长三角城市群工业韧性的时空演变及影响因素研究

在世界经济不确定性日益增加的背景下,推进优化我国区域工业韧性演变格局和厘清工业韧性影响机制具有重要现实意义。本文以长三角城市群为例,在突变级数模型对工业韧性评价的基础上,利用核密度估计、泰尔熵指数和Tobit空间滞后面板模型,对长三角城市群工业韧性的时空演变特征及其影响因素进行探讨。研究发现：（1）长三角城市群工业韧性提升显著,总体上达到了中高韧性水平。长三角城市群工业韧性的内部差距不断缩小,但仍然存在不同空间尺度的“核心-边缘”分异格局。（2）综合实力较强的中心城市工业韧性具有显著的空间溢出效应。上海、杭州、南京、合肥及宁波等城市周边形成高水平工业韧性的集聚区。（3）工业结构是影响长三角城市群工业韧性的最主要因素。区域金融环境、政府公共服务以及区域外贸依存度均不同程度对工业韧性产生显著影响。     

琼东南盆地中央峡谷上新统块体搬运沉积体系地震特征及其分布

根据琼东南盆地深水区高分辨率2D/3D地震资料精细解释,和基于三维地震资料的相干分析,在琼东南盆地中央峡谷区发现了多期次的块体搬运沉积体系(MTDs)。研究表明,该区域块体搬运沉积体系包括3个主要的结构单元,即头部拉张区、体部滑移区和趾部挤压区,不同位置地震特征不同。大规模的块体搬运沉积体系构成了琼东南盆地中央峡谷区新近系以来地层中的重要沉积单元,并对深海沉积物的空间展布有重要的控制作用。上新世发育的一期块体搬运沉积体系,分布面积达300 km2,厚度达240 m,平面展布形态似扇形。高沉积物供给速率和不断的构造活动可能是该区域MTDs发育的主要原因。此外,地震活动、海平面变化也间接影响了MTDs的发育。     

海底峡谷水动力系统研究

海底峡谷作为海洋中油气勘探的重要指示器和富集场所,研究其复杂的水动力系统变得十分重要。海底峡谷中水动力系统包括了重力流、浊流、潮汐/内潮汐、内波、底层流、上升流和高密度陆架瀑布流(Dense Shelf Water Cascading)等要素,与峡谷外有明显的不同。首次从海底峡谷水动力系统的综合概况出发,研究了水动力作用对峡谷的侵蚀、沉积物的搬运与沉积以及特殊生态系统的塑造,总结分析了峡谷中水动力系统的主要研究手段。结果表明,海底峡谷中的水动力作用由于成因不同,各自的表现特征也不一样;重力流、内潮汐、上升流等水动力作用对峡谷的形态地貌、物质搬运以及生态系统的影响较为显著;对于常用的4种水动力系统的研究方法而言,其研究背景各不相同,且存在一定的局限性。本文为我国海底峡谷水动力系统的研究起到了一定的指导作用。     

一维热扩散湖模式在太湖的应用研究

太湖微气候条件及局地热环境的研究对于太湖周边城市地区可持续发展以及大气宏观调控具有重要意义。为了更准确模拟太湖湖-气交换,将CLM4-LISSS浅水湖泊陆面过程参数化方案耦合进入WRF中的Noah陆面过程模型。采用太湖湖上平台及岸边陆上测站观测的数据,评估了CLM4-LISSS浅水湖泊过程方案对太湖区域近地层气象条件的模拟性能。并基于耦合模型模拟研究了太湖对周边城市区域热环境的影响。结果表明,CLM4-LISSS湖泊陆面过程方案模拟的湖表面温度能反映真实温度的变化趋势。两种陆面过程方案在2 m气温的模拟值也存在一定的差异。CLM4-LISSS与Noah方案计算所得湖上2 m气温的模拟值与观测值的平均均方根误差分别为1.77和2.22℃,平均相关系数分别为0.88和0.84;模拟10 m风速的平均均方根误差分别为1.93和2.78 m/s,平均相关系数为0.72和0.68。太湖对周边城市热环境存在明显的影响。8月太湖对周边地区15时（北京时）近地层平均降温0.5-0.7℃,影响范围达60 km。06时太湖导致周边近地层平均升温达0.7-1℃,影响范围达50 km。湖风带来的冷空气抑制了城市热岛的垂直运动,在高温天气下使得苏州、无锡和常州城市地区昼间边界层下降高度可达300、400和100 m。无锡地区边界层内气温最高降幅可达0.5-0.7℃。通过选取无锡地区2015年8月28日高温小风天气作为背景条件,分析该地区湖风对城市热岛环流的影响机制。结果表明湖风能够破坏无锡地区的热岛环流结构,改变近地面热量和水汽的分布,抑制城市热岛的垂直发展,并影响至整个无锡地区。局地热力环流的变化对于局地气候以及污染物质的输送与扩散有可能产生重要影响,准确的湖泊陆面过程参数化方案对于天气预报、空气污染模拟,以及气候模拟研究等均具有重要意义。     

