引用本文
匡文慧.
城市土地利用/覆盖变化与热环境生态调控研究进展与展望[J].
地理科学,
38
(10):
1643-
1652.
[ Kuang Wenhui. Advance and Future Prospects of Urban Land Use/Cover Change and Ecological Regulation of Thermal Environment[J]. Scientia Geographica Sinica, 38 (10): 1643- 1652. ]
Doi: 10.13249/j.cnki.sgs.2018.10.008[ Kuang Wenhui. Advance and Future Prospects of Urban Land Use/Cover Change and Ecological Regulation of Thermal Environment[J]. Scientia Geographica Sinica, 38 (10): 1643- 1652. ]
Permissions
Copyright©2018,
《地理科学》编辑部
本文是开放获取期刊文献，在以下情况下可以自由使用：学术研究、学术交流、科研教学等，但不允许用于商业目的.
城市土地利用/覆盖变化与热环境生态调控研究进展与展望
作者简介：匡文慧(1978-),男,内蒙古乌兰察布人,副研究员,博士,主要从事土地利用/覆盖变化和城市生态环境研究。E-mail:
摘要
城市土地利用/覆盖变化(LUCC)与热环境生态调控是城市生态学和城市气候适应性关注的热点问题。在提出城市LUCC/空间结构与生态服务热调节功能连接的重要性的基础上,综述了城市土地利用变化、城市绿色基础设施在热岛减缓和气候适应性发挥的作用,评述了观测实验、定量遥感和过程模型方面以及热调控的进展情况。基于此认为,局地或区域尺度城市高精度结构组分高精度遥感探测方法、城市高精度下垫面多尺度(功能区/覆盖组分/构造或材质等)对局地气温和辐射能量平衡影响机理和定量贡献识别、城市生态系统热调节功能的城市地表结构组分调控阈值确定、以及区域或全球尺度城市土地利用/覆盖变化影响的生物地球物理机制定量化认知等,是未来重要的发展方向。
关键词:
城市土地利用/覆盖变化;
城市热岛;
热环境生态调控;
气候适应性;
不透水地表;
定量遥感;
Abstract
Urban land use/cover change (LUCC) and ecological regulation on thermal environment are hot topics of urban ecology and climate adaptation. This study proposed the significances in linking urban LUCC/spatial structure with the thermal regulation of ecological services. In this paper, the research progress of urban LUCC, the role of urban green infrastructure in heat island mitigation and climate adaptability, the integration of observational experiments, quantitative remote sensing, quantitative modeling of process models, and ecological regulation of thermal environment are reviewed. On this basis, a remotely sensed detection methods on urban structure components with high-precision at local or regional scales was proposed. We advanced synchronically implement field observation with satellite transits (e.g., Landsat 8, MODIS) and remotely sensed retrieval of micro-climate, eddy covariance, land surface temperature and other parameters along an urban-rural gradient in metropolitan area. The integration of these parameters into EcoCity V1.0 will be used to examine the mechanisms of the impacts of impervious surface area and green space components, their radiation and surface heat fluxes, and anthropenic heat sources on urban thermal environment, and to analyze the spatio-temporal heterogeneity of urban heat island effect induced by urban expansion of different city sizes and configuration. The impacts of urban high-precision underlying surface with multi-scale (functional zones/land-cover components/configuration and material, etc.) on local air temperature, and radiation and energy budget, the regulating threshold of urban surface structure components for alleviating urban heat island, and the quantitative knowledge of influence of urban LUCC on biogeophysical mechanisms at regional and global scales will be the important prospective contents in the future. So, the effective linking between spatial planning with urban ecology and urban climate will be of significance in this field. The overarching objectives of this study are to identify the ecological threshold on regulating urban underlyding impervious surface area and green space component for alleviating extreme weather heat and improving human comfortability aiming to UN Sustainable Development Goals 2030. This research will promote our understanding of the urban biophysical mechanisms of the urban thermal environment and provide the scientific fundamentals in building livable urban environment and urban ecology security.
Keyword:
urban land use/cover change;
heat island;
regulation of thermal environment;
climate adaptability;
impervious surface;
quantitative remote sensing;
城市生态服务功能直接影响城市人居环境和人类福祉[1]。在当前乡村人口不断向城市集聚、城市快速向外扩张加之全球环境变化加速(温度升高、洪水及热浪加剧)的影响下,城市生态服务功能正面临着前所未有的挑战[2,3]。城市热环境生态调控以城市地理学、城市气候学和城市生态学等多学科理论方法为基础,耦合“空间区位理论”“等级理论”和“辐射能量平衡理论”,综合应用遥感地面同步观测、GIS空间分析以及机制模型,核定服务于城市热岛减缓与局地气候热调节服务功能的城市内部空间组分的调控阈值[4]。城市热环境生态调控功能作为重要的生态调节服务功能之一,对城市居民健康和宜居有深刻影响[5,6]。城市不透水地表(Impervious Surface Area, ISA)与绿地格局(Green Space),作为城市土地利用/覆盖结构特征的重要组合模式,会对地表辐射与能量的分配方式产生不同甚至截然相反的作用,进而对城市热岛、大气环境及局地气候产生重要影响,从而对城市生态服务热调节功能产生决定性作用[2,7]。
21世纪以来,中国城市以每年1 788 km2的速度对外扩张,其中以高密度不透水地表扩张为主[8]。2012年约50%（约6亿）人口居住在城市,约占6×104km2国土面积[9,10],如何统筹布局好城市用地面积,实现城市内部生活空间、生产空间、服务空间和生态空间格局优化组合,事关国家整体城镇化发展的质量。进入21世纪,国家强调加快新型城镇化建设,提升城镇化质量,优化空间格局,推进生态文明建设。承载高密度的人口、产业的城市用地如何有效布局,以实现城市生活空间、生产空间、服务空间与生态空间的不透水地表、绿地组分与结构的合理布局,对于提高城市生态服务功能、改善人居环境质量、建设低碳型生态城市,乃至提高全球气候变化的适应能力具有重要的现实意义。
城市不透水地表与绿地格局通过改变城市下垫面结构,引起地表反照率、比辐射率、地表粗糙度的变化,从而对区域垂直方向辐射平衡产生直接影响。具体而言,不透水地表会增强地表显热通量,城市绿地会增加潜热通量,从而加剧或减缓城市热岛强度改变局地/区域气候,影响城市生态服务功能,特别是热调节功能[11]。当前国内外研究仍缺乏具有空间针对性的城市内部功能结构组合(特别是土地利用等级尺度空间格局)与生态服务功能(热调节功能)之间的紧密结合和统筹考虑[12]。因此,加强城市土地利用/覆盖变化与热环境生态调控及气候适应性研究,有助于提高城市土地覆盖组合结构与地表覆盖能量平衡互馈关系内在机理性认知能力,加深对城市化与全球环境变化生物地球物理机制重要科学问题的理解。定量评估城市地表覆盖格局对城市生态系统服务热调节功能胁迫关系,是解答城市热环境从“科学量测”向“科学调控”发展的关键科学问题,可以为优化城市生产、生活、服务和生态空间布局,控制城市适度规模以及城市生态规划与整治提供科学参考。
1 城市空间结构与生态服务热调节功能的连接与重要性
城市空间结构历来是人文地理学关注的焦点问题。16世纪英国学者摩尔(More)提出了乌托邦式的城市建设模式[13],19世纪末英国科学家霍华德(Howard)提出田园城市(Garden City)思想[14],更强调公共绿地布局与生态城市建设的理念,对现代城市规划思想起了重要的启蒙作用。在现代城市发展中,城市空间结构布局中商业、工业等产业用地,住宅用地以及城市绿地如何有机组合?城市建筑红线（不透水地表面积比例）、生态绿线（绿地）和蓝线（水域）如何调控?如何在城市有限空间中调节局地气候、改善人居环境、减缓城市污染,营造良好生态环境?仍有待于城市规划科学、城市土地利用科学、城市生态学、城市气候学等自然和社会科学协同解答[15,16]。
城市热岛效应（Urban Heat Island, UHI）是人类活动对城市气候环境系统产生的最显著影响之一。1833年Howard通过对伦敦城区和郊区的气象进行对比观测,首次对城市中心温度高于郊区的现象进行了文字记载[17]。Manley于1958年提出城市热岛(UHI)的概念[18]。城市不同土地利用类型会改变城市局地大气和地表与其周围的郊区温差,因而过度和无序的城市扩张使土壤和植被表面转变为城市不透水地表(如混凝土、沥青等)是引起城市热岛效应的主要原因,从而产生全球性的负效应[19]。城市热环境生态调控是减缓城市热岛效应的有效手段之一,该方法通过地表热环境要素的差异来识别城市不同土地利用/覆盖类型的热贡献,提出有利于热岛强度减缓的城市内部空间结构和组分,进而优化城市空间格局[4]。
从城市内部不同功能区到相应的不透水地表、绿地覆盖状态,再到城市建筑、道路、广场等类型是城市生态系统的重要研究内容[20],不同等级结构组合与城市人为热源、潜热、显热等热通量之间具有直接关系（
|
图1 城市等级空间结构与生态服务热调节功能相互作用关系 Fig. 1 The relationship between hierarchical structure and ecological regulation in cites on thermal environment |
2 城市土地利用/覆盖变化与热环境研究进展
2.1 城市土地利用/覆盖变化
