基于遥感和CFD模拟的城市绿地形态对热环境的影响研究

为探寻不同绿地分布形态对城市热环境的改善效果及差异,结合遥感技术和CFD(Computational Fluid Dynamics)数值模拟方法,对城市中五类常见的绿地布局形式的温度场进行数值模拟。利用遥感影像以及LIDAR数据建立三维模型,并通过实地测量温度值对ENVI\|met软件模拟结果的真实性做了检验,得到在不同高度上不同绿地分布形态的温度场模拟结果。实验结果表明:将CFD技术引入城市热环境研究这一思路是可行的,根据典型绿地分布形态的热环境模拟分析,不同分布形态在不同高度上具有不同的降温效果。地表处点状分布效果最好,2 m处楔状分布效果最好,而在10 m左右的高空条带状的降温效果最好。
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基于热红外遥感的城市热场形成机制及特征分析--以成都市为例

利用LANDSAT5的TM6热红外数据和实时的地表温度，优选了一种方法进行成都市地面温度场反演，根据反演结果对成都市地表温度场分布特征进行了分析，同时定量分析了植被覆盖和水域廊道对地表温度场分布的影响，定量分析的结果对城市区域布局和规划有积极意义。     

作平面运动的二维平面板的热耦合动力学问题

研究受到热冲击的作平面运动的二维平面板的温度场和动力学响应.考虑温度场和应变场的耦合,通过计算熵密度,建立了平面板的热传导变分方程,此外,在本构关系式中考虑热应变,基于平面应力假设建立了作平面运动的二维平面板的动力学变分方程.用有限元方法分别对温度场和变形场进行离散.最后,计算了作直线平动的平面板的温度场和变形场,揭示了温度和变形的相互耦合特征,体现了板运动对温度和变形的影响.     

缺陷表面温度场的红外无损检测分析

关于复合材料表面缺陷无损检测优化问题,利用闪光灯激励脉冲热像法的红外无损检测,对近表面不同尺寸(大小、深度)的预埋缺陷进行检测与评价.通过实验与有限元软件ANSYS仿真,获取缺陷近表面温度场,根据对温度场中温度的均匀性分布,以及对温度场中温度特征值的提取,研究缺陷尺寸对温度场分布影响.在加热-冷却过程中,对温度场与最大温差曲线进行分析,实验与仿真结果表明:在不同阶段内,缺陷大小、深度对温度场影响不同;通过合理选取不同阶段并进行分析,可以对缺陷做出定性与半定量判断.     

拉瓦尔喷管流固耦合换热数值模拟

针对颗粒的存在引起喷管内流场变化,进而对喷管热防护性能产生影响的问题,基于计算流体动力学(CFD)方法,建立了欧拉-欧拉两相流数值模型,利用软件Fluent对喷管两相流场进行了模拟,并以两相流流场计算结果为热边界条件,对喷管热防护层进行了瞬态换热数值计算,比较了有无颗粒两种状态下的流场分布情况,并获得了喷管整体结构温度场的分布规律.仿真结果表明,在发动机工作过程中,颗粒的存在使喷管内流场结构发生变化,导致燃气流速降低,温度升高,且喷管内壁逐渐向外壁传递热量,进一步影响喷管热防护性能,研究结果可为发动机喷管部件热防护设计提供参考.     

利用ANSYS热分析模块分析渗流场问题的探究

本文分析了温度场与渗流场的基本理论、微分方程、初始条件和边界条件的相似性，为后续利用ANSYS的热分析模块来求解渗流问题提供了依据。通过计算黑河金盆大坝0＋225主断面的在正常蓄水位下的流场分布情况，验证了热分析模块对渗流分析结果的可行性与正确性。     

发动机排气管流-固-热强耦合分析

为研究发动机排气管在流-固-热强耦合作用下的复杂工况,用INTESIM软件中流-固-热强耦合的方法计算某型发动机排气管在工作过程中流场、温度场、热变形和热应力的分布情况.结果表明,与传统的分析方法相比,INTESIM的强耦合方法收敛性更好,并且可以在同一软件平台下对模型耦合矩阵方程直接求解得到结构应力场、位移场、流场和温度场的所有结果.     

