局地气候分区视角下城市气候与人居环境研究进展

城市气候与人居环境交互影响。局地气候分区(Local Climate Zone, LCZ)推动了城市形态刻画与气候演变规律探索,为城市气候与人居环境研究提供了统一框架。学术界对其研究大多聚焦在城市热环境和气候风险方面,正在向多要素气候模拟和考虑社会经济因素方向发展。审查了主题、方法和主要结论,发现"局地气候分区"、"城市热岛"、"地表温度"、"管理"和"社区"出现频率最高。采用文献计量和专题分析方法,梳理并总结了2012-2023年6月LCZ城市气候与人居环境研究在LCZ制图、相互作用和适应性策略三方面的进展,并展望了未来的研究重点。结果表明,① 全球已在超过280座城市开展了LCZ研究,LCZ全球数据集的推广扩大了研究尺度且丰富了研究内容;② 大多研究分析了风热环境为主的气候要素在局地尺度上的时空特征,探讨产生异质性的原因及其对人居环境的作用机理,揭示了城市蓝绿空间对于优化冷却效果、防范和治理热源等缓解性策略的重要性。其中自2018年起LCZ热环境研究向多元化发展,研究区域开始出现大都市圈或城市群;③ LCZ能够辅助识别人居环境中高度暴露和脆弱的地区,近年来的研究趋向于在气候/生态风险评估中寻找适应性策略,且更加关注易感人群和低收入者。综述将有利于LCZ框架下城市气候与人居环境研究现状和发展趋势的宏观把握,为后续研究提供思路。     

Profiling urban vulnerabilities to climate change: An indicator-based vulnerability assessment for European cities

Governing climate change in cities entails a good understanding of urban vulnerabilities. This research presents an Indicator-based Vulnerability Assessment for 571 European cities. Basing on panel data from Urban Audit database and a set of newly developed indicators, we assessed urban vulnerabilities for the following impact chains: (i) heatwaves on human health; (ii) drought on water planning, and; (iii) flooding (sub-divided into pluvial, fluvial and coastal) on the socio-economic tissue and the urban fabric. Results shed light on the key challenges that specific groups of European cities face in order to better deal with the expected impacts of climate change. This knowledge is a necessary step to advance in the understanding of urban risks to climate change and the development of effective EU policies for urban adaptation.     

From the urban metabolism to the urban immune system

Urban areas face mounting risks from many sources. Cities pursue myriad tactics to resist, recover from and adapt to shocks and stresses, but little is known about how these approaches relate across the scales of a city nor how cities compare in their abilities. Part of the challenge in addressing these gaps is that the risk to cities is typically studied with an emphasis on one or a few hazards or through the lens of a singular sector. This paper proposes a framework, dubbed the Urban Immune System (UIS) to coalesce and expand industrial ecology research on urban risk management. In the same way that Urban Metabolism (UM) is a unifying framework for urban environmental sustainability, UIS can be a unifying framework for urban resilience, especially related to climate change. Herein, UIS is defined, its many capabilities are dissected and linked to disparate studies; and opportunities for application of the concept are provided. The paper concludes by examining the relationship between UIS and climate change and by identifying those attributes of the UIS that are expected to be of increasing importance under climate change.     

Heat island effects in urban life cycle assessment: Novel insights to include the effects of the urban heat island and UHI‐mitigation measures in LCA for effective policy making

Urbanization often entails a surge in urban temperature compared to the rural surroundings: the Urban Heat Island (UHI) effect. Such a temperature increase triggers the formation of pollutants worsening the urban air quality. Jointly, bad air quality and UHI affect ecosystems and human health. To alleviate the impacts on the population and the environment, it is crucial to design effective UHI‐mitigation measures. Life Cycle Assessment (LCA) is an assessment tool able to capture the complexity of urban settlements and quantify their impact. Yet, as currently implemented, LCA neglects the interactions between the built environment and the local climate, omitting the resulting impacts. This study reviews the existing literature, showing the lack of studies that organically include interactions between the built environment and local climate in LCA. This forms the basis to identify the unsuitability of the current LCA framework for comprehensively capturing the impact of urban settlements. To overcome this limitation, this research offers a pathway to expand the LCA methodology, indicating the necessity to (a) couple the LCA methodology with climate models or physical relations that quantify the interactions between the local climate and the built environment; (b) include novel impact categories in LCA to address such interactions; and (c) use existing or ad hoc developed characterization factors to assess the impacts related to the UHI effect. The LCA community can build on the frame of reference offered by this research to overcome the current limitations of LCA and enable its use for a comprehensive assessment of the impacts of UHI and its mitigation measures.     