城市土地利用是城市内部与外部社会、政治、经济、技术等多种因素作用的结果,也是影响城市发展的要素在城市土地上的反映[21,22]。城市土地覆盖反映了地表不同类型自然状态,包括城市不透水地表、绿地、水域和裸土等。城市不透水地表（Urban Impervious Surface, UIS）是由城市发展建设产生的一种地表水不能直接渗透到土壤的人工地貌特征,包括城市中的道路、广场、停车场、建筑屋顶等[23]。城市不透水地表作为城市空间结构的重要组成部分,直接影响着城市生态系统服务功能,是反映人类活动强度和评价城市人工建设用地增长的重要指标[24,25],对于评价城市生态系统健康程度与人居环境质量具有重要的理论与现实意义。遥感手段由于其多时段、大范围等特性,成为提取城市不透水地表信息的主要方法[26]。Ridd[27]构建了基于遥感信息的V-I-S （Vegetation-Impervious Surface-Soil）概念模型,该模型将城市土地覆盖分为绿地植被、不透水地表与裸土,模型建立对于解决混合像元问题,提高不透水地表信息提取的精度具有重要作用。此类方法在研究中得到广泛的应用[28]。
世界上主要地区和城市,不透水地表呈现出增长趋势。遥感监测结果表明,美国城市内部不透水地表面积比例平均约为40%~50%,中国城市不透水地表面积比例估算约为66%,且均呈现出高速增长的特征[28]。不透水地表的增长通过改变地表辐射能量平衡,从而增强局地气温,产生热岛效应[29],进而影响居民的舒适性和健康状况,以及污染物排放等。中国学者逐渐意识到城市不透水地表分布对生态环境影响的重要性,进而对北京、上海、福州、珠三角等城市和地区不透水地表开展相关研究[30, 31]。前人研究由集中于城市扩张及其相应的土地利用变化,逐渐转为城市内部城市土地组分提取,在此情景下,更加需要等级结构土地利用精细化分类。
2.2 定量遥感、观测实验与过程模型集成研究
在欧洲和美国,很多城市都开展了相应的观测试验和计划,甚至形成了全球城市通量观测网络[32,33]。美国的巴尔的摩(Baltimore)和凤凰城(Phoenix)均开展了长期城市生态研究,建立了通量和气象观测站点[34]。国内城市相继也开展了相关的观测研究,例如在南京进行的城市边界层三维结构和热岛三维结构观测试验,定量分析城市微气象及中小尺度、非均一三维特征对地表与大气间能量交换的影响,并对城市热岛的特征及其成因、影响程度开展研究[35]。中国科学院大气物理研究所在北京城区建造了325 m气象观测塔应用涡动相关方法开展47 m、120 m和280 m城市下垫面的动量和感热等湍流通量观测实验[36]。中国科学院生态环境研究中心在本单位地址和北京植物教学中心开展了辐射和气象观测[34]。为了建立城市不透水面和绿地不同土地利用类型与地表辐射和热通量之间的直接关联,匡文慧等[29]在北京城区奥林匹克公园(代表城市绿地)和附近科学园南里建筑屋顶(代表城市不透水地表)布设了涡度相关通量实验观测站,比较相同气象条件下不同城市结构类型对地表辐射和通量影响的差异。
当前地表热量平衡模拟模型有SEBS（ Surface Energy Balance System）、SEBAL（Surface Energy Balance Algorithm for Land）,PCACA（Pixel Component Arranging Comparing Algorithm）和能量切割法等[37]。耦合陆表模型或城市冠层模型,在中尺度区域上形成的MM5（Fifth-Generation Penn State/NCAR Mesoscale Model）、RAMS（ Regional Atmospheric Modeling System）、WRF（Weather Research and Forecasting Model）等。Grimmond等[38,39]在全球范围内开展了城市能量平衡的模型比较计划,涉及到的模型有LUMPS（Local-Scale Urban Meteorological Parameterization Scheme）、BEP02（Building effect Parameterization）、CLMU（Community Land Model-urban)、MUCM （Multi-layer Urban Canopy Model)、NJU-UCM-S/M （Nanjing University Urban Canopy Model-single/multi Layer)、SM2-U（Soil Model for Sub-Mesoscale Urban)、TEB （Town Energy Balance)等数十个模型。它们既包括了单层模型,也包括了多层模型;既有中尺度下的模块,也有单独的城市气候模型,既有半经验模型,也有基于数值模拟的模型。针对城市生态评价模型有美国林业组织开发的Citygreen模型等。
城市生态学理论研究一再强调理解和分析城市生态系统的复杂性：包括空间格局和结构组成的异质性对生态过程和服务功能的影响机制。Pickett等[40]和Grimm等[41]呼吁发展新一代的空间显式的多尺度生态系统模型,以将人类控制下的格局动态和环境干扰同生物地球化学循环过程有机整合。基于Wu等[12]提出的HPDM-PHX（Hierarchical Patch Dynamics Model of the Phoenix urban landscape）城市模型框架,Zhang等[42]发展了多尺度耦合的HPM-UEM(Hierarchical Patch Mosaic-Urban Ecosystem Model)模型,这些模型主要针对城市生物地球化学过程。但是长期以来缺乏将城市空间等级尺度结构与生物地球物理机制相互有效联系起来的研究方法和案例。城市作为一个高度空间异质性和多因素耦合的复杂有机体,在城市土地利用/覆盖变化和热环境调控方面仍有待通过观测实验、过程模型模拟和定量遥感集成方法深入解决如下问题（
|
图2 定量遥感、观测实验与过程模型集成研究框架与方法 Fig. 2 Integrated methods of quantitative remote sensing, observational experiments and process models |
2.3 城市绿色基础设施在热岛减缓和气候适应性方面发挥的作用
城市绿地(Urban Green Space, UGS)作为城市生态系统的重要组成部分,在改善城市环境,特别是空气和水质净化,建筑节能,适宜空气温度,紫外线减少方面具有重要作用[43,44]。城市中适宜比例的绿地面积有调节城市内部气候环境,影响城市内部辐射能量平衡,降低城市地表温度等作用,对生态服务热调节功能具有决定性作用[45,46,47]。通过仪器测量方法分析公园绿地对周边区域的温度影响,发现绿地温度明显低于周边区域[47],且面积越大,植被覆盖越高的绿地冷岛效应越明显[48]。研究表明,增加10%的绿地,城市热辐射将减少2℃,当绿地斑块面积大于5 km2,地表辐射温度急剧下降[48]。绿地和周边城市温度差异夏季大,冬季小,冷岛效应可以在夜晚的城市区域延伸200~300 m,而夏季8~10月间,范围可以超过500 m[49],有效地降低了城市温度。中国城市不透水地表比例过高,绿地面积不够集中,较大程度上影响了城市热调节功能。
为进一步保护城市内部绿地覆盖,美国已实施了不同的城市绿地发展计划,如种植大量绿地植被[50,51]、保护现有植被[52]和发展城市冠层目标[53]等。针对城市内部不透水与森林覆盖结构组分研究,国际林业研究组织联盟(International Union of Forestry Research Organizations,IUFRO)曾建立专门的项目组来探讨人类居住区的绿地和城市森林覆盖方面的问题[54]。2000年以来,欧洲、中国等多个国家政府以绿地结构和城市规划为研究内容,展开专项科研计划[55,56]。国内外绿地植被对缓解城市热岛效应的作用研究证实了公园绿地的“冷效应”和不透水层的“热效应”[57,58,59]。不仅如此,已有研究表明部分位于热带荒漠环境中的城市,由于城市内部大面积的灌溉植被增加了地表蒸散发,进而呈现城市“冷岛效应”[60,61]。多项研究证明绿地和水体具有缓减热岛效应的作用,但是针对一定面积的绿地或水体具体的影响范围的量化研究不多,而绿地和水体的结构、配置等对热效应的调节作用,需要深入研究[62]。
2.4 城市地表热环境生态调控阈值
人类活动对自然界的影响强度呈现出逐渐增大的趋势,其中,不合理活动将会导致生态环境恶化,为了维持区域环境与经济的可持续发展,需要对生态环境进行调控[63,64]。城市化进程的加快,严重地影响生态系统的服务功能,使城市自然生态系统的服务功能不断降低。世界各地政府制定不同的生态调控策略,保护城市生态环境。1938年,英国伦敦实施“绿带法”(Green Belt Law),建设城市绿地,控制城市规模[65]。该模式在一系列城市中得到推广[66,67]。欧洲实施泛欧洲生态网络（Pan Europeen Ecological Network, PEEN）计划,建立覆盖欧洲的生态网络,实现对区域生态环境的系统保护[68]。中国政府在城市中推动“五规合一”,统一进行城市规划,以解决包括环境问题在内的诸多问题,而生态调控阈值,在其中扮演着“底线”的重要角色[69]。国内学者逐渐认识到城市生态问题的重要性,对深圳等城市化区域和京津冀等区域的生态调控问题,进行了各种方面的研究[70,71]。李杨帆等以厦门市为例,通过景观格局识别分析,结合生态风险预警方法,进行关键区域识别[72]。匡文慧等提出热岛效应与极端热事件发生的生态风险缓减的城市内部功能布局调控策略,发展了EcoCity V1.0 模型（
|
图3
EcoCity V1.0模型结构框架[ |
以雄安新区规划为例,在2017年4月1日,中共中央、国务院决定设立雄安新区,作为一项千年大计、国家大事,对于集中疏解北京非首都功能和调整优化京津冀城市布局和空间结构具有重大意义。4月8日研究组基于EcoCity V1.0 模型应用于未来雄安新区的规划,分析结果撰写提交了“中科院专家关于加强河北雄安新区建设区域生态管控的建议”,提出需要加强城市绿色基础设施建设,适当提高城市绿化比例,建成区内不透水地面整体比例应不超过50%,核心区不超过70%,通过科学规划,热岛强度应控制在1℃~1.5℃[71]。相关建议获得中办采纳,并与《河北雄安新区规划纲要》相关指标具有较高的契合性。可见,EcoCity V1.0 模型在优化未来城市布局和空间规划中有很好的应用前景。
3 未来研究展望——从“城市热岛”到“热调节服务功能”
城市化与极端热、热岛效应、大气污染以及气候变化适应性等问题逐渐得到学术界的重视。城市极端热事件发生的频率呈现加剧态势,全球范围未来有更多人口暴露或死于极端热、户外大气污染(PM2.5)[73,74]。同时,城市化导致气温日较差缩小(Diurnal Temperature Range, DTR),大都市区及湿润地带受热岛影响更为剧烈[75,76]。
千年生态系统评估(Millennium Ecosysterm Assessment, MA),城市化与全球环境变化(Urbanization and Galobal Environmental Change, UGEC)直到未来地球计划(Future Earth)更加关注城市生态系统服务功能的提升和人类幸福安康。由此,低影响开发(Low Impact Development, LID)、弹性城市(Resilient City)、海绵城市建设成为近期学术探讨和应用实践优先主题和热点问题[77,78]。学界提出通过城市绿色基础设施(Urban Green Infrastructure, UGI)建设适应气候变化,屋顶绿化、透水砖、雨洪设施等,会截流、滞流降水,降低能耗,降温,缩减热岛,缩减温室气体排放,由此,相互之间综合效应量测和评估是至关重要的[79]。Jones等[80]提出基于生态系统适应性(Ecosystem-based approaches to Adaptation, EbA)策略,与之密切相关的城市生态系统热调节机理研究,是提高城市生态系统服务认识的最核心和关键环节,也是城市生态系统物质能量循环研究的基础和前沿内容。联合国2030年可持续发展议程提出城市可持续性发展,提出建设更好的人居环境,亟需对城市绿地比例进行合理调控。
当前,对城市生态系统热调节和气候适应性研究更加重视城市生态服务功能以及人居环境的改善,特别在城市对全球气候变化的适应性策略。在学科协同方面,由传统的单一科学,转向社会科学与自然科学的耦合和多学科交叉,协同解决城市土地利用动态过程与生态系统服务功能之间的互馈过程、作用机理以及人文
1） 城市不透水地表/绿地格局对热岛/冷岛效应通量特征影响机理认识。热岛强度表达了城市中心区高于周边乡村地表气温的强度,虽然表达了城市热岛现象,但更多反映的是热岛效应这一现象本身,解释其内在机理以及产生的原因仍显不足。进而,围绕联合国2030可持续发展目标,在未来城市扩张模式和未来气候情景下,人工下垫面大规模的建设对区域增温的影响,特别是高密度大都市集聚区夏季极端热过程和对热舒适性的影响幅度。
2） 支持城市内部功能结构以及生态服务功能评估的数据资料的精细化。城市内部结构精细化信息获取具有一定难度。城市生态/气候模型的适用性缺乏充分的参数本地化和验证工作。将国际模型本土化,开发城市地表过程热通量遥感反演模型,通过科学实验与模型模拟的有效结合,进一步提高模型的可靠性和模拟精度,是当前研究亟待解决的问题。
3） 城市结构与城市生态服务功能之间的定量关系认识水平,会影响城市规划及景观设计方面的应用能力。对于解答具有空间针对性的不透水地表和绿地规模、组分以及格局与热调节功能之间的互馈关系,从而使城市热环境研究从“科学量测”向“科学调控”发展。
4） 全球气候变暖背景下,区域尺度极端气候(如极端热、洪水)对于城市生态系统服务影响和适应性策略认识能力的提升。
The authors have declared that no competing interests exist.