温度场模糊随机有限元法研究

不确定性广泛存在于工程分析和设计过程中,正确估计不确定参数对温度分布的影响,对工程热设计具有十分重要的意义。以飞机刹车装置为例将模糊随机参数模型引入热传导温度场研究中,使用模糊随机参数模型对温度场不确定性进行描述,对随机性进行泰勒展开,建立方程求解温度响应变化区间。最后给出数值算例,说明模糊随机对温度场的影响,分析了各参数具有不确定性时,温度响应的模糊性与随机性,得到了相应条件下温度场响应,证明了使用模糊随机参数所建立的瞬态温度场模型合理、可行,为工程热设计提供了理论支持。     

配电室温度场与湿度场的建模与仿真分析

考虑到变电站配电室内配电设备对环境温度和湿度有较严苛要求,因此有必要研究配电室内温度和湿度分布规律,有助于提高配电设备可靠性。按照与温度计算有关的能量传递方程和与湿度计算有关的气体扩散方程,由理论计算公式分析可知直接计算涉及多变量的耦合,求解难度大。本文采用有限元分析软件ANSYS对配电室的温度场和湿度场进行仿真计算,首先根据实际的典型配电室建立仿真计算模型,并高精度划分有限元网格。其次根据现场运行情况整定计算仿真需要的计算参数,利用仿真计算模型得到了室内温度场和湿度场的水平面分布情况。通过改变风机流量,分析了风机流量变化对配电柜内部温度的影响效果,总结了配电室内温度场与湿度场的分布规律。     

考虑人体散热的轿车座舱内流场数值仿真研究

研究提高轿车热舒适性,汽车座舱空气的对流和人员体温,都会影响舒适度,有必要在开发前期,用数值方法对轿车座舱内流场进行仿真.根据雷诺平均的方法,应用RNGc-E湍流模型,为了控制舱内舒适性能,采用分区域划分网格的方法,对座舱内空气三维流场和温度场进行了数值仿真研究.引入人体模型,考虑车内人体散热对座舱内环境的影响,建立了轿车座舱舒适性研究的模型.给出了座舱内不同位置的速度分布和温度云图,分析了空调给风角度、空调给风口位置以及空调回风口位置对座舱内气流组织及温度场的影响.结果表明,采用前-中给风的给风口布置和后回风形式以及上攻角的给风口设计,均可以提高轿车座舱内乘员的热舒适性.     

基于遥感和GIS 的城市绿地缓解热岛效应作用研究

以气象卫星和资源卫星遥感资料为主要信息源, 结合气象、绿地观测等相关资料, 采用星、地同步或准同步观测的点面结合方法, 通过研制GIS 多要素空间分析模式, 对近年来上海城市“热岛、绿岛”分布以及相关关系、作用效果进行综合分析, 进而揭示了城市绿地对城市气温的调节作用和影响效果, 为市政府各级领导和有关城建、绿化部门的合理性规划提供了科学依据。     

Comparative Study on Thermal Environment between Old Urban Areas and New Urban Areas based on Landsat 8 Remote Sensing Image：A Case Study of Chengdu City

A large number of new urban areas have emerged under the rapid urbanization background in recent years in China，and the characteristics of urban thermal environment have significant changes.To analyze the thermal environment diversities between old urban areas and new urban areas and explore the impacting factors，we chose Chengdu City in Sichuan Province as a typical study area.Key surface parameters，including Land Surface Temperature (LST)，building index and vegetation index were derived based on Landsat 8 satellite image acquired on August 13，2014.The comparison study was conducted to analyze the differences of the parameters related to thermal environment changes，and the results indicated that：①Overall,the average surface temperature of the old urban area was higher than that of the new urban area.Regarding the spatial distribution，the central and northern region had higher temperature than the southern region for the old urban areas.In the new urban areas，although high temperature spots can be found in the central west or north，this region generally had a relatively low temperature.②The old urban area emphasized a higher Urban\|Heat\|Island\|Ratio\|Index (URI)，which revealed the descending trend of surface temperature via analyzing the thermal field profile from the old to the new.This showed that the urban thermal environment effect of the old city was stronger than the new urban area.③“Heat Island Effect” was easy to emerge in those areas with high density urban construction and little urban vegetation coverage，whereas reasonable urban landscape planning and layout would help to perfect the urban thermal environment.The comparison of the thermal environment effects between the new urban areas and the old urban areas shows the new urban planning in Chengdu has positively contributed to improve the thermal environment in the new urban areas，which can provide important reference for the future urban planning.     

