Urban Core Areas Research Articles

An Uncertainty Assessment of Human Health Risk for Toxic Trace Elements Using a Sequential Indicator Simulation in Farmland Soils

Toxic trace elements in farmland soils are potential threats to human health. In this study, we collected soil samples from the farmlands of southern Guangzhou. We used a sequential indicator simulation (SIS) to deal with the problem of skewed distribution in the sample data. We assessed the human health risks, as well as the uncertainties, of five toxic trace elements: arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), and mercury (Hg). The results were as follows: (1) The risk indices of two trace elements (Cd and Hg) were less than the standard threshold, which means that there was no human health risk due to Cd and Hg in the study area. However, the maximum risk indices of As, Cr, and Pb exceeded the standard threshold. In particular, the maximum risk index of Pb was twice the standard threshold; (2) The risk probabilities of As and Cr were less than 25% in most areas, and only a few parcels of farmland have a 100% risk probability. The risk map of Pb was used to identify contiguous areas of high-risk probability (i.e., 75%–100%) in the center of the study area. (3) E-type estimation by the SIS method overestimates the risk when the number of samples with concentrations above the threshold have a large proportion of total samples. Our conclusions are as follows: (1) The simulation results show that areas with high-risk indices were concentrated in the Panyu District, which is close to the Pearl River and the core urban area of Guangzhou; (2) Except for Pb, these trace elements are not likely to pose health risks in southern Guangzhou; (3) This study considers the risk probability found with the SIS method to be more reliable for visualizing regional risk.

Introduction of 35 kV km Level Domestic Second Generation High Temperature Superconducting Power Cable Project in Shanghai, China

This paper introduces the basic situation of the 35-kV domestic high temperature superconducting (HTS) power cable project in Shanghai. The target of this project is to construct and put into operation the first 35-kV km level three-phase turn-key HTS power cable project in the world. The cable transmission capacity, cable routing selection, cable structure design, cooling system configuration, etc. of the project are introduced. The project is implemented by the State Grid Corporation Shanghai Electric Power Company. A 35-kV, 1.2-km-long 220-kV inter-substation connecting HTS cable line will be constructed in the core urban area of Shanghai. So far, the type test of the HTS power cable system has been completed, and the construction of the project has begun. The project is expected to be completed and put into operation in the second half of 2020.

Shelter availability and human attitudes as drivers of rock hyrax (Procavia capensis) expansion along a rural-urban gradient.

While anthropogenic land‐use changes threaten wildlife globally, some species take advantage of such changes and disperse into urban areas. The wildlife in urban areas often promotes conflicts with humans, notably when the animals are associated with the spread of zoonotic diseases. In Israel, current urban invasion of rock hyraxes (Procavia capensis) draws public attention, since the species is a reservoir host of cutaneous leishmaniasis, a serious skin disease. The rock hyrax, however, has seldom been studied in densely populated areas, and the drivers for its urban expansion, as well as its abilities to live and spread in core urban areas, are relatively unknown. Here, we explore the rock hyrax expansion to urban areas process by examining the availability, characteristics and use of shelter along an urban gradient. Our findings suggest that a series of factors determines shelter availability and quality for the rock hyrax, which facilitates its dispersion across the urban gradient. We found that rock hyraxes from the Judean Desert expand to the peri‐urban region of Jerusalem by colonizing new rocky shelters formed as by‐products of urban development. With their populations reaching extreme densities in this area and saturating the available shelters, there is some spill over to the adjacent core urban areas where they colonize littered sites, which are made available due to the local socio‐economic conditions and cultural norms of waste disposal and illegal placement of temporary structures. Our work emphasizes the significance of the urban gradient approach for studying the mechanisms promoting wildlife expansion to cities. Our findings suggest that changes in shelter availability and quality due to urban development, and cultural norms promote shifts of the hyrax population by pushing from the already established areas and pulling into new environment across the urban gradient.