参考文献
| [1] |
[本文引用:1]
|
| [2] |
Urban areas are hot spots that drive environmental change at multiple scales. Material demands of production and human consumption alter land use and cover, biodiversity, and hydrosystems locally to regionally, and urban waste discharge affects local to global biogeochemical cycles and climate. For urbanites, however, global environmental changes are swamped by dramatic changes in the local environment. Urban ecology integrates natural and social sciences to study these radically altered local environments and their regional and global effects. Cities themselves present both the problems and solutions to sustainability challenges of an increasingly urbanized world.
|
| [3] |
Urbanizing regions increasing challenge the ecosystem's capacity to deliver important ecological services to the human population and support human well-being. Scholars of urban ecology have hypothesized that the patterns of urbanization control ecosystem dynamics through complex interactions and feedback mechanisms linking urban activities and their spatial organization to land cover and environmental change. However, empirical studies of the underlying processes and mechanisms linking urbanization patterns and ecosystem dynamics are still extremely limited. In this paper, I present a framework linking urban patterns to ecosystem functions and discuss a set of hypotheses based on the empirical evidence established in the literature.
DOI:10.1016/j.cosust.2010.07.002
[本文引用:1]
|
| [4] |
Urban land-use/cover changes and their effects on the eco-environment have long been an active research topic in the urbanization field. However, the characteristics of urban inner spatial heterogeneity and its quantitative relationship with thermal environment are still poorly understood, resulting in ineffective application in urban ecological planning and management. Through the integration of 渟patial structure theoryin urban geography and 渟urface energy balancein urban climatology, we proposed a new concept of urban surface structure and thermal environment regulation to reveal the mechanism between urban spatial structure and surface thermal environment. We developed the EcoCity model for regulating urban land cover structure and thermal environment, and established the eco-regulation thresholds of urban surface thermal environments. Based on the comprehensive analysis of experimental observation, remotely sensed and meteorological data, we examined the spatial patterns of urban habitation, industrial, infrastructure service, and ecological spaces. We examined the impacts of internal land-cover components (e.g., urban impervious surfaces, greenness, and water) on surface radiation and heat flux. This research indicated that difference of thermal environments among urban functional areas is closely related to the proportions of the land-cover components. The highly dense impervious surface areas in commercial and residential zones significantly increased land surface temperature through increasing sensible heat flux, while greenness and water decrease land surface temperature through increasing latent heat flux. We also found that different functional zones due to various proportions of green spaces have various heat dissipation roles and ecological thresholds. Urban greening projects in highly dense impervious surfaces areas such as commercial, transportation, and residential zones are especially effective in promoting latent heat dissipation efficiency of vegetation, leading to strongly cooling effect of unit vegetation coverage. This research indicates that the EcoCity model provides the fundamentals to understand the coupled mechanism between urban land use structure and surface flux and the analysis of their spatiotemporal characteristics. This model provides a general computational model system for defining urban heat island mitigation, the greening ratio indexes, and their regulating thresholds for different functional zones.
DOI:10.1007/s11430-016-9032-9
[本文引用:5]
|
| [5] |
Abstract China is the largest and most rapidly urbanizing nation in the world, and is projected to add an additional 200 million city dwellers by the end of 2030. While this rapid urbanization will lead to vast expansion of built-up areas, the possible climate effect and associated human health impact remain poorly understood. Using a coupled urban-atmospheric model, we first examine potential effects of three urban expansion scenarios to 2030 on summer climate in eastern China. Our simulations indicate extensive warming up to 500°C, 300°C, and 200°C in regard to low- (>0%), high- (>75%), and 100% probability urban growth scenarios, respectively. The partitioning of available energy largely explains the changes in 2-m air temperatures, and increased sensible heat flux with higher roughness length of the underlying urban surface is responsible for the increase of nighttime planetary boundary layer height. In the extreme case (the low-probability expansion pathway), the agglomeration of impervious surfaces substantially reduces low-level atmospheric moisture, consequently resulting in large-scale precipitation reduction. However, the effect of near-surface warming far exceeds that of moisture reduction and imposes non-negligible thermal loads on urban residents. Our study, using a scenario-based approach that accounts for the full range of urban growth uncertainty by 2030, helps better evaluate possible regional climate effects and associated human health outcomes in the most rapidly urbanizing areas of China, and has practical implications for the development of sustainable urban regions that are resilient to changes in both mean and extreme conditions.
|
| [6] |
The number of hot days is increasing in many parts of the world because of the heat island phenomenon and global climate change. High air temperature greatly affects human thermal comfort and public health, particularly in urban areas. Therefore, the challenging task of, urban designers and urban planners in accommodating the increasing population is to make cities with the least level of vulnerability to future climate change. Interest in transferring urban climatic knowledge into urban planning practices, and developing mitigation strategies to adapt to climate change, has been increased in recent years. The use of vegetation and appropriate urban geometry are shown very promising in mitigating the adverse effects of heat island and providing a better pedestrian thermal comfort. This article reviews studies on pedestrian level urban greening and geometry in improving thermal comfort in cities. Such strategies can be applied at the preliminary stages of urban planning and thus directly affect the microclimate. The analyzed data include simulation and field measurement studies. The discussion of this research clearly reflects how urban design guidelines can be applied to enhance outdoor thermal comfort and minimize the heat island effect. This study is helpful in controlling the consequences of city design from the early design stage.
DOI:10.1016/j.rser.2015.10.104
[本文引用:1]
|
| [7] |
Not Available
DOI:10.1256/smsqj.45501
[本文引用:1]
|
| [8] |
[本文引用:1]
|
| [9] |
China has experienced an unprecedented urbanization and industrialization in the past decades. In this research, we examined the dynamics of construction lands and impervious surface areas (ISA) based on land use/cover change and ISA datasets between 2000 and 2008, which were provided by the national resources and environmental remote sensing information platform. The results indicated that the construction areas and ISA increased by 3468.30 and 2212.24 km(2)/a in this period primarily due to the implementation of national macro-development strategies and fast-growing economy. In 2008, ISA accounted for 0.86% of the total land area in China. Urban land areas increased by 43.46% between 2000 and 2008. The annual growth rate of 1788.22 km(2)/a in this period was 2.18 times that in the 1990s. In particular, urban ISA increased by 53.30% between 2000 and 2008 with an annual growth rate of 1348.85 km(2)/a. During the 8 years, the ISA in China increased rapidly, especially in the Beijing-Tianjin-Tangshan Metropolitan Region, Pearl River Delta, Yangtze River Delta, and the western China region. The increasing ISA may influence potentially water environmental quality in the major basins. In particular, the number of subbasins having ISA of greater than 10% increased considerably, which were primarily distributed in the Haihe River, Yangtze River and Pearl River basins. In 2008, 14.42% of the basin areas were affected by the increased ISA.
DOI:10.1007/s11434-012-5568-2
[本文引用:1]
|
| [10] |
China's extensive urbanization has resulted in a massive loss of natural habitat, which is threatening the nation's biodiversity and socioeconomic sustainability. A timely and accurate understanding of natural habitat loss caused by urban expansion will allow more informed and effective measures to be taken for the conservation of biodiversity. However, the impact of urban expansion on natural habitats is not well-understood, primarily due to the lack of accurate spatial information regarding urban expansion across China. In this study, we proposed an approach that can be used to accurately summarize the dynamics of urban expansion in China over two recent decades (1992-2012), by integrating data on nighttime light levels, a vegetation index, and land surface temperature. The natural habitat loss during the time period was evaluated at the national, ecoregional, and local scales. The results revealed that China had experienced extremely rapid urban growth from 1992 to 2012 with an average annual growth rate of 8.74%, in contrast with the global average of 3.20%. The massive urban expansion has resulted in significant natural habitat loss in some areas in China. Special attention needs to be paid to the Pearl River Delta, where 25.79% or 1518 km(2) of the natural habitat and 41.99% or 760 km(2) of the local wetlands were lost during 1992-2012. This raises serious concerns about species viability and biodiversity. Effective policies and regulations must be implemented and enforced to sustain regional and national development in the context of rapid urbanization.
DOI:10.1111/gcb.12553
[本文引用:1]
|
| [11] |
Records of hemispheric average temperatures from land regions for the past 100 years provide crucial input to the debate over global warming. Despite careful use of the basic station data in some of these compilations of hemispheric temperature, there have been suggestions that a proportion of the 0.5 C warming seen on a century timescale may be related to urbanization influences - local warming caused by the effects of urban development. We examine here an extensive set of rural-station temperature data for three regions of the world: European parts of the Soviet Union, eastern Australia and eastern China. When combined with similar analyses for the contiguous United States the results are representative of 20% of the land area of the Northern Hemisphere and 10% of the Southern Hemisphere. The results show that the urbanization influence in two of the most widely used hemispheric data sets is, at most, an order of magnitude less than the warming seen on a century timescale.