Effects of City Expansion on Heat Stress under Climate Change Conditions

We examine the joint contribution of urban expansion and climate change on heat stress over the Sydney region. A Regional Climate Model was used to downscale present (1990–2009) and future (2040–2059) simulations from a Global Climate Model. The effects of urban surfaces on local temperature and vapor pressure were included. The role of urban expansion in modulating the climate change signal at local scales was investigated using a human heat-stress index combining temperature and vapor pressure. Urban expansion and climate change leads to increased risk of heat-stress conditions in the Sydney region, with substantially more frequent adverse conditions in urban areas. Impacts are particularly obvious in extreme values; daytime heat-stress impacts are more noticeable in the higher percentiles than in the mean values and the impact at night is more obvious in the lower percentiles than in the mean. Urban expansion enhances heat-stress increases due to climate change at night, but partly compensates its effects during the day. These differences are due to a stronger contribution from vapor pressure deficit during the day and from temperature increases during the night induced by urban surfaces. Our results highlight the inappropriateness of assessing human comfort determined using temperature changes alone and point to the likelihood that impacts of climate change assessed using models that lack urban surfaces probably underestimate future changes in terms of human comfort.     

基于暴露度-恢复力-敏感度的城市适应气候变化能力评估与特征分析

城市是人口和社会经济活动最密集的地方,随着城市化进程和气候变化的发展,城市地区面临的气候风险和影响日益凸显。提升城市适应气候变化能力已成为城市应对气候变化挑战最重要的任务和途径。通过梳理和评价我国城市适应气候变化能力及其关键要素,以期为区域适应政策的制定和实施提供科学依据。基于IPCC适应能力评价框架,构建了基于暴露度-敏感度-恢复力的城市适应气候变化能力评估框架,进而筛选了19项指标,将指标划分为适应气候变化能力对应的5个等级,以熵权法赋权重;采用集对分析方法,评估我国286个地级市的适应气候变化能力水平,并分析了主要限制因素。结果显示,我国东部的适应能力整体高于西部地区,适应能力较低的区域主要集中在西北的甘肃陕西部分城市、华中的两湖和江西等城市以及西南的广西云南等城市;城市适应能力的各项限制要素主要表现为,适应能力高主要为暴露度-恢复力-敏感度的(低-高-低)的组合;适应能力低则分别包括暴露度-恢复力-敏感度(高-高-高)、(低-低-低)和(高-低-低)3种组合。提高城市适应气候变化能力,对西部西北的甘肃-陕西等城市,重点在于提升应对气候变化的恢复力,例如建立良好的灾后恢复与应急系统等;对于华中、西南等城市则以提高气候风险的防御能力为主。     

Insurance Value of Green Infrastructure in and Around Cities

The combination of climate change and urbanization projected to occur until 2050 poses new challenges for land-use planning, not least in terms of reducing urban vulnerability to hazards from projected increases in the frequency and intensity of climate extremes. Interest in investments in green infrastructure (interconnected systems of parks, wetlands, gardens and other green spaces), as well as in restoration of urban ecosystems as part of such adaptation strategies, is growing worldwide. Previous research has highlighted the insurance value of ecosystems in securing the supply of ecosystem services in the face of disturbance and change, yet this literature neglects urban areas even though urban populations are often highly vulnerable. We revisit the insurance value literature to examine the applicability of the concept in urban contexts, illustrating it with two case studies: watersheds providing drinking water for residents of Vancouver, Canada; and private gardens ensuring connectedness between other parts of urban green infrastructure in London, UK. Our research supports the notion that investments in green infrastructure can enhance insurance value, reducing vulnerability and the costs of adaptation to climate change and other environmental change. Although we recommend that urban authorities consider the insurance value of ecosystems in their decision-making matrix, we advise caution in relying upon monetary evaluations of insurance value. We conclude by identifying actions and management strategies oriented to maintain or enhance the insurance value of urban ecosystems. Ecosystems that are themselves resilient to external disturbances are better able to provide insurance for broader social–ecological systems.     

