基于改进NDBI指数的重庆市内环城市热岛效应分布特征研究

对重庆市内环区进行研究,以2002年和2007年两景ETM+/TM影像为基础数据,反演提取归一化地表温度指数(NDSTI)及改进归一化建筑指数(NDBI)。研究结果较好地揭示了建设用地的NDBI与NDSTI、热岛效应等级的空间分布相关性规律;2002年重庆的内环城区强热岛效应显著,范围广;2007年随着城市化扩张,老城区强热岛效应降级消失,新城区强热岛效应凸显、升级;两江、湖泊和山体植被是冷岛区,对城市热岛效应起分隔、调节作用。     

高密度建成区城市生态空间的热环境缓释效应——以广州市中心城区为例

随着全球城市化进程的推进,城市热岛效应已成为当下严重的环境问题之一,严重制约人类健康与城市的可持续发展。城市生态空间对城市热岛效应的缓解具有重大意义,而目前,从局地效应角度研究城市生态空间对热环境影响还比较缺乏,影响城市生态空间降温效应的因素还未明了。因此,本文基于多源遥感数据,对广州市中心区生态空间进行识别并反演地表温度,定量刻画城市核心区内部生态空间的降温强度,以探讨广州市生态空间斑块结构特征和空间布局对周边环境温度的影响。结果表明:⑴生态空间与地表温度的空间分布具有明显的高低值耦合分布趋势,生态空间越集中连片分布,越有利于促进局地热量扩散,以缓解城市的热岛效应;⑵生态空间对周边环境降温强度主要由其空间结构特征和空间位置共同决定,当生态空间的空间结构特性保持一定时,其所处的空间位置不同对缓解周围城市热环境的作用也有所差异。本研究揭示城市生态空间的结构特征及其周围环境对冷却效应强度的影响机制,为促进城市的可持续发展提供有益的建议。     

地方政府发展竞争下的城市化进程

文章分析了以要素、环境和政策竞争为主的地方政府发展竞争对我国城市化的影响，并就如何积极稳妥推进城市化提出几点构想。研究发现：积极作用方面。要素竞争夯实了城市化基础；环境竞争改善了城市风貌；政策竞争加快了城市化步伐。消极作用方面，政府竞争导致城市用地扩张过快，户籍改革相对滞后和城市特色逐渐消逝等问题。为实现城市化进程的健康有序，需要增强城市“两规”的协调性、坚持产业发展与城市发展良性互动和加快土地与户籍制度改革。     

扬州市规划冲突分析及区域差异研究

研究目的:本研究基于GIS构建用于空间叠置分析的规划数据库,通过空间叠置分析,探讨扬州市土地利用总体规划、城市总体规划的冲突面积及区域差异,为合理用地与保护空间提供科学依据。研究方法:文献资料法和空间叠置法。研究结果:扬州市土地利用总体规划与城市总体规划之间冲突较为严重,现状建设用地与城市规划建设用地布局上的差异是冲突形成的主要原因之一。     

珠三角城郊土地利用变化研究——以广州市增城区为例

城郊是城市的昨天,乡村的明天。加速城市化、工业化进程是中国社会、经济发展的必然。作为受其影响最为显著的地区,大城市郊区在快速城市化进程中如何维持区域可持续发展的资源基础,实现土地资源可持续利用的目标,对其他地区起到借鉴与示范的作用,是城市化进程中实现全国土地资源可持续利用的"龙头"。文章以广州市增城区的遥感影像数据为基础,从数量结构、空间分布和景观格局特征等方面,分析了增城区土地利用的变化特征。     

高密度城市气候评估方法与应用

高密度城市和建筑群可对气候产生重要影响,例如热岛效应、空气污染和暴雨等。科学准确地评估城市对气候的影响并据此提出规划改善对策已成为建设生态城市和宜居环境必不可少的重要内容。本文对可用于城市气候评估的模型进行了归纳总结,发现以CFD耦合模型和WRF为代表的中尺度气象模型具有优势,前者更适合建筑、城市设计和详规尺度;后者更适合城市总规尺度;利用GIS平台将气候评估结果与城市信息数据库进行叠加分析或者绘制城市气候图可以更好地对接规划实践需求。     

城市理性发展与城市人居环境质量提升

城市发展中的人居环境质量问题近年来,随着我国社会经济的快速发展,城市化水平不断提高,城市人口规模和用地规模急剧增长。世界各国城市化历程表明,合理的城市化进程引导农村人口向城镇集中,对于提高土地集约利用水平和提高居民生活质量具有积极意义。但我国城市空间增长趋向于“摊大饼”式的扩张,城市土地开发呈外延平面式扩张趋势,忽视了内涵立体的综合开发与利用,     

