基础设施韧性:理解城市空间风险治理的新视角

基础设施既是政府治理的有力工具,又是城市空间风险的重要来源。在风险时代,基础设施韧性作为研究城市空间风险治理的新视角开始受到关注,但因韧性概念界定的模糊性及其关键要素内涵之间的张力,使得基础设施韧性理论的解释力不足。通过深入分析基础设施韧性概念,可以揭示其螺旋上升的动态建设路径。基础设施韧性建设通过增强城市空间的预警、响应、恢复和学习等功能,有效化解城市空间风险。但政府的基础设施风险意识不强、基础设施韧性跨域协同建设困难、相关治理职能分散等因素,导致基础设施韧性建设面临困境。应采取系统治理措施,强化基础设施韧性建设理念,通过与各建设主体协调联动形成合力,从整体上提高基础设施韧性,以有效化解城市空间风险。

The vulnerability evolution and simulation of social-ecological systems in a semi-arid area: A case study of Yulin City, China

Taking the semi-arid area of Yulin City as an example, this study improves the vulnerability assessment methods and techniques at the county scale using the VSD(Vulnerability Scoping Diagram) assessment framework, integrates the VSD framework and the SERV(Spatially Explicit Resilience-Vulnerability) model, and decomposes the system vulnerability into three dimensions, i.e., exposure, sensitivity and adaptive capacity. Firstly, with the full understanding of the background and exposure risk source of the research area, the vulnerability indexes were screened by the SERV model, and the index system was constructed to assess the characteristics of the local eco-environment. Secondly, with the aid of RS and GIS, this study measured the spatial differentiation and evolution of the social-ecological systems in Yulin City during 2000–2015 and explored intrinsic reasons for the spatial-temporal evolution of vulnerability. The results are as follows:(1) The spatial pattern of Yulin City's SESs vulnerability is "high in northwest and southeast and low along the Great Wall". Although the degree of system vulnerability decreased significantly during the study period and the system development trend improved, there is a sharp spatial difference between the system vulnerability and exposure risk.(2) The evolution of system vulnerability is influenced by the risk factors of exposure, and the regional vulnerability and the spatial heterogeneity of exposure risk are affected by the social sensitivity, economic adaptive capacity and other factors. Finally, according to the uncertainty of decision makers, the future scenarios of regional vulnerability are simulated under different decision risks by taking advantage of the OWA multi-criteria algorithm, and the vulnerability of the regional system under different development directions was predicted based on the decision makers' rational risk interval.

Soil Polycyclic Aromatic Hydrocarbons Across Urban Density Zones in Shenzhen, China: Occurrences, Source Apportionments,and Spatial Risk Assessment

Urbanization may cause increased exposure levels to polycyclic aromatic hydrocarbons （PAHs） and associated health risks for over half of the world＇s population living in cities, but little evidence has shown a direct spatial relationship between urbanization and soil PAH pollution. Based on the monitored PAH concentrations in 188 topsoil （0-5 cm） samples in Shenzhen, the most rapidly developing city in China, in recent decades, we applied geographical demarcation to determine the occurrences, source apportionments, and spatial ecological risks of soil PAHs across five zones of varying urban densities. Mean concentrations of the 16 US Environmental Protection Agency （EPA） priority PAHs （∑16PAHs） and the 7 carcinogenic PAHs （2E7CarPAHs） both followed the order： Zone D （60%-80% constructive land density （CLD）） 〉 Zone E （80%-100% CLD） 〉 Zone C （40%-60% CLD） 〉 Zone B （20%-40% CLD） 〉 Zone A （0%-20% CLD）, suggesting that the highest PAH levels occurred in the suburban-urban center transitional zone （Zone D） rather than the urban center zone （Zone E） in Shenzhen. There were significant correlations of ∑16PAHs to TOC and sampling altitude across all samples but not within highly-urbanized regions （Zones D and E）, implying a considerable disturbance of urbanization to the soil PAH pool. Source apportionments suggested that soil PAHs of all zones were mainly derived from fossil fuel combustion, with Zone E showing the highest contribution from oil sources among different zones. Spatial ecological risk analysis showed that the contaminated area （467 km2; 23.9% of total area; toxic equivalency quotients 〉 33 ng g^-1） had a higher contribution from the highly-urbanized regions （Zones D and E） than the uncontaminated area （42.3% vs. 18.1%）. Overall, our study highlighted a strong spatial relationship between urbanization and soil PAH pollution.

Urban Risk Generalization in China： Space and Governance

As an issue in Chinese urban development, handling urban risk generalization invites reflection on the structural features and internal development of the immediate or potential risks entailed in rapid urbanization across the globe. As part of research on national governance modernization, China has reached a consensus on managing urban risks. A study of spatial theory indicates that urban risk generalization in China is essentially a structural issue arising from an immature system of generalized benefits in urban space rights and interests along with an unbalanced spatial structure, functional disarray and ecological disruption arising from inequitable and unbalanced urban spatial development, readjustment and renovation. As an innovative form of modern urban public management with its target shifting from the pursuit of material things to people-centered development, spatial management enlists actors including government, business, society and citizens to seek a ＂community of shared spatial interests＂ with a rational structure, effective functions and an optimized environment at the level of spatial production and interest distribution. We need innovation in the spatial structures, drivers and mechanisms of urban public management and cultural ecology to realize their institutionalization, synthesis and reordering, strategically forestalling and resolving urbanization risks and realizing a spatial governance vision of the scientific, fair and sustainable allocation, growth and renovation of urban space in the risk era.