Strategies for Improving Urban Fabric in Core Area of Mysore City

The core of historical cities in India is complex areas; having historical urban fabric symbolizing the origins of the city usually endowed with significant heritage buildings and serving as a place of identity for the entire city. The core of Mysore is one such historical and prime heritage city in India. The city is known as the ‘city of palaces’. The City of Mysore originated as a small nucleus with Ambavilas palace as the focal point and has expanded around the palace as when required. The origination point is currently the core area which is the oldest city part having many prevailing heritage buildings. The core of Mysore has historic urban fabric and exhibits unique characteristics that contribute significantly to the good imageability of the city. The core is in the phase of transformation due to rapid urbanization. The disharmonious developments have resulted in the loss historical urban fabric and character, thus tarnishing the image of the city. The methodology for the study is based on field survey adopting visual survey method for data collection by techniques like photography, diagrams or maps and analyzing various literatures to comprehend the elements of urban fabric, historic evolution, growth and development of urban core areas. The paper attempts to analyze the urban fabric of Mysore core, factors affecting and suggest strategies and measures for improving the urban fabric for conserving the character of city core. The paper also intends to emphasize on challenges of core areas undergoing constant pressure of transformation prone to consequential effects of urbanization resulting in loss of character. The proposed strategies are some of the tools and techniques that could be adopted by urban designer, planner, and local planning authorities in improving the urban fabric of core area.

Spatiotemporal Changes in Ecosystem Services along a Urban-Rural-Natural Gradient: A Case Study of Xi’an, China

Urban areas are the areas that are most strongly affected by human activities, which presents many challenges to the ecosystem and human well-being. Ecosystem services (ES) are a comprehensive indicator to measure the ecological effects of urbanization. To effectively identify and evaluate the impact of urbanization on ES, the spatial-temporal pattern of ES should be considered. According to the level of urbanization, Xi’an city is divided into four regions: the urban core area, the urban extended area, the rural area, and the ecological conservation area, then, five comprehensive ecosystem services (CES) are evaluated by In VEST model. The results showed the following: (1) There is an obvious spatial heterogeneity in the distribution of ES. The ecological conservation area is the hot spot of ES supply, and the low value is mostly distributed in the urban core area. (2) The CES in the urban extended area that has undergone the greatest change between 2000 and 2015, and the rates of change in the ecological conservation area are the smallest. (3) There is a significant correlation between urbanization and ES, and the correction between landscape urbanization and ES is the most significant. (4) The agglomeration relationship between urbanization and ES in different regions is not consistent. Regional division provides a new way to understand the interaction between urbanization and ES in time and space, so as to provide better guidance for policy makers in formulating sustainable development policies to alleviate the loss of ES caused by the process of urbanization.

Effects of urbanization on resource use and individual specialization in coyotes (Canis latrans) in southern California

Urban environments are unique because fragments of natural or semi-natural habitat are embedded within a potentially permeable matrix of human-dominated areas, creating increased landscape and, potentially, habitat heterogeneity. In addition, urban areas can provide diet subsidies for wildlife species in the form of fruiting ornamental plants, trash, and domestic animals. Ecological opportunity in the forms of habitat and food heterogeneity are thought to be important mechanisms in maintaining individual specialization. Identifying which contexts, traits, and mechanisms determine the success or failure of individuals within an urban wildlife population could potentially provide predictions about which populations may succeed in human-dominated landscapes and which may experience local extinction. We used both scat and stable isotope analysis of whiskers to investigate the degree to which coyotes (Canis latrans) utilized anthropogenic subsidies and exhibited individual diet specialization across the urban-rural gradient in southern California. Land use surrounding scat and isotope sample locations was also evaluated to determine the effect of land cover on diet. Human food constituted a significant portion of urban coyote diet (22% of scats, 38% of diet estimated by stable isotope analysis). Domestic cats (Felis catus) and ornamental fruit and seeds were also important items in urban coyote diets. Consumption of anthropogenic items decreased with decreasing urbanization. In suburban areas, seasonality influenced the frequency of occurrence of anthropogenic subsidies with increased consumption in the dry season. The amount of altered open space (areas such as golf courses, cemeteries, and landscaped parks) nearby had a negative effect on the consumption of anthropogenic items in both urban and suburban areas. Contrary to our hypothesis, urban coyotes displayed reduced between-individual variation compared to suburban and rural coyotes. It is possible that the core urban areas of cities are so densely developed and subsidized that wildlife inhabiting these areas actually have reduced ecological opportunity. Suburban animals had the broadest isotopic niches and maintained similar individual specialization to rural coyotes. Wildlife in suburban areas still have access to relatively undisturbed natural areas while being able to take advantage of anthropogenic subsidies in neighboring residential areas. Therefore, areas with intermediate urban development may be associated with increased ecological opportunity and specialization.