广州城市旅游竞争力研究及其发展战略

随着经济的发展和产业升级的不断推进,旅游业作为第三产业的重要组成部分受到高度重视,国际旅游市场竞争也日益激烈。基于国际旅游竞争力理论,选取18项旅游竞争力评价指标,采用主成分分析法对我国15个大城市进行了旅游竞争力计算与排序,并将广州与各主要城市进行对比分析。结果表明,在城市旅游综合竞争力方面,广州仅次于北京、上海位于第3位,广州在旅游市场、设施、企业等方面有竞争优势,但在旅游文化、城市环境质量、旅游意识等方面存在明湿差距。据此从营销导向、产品升级、品牌带动、持续发展和区域联动等5个方面对广州旅游发展战略选择进行了详细探讨。     

梅州城市空间形态演化及其成因分析

在把握梅州城市近千年的形成与发展历史的基础上,总结梅州城市空间形态的演化特征,剖析其空间形态演化的成因。受河流的阻碍与切割、行政建制的变迁与政府导向、城市规划的引导与控制、城市的职能转变与规模扩张等多因素的作用和影响,梅州城市空间形态呈"块状-星状-纺锤形-圈层状"演化。梅州城市空间形态的嬗变要满足历史文化名城保护的要求,分散组团状空间形态将是梅州城市空间形态的演化方向。     

Urban re-generations: afterword to special issue on the politics of urban greening in Australian cities

ABSTRACT

‘Urban re-generations' is written as an afterword to the special issue of Australian Geographer on ‘The Politics of Urban Greening in Australian Cities'. The collection prompts a deep questioning of reparative and regenerative work associated with greening, green spaces and green infrastructures. The climate-driven 2019-2020 bushfire crisis and COVID-19 have amplified the visibility of the more-than-human connectivity of our cities and the deep underlying structures of social and environmental inequity underpinning a variety of urban green spaces and agendas. Inspired by the articles in this special issue, the afterword explores how we might call back the grammars and practices of regeneration from their service to the neo-liberal, settler-colonial city and instead nurture reparative de-colonial practices that aid in the collaborative work of re-composing, becoming into better relation with, and working in modes of situated historical and cultural difference, with green and just cities.     

Rights in places: An analytical extension of the right to the city

Following recent scholarship on place and place-making, we identify key challenges for contemporary empirical research using the “Right to the City” as an analytic. We seek to distinguish between the aspirational “right” articulated as a political and conceptual call to arms on one hand, and the “actually existing rights” that are carved out through both formal and informal mechanisms (including political protest) in the everyday city on the other. Actually existing rights are defined not through fiat or via momentary revolutionary acts, but through the durability of relationships between multiple actors, including residents, citizens, states, and corporate agents. We re-articulate urban rights as actually contingent and agonistic properties of the relationships that citizens have with places. This paper uses the historic conflict over community gardens in New York as an illustration of how thinking of rights regimes as multiple, overlapping, and placed helps better illuminate potential political interventions. Thinking of rights and places as plural, overlapping, and contingent is analytically productive because it highlights (rather than overwriting) conflicts between competing articulations of rights and privileges in cities.     

Regional assessment of pan-Pacific urban environments over 25 years using annual gap free Landsat data

Urbanization and the associated change in land cover has been intensifying across the globe in recent decades. Regional studies on the rate and amount of urban expansion are critical for understanding how patterns of change differ within and among cities with varying structure and development characteristics. Yet spatially consistent and timely information on urban development is difficult to access particularly across international jurisdictions. Remote sensing based technologies offer a unique perspective on urban land cover with the data offering significant potential to urban studies due to its consistent and ubiquitous nature. In this research we applied a pixel-based image composite technique to generate annual gap-free surface reflectance Landsat composites from 1984 to 2012 for 25 urban environments across 12 countries in the Pacific Rim. Using time series composites, spectral indices were calculated and compared using a hexagonal grid ring model to assess changes in vegetative and urban patterns. Trajectories were then clustered to further investigate the spatio-temporal dynamics and relationships among the 25 cities. Performance of the clustering analyses varied depended on the temporal and spatial metrics however overall clustering results indicated relatively strong spatio-temporal similarities among a number of key cities. Three pairs of cities—Melbourne and Sydney; Tianjin and Manila; and Singapore City and Kuala Lumpur were found to be highly similar in their urban and vegetation dynamics temporally and spatially. In contrast Vancouver and Las Vegas had no similar analogous. This work demonstrates the value of utilising annual Landsat time series composites for assessing urban vegetation and urban dynamics at regional scales and potential use in sustainable urban planning, resources allocation, and policy making.     

Contamination,bioaccessibility and human health risk of heavy metals in exposed-lawn soils from 28 urban parks in southern China's largest city,Guangzhou

The total concentrations and oral bioaccessibility of heavy metals in surface-exposed lawn soils from 28 urban parks in Guangzhou were investigated, and the health risks posed to humans were evaluated. The descending order of total heavy metal concentrations was Fe > Mn > Pb > Zn > Cu > Cr > Ni > Cd, but Cd showed the highest percentage bioaccessibility (75.96%). Principal component analysis showed that Grouped Cd, Pb, Cr, Ni, Cu and Zn, and grouped Cr and Mn could be controlled two different types of human sources. Whereas, Ni and Fe were controlled by both anthropogenic and natural sources. The carcinogenic risk probabilities for Pb and Cr to children and adults were under the acceptable level (<1 × 10⁻⁴). Hazard Quotient value for each metal and Hazard Index values for all metals studied indicated no significant risk of non-carcinogenic effects to children and adults in Guangzhou urban park soils.