城市热岛效应演变与成因遥感研究

【作者】 冯晓刚；

【导师】 李锐；

【作者基本信息】 陕西师范大学 ， 地图学与地理信息系统， 2011， 博士

【摘要】 持续快速的城市化对城市局地气候、生态环境和生态安全产生了持久而深远的影响,随着地表覆被类型的急剧变化、地表物化性质的改变使得地表与大气间的水分与能量物质交换过程发生变化,进而影响到城市“热”环境系统。并由城市“热”引发的一系列环境、生态安全等问题已经成为制约城市可持续发展的瓶颈。为此,2005年国务院发布的《国家中长期科学和技术发展规划纲要(2006-2020)》中明确要求,为提升城市功能与空间节约利用,要把城市“热岛”效应的形成机制与入工调控技术作为重点研究内容。其强调了城市热环境研究对构建新型现代化都市的重要性,并将此作为构建城市可持续发展的必经之路。本文以西安都市圈为例,以1988～2009年21年间的陆地卫星(Landsat) TM/ETM+数据为主要信息源,以气象站点资料和土地利用图件为辅助,以遥感定量反演和GIS空间分析为技术支撑,对不同年份的西安都市圈地表温度和不同时相的西安市地表温度状况进行分析与评价；并引入景观生态学理论,利用景观格局指数对西安都市圈典型城镇(西安市、咸阳市和兴平市)热环境格局动态变化进行分析与评价；同时,采用分形理论,探讨了西安市地表温度的时空分形特征与尺度效应特征；基于研究区下垫面类型的变化与地表温度间的定量关系,以西安市主要公园为例探讨了公园下垫面类型对周边地区温度的定量影响,在此基础上,运用元胞自动机理论和马尔可夫模型,构建了可用于城市热环境模拟的UHI-CA-Markov模拟与预测模型；在定性分析城市热岛效应影响因素的基础上,基于多元目标的主成分分析的方法,定量探讨了各影响因子对城市热岛效应的贡献率大小,并从调整城市规划思路、控制工业热源、调控民用热源等三个方面构建了应对西安都市圈典型城镇热岛效应的调控体系和措施。研究过程中,主要得出以下重要结论：(1)西安都市圈典型城镇均存在不同程度的热岛效应①基于等距的热岛类型划分体系适用于大中城镇构建热环境指标与评价体系；而基于中误差的划分体系更适合于构建市、县、镇、乡四级热环境指标及评价体系；②西安市、咸阳市和兴平市热环境结构中常温区均占主导地位。西安市和咸阳市不同热岛类型面积大小依次为：常温区>绿岛区>热岛区>强热岛区>强绿岛区；而兴平市不同热岛类型面积大小依次为：常温区>热岛区>绿岛区>强热岛区>强绿岛区；③西安市不同年份不同时间城郊地表温度差异较大。(2)西安都市圈典型城镇热景观格局时空差异较大①类型景观水平指数显示,1988～2006年18年间常温区始终是西安市、咸阳市和兴平市域内的优势斑块；②蔓延度指数表明：西安市、咸阳市和兴平市整个景观要素先趋于密集化,破碎度增加,呈现无序化趋势；之后,破碎度降低,斑块分布趋于稳定；③多样性指数和均匀度指数的变化趋势表明：西安市、咸阳市和兴平市土地利用方式随着时间推移均趋于稳定,破碎度降低,热景观格局亦趋于稳定；④不同粒度下,地表温度剖面线表现为相似的结构特征,但当尺度达到150m的时候,会发生跳跃现象。