Parking futures: Shared automated vehicles and parking demand reduction trajectories in Atlanta

The coming of automated vehicles (AVs) and Mobility-on-Demand (MoD services) is expected to reduce urban parking demand and correspondingly alter the urban parking landscape in a significant way. Multiple modeling efforts have already demonstrated that Shared AVs (SAVs) have promising potential to decrease urban parking demand. However, previous studies have only examined SAV parking demand at one point in time, with various market penetrations. It remains unclear what the demand reduction trajectory will be like during the transition period when there is a mix of SAVs, Privately-Owned AVs (PAVs), Shared Conventional Vehicles (SCVs), and Conventional Private Vehicles (CPVs). This study fills this gap by developing an agent-based simulation model to examine the spatially and temporally explicit parking reduction trends with mixed travel modes from 2020–2040. The results indicate that in the most optimal AV and MoD adoption scenario, the parking demand will decrease by over 20% after 2030, especially in core urban areas. Meanwhile, the parking demand in residential zones may double, which could lead to transportation equity concerns. Additionally, parking relocation may also induce environmental issues by generating a considerable amount of empty Vehicle Miles Traveled (VMT). To reap the benefits brought by AVs and MoD systems and to mitigate the accompanying social and environmental issues, our results suggest that proactive policymakers in the next decade will need to modify land use regulations for both new developments and existing parking infrastructure in commercial and residential zones, as well as update travel demand management policies.