基于混合光谱分解的兰州城市热岛与下垫面空间关系分析

利用Landsat ETM+数据,采用混合像元线性光谱分解方法提取的城市植被覆盖度与不透水面表征城市下垫面,通过单窗算法反演地表真实温度,对兰州市中心城区的夏季城市热岛强度与城市下垫面的空间分布关系进行相关分析。结果显示,利用中等分辨率ETM+影像对兰州中心城区不透水面和植被盖度分布提取,其成本较低,精度令人满意;兰州城区植被覆盖、不透水面与热岛强度的分布呈空间正自相关,地表温度的空间依赖性极强,与植被盖度和不透水面在空间方向上的相关性差异较大。     

利用Landsat ETM+影像研究土地利用/覆盖与城市热环境的关系 --以福州市为例

如何更好地研究土地利用/覆盖与城市热环境的关系,将对城市规划、城市生态环境的改善产生积极的影响.本文利用Landsat ETM＋影像的热红外波段,研究城市热岛的分布规律,同时研究了不同土地利用类型的可见光、近红外、中红外与热红外波段的关系,以揭示土地利用/覆盖与城市热环境的关系.研究表明,在卫星影像上,城市建成区的可见光、近红外、中红外与热红外波段的相关性较为显著,通过对不同土地利用类型上可见光波段、近红外、中红外与热红外波段的分析,获取城市建成区上的热环境分布.     

Assessment of multi-resolution and multi-sensor data for urban surface temperature retrieval

Data from three thermal sensors with different spatial resolution were assessed for urban surface temperature retrieval over the Yokohama City, Japan. The sensors are Thermal Airborne Broadband Imager (TABI), Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and MODerate resolution Imaging Spectroradiometer (MODIS). Two algorithms were developed for land surface temperature (LST) retrieval from TABI image and ASTER thermal infrared (TIR) channels 13 and 14. In addition, ASTER LST and MODIS LST products were also collected. All the LST images were assessed by analyzing the relationship between LST and normalized difference vegetation index (NDVI) and by spatial distributions of LST profiles, derived from typical transects over the LST images. In this study, a strong negative relationship between LST and NDVI has been demonstrated although the degree of correlation between NDVI and LST varies slightly among the different LST images. Cross-validation among the LST images retrieved from the three thermal sensors of different spatial resolutions indicates that the LST images retrieved from the 2 channel ASTER data and a single band TABI thermal image using our developed algorithms are reliable. The LST images retrieved from the three sensors should have different potential to urban environmental studies. The MODIS thermal sensor can be used for the synoptic overview of an urban area and for studying urban thermal environment. The ASTER, with its TIR subsystem of 90-m resolution, allows for a more accurate determination of thermal patterns and properties of urban land use/land cover types, and hence, a more accurate determination of the LST. In consideration of the high heterogeneity of urban environment, the TABI thermal image, with a high spatial resolution of 2 m, can be used for rendering and assessing complex urban thermal patterns and detailed distribution of LST at the individual house level more accurately.     

Inversion of Land Surface Temperature and Its Application in Urban Agglomeration Thermal Environment Monitoring based on Tiangong-2 Data

According to the characteristics of thermal infrared spectrum of wide band imager of Tiangong-2 data,a spilt-window algorithm applied to Tiangong-2 data was proposed.Taking the South of Jiangsu urban agglomeration as the research area,the inversion of the land surface temperature was carried out.On this basis,the spatial distribution characteristics of thermal environment of South of Jiangsu urban agglomeration were analyzed through SUHI index.The results show that the split-window algorithm can be effectively applied to the thermal infrared of Tiangong-2 data.The root mean square error of land surface temperature inversion is within 1 K.The result of land surface temperature are in good agreement with the types of land use in the research area,and the temperature of the building land is the highest and the water is the lowest.A global heat island is formed in Suzhou-Wuxi-Chanzhou,and the intensity and spatial distribution of the heat island in the urban agglomeration are monitored by SUHI index.     

