基于MODIS的2001年—2012年北京热岛足迹及容量动态监测

利用2001年—2012年MODIS分裂窗算法反演得到的1 km分辨率地表温度产品分析了北京城市热岛效应。首先计算北京2001年—2012年地表温度年平均值,其次利用半径法确定热岛足迹并计算热岛容量。结论如下:(1)热岛足迹及热岛容量昼夜差异明显,2012年白天热岛足迹是夜间的1.5倍,这是由于城市下垫面热特性差异及人为活动的综合影响。(2)2001年—2012年北京城市高温区在空间上向南北扩展,热岛足迹和热岛容量呈阶段性增长。2010年白天热岛足迹最大,半径为28 km,面积是2001年的2.4倍。当热岛足迹相同时,城市绿地和水体功能区的分布和布局方式等因素能够影响热岛容量。城市建设用地和农村居民点对城市热环境贡献率明显高于其他土地利用类型。当建设用地面积比例超过50%时,区域会产生显著的热岛现象。(3)根据北京热岛足迹及容量时空动态变化特征,提出改善城市热岛的措施。     

济南市中心城区地表热环境时空变化分析

针对目前众多学者主要针对夏季热环境进行研究,分析方法相对单一,且融合地理探测器等多种方法针对不同季节相关分析研究相对较少的问题,该文基于2017-2018年Landsat8遥感数据,反演济南市中心城区四季的地表温度,综合运用景观格局指数法和剖面法分析不同季节热环境空间分布变化;利用相关性分析方法和地理探测器模型针对地表遥感指标和热环境进行相关性和影响力研究.结果表明:济南市中心城区除冬季,地表温度分布东高西低,与 自然地表、工业生产、人口活动等区位要素关联密切;气温骤降与骤增导致温度斑块割裂、聚合;水体、水汽与建筑的交互作用对春、夏、秋季的城市热环境影响最大,水体与不透水面(交互因子:0.392 952)对冬季热环境交互影响最大;城市热环境的空间分异特征受多因子影响,其中植被与水体(交互因子:0.379 927)、植被与水汽(交互因子:0.380 707)协同降温效应最优,建筑与植被(交互因子:0.278 922)协同保温效应最优.     

利用TPCA分析北京平原区地面沉降的时空演化特征

时间主成分分析（temporal principal component analysis,TPCA）可用于地学领域中提取时空数据的时序特征和空间分布特征,北京平原区的地面沉降具有典型的时序和空间特征。在利用永久散射体干涉测量技术获取的北京平原区2003—2010年地面沉降数据的基础上,采用TPCA方法分析了北京平原区地面沉降时空演化特征。经分析发现:（1）TPCA分析得到的第一主成分反映了地面沉降在该长时序阶段的空间分布特征。（2）第二主成分得分为正的空间点与可压缩层厚度在130 m以上的区域在空间分布上有一致性和相关性。（3）在空间上,第一主成分为负值与第二主成分为正值的永久散射体点分布在年均沉降速率30 mm/a以上的严重沉降区域。严重沉降区具有明显的南北沉降分类现象和季节性差异,具体表现为:北部沉降区在春夏季节的沉降量大于秋冬季节;南部沉降区则与之相反。总之,基于时间主成分分析方法可分析得到研究区的地面沉降时空演化规律,为城市安全监测提供数据支撑。     

武汉市热环境时空分布特征

针对城市热岛效应的演化规律问题,该文以2002年7月9日湖北武汉市的Landsat遥感影像和中分辨率成像光谱仪遥感影像为研究基础,采用归一化差分植被指数,归一化建筑指数,修正后归一化水体指数分别提取了武汉市的植被区域、建筑区域、水体区域,采用密度分割方法对武汉市白天和晚上的温度进行了分区,利用改进的间隙度维数对武汉市热环境白天和晚间的分布特征进行了研究。实验结果表明:对于城市特高温区,白天比晚上的面积大而且集中;对于城市特低温区,白天比晚间面积小而且分散;为研究城市白天和夜间的热岛效应变化提供了一定的参考依据。     

北京西城区下垫面与城市热岛的关系研究

采用遥感卫星影像数据,对北京西城区地面热场状况进行研究。通过对遥感影像进行信息提取和分类,建立西城区热岛分布图,分析城市热岛的分布和强度特征;进行不同类型下垫面热特性的系统测定,对热岛效应与城市下垫面绿化分量、道路、水体的关系进行分析;研究西城区热岛的发生规律、影响因素和缓解热岛的措施。     