DOI:10.1038/347169a0
[本文引用:1]
|
| [12] |
[本文引用:2]
|
| [13] |
[本文引用:1]
|
| [14] |
[本文引用:1]
|
| [15] |
Efforts to develop a global understanding of the functioning of the Earth as a system began in the mid-1980s. This effort necessitated linking knowledge from both the physical and biological realms. A motivation for this development was the growing impact of humans on the Earth system and need to provide solutions, but the study of the social drivers and their consequences for the changes that were occurring was not incorporated into the Earth System Science movement, despite early attempts to do so. The impediments to integration were many, but they are gradually being overcome, which can be seen in many trends for assessments, such as the Intergovernmental Platform on Biodiversity and Ecosystem Services, as well as both basic and applied science programs. In this development, particular people and events have shaped the trajectories that have occurred. The lessons learned should be considered in such emerging research programs as Future Earth, the new global program for sustainability research. The transitioning process to this new program will take time as scientists adjust to new colleagues with different ideologies, methods, and tools and a new way of doing science.
DOI:10.1073/pnas.1107484110
[本文引用:1]
|
| [16] |
[本文引用:2]
|
| [17] |
[本文引用:1]
|
| [18] |
No abstract is available for this article.
DOI:10.1002/qj.49708435910
[本文引用:1]
|
| [19] |
The regional-scale climatic impact of urbanization is examined using two land cover parameters, fractional vegetation cover (Fr) and surface moisture availability (M0). The parameters are hypothesized to decrease as surface radiant temperature (T0) increases, forced by vegetation removal and the introduction of non-transpiring, reduced evaporating urban surfaces. Fr and M0 were derived from vegetation index and T0 data computed from the Advanced Very High Resolution Radiometer (AVHRR), and then correlated to a percentage of urban land cover obtained from a supervised classification of Landsat TM imagery. Data from 1985 through 1994 for an area near State College, PA, USA, was utilized. Urban land cover change (at the rate of 3 per cent perkm2 per year) was statistically significant when related to a decrease in normalized values of Fr and increase in normalized values of T0. The relationship between urbanization and M0, however, was ill-defined due to variations in the composition of urban vegetation. From a nomogram of values of Fr and T0, a Land Cover Index (LCI) is proposed, which incorporates the influence of local land cover surrounding urbanized pixels. Such an index could allow changes in land use at neighbourhoodscale to be input in the initialization of atmospheric and hydrological models, as well as provide a new approach for urban heat island analyses. Furthermore, the nomogram can be used to qualify urbanization effects on evapotranspiration rates.
DOI:10.1080/014311698215171
[本文引用:1]
|
| [20] |
[本文引用:1]
|
| [21] |
[本文引用:1]
|
| [22] |
城市建设用地总量及其用地结构动态变化的合理性是衡量一个国家和地区城镇化进程是否健康、城镇化发展质量是否高效的晴雨表。1981—2014年间的35 a来,中国城市建设用地在数量、人均面积和用地扩张弹性系数上均发生了巨大变化,城市建设用地增加了6.44倍,年均净增1 311 km2;人均城市建设用地增加了2.78倍,年均净增2.37 m2;城市建设用地扩张速度明显高于人口增长速度,且呈现出大快大慢的波浪状起伏变化态势。城市建设用地结构总体处在稳定变化的合理区间,东部地区各类城市建设用地总量占全国50%以上,近年呈微降趋势;大中小城市建设用地比例基本保持在50%∶20%∶30%的区间。近35 a来中国城市建设用地扩张存在的主要问题表现为城市建设用地无序蔓延问题严重,人均建设用地居高不下;城市建设用地结构不尽协调,降低了城市用地集约利用效率;城镇化和经济增长过于依赖建设用地,短期难以扭转;新城新区建设过多过大,加剧了城市建设用地的过度扩张。未来中国城市建设用地调控中,要综合防范城市用地无序扩张蔓延,提高土地集约利用水平;优化城市建设用地结构和功能,实现城市精明集约增长;因地因城因类地制订出差别化的建设用地调控措施;进一步科学引导我国新城新区的适度理性建设。
DOI:10.11849/zrzyxb.20160361
[本文引用:1]
|
| [23] |
We present the first global inventory of the spatial distribution and density ofconstructed impervious surface area (ISA). Examples of ISA include roads, parking lots,buildings, driveways, sidewalks and other manmade surfaces. While high spatialresolution is required to observe these features, the new product reports the estimateddensity of ISA on a one-km2 grid based on two coarse resolution indicators of ISA 01040000“ thebrightness of satellite observed nighttime lights and population count. The model wascalibrated using 30-meter resolution ISA of the USA from the U.S. Geological Survey.Nominally the product is for the years 2000-01 since both the nighttime lights andreference data are from those two years. We found that 1.05% of the United States landarea is impervious surface (83,337 km2) and 0.43 % of the world0104000064s land surface (579,703km2) is constructed impervious surface. China has more ISA than any other country(87,182 km2), but has only 67 m2 of ISA per person, compared to 297 m2 per person in theUSA. The distribution of ISA in the world0104000064s primary drainage basins indicates that watersheds damaged by ISA are primarily concentrated in the USA, Europe, Japan, China and India. The authors believe the next step for improving the product is to include reference ISA data from many more areas around the world.
|
| [24] |
Mapping and monitoring impervious surface dynamic change in a complex urban–rural frontier with medium or coarse spatial resolution images is a challenge due to the mixed pixel problem and the spectral confusion between impervious surfaces and other non-vegetation land covers. This research selected Lucas do Rio Verde County in Mato Grosso State, Brazil as a case study to improve impervious surface estimation performance by the integrated use of Landsat and QuickBird images and to monitor impervious surface change by analyzing the normalized multitemporal Landsat-derived fractional impervious surfaces. This research demonstrates the importance of two-step calibrations. The first step is to calibrate the Landsat-derived fraction impervious surface values through the established regression model based on the QuickBird-derived impervious surface image in 2008. The second step is to conduct the normalization between the calibrated 2008 impervious surface image with other dates of impervious surface images. This research indicates that the per-pixel based method overestimates the impervious surface area in the urban–rural frontier by 50%–60%. In order to accurately estimate impervious surface area, it is necessary to map the fractional impervious surface image and further calibrate the estimates with high spatial resolution images. Also normalization of the multitemporal fractional impervious surface images is needed to reduce the impacts from different environmental conditions, in order to effectively detect the impervious surface dynamic change in a complex urban–rural frontier. The procedure developed in this paper for mapping and monitoring impervious surface area is especially valuable in urban–rural frontiers where multitemporal Landsat images are difficult to be used for accurately extracting impervious surface features based on traditional per-pixel based classification methods as they cannot effectively handle the mixed pixel problem.
|
| [25] |
Impervious surface can be defined as any materials that prevent the infiltration of water into the soil. Principally, roads and rooftops in the urban are the most prevalent and easily identified types of impervious surfaces. Other types include sidewalks, patios, bedrock outcrops, and compacted soils in the urban areas. Impervious surface not only indicates urbanization, but also is a major contrihutor to the environmental impacts of urbanization. Impervious surface area (ISA) is the index of impervious surface landscape components, which uses the percentage in a pixel for representation. It is an index to monitor the urban ecological system and environmental change, and is an important indicator of the ecological and environmental model, which can affect urban hydrological cycle, surface runoff, water quality, local climate, and biological diversity. This paper reviews the development of remote sensing technology of impervious surface, and summarizes how it impacts urban ecosystem and urban environmental system. From the aspect of remote sensing technology, sub-pixel decomposition including spectral mixture analysis and regression analysis, and other new methods for interpreting image, will be the trend of the application of remote sensing research to urban natural resources and environmental studies in the future. From the aspect of remote sensing data source, the data of medium-resolution (10-100 m) image and high-resolution (0.3-5 m) image, which are used to estimate the index of impervious surface in multi-temporal and large-spatial area, can provide a reliable basis to monitor urban land use/cover change and environmental response. As an environmental indicator, impervious surface area (ISA) can be used to monitor urban land cover change and simulate future urban development, providing a basis for the decision making of urban planning and management. Referring to the fact that impervious surface has an important relation to the hydrological cycle, non-point source pollution, land surface temperature, vegetation variation and biological diversity, if we can understand the relationship between impervious surface area and the environmental or ecological indicators, we(an better understand urban landscape pattern and ecological processes. Impervious surface area plays an important role in studying the eco-environmental effects of urbanization.
DOI:10.11820/dlkxjz.2010.09.018
[本文引用:1]
|
| [26] |
地理国情监测是我国测绘工作在新时代的主要任务和发展方向.不透水层分布是城市和区域环境的生态考核指标之一,对城市和区域的发展规划和生态评估具有重要意义.但是,目前我国地理国情普查和监测工作中依然缺少对不透水层分布的调查和统计.基于遥感技术的不透水层提取具有实时、快速、精确的特点,本文首先针对不同遥感影像的数据特点和优势介绍了不透水层提取的经典理论,然后对现有的不透水层应用方向进行了总结,主要包括水文、城市热岛效应、土地利用及变化、城市生态环境监测以及城市规划,最后展望其在相关行业中的潜在应用,并建议将不透水层分布列为我国地理国情调查和监测的内容.
DOI:10.13203/j.whugis20160038
[本文引用:1]
|
| [27] |
ABSTRACT Growing interest in urban systems as ecological entities calls for some standards in parameterizing biophysical composition of urban environments. A vegetation-impervious surface-soil ( V-I-S) model is presented as a possible basis for standardization. The V-I-S model may serve as a foundation for characterizing urban/near-urban environments universally, and for comparison of urban morphology within and between cities. Inasmuch as the model may be driven by satellite digital data, it may serve as a global model of urban ecosystem analysis and comparison world-wide. The V-I-S model may prove useful for urban change detection and growth modelling, for environmental impact analysis from urbanization, for energy- and water-related investigations, and for certain dimensions of human ecosystem analysis of the city as well.