多时相影像福州市不透水面对城市地表温度的空间分布研究

随着城市化进程的加快,城市热力场也随之发生变化,从而影响着城市区域环境、社会经济以及社会环境。由于NDVI具有季相变化的不稳定性,本研究采用两个时相TM/ETM+影像分析福州市及其周边地区不透水面对热力场的时空分布变化状况。为了获取精确的城市不透水面信息,本实验采用NDVI二元法结合2000年同区域的IKONOS影像提取不透水面信息。通过定量分析不透水面百分比、NDVI与地表温度的关系,得出不透水面百分比与城市地表温度呈线性相关,其相关系数在0.7左右;尤其30%以上的不透水面对地表热环境的空间分布影响最为突出,因此,相对于不稳定的NDVI而言,不透水面信息能更好地反映城市热环境的空间分布状况。     

基于RTI的城市热岛效应变化分析研究-乌鲁木齐市为例

以乌鲁木齐市区为例，利用Landsat TM/ETM+第6波段数据反演地表温度,并计算出其相对温度指数(RTI)。从气温相对性、动态性的角度，对其相对温度指数的变化分布模式进行分析，得出城市热岛的变化特征及其空间分布规律。该方法避免了下垫面复杂性及地-气模型建立的困难性等因素对城市热岛效应变化分析研究的影响。     

Spatial variability of air temperature and appropriate resolution for satellite‐derived air temperature estimation

This study investigates the spatial variability of air temperature over Hong Kong using in situ air temperature recorded from a mobile traverse combined with an ASTER thermal satellite image. Three different degrees of urbanization in Hong Kong, including city downtown (Kowloon), suburban areas (Yuen Long and Shatin), and rural countryside (Tai Mo Shan and Lam Tsuen) are analysed. The spatially variable relationship between air and surface temperature was evaluated using two spatial averaging techniques, namely spatial resampling and buffering around air temperature points. The strength of the correlation coefficient was tested for every decreasing resolution and the appropriate spatial scales of air temperature in urban, suburban and rural areas were found to be 200 m, 450 m and 700 m, respectively. The differences in the spatial scales of air temperature in these regions are attributed mainly to structural factors of land cover such as city block size, building density and percentage of green areas, and secondarily to the climatic conditions being operating in, and which commonly typify these individual regions. Thus small scale lengths in the urban area corresponded to heterogeneous land cover, a well developed urban boundary layer, low wind speeds and a low lapse rate, whereas longer scale lengths were observed in suburban and rural areas having more homogeneous land cover, higher wind speeds and higher lapse rate.     

Effects of Landscape Pattern on Annual Variation of Thermal Environment in Hangzhou

Taking the Hangzhou city as an example,this paper retrieves the urban land surface temperature (LST) using 4 Landsat ETM+/OLI_TIRS images and investigates the effects of landscape pattern on the urban thermal environment change.The hot spot analysis was used to identify both the urban heat island and cold island.Landscape pattern indices were adopted to analyze the relationship between the change of the thermal environment and the landscape pattern.Analysis results show that：(1) The proportions of area in urban heat island and cold island in Hangzhou increase first and then decrease with the alternating four seasons;The urban heat island of Hangzhou is the most significant in summer,and the urban cold island effect is more dominant in autumn;(2) Throughout the year,all kinds of landscape has the highest average land surface temperature in summer and the lowest in winter;As for a variety of landscapes,the construction land has the highest average land surface temperature,while,the water body and forest have the relatively low average land surface temperature;(3)On the landscape level,the selected landscape pattern indices are significantly correlated with average land surface temperature in four seasons,the strength of correlation fluctuates with alternating four seasons and the enlargement of analysis window;On the class level,landscape pattern indices of construction land,water body and forest are significantly and highly correlated with average land surface temperature in different seasons.The research in our paper could help to lay out construction land rationally and execute planning and design on urban green space and waters to effectively alleviate the urban heat island effect of Hangzhou.