多维空间下长沙市热环境影响因素的研究

以长沙为研究区域,综合多源遥感数据,引入不同维度空间内的多种参数,从生态景观格局、城市多维空间发展的角度探索了城市热环境的主要影响因素,并提出了相关的建议。结果表明,长沙城市扩张迅速,热环境在多维空间内受多种因素影响,与之相关性最高的是建筑物的相关参数。城市体积的增加、建筑物破碎化下降及裸土地破碎化上升是影响城市热环境的关键参数。因此,控制城市扩张速度,避免建筑大规模集中布局,适当增加绿地、水体斑块,是缓解长沙热环境的重要举措。本研究可为长沙市改善城市热环境提供决策参考,也可为其他自然禀赋相似的城市提供热环境影响分析的案例借鉴。     

北京降尘元素特征与重金属污染成因分析

大气降尘可以反映大气颗粒物的自然沉降量,具有重要的环境指示意义.其携带的有毒重金属易沉积在植物、土壤和水体中,通过食物链的传递和累积,对人体健康、植物和水生生物等造成严重的危害,已经引起人们的广泛关注.研究大气降尘的元素特征、重金属污染评价及成因分析对于大气环境治理以及居民健康防护意义重大.针对北京大气降尘重金属污染成因这一科学问题,论文首先基于北京及周边地区大气降尘、地表土以及典型污染端元样品的元素含量IC P-M S测试结果,分析了北京大气降尘的元素特征;基于 G IS地统计分析理论交叉验证并选取了北京降尘中主要重金属的最优空间插值模型,并探讨了北京降尘重金属污染的空间分布;其次,在传统的单一重金属污染评价方法的基础上提出并构建了"降尘重金属综合污染指数"模型,对北京降尘重金属污染状况进行了综合评价;然后,通过各污染端元显著因子识别方法构建了北京降尘局部污染源重金属成分谱,并综合应用多元统计分析解析了北京大气降尘重金属的局地污染源;同时探讨了地表土重金属污染以及下垫面土地利用类型对北京降尘重金属污染的影响;最后,利用HYSPLIT-4区域传输模型,并结合区域站点实测数据,综合分析了北京大气降尘重金属污染受区域传输的影响.主要结论如下.     

基于DEM的桂西北土地利用与地形关系特征分析

以都安瑶族自治县为例,利用DEM数据、土地利用现状图,以及野外实际调查资料,通过建立基于高程的地貌分区、叠加分析,分析了研究区土地利用空间分布特征及与地形因子的关系.结果表明,土地利用类型空间分布具有强烈的区域差异性,各地貌分区区域的土地利用组合不同,同一土地利用类型在不同高程区域的分布存在差异;随海拔高程增加,居民地...     

上海城市空间热环境的遥感图像分析与应用研究

城市热环境是城市空间环境在热力场中的综合表现,通过对城市热环境的研究可以揭示城市空间结构、城市规模的发展变化,有助于引导城市的可持续发展,提高人居环境质量.本文在RS、GIS的支持下,侧重研究城市空间热环境与影响因子间的定量分析模型和城市热环境的空间格局、动态演变描述体系以及城市热环境对城市降雨系统的影响.其主要工作如下:     

出租车数据的时间序列谱聚类分析

城市空间运行的出租车产生大量的OD数据，数据的时序呈现周期性特点，客观反映人们的出行行为模式，本文采用谱聚类算法对北京五环区域内各空间单元的出行特征及其相似性进行探究。由于空间单元的时空行为特征受空间邻域和功能区划的影响，研究添加邻域因子和功能区因子以改进时间序列的相似性度量方法，从而实现时间序列谱聚类算法的空间和功能区拓展，进而增加人们对不同时空条件下出行行为特征的了解，以便对不同空间单元提供差异性服务，如不同时段公交的发车频次、动态调整商场营业时间、不同时空环境出租车候车点的实时变换、调控和优化不同区域服务保障等，将有助于降低城市能耗，更加合理地利用资源，也有助于居民实现智慧生活。     

基于遥感和GIS的上海城市空间热环境研究

城市热环境的空间格局对城市微气候、城市生态环境演变有重要影响。为探讨城市热环境空间格局的研究方法,借鉴景观生态学的研究方法,首次提出热力景观概念,以景观的观点来研究城市热环境的空间格局。在RS,GIS的支持下,创建了热力景观空间格局的评价指标体系。应用转移矩阵法对1990年,1995年和1998年上海城市多时相热力景观的转移概率进行,分析了热力景观的动态变化和热力景观类型的组分转换过程。通过分析,揭示了上海城市近10年热力景观类型的变化强度和趋势。     

Diurnal and seasonal impacts of urbanization on the urban thermal environment: A case study of Beijing using MODIS data

Beijing has experienced rapid urbanization and associated urban heat island effects and air pollution. In this study, a contribution index was proposed to explore the effect of urbanization on land surface temperature (LST) using Moderate-Resolution Imaging Spectroradiometer (MODIS)-derived data with high temporal resolution. The analysis indicated that different zones and landscapes make diurnally and seasonally different contributions to the regional thermal environment. The differences in contributions by the three main functional zones resulted from differences in their landscape compositions. The roles of landscapes in this process varied diurnally and seasonally. Urban land was the most important contributor to increases in regional LSTs. The contributions of cropland and forest varied distinctly between daytime and nighttime owing to differences in their thermal inertias. Vegetation had a notable cooling effect as the normalized vegetation difference index (NDVI) increased during summer. However, when the NDVI reached a certain value, the nighttime LST shifted markedly in other seasons. The results suggest that urban design based on vegetation partitions would be effective for regulating the thermal environment.     