DOI:10.1080/01431169508954549
[本文引用:1]
|
| [28] |
Research on physical characteristics and land-cover dynamic changes of megacities over time provides valuable insights for effectively regulating urban planning and management. This study conducts a comparative analysis of 30-year urban expansion patterns and rates among three metropolises in China (Beijing, Shanghai, and Guangzhou) and another three in the USA (New York, Los Angeles, and Chicago) based on time-series impervious surface area (ISA) data extracted from multitemporal Landsat images using the linear spectral mixture analysis approach. This research indicates significantly different urbanization patterns and rates between the Chinese and American megacities. The ISA expansion area in Chinese megacities was five times higher than that in American megacities during the past three decades. The Chinese megacities expand outward from the urban core to the periphery in a concentric ring structure, whereas the American megacities increase ISA mainly within the inner cities with patch-filling patterns. The Chinese megacities are in the development stage where population and economic conditions significantly influence urban expansion patterns and rates, but the American megacities are in the developed stage where population and economic conditions are not important forces driving the ISA expansion. The ISA intensity in the American megacities decreases constantly and smoothly, but ISA intensity in Chinese megacities decays abruptly within certain distances, depending on different cities and years. The most obvious urban expansions were between 8 and 20km in Beijing in the 1980s, between 14 and 50km in Shanghai in the 2000s, and between 8 and 18km in Guangzhou in the 1990s.
DOI:10.1016/j.landurbplan.2014.08.015
[本文引用:2]
|
| [29] |
Context Understanding how landscape components affect the urban heat islands is crucial for urban ecological planning and sustainable development.
DOI:10.1007/s10980-014-0128-6
[本文引用:2]
|
| [30] |
城市化的一个重要表现就是不透水面分布比率的上升，城市内部不透水面分布是城市生态环境的一个重要指标。对于规模较大的大城市，采用高性价比的中等分辨率影像，获取不透水面的分布，是当前国际研究的一个热点。本研究利用Landsat 7的ETM＋影像，在线性光谱分解的技术上，提取了上海市的不透水面分布并对其空间特征进行了分析。研究揭示，ETM＋影像对于城市尺度的信息提取，其成本是较低的；对于城市地域来说，利用植被、高反照度、低反照度和裸露的土壤四种最终光谱端元的线性组合，可以较好地模拟ETM＋波谱特征，而除了水面以外的高反照度、低反照度两种最终光谱端元，可以较好地表达城市不透水表面信息。结果显示，利用中等分辨率影像对上海中心城区不透水面分布提取的精度还是令人满意的，总体上，上海市不透水面分布比率较高，不透水面分布的空间差异进一步揭示了城市土地覆被空间结构以及城市空间扩展的差异性。
DOI:10.3321/j.issn:1007-4619.2007.06.020
[本文引用:1]
|
| [31] |
react-text: 444 Accurate, up-to-date, and consistent information of urban extents is vital for numerous applications central to urban planning, ecosystem management, and environmental assessment and monitoring. However, current large-scale urban extent products are not uniform with respect to definition, spatial resolution, temporal frequency, and thematic representation. This study aimed to enhance,... /react-text react-text: 445 /react-text [Show full abstract]
DOI:10.1016/j.rse.2017.08.036
[本文引用:1]
|
| [32] |
Results from an experimental network of seven energy balance stations in and around a European city are presented. The network of micrometeorological stations was part of the Basel Urban Boundary Layer Experiment (BUBBLE) carried out in the city of Basel, Switzerland. Three urban sites provided turbulent flux densities and radiation data over dense urban surfaces. Together with a suburban site and three rural reference sites, this network allowed the simultaneous comparison of urban, suburban, and rural energy balance partitioning during one month of summertime measurements. The partitioning is analysed together with long-term data to evaluate the magnitude of the urban flux density modification, and to document characteristic values in their diurnal and yearly course. Simple empirical relations between flux densities and surface characteristics are presented. The energy balance partitioning is addressed separately for daytime and nocturnal situations. All four components of the surface radiation budget are analysed. Moreover, the vertical flux density divergences within the urban canopy layer are discussed.
DOI:10.1002/joc.1074
[本文引用:1]
|
| [33] |
[本文引用:1]
|
| [34] |
随着全球和中国的快速城市化，城市生态系统的长期研究受到了高度关注。在分析城市生态系统结构、格局、过程和功能特点的基础上，评述了近些年来城市生态系统研究的主要框架和学术观点，比较了Phoenix、Baltimore和北京3个城市生态系统研究站在研究目的、基本科学问题、研究内容和研究方法上的特点，并介绍了这3个城市生态站的一些主要研究思路和研究成果，指出了今后城市生态系统的研究重点是从理论上和研究方法上创新，将自然过程和人类社会经济过程很好地结合起来，为城市可持续发展提供科学依据。
[本文引用:2]
|
| [35] |
[本文引用:1]
|
| [36] |
The 1-year (2009–2010) measurements are analyzed of the urban surface energy balance (SEB) obtained from the sensors located at three vertical layers of a 325-m tower in downtown Beijing. Results show that: (1) The measurements from the 325-m tower represent the SEB characteristics of the cities located in semi-humid warm-temperate continental monsoon climate zone. In a typical hot and rainy summer, cold and dry winter, the measured Bowen ratio is minimum in summer and maximum in winter. The Bowen ratio measured at 140 m for spring, summer, autumn, and winter are 2.86, 0.82, 1.17, and 4.16 respectively. (2) At the height of 140-m (in the constant flux layer), the noontime albedo is 650.10 for summer, 650.12 for spring and autumn, and 650.14 for winter. The ratios of daytime sensible heat flux, latent heat flux, and storage heat flux to net radiation are 0.25, 0.16, and 0.59 for clear-sky days, and 0.33, 0.19, and 0.48 for cloudy days respectively. (3) Under clear-sky days, the nighttime sensible heat flux is almost zero, but the latent heat flux is greater than zero. For cloudy days, the nighttime sensible heat flux is slightly greater than the latent heat flux in winter. The nighttime upward heat flux is presumably due to the anthropogenic release (mainly latent heat for summer, while latent and sensible heat for winter).
DOI:10.1007/s11430-012-4411-6
[本文引用:1]
|
| [37] |
以修正的二层模型耦合机制，提出了PCACA算法以及理论定位算法，结合干点和湿点定标场的 参数测定值，推算到4个极端的混合像元真实温度．提高了干线和湿线的定位的可靠性．并且提出了二层分层能量切割算法，算法简捷明了，具有物理基础．摆脱了 难以逐个像元获取的通量阻力网参数．对平流的影响提出了新的思考．又以PCACA算法分解了混合像元的反照率．联合二层分层能量切割算法，分解了混合像元 的净辐射通量．克服了传统以Beer定律分解净辐射通量的不确定性．通过反演结果的验证分析，方法是可行的也是易于操作的．在论述上述算法可操作性的同时 也客观地指出了不确定性．
[本文引用:1]
|
| [38] |
[本文引用:1]
|
| [39] |
Urban land surface schemes have been developed to model the distinct features of the urban surface and the associated energy exchange processes. These models have been developed for a range of purposes and make different assumptions related to the inclusion and representation of the relevant processes. Here, the first results of Phase 2 from an international comparison project to evaluate 32 urban land surface schemes are presented. This is the first large-scale systematic evaluation of these models. In four stages, participants were given increasingly detailed information about an urban site for which urban fluxes were directly observed. At each stage, each group returned their models' calculated surface energy balance fluxes. Wide variations are evident in the performance of the models for individual fluxes. No individual model performs best for all fluxes. Providing additional information about the surface generally results in better performance. However, there is clear evidence that poor choice of parameter values can cause a large drop in performance for models that otherwise perform well. As many models do not perform well across all fluxes, there is need for caution in their application, and users should be aware of the implications for applications and decision making. Copyright 2010 Royal Meteorological Society
DOI:10.1002/joc.2227
[本文引用:1]
|
| [40] |
As defined by Ascher, biocomplexity results from a "multiplicity of interconnected relationships and levels." However, no integrative framework yet exists to facilitate the application of this concept to coupled human-natural systems. Indeed, the term "biocomplexity" is still used primarily as a creative and provocative metaphor. To help advance its utility, we present a framework that focuses on linkages among different disciplines that are often used in studies of coupled human-natural systems, including the ecological, physical, and socioeconomic sciences. The framework consists of three dimensions of complexity: spatial, organizational, and temporal. Spatial complexity increases as the focus changes from the type and number of the elements of spatial heterogeneity to an explicit configuration of the elements. Similarly, organizational complexity increases as the focus shifts from unconnected units to connectivity among functional units. Finally, temporal complexity increases as the current state of a system comes to rely more and more on past states, and therefore to reflect echoes, legacies, and evolving indirect effects of those states. This three-dimensional, conceptual volume of biocomplexity enables connections between models that derive from different disciplines to be drawn at an appropriate level of complexity for integration.
DOI:10.1007/s10021-004-0098-7
[本文引用:1]
|
| [41] |
[本文引用:1]
|
| [42] |
Urbanization effects on ecosystem functions are both important and complex, characterized by scale multiplicity, spatial heterogeneity, and intensive human disturbances. Integrating the hierarchical structure of urban landscape pattern with ecosystem processes through simulation modeling can facilitate our understanding of human揺nvironment interactions in urban environment. Current ecosystem models often focus on plant physiological and biogeochemical processes in homogeneous land covers, incapable of addressing the structural complexity in urban landscapes with multiple anthropogenic drivers across a range of spatial scales. Here we present the Hierarchical Patch Mosaic-Urban Ecosystem Model (HPM-UEM), a multi-scaled model that explicitly treats spatial pattern and hierarchical structure of urban landscape by incorporating both top-down controls and bottom-up mechanisms in urban environment. By addressing six hierarchical levels from individual plant to the urbanized region, HPM-UEM provides a ierarchical ladderto scale up local ecosystem functions across the nested urban land hierarchies (i.e., land cover, land use, landscape, and the urbanized region), and facilitate linking ecosystem processes and socioeconomic drivers. By organizing human influences in a spatially nested hierarchical patch mosaic structure, HPM-UEM models the complex spatiotemporal pattern of multiple environmental constraints on urban ecosystem functions. The model was evaluated based on extensive datasets developed by the Long-Term Ecological Research (LTER) network, especially the Central Arizona-Phoenix (CAP) LTER. Model testing results showed that HPM-UEM predicted both C fluxes and spatial pattern of C stocks with reasonable accuracy. HPM-UEM enabled us to assess spatial patterns and multiple-scaled dynamics of C cycle of the urban landscape, revealing the distinct productivities and C densities of different urban land types across different spatial scales. Sensitivity analyses indicated that future environmental changes and landscape modifications could have strong and complex effects on urban ecosystem functions. By matching ecological processes, anthropogenic environmental controls, and land and socioeconomic dynamics based on hierarchical levels, HPM-UEM could be coupled to multiple-scaled urban land-use models, climate models, and socioeconomic models to gain a comprehensive understanding of urban biogeochemical cycles.
