reveal how these factors influence the street canyon thermal environment. Results also give the recommended optimal height-width ratios for urban street canyons and question and revise some design ideas prevalent in China today.     

面向城市高密度街区舒适风环境的设计策略研究——以北京三条商业街的实地数据分析为例

城市建筑布局与城市外部风资源的相互作用决定了城市建成环境内部风环境的特征,对城市热岛效应、建筑能耗、建筑室内外的热舒适、空气质量以及居民健康都具有一定的影响作用。本研究试图避免复杂且高成本的计算机模拟,而基于常年大量现场测试的物理环境指标,采用数据统计分析的方法,通过相对简单的城市建成环境的形态参数和外部城市风环境获取步行街区行人高度下的微环境风速,而同时又保证风环境关键信息的可接受精度和准确性。研究数据的获取主要基于北京王府井步行街、前门大街、大栅栏商业街三处街区环境,并同步采集了城市外部的风向与风速数据。提出并建立的城市行人尺度下的风环境模型能够更加有效地应用于高密度城市区域规划与设计实践的初步设计阶段。     

Detecting urbanization effects on surface and subsurface thermal environment--a case study of Osaka

Tremendous efforts have been devoted to improve our understanding of the anthropogenic effects on the atmospheric temperature change. In comparison, little has been done in the study of the human impacts on the subsurface thermal environment. The objective of this study is to analyze surface air temperature records and borehole subsurface temperature records for a better understanding of the urban heat island effects across the ground surface. The annual surface air temperature time series from six meteorological stations and six deep borehole temperature profiles of high qualities show that Osaka has been undergoing excess warming since late 19th century. The mean warming rate in Osaka surface air temperature is about 2.0 °C/100a over the period from 1883 to 2006, at least half of which can be attributed to the urban heat island effects. However, this surface air temperature warming is not as strong as the ground warming recorded in the subsurface temperature profiles. The surface temperature anomaly from the Osaka meteorological record can only account for part of the temperature anomaly recorded in the borehole temperature profiles. Surface air temperature is conventionally measured around 1.5 m above the ground; whereas borehole temperatures are measured from rocks in the subsurface. Heat conduction in the subsurface is much less efficient than the heat convection of the air above the ground surface. Therefore, the anthropogenic thermal impacts on the subsurface can be more persistent and profound than the impacts on the atmosphere. This study suggests that the surface air temperature records alone might underestimate the full extent of urban heat island effects on the subsurface environment.     

夏热冬冷气候城市公共空间热环境季节特征

城市公共空间热环境是影响人们热舒适程度的重要因素。夏热冬冷气候城市公共空间的热环境在一年内会发生很大变化。在长沙市内选择3个典型公共空间(街道、公园和广场)进行长期热环境参数实测实验。通过对不同季节3个实测点的空气温度、相对湿度、黑球温度和风速4个重要热环境参数进行分析,获得夏热冬冷气候城市公共空间的全年热环境特征。研究结果表明:自然气候决定了城市热环境的基本特征,而城市物理结构是引起室外局部热环境发生改变的重要因素;受植物(乔木)和水体(湘江)的影响,沿江街道在全年大部分时间中空气温度显著较低,相对湿度较高,太阳辐射较弱;广场温度较高,太阳辐射较强。     

Thermal conditions and ventilation in an ideal city model of Hong Kong

Urban heat island can significantly increase the demand for cooling of buildings in cities. This paper investigates one of the main causes of the urban heat island phenomenon, i.e. reduced city ventilation. Two simple Hong Kong city models with relatively complex terrain were considered here under different atmospheric conditions. A 3D RNG k-? turbulence model was used for modeling turbulence effects. The simulation results showed that the influence of thermal stratification can be significant on city ventilation driven partially by thermal buoyancy. When the wind speed is relatively large, the impact of thermal stratification on air flow in city street canyons is minor. When the wind speed is small relative to the buoyancy force, the airflow in the street canyons is dependent on thermal stratification. When there is an adverse vertical temperature gradient, the greater the instability, the stronger the vertical mixing and the greater the flow rate caused by turbulence. The heat and pollutants can easily accumulate under stable atmospheric conditions when there is only a weak background wind or none at all.     

Anthropogenic effects on the subsurface thermal and groundwater environments in Osaka, Japan and Bangkok, Thailand

Anthropogenic effects in both Osaka and Bangkok were evaluated to compare the relationships between subsurface environment and the development stage of both cities. Subsurface thermal anomalies due to heat island effects were found in both cities. The Surface Warming Index (SWI), the departure depth from the steady geothermal gradient, was used as an indicator of the heat island effect. SWI increases (deeper) with the magnitude of heat island effect and the elapsed time starting from the surface warming. Distributions of subsurface thermal anomalies due to the heat island effect agreed well with the distribution of changes in air temperature due to the same process, which is described by the distribution of population density in both Osaka and Bangkok. Different time lags between groundwater depression and subsidence in the two cities was found. This is attributed to differences in hydrogeologic characters, such as porosity and hydraulic conductivity. We find that differences in subsurface degradations in Osaka and Bangkok, including subsurface thermal anomalies, groundwater depression, and land subsidence, depends on the difference of the development stage of urbanization and hydrogeological characters.     