多时相遥感数据对城市热岛效应的研究——以西安市为例

热岛效应是影响我国城市环境的重要因素,本文基于多时相的Landsat 7 ETM+和Landsat 8 TIRS影像,对西安市2002年和2013年的土地进行分类以及地表温度反演,在此基础上将土地分类影像图和温度分割影像图进行叠加,分析了不同的土地利用类型温度差异、下垫面的空间结构与热场分布的关系以及热场的分布变化与城市变迁的关系。结果表明:不同的土地利用类型的物理属性和生物学属性差异是造成城市热岛效应的内在原因,下垫面空间结构的差异是造成城市热岛效应的外在原因,城市热场的动态变化方向与城市的变迁方向具有一致性。     

Area Delineation and Spatial-Temporal Dynamics of Urban Heat Island in Lanzhou City,China Using Remote Sensing Imagery

One of the key impacts of rapid urbanization on the environment is the effect of urban heat island (UHI). By using the Landsat TM/ETM+ thermal infrared remote sensing data of 1993, 2001 and 2011 to retrieve the land surface temperature (LST) of Lanzhou City, and by adopting object-oriented fractal net evolution approach (FNEA) to make image segmentation of the LST, the UHI elements were extracted. The G* index spatial aggregation analysis was made to calculate the urban heat island ratio index (URI), and the landscape metrics were used to quantify the changes of the spatial pattern of the UHI from the aspects of quantity, shape and structure. The impervious surface distribution and vegetation coverage were extracted by a constrained linear spectral mixture model to explore the relationships of the impervious surface distribution and vegetation coverage with the UHI. The information of urban built-up area was extracted by using UBI (NDBI-NDVI) index, and the effects of urban expansion on city thermal environment were quantitatively analyzed, with the URI and the LST grade maps built. In recent 20 years, the UHI effect in Lanzhou City was strengthened, with the URI increased by 1.4 times. The urban expansion had a spatiotemporal consistency with the UHI expansion. The patch number and density of the UHI landscape were increased, the patch shape and the whole landscape tended to be complex, the landscape became more fragmented, and the landscape connectivity was decreased. The heat island strength had a negative linear correlation with the urban vegetation coverage, and a positive logarithmic correlation with the urban impervious surface coverage.     

Spatial and Temporal Dynamics of Urban Heat Island and Their Relationship with Land Cover Changes in Urbanization Process: A Case Study in Suzhou, China

One of the significant environmental consequences of urbanization is the urban heat island (UHI). In this paper, Landsat TM images of 1986 and 2004 were utilized to study the spatial and temporal variations of heat island and their relationships with land cover changes in Suzhou, a Chinese city which experienced rapid urbanization in past decades. Land cover classifications were derived to quantify urban expansions and brightness temperatures were computed from the TM thermal data to express the urban thermal environment. The spatial distributions of surface temperature indicated that heat islands had been largely broadened and showed good agreements with urban expansion. Temperature statistics of main land cover types showed that built-up and bare land had higher surface temperatures than natural land covers, implying the warming effect caused by the urbanization with natural landscape being replaced by urban areas. In addition, the spatial detail distributions of surface temperature were compared with the distribution of land cover by means of GIS buffer analysis. Results show remarkable show good correspondence between heat island variations with urban area expansions.     

利用Landsat ETM+分析城市热岛与下垫面的空间分布关系

采用数理统计与空间统计相结合的方法,利用Landsat ETM 数据对北京、上海、沈阳和武汉等4个大城市的夏季城市热岛相对强度与城市下垫面的空间分布关系进行对比研究。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;用城市地表亮温与水体亮温差值表征城市热岛相对强度。结果显示,4个城市的植被覆盖、不透水面与热岛强度的分布呈较强的空间正自相关,并且存在较为一致的自相关范围,该范围相当于城市街道与建筑组合特征尺度;自相关引起的结构性是导致3者空间分布异质性的主要因素。植被覆盖对城市热岛的缓解效果与不透水面对城市热岛的增强作用均呈分段线性特征,但区域差异较为明显;交叉相关系数曲线则显示出相关性的空间异质性与多尺度现象,同时存在一个约550 m的空间作用特征尺度。该研究结果有助于在城市规划实践中合理配置建筑与植被的间隔和比例,以缓解城市热岛效应。     