DOI:10.1016/j.ecolmodel.2012.09.020
[本文引用:1]
|
| [43] |
[本文引用:1]
|
| [44] |
AbstractGreen space is particularly indispensable for proper functioning of the ecosystem in an urban environment. This study was an attempt to dynamically map and monitor green spaces in Greater Dhaka of Bangladesh. Both primary and secondary data were acquired to document the spatial–temporal dynamics of green spaces in the study area. Using a supervised classification algorithm, multi-temporal land use/cover data were extracted from a set of satellite images. A number of spatial metrics were employed to understand the landscape condition in a multi-temporal manner. In addition, 50 key informants along with focus group discussion and observation techniques were used to document existing management aspects of green spaces and their conservation policies. The analysis revealed that green spaces in Greater Dhaka are rapidly disappearing over the course of time even though they provide a number of natural, economic and social benefits. The disappearance of green spaces was primarily attributed to a rapid increase in the urban population, mainly driven by rural–urban migration. As a result, the landscape became highly fragmented and less connected. A substantial reduction of green patches is also leading to deterioration of the ecological condition of the landscape. The drastic reduction of green spaces in Greater Dhaka has been attributed to a lack of policy, low political motivation, and poor management. In order to ensure sustainability of green spaces and proper functioning of the city’s ecosystem, there is an urgent need for strategic green space planning.
DOI:10.1007/s11355-010-0147-7
[本文引用:1]
|
| [45] |
61LST dynamic was examined in Beijing during 2001–2009.61LST increased averagely in the whole metropolitan area but decreased in city center.61Built-up areas and barren land contribute most to UHI.61Cooling effects of ecological land is obvious with the proportion above 70%.61LST is determined more by landscape composition than spatial configuration.
DOI:10.1016/j.rse.2015.11.027
[本文引用:1]
|
| [46] |
Field observations were carried out to determine the influence of a park on the urban summer climate in the nearby areas. The possibilities of reduction in air conditioning energy were investigated. Air temperature, relative humidity and other meteorological factors were measured at many locations inside a park and in the surrounding areas in the Tama New Town, a city in the west of the Tokyo Metropolitan Area, Japan. The observations indicated that vegetation could significantly alter the climate in the town. At noon, the highest temperature of the ground surface of the grass field in the park was 40.3 °C, which was 19 °C lower than that of the asphalt surface or 15 °C lower than that of the concrete surface in the parking or commercial areas. At the same time, air temperature measured at 1.2 m above the ground at the grass field inside the park was more than 2 °C lower than that measured at the same height in the surrounding commercial and parking areas. Soon after sunset, the temperature of the ground surface at the grass field in the park became lower than that of the air, and the park became a cool island whereas paved asphalt or concrete surfaces in the town remained hotter than the overlying air even late at night. With a size of about 0.6 km 2 , at noon, the park can reduce by up to 1.5 °C the air temperature in a busy commercial area 1 km downwind. This can lead to a significant decrease of in air conditioning energy in the commercial area.
DOI:10.1016/S0378-7788(98)00032-2
[本文引用:1]
|
| [47] |
Abstract <p>Quantifying the effects of urban land use/land cover with regard to surface radiation and heat flux regulation is important to ecological planning and heat stress mitigation. To retrieve the spatial pattern of heat fluxes in the Beijing metropolitan area, China, a remote sensing-based energy balance model was calibrated with synchronously measured energy fluxes including net radiation, latent heat flux (LE), and sensible heat flux ( H ). Our model calibration approach avoided the uncertainties due to subjective judgments in previous empirical parameterization methods. The land surface temperature (LST), H , and Bowen ratio ( 尾 ) of Beijing were found to increase along the outskirt-suburban-urban gradient, with strong spatial variation. LST and H were negatively correlated with vegetation fraction cover (VFC). For example, the modern high-rise residential areas with relatively higher VFC had lower H and 尾 than the traditional low-rise residential areas. Our findings that indicate thermal dissipation through vegetation transpiration might play an important role in urban heat regulation. Notably, the thermal dissipating strength of vegetation (calculated as LE/VFC) declined exponentially with increased VFC. For the purpose of heat stress regulation, we recommend upgrading the traditional low-rise residential areas to modern high-rise residential areas and focusing urban greenery projects in areas whose VFC
DOI:10.1002/2014JD022249
[本文引用:2]
|
| [48] |
用遥感和地理信息系统的方法定 量地获取哈尔滨市的热岛效应和绿地状况的空间信息,探讨哈尔滨市热力场空间格局影响因素和城市绿地缓解热岛效应的机制。结果表明:地表辐射温度随绿地覆盖 率的增加而下降;绿地面积小于5hm2时,地表辐射温度在16～30℃间变动,此时绿地面积大小对地表辐射温度影响所占比重较小,辐射温度的主要决定因子 为绿地覆盖率,如增加10%的绿地,辐射温度将降低2℃左右。当绿地面积大于5hm2时,绿地对地表辐射温度的改善大大提高,地表辐射温度呈明显下降趋 势,此时地表辐射温度值由绿地面积与绿地覆盖率共同决定。
DOI:10.3969/j.issn.1000-5382.2010.08.020
[本文引用:2]
|
| [49] |
We measured air temperature in an urban green area that includes forest and grassland and in the surrounding urban area for a full year in Nagoya, central Japan, to elucidate seasonal variations of the difference in air temperature between urban and green areas. We determined the range of the “cool-island” effect as well as the relationship between vegetation cover and air temperature throughout the year. The temperature difference between urban and green areas was large in summer and small in winter. The maximum air temperature difference was 1.9 °C in July 2007, and the minimum was 610.3 °C in March 2004. The difference was larger during the day than during the night in summer, whereas in winter the opposite relationship was true. However, winter diurnal variation was not particularly noticeable, a behaviour thought to be related to reduced shading by deciduous trees in the green area. During the night, the cooling effect of the green area reached 200–300 m into the urban area. During the day, the cooling effect between August and October 2006 exceeded 300 m and varied widely, although there was no correlation beyond 500 m. The correlation between air temperature and forest-cover ratio within a radius of 200 m from each measurement site was significant from 16:00 to 19:00. There was also a correlation during the night; this correlation was weakest in the early morning. The effect of the forest-cover ratio on air temperature was most pronounced in August 2006 and June 2007.
DOI:10.1016/j.ufug.2009.10.002
[本文引用:1]
|
| [50] |
[本文引用:1]
|
| [51] |
[本文引用:1]
|
| [52] |
[本文引用:1]
|
| [53] |
[本文引用:1]
|
| [54] |
[本文引用:1]
|
| [55] |
With the release of March 2006 data, BLS has updated the ECI to reflect the new industry and occupational classifications systems; rebased the index to 2005; and implemented new procedures to account for missing data and to compute seasonal adjustments
DOI:10.2307/41863035
[本文引用:1]
|
| [56] |
不仅城市绿地的植被数量对热岛效应产生影响,而且其绿地斑块的面积、形状及空间分布特征都会 对热岛效应产生影响,为充分发挥城市绿地对热岛效应的缓解作用,需要对城市绿地与热岛效应的关系进行深入研究。结合研究成果,对城市绿地与热岛效应关系领 域的研究成果作综述,包括：缓解城市热岛效应的措施研究;绿地对热岛影响的定量研究;植被数量与热岛关系、植被种类与热岛关系和绿地空间特征与热岛关系等 的规律研究;并提出了该领域的一些问题和进一步研究的方向。
DOI:10.3969/j.issn.1000-6664.2012.04.010
[本文引用:1]
|
| [57] |
Urban parks can help mitigate urban heat island (UHI) effects and decrease cooling energy consumption in summer. However, it is unclear how park characteristics affect the formation of a park cool island (PCI). In this study, PCI intensity values for 92 parks in Nagoya, Japan were obtained from ASTER land surface temperature (LST) products and then correlated to detailed and use information derived from high-spatial-resolution IKONOS satellite data. The results indicate that (1) the cooling effect depends on the park size and seasonal radiation condition, and park size is non-linearly correlated to PCI intensity; (2) PCI intensity is mainly determined by the area of tree and shrub inside the park as well as the park shape, and grass has negative impact on PCI formation. The park vegetation and shape index (PVSI) proposed here well predicted PCI intensity of selected parks. These findings can help urban planners to understand PCI formation and design cool parks to counteract UHI effects.
DOI:10.1016/j.landurbplan.2010.03.008
[本文引用:1]
|
| [58] |
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.
DOI:10.1016/j.jag.2009.03.001
[本文引用:1]
|
| [59] |
We find that ecological context significantly influences the amplitude of summer daytime UHI (urban–rural temperature difference) the largest (802°C average) observed for cities built in biomes dominated by temperate broadleaf and mixed forest. For all cities combined, ISA is the primary driver for increase in temperature explaining 70% of the total variance in LST. On a yearly average, urban areas are substantially warmer than the non-urban fringe by 2.902°C, except for urban areas in biomes with arid and semiarid climates. The average amplitude of the UHI is remarkably asymmetric with a 4.302°C temperature difference in summer and only 1.302°C in winter. In desert environments, the LST's response to ISA presents an uncharacteristic “U-shaped” horizontal gradient decreasing from the urban core to the outskirts of the city and then increasing again in the suburban to the rural zones. UHI's calculated for these cities point to a possible heat sink effect. These observational results show that the urban heat island amplitude both increases with city size and is seasonally asymmetric for a large number of cities across most biomes. The implications are that for urban areas developed within forested ecosystems the summertime UHI can be quite high relative to the wintertime UHI suggesting that the residential energy consumption required for summer cooling is likely to increase with urban growth within those biomes.
DOI:10.1109/IGARSS.2010.5653907
[本文引用:1]
|
| [60] |
[本文引用:1]
|
| [61] |
Abstract Urban climate modifications like the urban heat island (UHI) have been extensively investigated in temperate regions. In contrast, the understanding of how urbanization relates to climate in hot, hyperarid environments is still extremely limited, despite the growing socioeconomic relevance of arid lands and their fast urbanization rate. We explore here the relationship between land cover and temperature regime in hot desert cities (HDCs) based on estimates of land surface temperature, normalized difference vegetation index, and impervious surface areas inferred from Moderate Resolution Imaging Spectroradiometer and Landsat satellite products. Our analysis shows that HDCs display common climatic patterns, with downtown areas on average cooler than suburbs during the daytime (urban cool island) and warmer at night (classical UHI). The observed diurnal cool island effect can be largely explained by relative vegetation abundance, percentage of bare soil, and local climatic conditions and calls for a more in deep investigation of the physical processes regulating boundary layer dynamics in arid regions.