Measuring the influence of the greening design of the building environment on the urban real estate market in Taiwan

To address the worsening problems of global warming and the urban heat island effect, ecological cities and building environment greening are being promoted in population-dense urban areas domestically and abroad. For example, the Japanese Ministry of Land, Infrastructure, Transport, and Tourism announced the CASBEE-HI (Heat Island) assessment system in 2008 as a response to worsening urban warming and urban heat island effects. The Ministry implemented “Building Space Greening Plans” in Tokyo, Osaka, and other cities, enforcing by law the effective reduction of urban temperatures and improving urban living environments and alleviating the threat of urban ecological disasters. Therefore, this study integrates Taiwan domestic and foreign building space greening design, derived greening benefits, implementation promotion methods, and greening design policies as measurement constructs to examine the mutual influence between different constructs and to analyze the degree of influence on the urban real estate market.     

基于电路理论的多尺度城市热环境网络 构建及格局优化：以成都市中心城区为例

高密度、高强度的城市建设和扩张导致城市热岛效应不断增强，研究城市热环境网络格局以优化规划布局是改善城市热环境的有效方法。将形态学空间格局分析与电路理论相结合，立足多尺度，以成都市中心城区及其核心区为研究对象，选取连通性强的冷岛、热岛源地，根据景观格局特征与地表覆盖构建阻力面，运用Linkage Mapper识别廊道、冷岛障碍点和热岛夹点，并进行分级和评价，构建研究区热环境网络，提出多尺度下的格局优化建议。结果表明：1)中心城区尺度识别出23处冷岛源地、34条关键廊道、48处障碍点，廊道呈“串珠状”环绕研究区边缘分布，连通性和稳定性较弱；2)中心城区核心区尺度识别出34处热岛源地、81条关键廊道、98处夹点，廊道呈网状分布且普遍连通性较高，夹点是未来阻断热岛廊道连通的关键区域；3)研究区形成“两环多分支五组团多点”结构的城市热环境网络格局。研究结果可为成都市及其他城市的热环境改善提供科学参考，丰富电路理论在热环境领域中的应用。     

浅谈城市热岛

对城市热岛现象的产生原因以及城市热岛对人类生存环境以及人体健康的危害进行了初步的探讨,而后对于城市热岛现象,提出了几种可行的改善措施,从而缓解城市热岛效应.     

城市热缓解的基于自然的解决方案与实施路径——以北京市为例

城市热岛与高温热浪威胁当代人类的生活与健康。基于自然的解决方案（NbS）不仅能够有效应对社会风险挑战、提升人类福祉,还有助于生物多样性保护与区域可持续发展。首先论述了NbS框架下的城市热缓解方案：1）优先识别应对城市热岛与热浪的社会挑战的关键区域;2）基于适宜尺度和面向生态系统完整性提升,进行热缓解方案设计;3）热缓解方案的经济可行性、包容性治理、适应性管理、主流化与可持续性。其次以北京市为例,探索基于NbS的城市热缓解方案设计及其实施路径。结果显示：北京市五环内城市热岛效应明显,区域内地表温度（land surface temperature, LST）对植被和不透水地表等覆被特征的变化响应在600 m×600 m的网格单元最稳定;热单元主要分布在五环内的南部,景观组分特征呈现为集中连片的建筑和不透水地表以及分散的裸地和蓝绿空间斑块;针对不同的热单元应采取适应性的热缓解措施,如分散的裸地型单元适宜采用建设城市森林公园的办法,大型低层建筑型单元适宜采用立体绿化,小型低层建筑型单元适宜“见缝插绿”,交通型单元适宜构建绿道等。研究可为未来基于NbS的城市热缓解方案设计提供科学依据与技术参考。     

Developing a modified typical meteorological year weather file for Hong Kong taking into account the urban heat island effect

Building energy computer simulation software is a useful tool for achieving sophisticated design and evaluation of the thermal performance of buildings. For successful thermal and energy simulation of buildings, it requires hourly weather data such as dry bulb air temperature, relative humidity, solar radiation, wind speed, etc. Nowadays, an urban city faces a problem of an urban heat island which causes the urban area to have a higher air temperature than the rural region. Since the currently available weather dataset used in building simulation software mainly comes from weather stations located in remote and rural areas, the impact of the urban heat island on thermal and energy performance of buildings may not be effectively reflected. This paper reports an approach to construct a modified typical meteorological weather file, taking into account the urban heat island effect in the summer season. Field measurements have been carried out in the summer months and the corresponding urban heat island intensities were then determined. With a morphing algorithm, an existing typical meteorological year weather file was modified. An office building and a typical residential flat were modeled with a renowned building energy simulation program EnergyPlus. Computer simulations were conducted using the existing and modified typical meteorological year weather files. It was found that there was around a 10% increase in air-conditioning demand caused by the urban heat island effect in both cases. The implications of this and further work will also be discussed in this paper.     