(3)西安市地表温度与下垫面覆盖(利用)类型的定量关系表达①夏季西安市不同地表覆盖(利用)类型中,其平均地表温度由高到低的次序为：裸露地>建设用地>耕地>草地>林地>水体；冬季西安市不同地表覆盖(利用)类型的平均地表温度由高到低依次为：林地>耕地>裸露地>建设用地>草地>水体；②夏季西安市地表温度(LST)与归一化植被指数(NDVI)呈现显著的负相关关系；LST与归一化裸露指数(NDBI)呈现正相关关系；LST与水体指数(NDWI)呈现典型的负相关关系,表明夏季水体具有很好的降温作用；③不同形态参数(面积、长宽比、形状指数等)的公园对其周边区域的热环境影响不同。公园面积是其平均温度高低的决定性因素；公园平均降温范围与公园长宽比和形状指数呈现较强的正相关关系,降温幅度与水域面积、长宽比和形状指数呈较低程度的正相关；水体面积比例较高(≥30%)的兴庆公园、大唐鞭蓉园,其平均降温影响范围Lmax以及△Tmax整体略高于其它公园。因此,城市公园建设中建议水体面积占公园面积30%以上为佳。(4)西安市热环境模拟结果显示未来城市热趋于好转①基于UHI-CA-Markov模型的空间模拟结果显示,预计到2012年西安市热环境相比2006年表现为：强热岛区和热岛区均呈现小幅减少的趋势,常温区、绿岛区呈现略微增加的趋势,强绿岛区呈现稳定的趋势；②到2018年,西安市热环境类型与2012年相比,预计强热岛区呈现小幅增加的趋势,热岛区呈现持平的趋势,常温区出现较大幅度的增加,绿岛区和强绿岛区均呈现不同程度的减少；③2006～2018年12年间模拟结果表明：未来西安市热环境状况整体趋于良好,常温区占绝对优势,但局部地区热环境有进一步恶化的趋势。因此,建议城市规划建设中居民热环境规划作为一项重要内容予以考虑。(5)西安都市圈热岛成因与对策分析①从有利于增加城市热岛(Urban Heat Island, UHI)的因素被加强、有利于缓解UHI的因素被减弱、临时性和持久性影响因素共4个方面构建了“热岛”影响因素体系,并将4个方面内容进一步细分为11个一级类型,20个二级类型;②PCA分析结果表明：主成分1集中反映了城市发展水平及规模对城市热环境的影响；主成分2集中反映了气象因素对城市热环境的影响；主成分3集中反映了天气状况对城市热环境的影响；主成分4集中反映了城市人口及人口密度对城市热环境的贡献；③构建了应对西安都市圈城镇热岛效应的宏观调控体系,体系由3个一级指标和15个二级指标构成；④针对城市规划提出了城市热环境调控的总体规划,包括城市规模规划、人口和人口密度规划、城市绿化和水域的总体规划；针对工业热源提出了控制高热企的比例、有效降低企业能耗和控制三废排放的绝对量；针对民用热源提出了倡导低碳生活理念和营造低碳生态环保氛围的对策和建议。本文在以下几个方面有所创新：①将景观生态学理论引入城市热环境研究中,利用景观格局、过程机制探讨城市热环境演变,结果表明这种方法能够很好的阐释城市热环境时空格局动态演变特征；②定量剖析了不同遥感指数(NDVI、NDBI和NDWI)与城市地表温度间的定量关系。并引入分形理论,能够较好的闸释LST与不同土地利用类型间的相关系；③将元胞自动机理论与马尔可夫模型相结合,提出了用于城市热环境模拟与预测的UHI-CA-Markov模型,并取得了较好的模拟与预测结果；④针对城市热环境,在定性分析影响因素的基础上,应用基于多元目标分析的PCA方法,计算了不同影响因子对城市热环境的贡献率大小,并提出了城市热岛效应的评价指标和应对与缓解城市热岛效应的宏观调控建议。更多还原