DOI:10.1002/2015GL066534
[本文引用:1]
|
| [62] |
首先对城市热岛效应的研究历史、大气城市热岛(AUHI)和地表城市热岛(SUHI)等概念、以及数据获取方式等方面进行简要地概述;随之着重综述从景观格局角度对城市热岛效应进行的研究。统计描述、传统景观格局指数分析和模型模拟法是目前该方向研究的主要方法,统计和景观格局指数分析的研究方法相似,主要统计地表参数或地表景观格局指数与地表温度的相关关系,在SUHI的研究中用得较多;AUHI和SUHI的数据源和机理不尽相同,其研究方法也不同;AUHI一般使用固定气象站点的数据和精细的局部移动气象站数据,较难和景观格局指数结合;模型模拟法则既可以使用地表温度也可以使用大气温度,其结果具体可靠,但目前模型模拟中涉及的景观格局参数,尤其是二维或多维的格局参数并不多;最后从数据源和景观格局参数的参与两个角度讨论了该方向研究存在的问题并提出今后研究的重点,包括(1)针对研究目标,选取或生产最合适的高质量数据;(2)深入从景观格局角度模拟城市热岛效应的研究,尤其是二维和三维景观格局的模拟,并发展多维度的景观格局指数;(3)中尺度上充分利用多光谱遥和热红外遥感数据,结合小尺度的测量和模拟,建立基于机理的景观模型或格局指数以评价中尺度的城市热岛效应;(4)多领域数据的融合和多学科方法的交叉研究和应用。
DOI:10.5846/stxb201106280965
[本文引用:1]
|
| [63] |
人口的剧烈增长和科技、经济的飞速发展使人类活动对地球的影响越来越深刻。人类的不合理活动导致生态环境恶化,自然灾害频繁。为此,探求人类活动对生态环境的影响机制和作用规律,实现对人类活动方向和速率的有效调控,维持区域环境与经济的可持续发展,已经成为人地关系研究中的重要科学问题。本文综述和讨论了人类活动对生态环境影响的主要类型、途径和作用尺度;强调进行区域生态建设,发挥人类活动的能动作用在我国条件下的重要性;列举和评述了人类活动强度评价指标和对生态环境影响的临界调控指标与调控原则,为正面评估和规范人类活动提供研究思路。
DOI:10.11820/dlkxjz.2006.02.005
[本文引用:1]
|
| [64] |
Abstract Ecosystem service is the key comprehensive indicator for measuring the ecological effects of urbanization. Although various studies have found a causal relationship between urbanization and ecosystem services degradation, the linear or non-linear characteristics are still unclear, especially identifying the impact thresholds in this relationship. This study quantified four ecosystem services (i.e. soil conservation, carbon sequestration and oxygen production, water yield, and food production) and total ecosystem services (TES), and then identified multiple advantageous area of ecosystem services in the peri-urban area of Beijing City. Using piecewise linear regression, the response of TES to urbanization (i.e., population density, GDP density, and construction land proportion) and its thresholds were detected. The results showed that, the TES was high in the north and west and low in the southeast, and there were seven multiple advantageous areas (distributed in the new urban development zone and ecological conservation zone), one single advantageous area (distributed in the ecological conservation zone), and six disadvantageous areas (mainly distributed in the urban function extended zone). TES response to population and economic urbanization each had a threshold (229personkm -2 and 107.15millionyuankm -2 , respectively), above which TES decreased rapidly with intensifying urbanization. However, there was a negative linear relationship between land urbanization and TES, which indicated that the impact of land urbanization on ecosystem services was more direct and effective than that of population and economic urbanization. It was also found that the negative impact of urbanization on TES was highest in the urban function extended zone, followed in descending order by that in the new urban development zone and ecological conservation zone. According to the detected relationships between urbanization and TES, the economic and population urbanization should be strengthened accompanied by slowing or even reducing land urbanization, so as to achieve urban ecological sustainability with less ecosystem services degradation. Copyright 脗漏 2017 Elsevier B.V. All rights reserved.
|
| [65] |
DOI:10.2307/1794894
[本文引用:1]
|
| [66] |
Many states in the USA attempt to manage urban growth so that development is directed to urban areas equipped to accommodate development, and rural lands are preserved for resource and other non-urban uses. The state of Oregon is entering its third decade of what many commentators describe as the nation's most aggressive urban growth management programme administered statewide. This article reports a recent evaluation of the effectiveness of the state urban growth management policies as they are implemented by the metropolitan Portland area. The metropolitan Portland area contains the largest population, employment and land base within a single urban growth boundary in the USA. Using primary data collection and analysis, the effectiveness of the urban growth management and resource land preservation effort is assessed. Nearly all regional development has been directed to the urban growth boundary and away from resource lands. Many problems with administration are found, however. Policy implications are suggested.
DOI:10.1016/0264-8377(93)90039-D
[本文引用:1]
|
| [67] |
Regarding the relationship of city and landscape, two main positions of planning have to be distinguished: at the one side, landscape is seen as a separating element of city and suburbia. According to this view, Greenbelts are designed to protect a compact urban form. At the other side, landscape is seen as a connecting element in city regions, integrating them to regional cities. According to this view, landscape is seen as a Green middle. This article presents two contrasting case studies of planning approaches in European city regions, which represent a reversed relationship of city and landscape: the Regional Parks Berlin-Brandenburg, forming a Greenbelt around the German capital and the Green Heart as a Middle of the Dutch Randstad. In comparing both cases, the conclusion is drawn, that a negative definition of landscape form, which is derived as an urban containment, can hardly be successful to protect open spaces in growing city regions. Instead landscape has to have a positive definition, basing on the uses and perception by people.
DOI:10.1016/S0169-2046(02)00198-6
[本文引用:1]
|
| [68] |
AbstractThe pan European biological and landscape diversity strategy (PEBDLS) was developed under the auspices of the Council of Europe in order to achieve the effective implementation of the convention of biological diversity (CBD) at the European level. A key element of PEBLDS has been the development of the Pan European Ecological Network (PEEN) as a guiding vision for coherence in biodiversity conservation. PEEN has been developed in three subprojects: Central and Eastern Europe, completed in 2002; South-eastern Europe, completed in 2006; and Western Europe, also completed in 2006. The methodology of the development of the three maps has been broadly comparable but data availability, differences in national databases, technical developments and geographical differences caused variations in the detailed approach. One of the challenges was to find common denominators for the habitat data in Europe; this was solved differently for the subprojects. The project has resulted in three maps that together constitute the PEEN. They differ in terms of ecological coherence and the need for ecological corridors; for example, in Central and Western Europe corridors are essential to provide connectivity, while in Northern, Eastern and South-eastern Europe larger, coherent natural areas still exist. The future steps in developing PEEN should include the implementation of national ecological networks and, in particular, the pursuit of international coherence through the development of trans-European ecological corridors. The big challenge is to develop a common approach among the over 100 European-wide agencies that are responsible for biodiversity conservation.
DOI:10.1007/s10980-010-9567-x
[本文引用:1]
|
| [69] |
Abstract Ecological control line is a system innovation in the field of ecological environment protection in China and it has become as an important strategy of national ecological protection. Ten years have passed since the first ecological control line in Shenzhen was delimited in 2005. This study examines the connotations of ecological control line and the current study status in China and abroad, and then takes a brief description about the delimitation background and existing problems of the ecological control line in Shenzhen. The problem-solving strategy is gradually transforming from extensive management to refined management. This study proposes a differential ecological space management model that merges the space system, management system, and support system. The implementation paths include the following five aspects: delimiting ecological bottom lines to protect core ecological resources; formulating access systems for new construction projects to strictly control new construction; implementing construction land inventory reclamation assisted by market means; regulating boundary adjusting procedures and processes; and constructing ecological equity products by using multiple means to implement rights relief. Finally, this study illustrates the progress of the implementation and discusses the rigorousness and flexibility problems of ecological control line and calls for the promotion of the legislation. The management model and implementation paths proposed in this study have referential significance for developing countries and megacities to achieve ecological protection and sustainable development. Copyright 2017 Elsevier Ltd. All rights reserved.
|
| [70] |
城市地域的可持续发展必须以生态环境的可持续发展为前提和保障。景观生态学主要研究地表各种景观空间格局与生态过程及其相互作用,其原理和规律为在实践中通过优化景观格局,提高生态系统稳定性提供了理论框架。以深圳市为例,尝试综合运用生态敏感性与适宜性分析和景观格局整体优化的方法,通过对生态系统的格局分析与问题诊断,构建合理、稳定的生态系统结构,保障生态系统服务功能的正常发挥。案例研究将深圳市域的整体生态结构分为自然生态空间、城镇发展空间和生态廊道3部分。城镇发展空间具有文化支持的生态功能,自然生态空间具有环境服务和生物生产的生态功能;生态廊道主要起到加强生态联系,提高生态系统稳定性,并防止城市发展空间无序蔓延的功能。城镇景观斑块镶嵌于自然生态景观基质中,并通过多种类型的生态廊道相连,形成区域生态系统的良性循环。案例研究表明,景观生态规划方法的综合应用,可以将景观生态学原理和规律比较合理的运用于实践。
DOI:10.3321/j.issn:1000-0933.2003.09.016
[本文引用:1]
|
| [71] |
[本文引用:2]
|
| [72] |
海岸带地区是中国乃至全球人口最稠密、城市化进程最快的区域,其生态风险与安全问题是关系人群和区域可持续发展的关键。运用景观生态学和景观生态安全格局理论方法,以厦门海岛型城市向海湾型城市战略转型这一快速、大规模城市化进程为大背景,提出基于2006-2015年城市不透水面变化率、风险受体敏感指标和生态红线管控的景观生态风险空间预警模型,与通过景观源—汇理论构建的景观生态安全格局相叠加,揭示厦门市景观生态安全格局在快速城市化的胁迫下现状与未来潜在风险状态,进而提出调控措施。研究表明：（1）城市区域景观生态风险明显升高,风险预警高值区与ISA分布情况保持了较好的一致性,主要分布在以九溪流域、马銮湾、杏林湾、同安湾等港湾快速城市化区域,该部分地区城市沿河口空间外扩迅速,不透水面增长较快,对沿海湿地的侵占围填也较为严重,未来面临湿地或保护区破坏的生态风险较大。（2）生态风险预警结果与景观生态安全格局相叠加,识别出区域景观生态安全格局中处于风险状态的关键源、缓冲区、廊道、战略点,设计规划未来厦门港湾区域景观生态安全优化格局,提出景观生态恢复与重建措施。将生态风险预警方法与景观生态安全格局调控设计相结合,能为城市区域环境管理与景观调控提供科学支撑。
DOI:10.11821/dlyj201703007
[本文引用:1]
|
| [73] |
Extreme heat events are likely to become more frequent in the coming decades owing to climate change. Exposure to extreme heat depends not only on changing climate, but also on changes in the size and spatial distribution of the human population. Here we provide a new projection of population exposure to extreme heat for the continental United States that takes into account both of these factors. Using projections from a suite of regional climate models driven by global climate models and forced with the SRES A2 scenario and a spatially explicit population projection consistent with the socioeconomic assumptions of that scenario, we project changes in exposure into the latter half of the twenty-first century. We find that US population exposure to extreme heat increases four- to sixfold over observed levels in the late twentieth century, and that changes in population are as important as changes in climate in driving this outcome. Aggregate population growth, as well as redistribution of the population across larger US regions, strongly affects outcomes whereas smaller-scale spatial patterns of population change have smaller effects. The relative importance of population and climate as drivers of exposure varies across regions of the country.