Urban environment influence on natural ventilation potential

Natural ventilation is less effective in urban than in rural environment, especially in street canyons. Reduced wind velocity, urban heat island, noise and pollution, are considered to be important barriers to its application in urban environment. To quantify their effect on ventilation, wind, temperature, noise attenuation and outdoor–indoor pollution transfer were measured for a large variation range and for various types of urban configuration. The models obtained can be used in the initial stages of building design in order to assess the viability of natural ventilation in urban environment, especially in street canyons.     

缓解热岛效应的居住区环境绿化探讨

城市热岛效应是伴随城市建设发展出现的一种负面现象,居住区环境绿化可解决在有限的城市空间提高绿地效率、缓解热岛效应的问题。文章从城市热岛效应出发,对缓解热岛效应的居住区环境绿化布局模式、方法及相关技术研究进展等方面进行了探讨。     

Study on outdoor thermal environment of apartment block in Shenzhen,China with coupled simulation of convection,radiation and conduction

Shenzhen City in China is developing rapidly now. Correspondingly, deterioration of the outdoor environment in phenomena such as heat island has become a serious problem. This aggravation of the thermal environment has spoiled urban sustainability. In this paper, (1) in order to predict the outdoors thermal environment in summer in an apartment block, unsteady coupled simulation of convection, radiation, and conduction is developed and used. The velocity, temperature, humidity, and MRT in the urban area are obtained from the simulation. In order to estimate the pedestrian level of thermal comfort in the outdoor thermal environment, the spatial distributions of New Standard Effective Temperature (SET¹) is calculated using the above results. (2) The actual situation of the outdoors thermal environment in summer in an apartment block in Shenzhen City is investigated by field measurements. (3) The effect of schemes to improve the outdoor thermal environment in this apartment block, such as changing building shapes, planting arrangements, etc. are examined using this prediction method.     

城市风环境研究的技术演进及其评价体系整合

随着城市化水平的提高以及城市空间密度不断加大,城市风环境问题成为了多学科研究关注的热点,风环境对景观环境设计、空气质量改善、开放空间热舒适度感知均具有重要的作用。从风环境研究的技术演进和其评价体系建构两个角度来分别对国内外城市风环境研究进行了梳理与总结,将其技术演进分为实地测量法研究、物理模拟法研究和计算机数值模拟法研究三个阶段进行详细分析,对现有的城市风环境评价体系特征进行了整合,相关技术方法能对城市规划起到积极的补充,具有明显的实践效果。     

温州市灵昆岛区域热环境的模拟初步研究

针对温州瓯江口新区灵昆岛新建规划设计,在城市规划设计阶段分析新建建筑群的热环境变化特征,研究其对周围区域热环境的影响,有效推动灵昆岛城市规划设计进展。应用Sketchup软件建立三维建筑模型,选择合适计算区域,利用PHOENICS计算流体软件进行离散求解并对模拟计算结果进行后处理,分析1.7 m行人高度处的风速和温度,分析区域内热岛效应形成的原因以及热风环境和热环境的分布特征,最后为优化城市区域热环境状况进而改善研究区域内的人居环境,有效降低城市区域建筑能耗提出合理化建议。     

建筑热反射研究

随着城市化进程的加快,城市变热问题凸显出来。如何改善我们所居住的城市环境,受到有关学者的广泛关注,控制好建筑热环境对提高人们的生活质量和降低建筑能耗大有裨益。文中结合“城市热岛”现象,从建筑的热反射角度分析了建筑物由于自身形式、布局规划以及建筑材料的热工特性而对其他建筑和周围环境的影响,阐述了其带来的环境问题,提出从建筑热反射角度解决热环境问题,为改善城市热环境,解决城市“热岛效应”开创了新的思路。     

Study on mitigation measures for outdoor thermal environment on present urban blocks in Tokyo using coupled simulation

The heat island phenomenon and degradation of the urban thermal environmental have become serious problems in Japan. In order to improve the outdoor thermal environment, it is necessary to understand quantitatively the effects of various measures. In this paper, the authors have performed coupled simulations of convection, radiation and conduction to evaluate the outdoor thermal environment over different urban blocks – ōtemachi as representative of a high-rise area and Kyobashi as a mid-rise area in Tokyo, Japan – to compare the effects of measures such as the heat release point and means of air-conditioning, greening, high surface albedo, and traffic volume. The results showed that the effectiveness of moderation countermeasures differed according to the configuration of the urban blocks.