长沙商业用地空间演变特征研究

商业用地是城市商业发展的重要空间载体，其中零售商业用地作为商业用地的核心要素，表征了商业用地在社会经济活动中的地位和效用。商业用地在城市土地利用过程中的演变状况和内在机制，可以客观地反映城市商业用地和零售商业空间结构的变化规律，对其进行研究，可以为更好地认识和解决其中的问题提供科学的思路和依据。笔者以长沙为例，应用GIS技术，通过解析2003年～2013年城市商业用地的演变过程与特征，揭示了商业用地的空间集聚和规模变化的规律，分析了演变动力机制，提出了城市空间资源有效配置和土地合理利用的对策和建议。     

重庆市中心型轨道站点地区紧凑度研究

当前我国正值轨道交通快速发展的关键时期,城市轨道站点地区是影响城市空间结构、提高城市土地空间利用效率、提升城市环境品质的重要地区,因此对轨道站点的周边地区规划研究显得尤为紧迫。本文选取了重庆轨道交通的六个中心型站点作为研究对象,使用GIS对站点周围800 m范围进行矢量化绘制,获取基础的量化数据。分别针对站点地区的空间效率以及空间质量的建立客体紧凑度和主体紧凑度评价指标,对每个站点的指标结果进行统计分析。然后,进一步从宏观层面研究不同指标结果的影响机制,发现地理环境、区位因素、功能定位和发展模式是站点地区空间形态的主要影响因素。最后提出轨道站点地区空间的优化策略,为轨道站点地区的规划设计提供参考。     

大型文化设施建设对土地价值影响的空间外溢特征 ——以天津文化中心为例

笔者的研究沿循单中心城市模型的理论分析框架,将大型文化设施作为区域的中心.有别于空间经济的大尺度研究,研究从微观尺度探究了天津文化中心建设后对其周边土地价值影响的空间外溢特征.研究表明:天津文化中心在2012年~2015年对其周边土地价值的引力作用呈现逐年降低的趋势,且在空间上天津文化中心对周边土地价值的影响力与距其的距离成幂函数反向关系;研究所构建的引力模型、 城市密度及区域增长模型,在微观尺度上评价区域的空间经济效益具有较好的拟合效果,为单中心城市结构的拓展提供了一定的参考.     

Getting closure: The role of urban forest canopy density in moderating summer surface temperatures in a large city

With a growing number of people living in urban areas, city residents are more frequently exposed to stresses related to the built environment including elevated summer surface temperatures contributing to the urban heat island (UHI) effect. This study examines the role of urban tree density in moderating surface temperature variation in a densely populated city (Toronto, Canada). By applying parallel aspatial (OLS) and spatial regression (GWR) approaches with satellite derived data describing tree canopy density and surface temperature, one dimension of tree canopy quality (i.e., canopy density) is shown to contribute directly to a reduction in the surface urban heat island (SUHI) effect at a local scale. Though the model fit differed between the two regression approaches, both exhibited moderately strong explanatory power and demonstrated that observed surface temperature decreases in locations with increasing high-density and closed tree canopy. Study findings provide an empirical basis to recommend that municipal urban forest strategies embrace canopy quality metrics, such as increasing the density of existing urban forest stands, as a part of tree planting objectives seeking to effectively deliver temperature moderation as a valuable ecosystem service.     

Microclimate in an urban park and its influencing factors: a case study of Tiantan Park in Beijing,China

Urban Ecosystems - Construction of urban green spaces may effectively mitigate urban heat island effect. Better design of green spaces may improve their thermal performance, and therefore provide...     

Urban climate change-related effects on extreme heat events in Rostock,Germany

Urban Ecosystems - The urban heat island effect poses a challenge in several cities, and may affect human and ecosystem health. It was proven that relatively small urban conglomerations in...     

The impact of urban forest structure and its spatial location on urban cool island intensity

Urban forest can help decrease land surface temperature (LST) and create urban cooling effect (UCI) to mitigate urban heat island (UHI). However, it is still unclear how urban forest structure and its location affect UCI, particularly under different seasons. In this study, with plot-based urban forest structure and UCI intensity extracted from Landsat-7 Enhanced Thematic Mapper Plus (ETM+) thermal data, we first conducted correlation analyses between UCI and different forest structures (crown closure, tree height, leaf area index, basal area, stem density and diameter at breast height, etc.) and spatial location (distances from buildings and from water bodies and elevation) attributes, and we then carried out quantitative regression analyses between them. Our results indicate that (1) Urban forest could create “urban cool islands”, which were higher in summer than those in autumn.(2) UCI could be significantly affected by urban forest structural attributes, especially by crown closure and LAI. All urban forest structural attributes had positive linear relationships with UCI except for LAI and basal area which had positive non-linear relationships with UCI.; (3) UCI in urban forest could also be affected by its spatial location but not by its elevation. The UCI non-linearly decreased with decreasing distance from buildings and with increasing distance from water bodies. The threshold values of DB for significantly affecting UCI variation is approximately between 100 m and 300 m in summer and autumn, respectively; and (4) the relationships between UCI and urban forest structure and its location attributes were complex and seasonal dependent. Urban forest attributes had greater effects on increasing UCI in summer than those in autumn. These findings would deepen our understanding of interactions between UCI and urban forest attributes and provide urban planners with useful information about how to design urban forest to effectively mitigate UHI effects.     