DOI:10.1038/nclimate2631
[本文引用:1]
|
| [74] |
Abstract Assessment of the global burden of disease is based on epidemiological cohort studies that connect premature mortality to a wide range of causes, including the long-term health impacts of ozone and fine particulate matter with a diameter smaller than 2.5 micrometres (PM2.5). It has proved difficult to quantify premature mortality related to air pollution, notably in regions where air quality is not monitored, and also because the toxicity of particles from various sources may vary. Here we use a global atmospheric chemistry model to investigate the link between premature mortality and seven emission source categories in urban and rural environments. In accord with the global burden of disease for 2010 (ref. 5), we calculate that outdoor air pollution, mostly by PM2.5, leads to 3.3 (95 per cent confidence interval 1.61-4.81) million premature deaths per year worldwide, predominantly in Asia. We primarily assume that all particles are equally toxic, but also include a sensitivity study that accounts for differential toxicity. We find that emissions from residential energy use such as heating and cooking, prevalent in India and China, have the largest impact on premature mortality globally, being even more dominant if carbonaceous particles are assumed to be most toxic. Whereas in much of the USA and in a few other countries emissions from traffic and power generation are important, in eastern USA, Europe, Russia and East Asia agricultural emissions make the largest relative contribution to PM2.5, with the estimate of overall health impact depending on assumptions regarding particle toxicity. Model projections based on a business-as-usual emission scenario indicate that the contribution of outdoor air pollution to premature mortality could double by 2050.
|
| [75] |
The summer of 2013 was the hottest on record in Eastern China. Severe extended heatwaves affected the most populous and economically developed part of China and caused substantial economic and societal impacts. The estimated direct economic losses from the accompanying drought alone total 59 billion RMB (ref. ). Summer (June-August) mean temperature in the region has increased by 0.82 C since reliable observations were established in the 1950s, with the five hottest summers all occurring in the twenty-first century. It is challenging to attribute extreme events to causes. Nevertheless, quantifying the causes of such extreme summer heat and projecting its future likelihood is necessary to develop climate adaptation strategies. We estimate that anthropogenic influence has caused a more than 60-fold increase in the likelihood of the extreme warm 2013 summer since the early 1950s, and project that similarly hot summers will become even more frequent in the future, with fully 50% of summers being hotter than the 2013 summer in two decades even under the moderate RCP4.5 emissions scenario. Without adaptation to reduce vulnerability to the effects of extreme heat, this would imply a rapid increase in risks from extreme summer heat to Eastern China.
DOI:10.1038/nclimate2410
[本文引用:1]
|
| [76] |
The urban heat island (UHI), a common phenomenon in which surface temperatures are higher in urban areas than in surrounding rural areas, represents one of the most significant human-induced changes to Earth's surface climate. Even though they are localized hotspots in the landscape, UHIs have a profound impact on the lives of urban residents, who comprise more than half of the world's population. A barrier to UHI mitigation is the lack of quantitative attribution of the various contributions to UHI intensity (expressed as the temperature difference between urban and rural areas, ΔT). A common perception is that reduction in evaporative cooling in urban land is the dominant driver of ΔT (ref. 5). Here we use a climate model to show that, for cities across North America, geographic variations in daytime ΔT are largely explained by variations in the efficiency with which urban and rural areas convect heat to the lower atmosphere. If urban areas are aerodynamically smoother than surrounding rural areas, urban heat dissipation is relatively less efficient and urban warming occurs (and vice versa). This convection effect depends on the local background climate, increasing daytime ΔT by 3.0 ± 0.3 kelvin (mean and standard error) in humid climates but decreasing ΔT by 1.5 ± 0.2 kelvin in dry climates. In the humid eastern United States, there is evidence of higher ΔT in drier years. These relationships imply that UHIs will exacerbate heatwave stress on human health in wet climates where high temperature effects are already compounded by high air humidity and in drier years when positive temperature anomalies may be reinforced by a precipitation-temperature feedback. Our results support albedo management as a viable means of reducing ΔT on large scales.
|
| [77] |
Low impact development (LID), a comprehensive land use planning and design approach with the goal of mitigating land development impacts to the environment, is increasingly being touted as an effective approach to lessen runoff and pollutant loadings to streams. Broad-scale approaches for siting LID have been developed for agricultural watersheds, but are rare for urban watersheds, largely due to greater land use complexity. Here, we introduce a spatially-explicit approach to assist landscape architects, urban planners, and water managers in identifying priority sites for LID based exclusively on freely available data. We use a large, mixed-use watershed in central Oklahoma, the United States of America, as a case-study to demonstrate our approach. Our results indicate that for one sub-catchment of the Lake Thunderbird Watershed, LID placed in 11 priority locations can facilitate reductions in nutrient and sediment loading to receiving waters by as much as 16% and 17%, respectively. We had a high rate of correctly identified sites (94卤5.7%). Our systematic and transferable approach for prioritizing LID sites has the potential to facilitate effective implementation of LID to lessen the effects of urban land use on stream ecosystems.
DOI:10.1016/j.landurbplan.2015.04.002
[本文引用:1]
|
| [78] |
Fostering resilience in the face of environmental, socioeconomic, and political uncertainty and risk has captured the attention of academics and decision makers across disciplines, sectors, and scales. Resilience has become an important goal for cities, particularly in the face of climate change. Urban areas house the majority of the world's population, and, in addition to functioning as nodes of resource consumption and as sites for innovation, have become laboratories for resilience, both in theory and in practice. This paper reviews the scholarly literature on urban resilience and concludes that the term has not been well defined. Existing definitions are inconsistent and underdeveloped with respect to incorporation of crucial concepts found in both resilience theory and urban theory. Based on this literature review, and aided by bibliometric analysis, the paper identifies six conceptual tensions fundamental to urban resilience: (1) definition of 榰rban; (2) understanding of system equilibrium; (3) positive vs. neutral (or negative) conceptualizations of resilience; (4) mechanisms for system change; (5) adaptation versus general adaptability; and (6) timescale of action. To advance this burgeoning field, more conceptual clarity is needed. This paper, therefore, proposes a new definition of urban resilience. This definition takes explicit positions on these tensions, but remains inclusive and flexible enough to enable uptake by, and collaboration among, varying disciplines. The paper concludes with a discussion of how the definition might serve as a boundary object, with the acknowledgement that applying resilience in different contexts requires answering: Resilience for whom and to what? When? Where? And why?
DOI:10.1016/j.landurbplan.2015.11.011
[本文引用:1]
|
| [79] |
To the Editor — Jones et al.1 lay out the strong case for the many virtues of using 'ecoysytem-based approaches to adaptation' (EbA) to address current and future climate change. However, their article did not mention the burgeoning use of this approach within cities to address climate-related impacts and other environmental…
DOI:10.1038/nclimate1685
[本文引用:1]
|
| [80] |
Adapting to climate change is among the biggest challenges humanity faces in the next century. An overwhelming focus of adaptation strategies to reduce climate change-related hazards has been on hard-engineering structures such as sea walls, irrigation infrastructure and dams. Closer attention to a broader spectrum of adaptation options is urgently needed. In particular, ecosystem-based adaptation approaches provide flexible, cost-effective and broadly applicable alternatives for buffering the impacts of climate change, while overcoming many drawbacks of hard infrastructure. As such, they are a critical tool at adaptation planners' disposal for tackling the threats that climate change poses to peoples' lives and livelihoods.
DOI:10.1038/nclimate1463
[本文引用:2]
|
| [81] |
Abstract Artificial surfaces, characterized with intensive land-use changes and complex landscape structures, are important indicators of human impacts on terrestrial ecosystems. Without high-resolution land-cover data at continental scale, it is hard to evaluate the impacts of urbanization on regional climate, ecosystem processes and global environment. This study constructed a hierarchical classification system for artificial surfaces, promoted a remote sensing method to retrieve subpixel components of artificial surfaces from 30-m resolution satellite imageries (GlobeLand30) and developed a series of data products of high-precision urban built-up areas including impervious surface and vegetation cover in Asia in 2010. Our assessment, based on multisource data and expert knowledge, showed that the overall accuracy of classification was 90.79%. The mean relative error for the impervious surface components of cities was 0.87. The local error of the extracted information was closely related to the heterogeneity of urban buildings and vegetation in different climate zones. According to our results, the urban built-up area was 18.18104 km2, accounting for 0.59% of the total land surface areas in Asia; urban impervious surfaces were 11.65104 km2, accounting for 64.09% of the total urban built-up area in Asia. Vegetation and bare soils accounted for 34.56% of the urban built-up areas. There were three gradients: a concentrated distribution, a scattered distribution and an indeterminate distribution from east to west in terms of spatial pattern of urban impervious surfaces. China, India and Japan ranked as the top three countries with the largest impervious surface areas, which respectively accounted for 32.77%, 16.10% and 11.93% of the urban impervious surface area of Asia. We found the proportions of impervious surface and vegetation cover within urban built-up areas were closely related to the economic development degree of the country and regional climate environment. Built-up areas in developed countries had relatively low impervious surface and high public green vegetation cover, with 50170% urban impervious surfaces in Japan, South Korea and Singapore. In comparison, the proportion of urban impervious surfaces in developing countries is approaching or exceeding 80% in Asia. In general, the composition and spatial patterns of built-up areas reflected population aggregation and economic development level as well as their impacts on the health of the environment in the sub-watershed.
DOI:10.1007/s11430-016-5295-7
[本文引用:1]
|
| [82] |
[本文引用:1]
|