Mean radiant temperature in idealised urban canyons—examples from Freiburg, Germany

Studies on the thermal comfort of humans in urban areas require meteorological data such as air temperature, air humidity, wind speed, and short- and long-wave fluxes. In such studies radiation fluxes can be expressed by the mean radiant temperature—a parameter with high variability in urban areas due to variability in global radiation. Wind speed in urban areas is influenced by urban obstacles and their orientation. Both mean radiant temperature and wind speed can be modified or changed by different height-to-width ratios or orientation of urban structures. Modifications to these parameters by typical urban structures (represented by the height-to-width ratio) can result in variation of mean radiant temperature over a range of more than 30°C, which can correspond to three levels of thermal stress. The results presented here provide a possible means of comparing different urban configurations in different climate regions.     

Effects of urbanization–climate interactions on range expansion in the invasive European pavement ant

Global changes, such as climate and urbanization, are strongly entwined and aggravated by the development of human activities, which also intensifies the human-mediated dispersal of species. However, few studies have explicitly considered the combined influence of urbanization and climate on species expansion. We investigated the combined roles of climate, urbanization and human-mediated dispersal in the expansion of Tetramorium immigrans (an invasive pavement ant in North America) in urban areas of South-eastern France. A total of 544 T. immigrans individuals were sampled from 16 urban gradients and genotyped at 14 microsatellite markers. Based on molecular ecology methods and statistical modelling, we evaluated the impact of climate and urbanization on its distribution patterns. Through the combined study of the occurrence probabilities of T. immigrans, its genetic structure and the founder effects within its populations, the effect of climate–urbanization interaction on species distribution was clearly evidenced, suggesting that in the north of its range, T. immigrans subsists under harsher climate by colonizing the most urbanized areas. Many taxa may conform to such pattern, making the combined study of climate and urbanization a necessary challenge for future studies. Distribution patterns concurred with similar observations in the American invasive range of T. immigrans, making it likely that it may not be native to the northernmost part of its European range. Cryptic invasions or discreet range shifts in response to increasing urbanization are likely to occur in many taxa, especially in ants, and deserve increased attention from researchers and managers alike.     

Urban alien plants in temperate oceanic regions of Europe originate from warmer native ranges

When colonizing new areas, alien plant species success can depend strongly on local environmental conditions. Microclimatic barriers might be the reason why some alien plant species thrive in urban areas, while others prefer rural environments. We tested the hypothesis that the climate in the native range is a good predictor of the urbanity of alien species in the invaded range. The relationship between climate in the native range and the percentage of artificially sealed surfaces (urbanity) at the occurrences of 24 emerging alien plant species, in European areas with a temperate climate (termed oceanic Europe) was evaluated. We found that alien species growing in more urban environments originated from warmer or drier native ranges than found in oceanic Europe. These results have strong conservation implications as climate-warming will likely lift climatic barriers that currently constrain numerous alien plant species to cities, boosting the role of cities as points of entry for invasive plants.

     

城市湖泊富营养化成因和特征*

城市湖泊的功能主要体现在旅游、如愿、洪涝调蓄排水、调节气候以及改善城市生态环境等方面。根据湖泊所处地理位置和湖泊水质退化现象,阐述了城市湖泊水体从贫营养到富营养转变的主要原因;从水质的理化指标、底质污染物含量和水生态系统等方面初步时论了城市型浅水湖泊富营养化的特征。同非城市湖泊相比:大部分城市湖泊的水体透明度下降,污染严重的湖泊还会出现水体发黑或出现水华;水质和底质的氮磷及其它污染物含量较高,水生态系统急剧退化,水生植物以浮游植物为主,藻类大量繁殖,高等水生植物不断消亡。根据综合营养度指数对我国主要城市湖泊进行分级评价的结果表明,我国城市湖泊均达到了富营养化或严重富营养化程度。     

城市森林研究进展

城市森林是一门正在形成和发展的新兴学科 ,它从森林学的角度 ,对城市这一人类活动的中心进行研究探讨 ,为我们认识和解决当代城市问题 ,开辟了新的思路。随着城市人口剧增 ,工业化进程加速发展 ,城市环境质量迅速下降 ,造成了大气、水、土壤、噪声等污染 ,而且使城市热岛效应不断加剧 ,严重损害了人类的身心健康。我国已经开始关注和探讨城市森林建设 ,但目前多局限于理论研究上 ,具体实践还刚起步 ,对城市森林的概念、范畴、原则、标准和实施措施还有不同的理解 ,并且许多研究还囿于林业的范畴 ,如何真正与城市有机结合还有待于进一步探讨…     