【Abstract】 The rapid development of urbanization has brought far-reaching implications to the environment and the ecological security in the city zone. With the rapid changes of the land use and cover, the physical and chemical features changes of land surface have made a great impact on the transformation between atmospheric water and the energy substance, which have an effect on the urban heat environment. A series of environmental problem and ecological security arised from the urban heat island have made a negative effect on the urban continual development. Therefore. State release《National Plan for Med-to-long-term Scientific and Technological Development》. in which it is requested to study the form mechanism of Urban Heat Island and the man-made technology in order to advance the city function and the city space managing use. Also it emphasizes the essentiality to the Urban Heat environment for constructing the modern urbanization.This study choose the Xi’an metropolitan as the research area, based on the Landsat TM and ETM+from 1988 to 2009, by using the climate data and land use/cover data as an assistant with the quantificational simulation and the GIS technology for evaluation the Land surface temperature in different years and different seasons. This paper also used the theory of Landscape Ecology for assessment of the Heat Island Landscape and the scale effects of Xi’an, Xianyang and Xingping. The paper also discussed the characteristics of spatial-temporal fractal and scale effect on surface temperature of Xi’an. The relationship between changes of land cover and various factors were studied quantitatively; and this paper also discussed the Quantitative influence of land cover of parks to surrounding areas. A UHI-CA-Markov model for urban thermal environment simulation has been developed based on Cellular automata and Markov model. We also analyzed the contribution of the factors to Urban Heat Island effect by using the method of Principal Component Analysis with multiple purposes. The system of control and countermeasures for Urban Heat Island effect were constructed from the adjustment of urban planning, control of industrial heat sources and control of civilian heat sources. In this research, some important results have been concluded:(1) There are different levels of Urban Heat Island effect in Xi’an metropolitan.①The classification system of Urban Heat Island based on the isometric way were suitable for medium and large scale building area to set up the thermal environment of urban indicators and evaluation system, and the Mean Error-based classification system were more suitable for construction four heat environmental indicators and evaluation system of city, county, town, township.②The normal temperature area were dominant at the structure of the thermal environment in Xi’an, Xian yang and Xingping. In the Xi’an and Xianyang, the area size of different UHI types were normal temperature zone>Green island zone>Heat island zone>Strong heat island zone>Strong green zone, and the Xiping city, the area size of different UHI types were normal temperature zone>Heat island zone>Green island zone>Strong heat island zone>Strong green zone.③The land surface temperature in different seasons were changed obviously.(2) The spatial-temporal differentiation of the UHI landscape pattern is very large.①It is indicated by the index of landscape level that:the normal temperature zones was always the dominant patch in Xi’an. Xianyang and Xingping from 1988 to 2006.②The Contagion index showed a higher intensive trend, which suggested that the entire landscape elements of Xi’an. Xianyang and Xingping become a intensive and an disorder trend, with the increasing fragmentation index. Shannon’s diversity index and Shannon’s evenness index showed a slight reduction at first, followed by slightly decreased trend, which indicated land use in Xi’an were stable over time, with the broken degree decreasing, the pattern of thermal landscape tend to be stabilization.③The surface temperature profile showed similar structural characteristics in different scales. As the research-scale increasing, the profile began to become more smooth and continuous, and the detailed features began to disappear, but the overall trend have been maintained, and when the scale reached 150m, the jump phenomenon were happened, therefore, the 150 m was the maximum scale to study the Urban Heat Island.(3) The expression of quantitative relationships between the land surface temperature and land use and land cover were set up.①The surface temperature of land use and land cover in Xi’an in summer from high to low were as follows:bare land> construction land> woodland> forest land>grass land>water. But in winter were that:forest land> cultivated land>bare land>the construction land>grass land>water.②LST and NDVI showed a significant negative correlation in summer. LST and NDBI presented positive correlation. LST and NDWI showed a typical negative correlation, which showed the water has a good cooling effect in summer.③With the morphological parameters (size, aspect, shape index,etc) of parks to its neighboring region of the thermal environment were different, The park area was a decisive factor to the average temperature. The park average temperature reducer range has a strong positive correlation between the aspect ratio and shape index of park. the extent of reducer average temperature showed a lower level of positive correlation between the water area, length-width and shape index. The Lmax and Tmax of Xing’ qing and Datang Park are higher than other parks which have the water less than 30%. Therefore, the park construction, not only should consider its shape, but also should consider the water area. Generally speaking, water area accounts for park area more than 30% is preferred.(4) The results of Xi’an thermal environment simulation indicated that the future heat island effect tend to be better.①The results of the thermal environment simulation of Xi’an in 2012 based on the UHI-CA-Markov model showed that, the strong heat island and heat island area minor reductions, normal temperature area, the green zone present slightly increasing, strong green zone showed a stable trend by contrasting with thermal environment in 2006.②The results of the thermal environment simulation of Xi’an in 2018 respectively compared with the 2012, the strong heat island area showed a few increasing, the heat island area showed a trend of stabilization, the normal temperature was a substantial increasing, green island and strong green island area showed a strong decreasing.③The results of simulation from 2006 to 2018 showed that the future thermal environment of Xi’an tends to be better, normal temperature area is dominated in the research area, but local thermal environment have further deterioration trend. Therefore, the proposal in urban planning and construction of the thermal environment planning for the resident should be considered as an important component.(5) The cause of Urban Heat Island was analyzed and countermeasures systerm was established.①The paper put forward the four aspects to construct the Urban Heat Island system including the factors to increase the UHI were strengthened, to alleviate the factors were reduced, the temporary and permanence factors. And four aspects were further broken down 11 categories and 20 secondary indicators.②The results of PCA analysis showed that the principal component 1 reflected the level and scale of city development, mainly including the urban population, building area information; principal component 2 concentrated reflection of urban heat meteorological factors, including the precipitation, relative humidity and other information; principal component 3 concentrated reflection the weather conditions on the urban thermal environment, including wind speed; principal component 4 concentrated reflection of the urban population, population density and the contribution of the urban thermal environment.③Construction the system of urban heat island effect of Xi’an metropolitan, the system consist of three first-order index and 15 sub-indicators.④Urban planning are presented in the overall planning of urban thermal environment, including the size of city planning, population and the population density planning, urban greening and water master plan. According to industrial heat proposed control the proportion of high fever; effectively reduce the enterprise energy consumption and emissions control "three wastes" absolute. According to civil heat proposed initiative low carbon life concept and build low-carbon ecological and environment protection countermeasures and suggestions.There are some progression and innovation in the article as follows:①The paper introduced the landscape ecology into the thermal environment study, by using the landscape index and the process mechanism of evolution of urban thermal environment. The results showed the approach could very well explanation of spatial-temporal urban thermal environment characteristics of dynamic evolution.②The paper also get the relationship between the different remote sensing index and the surface temperature by the way of the quantitative analysis. We can be better expalining the correlation changes between the different land use and the LST by the fractal theory.③A model named UHI-CA-Markov were set up by combining the cellular automata and markov model, which have achieved a good results for the UHI simulation.④For the thermal environment, A qualitative analysis were presented based on multiple objective analysis of the PCA method, and calculated the various factors on the constribution to the Urban Heat Island, then put forward a evaluation index system of the Urban Heat Island, a Relieving system of Urban Heat Island effect were also established.更多还原