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Ozone (O3) pollution has negative impacts on human health and property. The Guangdong–Hong Kong–Macao Greater Bay Area (GBA) is facing severe O3 pollution problems due to rapid economic development. In this paper, we used sensitivity experiments and GeoDetector to analyze the effects of meteorological factors, anthropogenic emissions, and landscape patterns on O3 concentrations as well as the contributions of NOx and NMVOC (non-methane volatile organic compounds) to the variation of O3 concentrations and the causes of sectoral emissions in the GBA in 2017. The results revealed that, in GBA, the contribution of meteorology to the variation of O3 concentration was dominant both in terms of region and extent, and the contribution of emissions was relatively weak. The contribution of meteorology and emissions to O3 production was mainly contributory. Meteorology contributed significantly to O3, and its non-linear interaction with anthropogenic emissions and surface landscape affected O3 concentration changes. The degree of contribution of NOx and NMVOC varied widely among seasons, and the variation of their relative contribution areas was related to residential sector emissions and agricultural sector emissions. This article enriches the exploration of the O3 formation mechanism in the GBA and provides theoretical support for the implementation of differentiated regional and seasonal mitigation strategies for O3 concentration. [ABSTRACT FROM AUTHOR]

Ecosystems are employed to effectively protect people and communities in coastal areas from tropical cyclone (TC) hazards. Although a spatially explicit TC hazard mitigation service (TCHMS) is essential for devising adaptation strategy and resilience policy, the process and delivery of this program are unclear. We improved a capacity–exposure–demand conceptual framework using Guangdong Province, China, as a case study area, and spatial analysis was employed to assess the ecosystem service. Under this framework, we assessed "capacity" as the natural potential protection against TC hazards, "exposure" as the need for services, and "demand" as the estimated necessity of protecting coastal populations and economic interests. The analysis results were then used to map the TCHMS flow and benefit gap. The results showed that 21.6% of the whole province had low capacity, 25.3% had high exposure, and 19.3% had high demand. A significantly negative correlation was present between the TCHMS capacity and exposure, and a positive correlation was shown between the exposure and demand. In particular, the TCHMS flow and benefit were sufficient in inland areas but were severely deficient in coastal megacities. In Guangdong Province, the Pearl River Delta, and Chaoshan (CS), 3.3%, 4.0%, and 15.3% of the areas showed high demand–low capacity–high exposure patterns, respectively. Our findings will deepen the scientific understanding of the degree of protection a given ecosystem will provide to communities and infrastructures exposed to TC hazards and will thus provide scientific support for coastal ecosystem planning and management. [ABSTRACT FROM AUTHOR]

In early 2008, forest ecosystems in southern China suffered damage due to a severe ice storm disaster. The area and degree of forest damage caused by the ice storm was assessed using Satellite Pour l’Observation de la Terre (SPOT)-Vegetation images for Guangdong Province acquired between 1999 and 2008. By using the maximum value composition method and image thresholding techniques, the forest vegetation loss, expressed as the change in net primary productivity (NPP) and two indicators (I1,I2), was estimated. The damage threshold was determined by comparing the standard deviation of pixels of the undamaged areas in 2008 and other years without any disaster, which was 10%. The area of damaged forest vegetation was 47,670 km2, with the northern Guangdong Province most seriously affected. The total loss of NPP for forest vegetation was 50,578,055 t (DW) year−1, with 52 counties (43.7%) suffering forest vegetation damage. Evergreen coniferous forest was most widely affected, but evergreen broad-leaved forest was the most severely damaged vegetation type. Terrain topography influenced the damage to forest vegetation, which was found to increase with increasing elevation and slope gradient. The range and degree of damaged forest determined by remote-sensing data is consistent with the extent of the ice storm, indicating that this study provides a new approach for rapid assessment of forest disasters at a regional scale. [ABSTRACT FROM AUTHOR]