A conceptual framework for urban ecological restoration and rehabilitation

Urban greenspace has gained considerable attention during the last decades because of its relevance to wildlife conservation, human welfare, and climate change adaptation. Biodiversity loss and ecosystem degradation worldwide require the formation of new concepts of ecological restoration and rehabilitation aimed at improving ecosystem functions, services, and biodiversity conservation in cities. Although relict sites of natural and semi-natural ecosystems can be found in urban areas, environmental conditions and species composition of most urban ecosystems are highly modified, inducing the development of novel and hybrid ecosystems. A consequence of this ecological novelty is the lack of (semi-) natural reference systems available for defining restoration targets and assessing restoration success in urban areas. This hampers the implementation of ecological restoration in cities. In consideration of these challenges, we present a new conceptual framework that provides guidance and support for urban ecological restoration and rehabilitation by formulating restoration targets for different levels of ecological novelty (i.e., historic, hybrid, and novel ecosystems). To facilitate the restoration and rehabilitation of novel urban ecosystems, we recommend using established species-rich and well-functioning urban ecosystems as reference. Such urban reference systems are likely to be present in many cities. Highlighting their value in comparison to degraded ecosystems can stimulate and guide restoration initiatives. As urban restoration approaches must consider local history and site conditions, as well as citizens’ needs, it may also be advisable to focus the restoration of strongly altered urban ecosystems on selected ecosystem functions, services and/or biodiversity values. Ecosystem restoration and rehabilitation in cities can be either relatively inexpensive or costly, but even expensive measures can pay off when they effectively improve ecosystem services such as climate change mitigation or recreation. Successful re‐shaping and re-thinking of urban greenspace by involving citizens and other stakeholders will help to make our cities more sustainable in the future.     

我国极端干旱天气变化趋势及其对城市水资源压力的影响

随着全球气候变化和水循环的改变,降水不均和持续干旱等极端天气事件的频度和强度增加,对水资源,尤其是人口和社会经济密度高的城市的水资源带来很大的影响和压力。为了探究我国干旱天气的变化趋势、区域特征、及其对城市水资源压力的影响,采用全国917个气象站点1951—2014年的逐日降水量数据集,分析了我国水资源及干旱的变化趋势和空间分布特征,并以我国289个主要地级市为研究对象,构建了气候变化情境下的城市基于区域降水禀赋的水资源压力评估方法,预测并展望了不同时段和不同代表性浓度路径(RCPs)情景下的未来城市水资源压力的情况。结果显示,我国极端干旱情况整体是随着全球气候变化增加的,年最长连续无降水天数变化速度的平均值为2.3d/100a,但是具有区域性,具体表现为南部地区干旱减缓而北部地区干旱严重。我国城市水资源压力受水资源禀赋的影响,呈现北方高而南方低的分布,除此之外水资源消耗大的大城市资源压力也比较大。随着气候变化,近期我国整体城市水资源压力相对现阶段增加了2%左右,具体水资源压力上升的城市有170个,水资源压力减少的城市有110个,剩下的9个城市水资源压力受气候变化的影响比较小。在低应对的RCP8.5情景下的城市水资源压力远远高于在RCP2.6情景,这说明减缓气候变化工作对降低我国城市水资源压力有积极作用;城市水资源压力的变化并不是均匀的,呈现南部减少而北部增加的变化趋势,我国华北地区城市的水资源压力最大,随着气候的变化,该地区的水资源压力也在随着时间不断增加,需要政府积极行动,提出有针对性和前瞻性的水资源规划方案,并依据方案采取措施,以应对气候变化造成的城市干旱增加。     

纽约弹性城市建设经验及其对上海的启示

面临气候变化带来的全球性环境、社会、经济灾难,许多国家、地区都制定了应对方案并采取行动。与上海市有着同样区位优势的纽约市,作为全球城市在有关气候变化的城市治理方面一直处于国际领先地位,引领全球城市开展弹性城市建设。在总结纽约弹性城市建设发展历程基础上,分析纽约市弹性城市建设所面临的挑战和机遇,未来100年总目标及其包含4个分目标,以及实现这4个分目标的具体措施。最后,对比纽约市与上海市的相似性,从弹性城市项目建设、投融资、区域合作、政府治理这4个方面为上海市弹性城市建设带来启示。     