Comparing the transpirational and shading effects of two contrasting urban tree species

Urban Ecosystems - Urban trees are getting increasing attention as a tool to mitigate urban heat island effects. A more functional and quantitative view of transpirational and shading effect,...     

Species change in an urban setting—ground and rove beetles (Coleoptera: Carabidae and Staphylinidae) in Berlin

The influence of environmental parameters on epigeic beetle communities of forest fragments in an urbanization gradient was studied in Berlin. Eight deciduous forests along a rural to urban gradient were sampled with pitfall traps. Species richness did not decline across the rural to urban gradient. As expected, impervious surface cover as an indicator of urbanization correlated not only with habitat fragmentation and heat island effect but also with altered soil properties. The proportion of forest specialist staphylinid species decreased with increasing urbanization. The differences between staphylinid communities of neighboring forest fragments were enhanced in the most urban parts, probably due to increased habitat fragmentation. Furthermore, the loss of flightless species with increasing habitat isolation emphasized the influence of habitat fragmentation. The carabid communities revealed the urbanization effects not as clearly as the staphylinid communities, but both taxa revealed that direct anthropogenic habitat alteration, indicated by removal of decaying wood, favors open-habitat specialists. The extent of the urbanization influence seems to vary seasonally. Environmental parameters associated with urbanization explain the ordination of species communities in the winter better than in the summer. Heat island effect is suggested as an explanation for this difference.     

1990年之后东京大城市圈的空间重构

本文探讨了1990年以来东京大城市圈空间扩展与变迁以及全球化对东京的影响。全球化对城市空间的重构有很大影响,经济全球化背景下,资本流动、劳动力转移、产业结构变化等因素是影响城市空间重构的主要要素。因此,需要从全球化的视角审视城市发展。     

Urban areas may serve as habitat and corridors for dry-adapted,heat tolerant species; an example from ants

We collected ants from six urban and one forest land-use types in Raleigh, NC to examine the effects of urbanization on species richness and assemblage composition. Since urban areas are warmer (i.e., heat island effect) we also tested if cities were inhabited by species from warmer/drier environments. Species richness was lower in industrial areas relative to other urban and natural environments. There are two distinct ant assemblages; 1) areas with thick canopy cover, and 2) more disturbed open urban areas. Native ant assemblages in open environments have more southwestern (i.e., warmer/drier) distributions than forest assemblages. High native species richness suggests that urban environments may allow species to persist that are disappearing from natural habitat fragments. The subset of species adapted to warmer/drier environments indicates that urban areas may facilitate the movement of some species. This suggests that urban adapted ants may be particularly successful at tracking future climate change.     

Urban impacts on tropical island streams: Some key aspects influencing ecosystem response

Improving our understanding of the impacts of urbanization on tropical island streams is critical as urbanization becomes a dominant feature in tropical areas. Although the ??urban stream syndrome?? has been successful in summarizing urban impacts on streams, the response of some island streams is different to that expected. Here we review available information on urban impacts to tropical island streams and describe unique responses to urbanization. We identified three key aspects that play particularly important or unique roles in determining tropical-island stream integrity: biotic response to water pollution, movement barriers along the stream network, and altered geomorphology that results in habitat loss. As expected, water pollution negatively impacts stream ecosystems in tropical islands and in some regions impacts can be severe, as untreated wastewaters are directly discharged into streams. While aquatic insects show the expected responses to pollution, other native fauna (e.g., shrimps and fishes) appear to be less impacted by moderate levels of pollution. Movement barriers along the stream network are especially important as much of the tropical island fauna have diadromous (either amphidromous or catadromous) life histories. Most native freshwater mollusks, shrimps, and fishes inhabiting tropical islands are diadromous and depend on unimpeded connections between freshwater and marine environments to complete their life cycles. The presence of these species in urban streams is best explained by longitudinal connectivity rather than by the degree of urban impact. Finally, in streams that remain connected to marine environments, the presence of native shrimps and fishes is strongly related to the physical habitat. Fish assemblages in channelized and severely altered stream reaches are almost completely devoid of native fauna and tend to be dominated by non-native species. In contrast, relatively diverse shrimp and fish assemblages can be found in reaches that retain their physical habitat complexity, even when they are impacted by urbanization. Our understanding of urban impacts on tropical island streams remains limited. However, the identification of key aspects can help us better understand urban impacts on streams in tropical islands, and best focus our management and research efforts to protect these unique ecosystems.     

建设国际旅游岛背景下海南城乡一体化模式探讨

国际旅游岛是海南发展的大战略。当前,在建设国际旅游岛的背景下,需要整合城乡旅游资源,实现城乡协调发展。本文分析了海南城乡一体化的现实需求和国际旅游岛框架下推进城乡一体化的突出矛盾,在此基础上,提出把经济一体化、社会一体化、行政一体化作为推进海南城乡一体化的具体思路。