张掖绿洲城市热效应的遥感研究

以张掖及周边绿洲为研究区,采用Gilabert大气校正模型对TM图像1～5,7等6个波段进行大气校正。在此基础上,采用基于TM6波段的单窗算法,反演出行星亮度温度和地表真实温度,进一步分析了区域热量分布差异并探讨这一差异形成原因。结果表明:张掖及周边绿洲区存在明显的热量分布差异,热岛现象非常显著,卫星图像反演的地表温度接近实测值,亮度温度和实际温度都与归一化植被指数(NDVI)存在着密切的反相关关系,表明植被在区域热量分布差异中起重要作用,显示出热红外图像与其它波段数据结合,在城市热岛效应及区域生态环境遥感研究方面有很大潜力。     

Coupling urbanization analyses for studying urban thermal environment and its interplay with biophysical parameters based on TM/ETM+ imagery

Studies of urbanization and urban thermal environment are now attracting wide interests among scientists all over the world. This study investigated the influences of urbanization on urban thermal environment as well as the relationships of thermal characteristics to other biophysical variables in Guangzhou, China utilizing three dates of Landsat TM/ETM+ images acquired in 1990, 2000, and 2005, respectively. Vegetation abundances and percent impervious surfaces were derived by means of linear spectral mixture model, and a method for effectively enhancing impervious surface has been developed to accurately examine the urban enlargement. As a key parameter for studying urban thermal characteristics, the land surface temperature (LST) was also retrieved from thermal infrared band of each TM/ETM+ dataset. Based on these parameters, the urban expansion, urban heat island effect and the relationships of LSTs to other biophysical parameters were then analyzed. Results indicated that the area ratio of impervious surface in Guangzhou increased significantly, which grew from 20.56% in 1990, to 34.72% in 2000, and further to 41.12% in 2005, however, the intensity of urban heat island was not always enlarged in observed years. In addition, Geostatistical analyses showed that the mean-centre of the impervious surface was moving towards the northwest during 1990–2005. And correlation analyses revealed that, at the pixel-scale, the association of LSTs to other two variables (vegetation abundance and percent impervious surface) was not straightforward, while LSTs possessed a strong positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at the regional-scale, respectively. This study provided an integrated research scheme and the findings can be very useful for urban ecosystem modeling.     

Bi-temporal characterization of land surface temperature in relation to impervious surface area,NDVI and NDBI,using a sub-pixel image analysis

As more than 50% of the human population are situated in cities of the world, urbanization has become an important contributor to global warming due to remarkable urban heat island (UHI) effect. UHI effect has been linked to the regional climate, environment, and socio-economic development. In this study, Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) imagery, respectively acquired in 1989 and 2001, were utilized to assess urban area thermal characteristics in Fuzhou, the capital city of Fujian province in south-eastern China. As a key indicator for the assessment of urban environments, sub-pixel impervious surface area (ISA) was mapped to quantitatively determine urban land-use extents and urban surface thermal patterns. In order to accurately estimate urban surface types, high-resolution imagery was utilized to generate the proportion of impervious surface areas. Urban thermal characteristics was further analysed by investigating the relationships between the land surface temperature (LST), percent impervious surface area, and two indices, the Normalized Difference Vegetation Index (NDVI) and Normalized Difference Built-up Index (NDBI). The results show that correlations between NDVI and LST are rather weak, but there is a strong positive correlation between percent ISA, NDBI and LST. This suggests that percent ISA, combined with LST, and NDBI, can quantitatively describe the spatial distribution and temporal variation of urban thermal patterns and associated land-use/land-cover (LULC) conditions.     

利用Landsat卫星影像进行东莞市地表温度反演与变化分析

随着快速城市化进程,我国东南沿海一些城市新增了大量的城市建设用地,影响到了城市的人居环境,诱发了城市热的环境问题。探索城市热环境时空布局与变化特征,分析变化原因对城市可持续发展和人居环境质量改善具有重要的现实意义。本文以东莞市为例,以1986—2017年间8个时相Landsat系列卫星影像为数据源,利用单通道算法对东莞市地表温度进行定量反演,分析东莞城市热环境的时空分布特征及其变化,并探讨其影响因素。结果表明,东莞市30多年的城市热环境主要表现为热岛的分布格局,由零散的点状分布逐渐发展成沿着主要交通路线的带状分布;东莞市城镇/街道中心的地表温度明显高于郊区、村落,存在较强的热岛效应;1986—2017年东莞市的热岛比例指数总体呈上升趋势,从0.06上升到0.15,在2009年东莞市热岛效应达到最高。研究结果对合理规划东莞城市建设,促进城市建设可持续发展等方面具有重要意义。