基于三温模型的南宁市蒸散量估算及其影响因素

蒸散发是水文能量循环和气候系统的关键要素.研究蒸散发的时空变化特征及其响应气候、土地利用的变化规律,对理解城市流域水循环和生态过程效应具有重要意义.本研究基于三温模型和MODIS影像,估算并分析2001-2018年南宁市的蒸散量时空演变特征,并探讨了主要气候要素、土地利用类型对蒸散量的影响规律和驱动模式.结果表明:20...     

The bioclimate in temperate and northern cities

Climate is a basic component of the human environment. Developments in building design and indoor climate control have contributed greatly to improving human health and comfort. By contrast, the possibilities for improving urban climatic conditions by deliberate planning have been poorly exploited. The structure and processes of the urban atmosphere in extratropical regions are briefly described. The impact of certain selected urban climates on human health is summarized. The need for relevant bioclimatological design tools for applications in urban planning is stressed, followed by a brief review of some recent work on human thermal comfort. It is argued that the modification of present day comfort criteria to reflect human adaptation to climate may be important for further improvements of indoor climate, as well as for deducing the emissions of air pollutants and greenhouse gases.     

Climate Change or Land Use Dynamics: Do We Know What Climate Change Indicators Indicate?

Different components of global change can have interacting effects on biodiversity and this may influence our ability to detect the specific consequences of climate change through biodiversity indicators. Here, we analyze whether climate change indicators can be affected by land use dynamics that are not directly determined by climate change. To this aim, we analyzed three community-level indicators of climate change impacts that are based on the optimal thermal environment and average latitude of the distribution of bird species present at local communities. We used multiple regression models to relate the variation in climate change indicators to: i) environmental temperature; and ii) three landscape gradients reflecting important current land use change processes (land abandonment, fire impacts and urbanization), all of them having forest areas at their positive extremes. We found that, with few exceptions, landscape gradients determined the figures of climate change indicators as strongly as temperature. Bird communities in forest habitats had colder-dwelling bird species with more northern distributions than farmland, burnt or urban areas. Our results show that land use changes can reverse, hide or exacerbate our perception of climate change impacts when measured through community-level climate change indicators. We stress the need of an explicit incorporation of the interactions between climate change and land use dynamics to understand what are current climate change indicators indicating and be able to isolate real climate change impacts.     

基于局地气候优化的城市蓝绿空间规划途径研究进展

在高密度、高强度的城市建设模式下,我国大中城市内部均面临着热岛效应加剧、通风能力下降、灰霾天气频发等局地气候环境问题。城市蓝绿空间作为调控城市风热环境、改善大气环境质量的关键要素,已成为城市空间规划设计领域应对局地气候问题的重要研究对象。本文通过对国内外城市蓝绿空间局地气候效应研究文献资料的回顾,从城市蓝绿空间规划布局、网络构建两个层面,梳理了冷岛景观特征优化、冷岛空间镶嵌布局、通风廊道网络连通、通风廊道界面管控的规划学途径研究进展,并总结了相关研究的主要成果及存在的主要问题,提出从智能仿真平台、评估指标体系、规划设计指南、实施保障机制4方面建立城市蓝绿空间规划应对局地气候问题的研究框架,以期为城市气候适应性规划理论创新提供有益启示。     

城市三维空间形态的热环境效应研究进展

城市的三维空间形态,通过影响地表能量平衡过程和空气流动,改变城市内部热环境,并可能加剧城市热岛效应。在三维空间上定量解析格局-过程-效应关系对于城市生态安全和可持续发展具有重要意义,可为城市生态规划与景观设计提供重要科学依据。从城市三维形态的热环境效应研究角度,综述了城市三维形态的定量化研究进展;总结了城市三维形态对热环境以及空气流动、太阳辐射等过程的影响;分析了当前城市三维形态的热环境效应研究领域存在的不足。未来的研究应注重建筑与植被三维特征的综合表征,三维形态指标的选择应综合考虑其对设计规划的指导作用,并加强城市三维形态对热环境影响机理及其尺度效应的研究。