Informal housing and industrial developments in the so-called urban villages have been key features of the recent Chinese urbanization. In this article we will examine the development of urban villages in one of the most dynamic Chinese cities — Shenzhen. The article first reviews the urbanization and migration process in the region and the emergence of urban villages. It then examines informal housing, commercial and industrial developments in these villages. We analyse the politics of village urbanization and highlight the important relationship between migration and informal village development. We emphasize the contribution made by urban villages in providing affordable housing and jobs for the low-income population during the rapid urbanization and urge cautious consideration with regard to hasty and large-scale redevelopment of these villages. We conclude that the development of urban villages is a very important part of the urbanization process. Résumé L’habitat informel et les aménagements commerciaux et industriels dans les villages dits urbains constituent des caractéristiques essentielles de la récente urbanisation chinoise. Cet article examine le développement des villages urbains dans l’une des villes les plus dynamiques: Shenzhen. L’article revient d’abord sur les processus d’urbanisation et de migration dans la région et sur l’émergence des villages urbains. Il s’attache ensuite à l’habitat informel, ainsi qu’aux aménagements commerciaux et industriels, dans ces villages. La politique d’urbanisation des villages est analysée, mettant en évidence le lien important entre migration et aménagement informel des villages. L’étude souligne que les villages urbains fournissent des logements accessibles financièrement et des emplois à la population à faible revenu pendant la phase rapide d’urbanisation, et insiste sur les précautions à prendre vis-à-vis d’un réaménagement précipité et à grande échelle de ces villages. La conclusion met en avant combien le développement des villages urbains est important dans le processus d’urbanisation. [ABSTRACT FROM AUTHOR]

• A total of 91 urban water bodies were analyzed using Landsat 5 TM images. • Water area, elevation, and surrounding land cover are main influencing factors. • Surrounding land cover has a greater influence than water area in cooling effect. • These main factors should be emphasized in urban planning of water bodies. Enhancing the water cooling islands (WCIs) effect of urban water bodies is one strategy to alleviate high temperatures in urban areas. At present, the influencing factors of WCIs effect have been investigated comprehensively, but the relative importance of these factors has not been compared. In this case, urban planners cannot give priority to the most important factors when using WCIs to weaken urban heat islands effect in urban planning. Shenzhen, located in the south of Guangdong Province, China, is a rapidly urbanizing city with abundant urban water bodies. The urban heat islands effect in Shenzhen has already become severe as the city is affected by the climate and the urbanization process. This study compared the seasonal variations of WCIs in Shenzhen and explained WCI intensity based on landscape pattern, geographical location, and surrounding land cover. The main influencing factors of the WCI intensity were identified by stepwise regression analysis. The results showed that the WCIs effect was evident in all four seasons, and the intensity of cooling was the greatest in the summer, followed in decreasing order by autumn, spring, and winter. The main influencing factors found in this study include water area, elevation, and surrounding land cover. In general, surrounding land cover has a greater impact than water area during all four seasons and has a greater impact than elevation in spring, summer, and autumn. These main influencing factors have a greater impact than other factors and can be used as indicators to predict the WCI intensity of water bodies in the future. In addition, the threshold of water area affecting WCI intensity was observed, and the heat island water bodies were found in all four seasons. Among the surrounding land cover buffers of water bodies, the optimal buffer was the most correlated to the WCI intensity, and the warmer the season, the smaller the optimal buffer. This study highlights these main influencing factors, and they will help urban managers reasonably modify existing water bodies or plan new ones. [ABSTRACT FROM AUTHOR]

Abstract: The effectiveness of landscape metrics in quantifying spatial patterns is fundamental to metrics assessment. Setting 36 simulated landscapes as sample space and focusing on 23 widely used landscape metrics, their effectiveness in quantifying the complexity of such spatial pattern components as number of patch types, area ratio of patch types and patch aggregation level, were analyzed with the application of the multivariate linear regression analysis method. The results showed that all the metrics were effective in quantifying a certain component of spatial patterns, and proved that what the metrics quantified were not a single component but the complexity of several components of spatial patterns. The study also showed a distinct inconsistency between the performances of landscape metrics in simulated landscapes and the real urban landscape of Shenzhen, China. It was suggested that the inconsistency resulted from the difference of the correlation among spatial pattern components between simulated and real landscapes. After considering the very difference, the changes of all 23 landscape metrics against changing of number of patch types in simulated landscapes were consistent with those in the real landscape. The phenomenon was deduced as the sign effect of spatial pattern components on landscape metrics, which was of great significance to the proper use of landscape metrics. [Copyright &y& Elsevier]