北京城市潜在林木树冠覆盖的区域分布、动态变化与评价研究

PDF HTML阅读 XML下载 导出引用 引用提醒 北京城市潜在林木树冠覆盖的区域分布、动态变化与评价研究 DOI: 10.5846/stxb201811012355 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 林业公益性行业科研专项经费项目（201404301）；北京市自然科学基金项目（8152031） The regional distribution, dynamic change and assessment research of possible urban tree canopy in Beijing Author: Affiliation: Fund Project: Forestry public welfare industry scientific research 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:城市林木树冠覆盖（urban tree canopy，UTC）既是衡量一个城市生态状况的标志性指标，也是衡量森林城市建设成就的关键指标，其中的潜在林木树冠覆盖（possible urban tree canopy，简称PUTC）又与城市森林建设目标的科学制定息息相关。在国外文献与实践案例研究的基础上，以北京市六环外1km以内范围为研究对象，利用2002和2013年的0.5m分辨率航、卫片影像，通过其解译的地表覆盖数据，对其两个年度的潜在林木树冠覆盖的区域分布和动态变化进行分析，并利用人口密度、道路密度和现实林木树冠覆盖率等指标，以村（社区）为单元对其潜在林木树冠覆盖的优先度进行了分析评价。结果显示，11年间，研究区域的PUTC从40882.18hm2减少到了18845.82hm2，空间分布也呈现出沿环路越是靠近城市中心区域，其分布也越少的格局，从其类型上看，随着时间的推移，其类型的丰富度也越来越低，到2013年，则呈现出荒草地类型绝对占优的格局。PUTC的斑块数量从109892个减少为7793个，但斑块平均面积从2002年的0.37hm2增加到了2013年的2.36hm2，斑块大小格局也从2002年的小斑块占绝对优势演变为各种类型"平分秋色"的状况。以PUTC为核心的村（社区）区域潜力评价结果显示，整个研究区域在2002年时低潜力和中潜力区域范围最大，分别占到了研究区域的32.39%和28.83%，2013年时潜力格局改变为极低潜力和低潜力区域面积最大，分别占研究区域总面积的25.83%和50.94%。极高优先度和高优先度区域应该是北京城市未来重点发展城市森林的区域，目前的潜在优先度评价结果表明，其面积占比分别达到了研究区域面积的13.11%和41.79%，其中极高优先度区域主要分布在构成城市核心区的东城区和西城区，因此北京城区未来的林木树冠发展策略应该走植被潜在斑块与不透水地表潜在斑块共同开发之路。 Abstract:Urban tree canopy (UTC) is not only a landmark index to measure the ecological condition of a city, but also a key index to measure the achievement of forest city construction.The possible urban tree canopy (PUTC) is closely related to the formulation of scientific urban forest construction objectives.On the basis of foreign literatures and practical case studies,this paper analyzed the regional distribution and dynamic changes of PUTC within 1 km outside the 6th Ring Road in Beijing by using surface canopy interpretation data of 0.5 m resolution aerial and satellite images in 2002 and 2013.In addition, the priority of PUTC in village (community) was analyzed and evaluated by using population density, road density, and existence urban tree canopy coverage.The results showed that,during the 11 years, the PUTC in the study area decreased from 40882.18hm2 to 18845.82hm2. Its spatial distribution showed that the more urban centers along the loop, the less the distribution.Moreover,as time goes on, the richness of PUTC types was also getting lower and lower. By 2013, the grassland types have occupied the absolute advantage.The number of PUTC patches decreased from 109892 to 7793, but the average patch area increased from 0.37 hm2 in 2002 to 2.36 hm2 in 2013. The patch size pattern also changed from the absolute dominance of small patches in 2002 to a more equal situation of various types.The PUTC assessment showed that the whole study area was dominated by low and medium potential areas in 2002, accounting for 32.39% and 28.83%, respectively. In 2013, the potential pattern changed to the region with the largest area of severe low potential and low potential areas, accounting for 25.83% and 50.94%, respectively. This obviously indicated that the severe high priority and high priority areas should be the key areas for Beijing to develop urban forests in the future. The current results of potential priority assessment showed that the proportion of the severe high priority area and high priority areas reached 13.11% and 41.79%, respectively. The severe high priority areas were mainly distributed in the eastern and western urban core areas. Therefore, the future development strategy of forest canopy in Beijing urban area should take the road of joint development of the possible urban tree canopy patches and potential patches on impervious surface. 参考文献 相似文献 引证文献

Factors Affecting the Supply of “Missing Middle” Housing Types in Walkable Urban Core Neighborhoods

Housing preferences are changing. According to (Koebel, Lang, & Danielsen, 2004; Kolson, 2016; Myers & Ryu, 2008; Shaver, 2017; Woo, 2016), the largest demographic, the millennials, prefer low- to mid-rise housing units that are in the walkable urban core areas. These areas have access to cultural activities, entertainment, restaurants, shopping and other amenities such as parks. The retiring baby boomers who are downsizing from their single-family suburban homes are also seeking the same. As suggested by Parolek (CNU. 2015).), the Missing Middle Housing types (MMH) are one possible solution to help meet the demand. However, the demand is greater than the supply (Koebel et al., 2004; Kolson, 2016; Myers & Ryu, 2008; Shaver, 2017). This review discusses the factors that affect the supply of the MMH types. It reveals that although these housing types once existed in the urban core, attempts to reintroduce them in the area meet with opposition from several stakeholders. Additional factors which hurt the supply of MMH types include land use and zoning regulations, a lack of developer interest to develop these units, and a lack of developer financing (Glaeser et al, 2009, Doherty, 2017).

Analysis and Evaluation of Contamination Status of Polycyclic Aromatic Hydrocarbons (PAHs) in Settled House and Road Dust Samples from Hanoi

Analysis and Evaluation of Contamination Status of Polycyclic Aromatic Hydrocarbons (PAHs) in Settled House and Road Dust Samples from Hanoi

Announcement effects of urban regeneration plans on residential property values: Evidence from Ulsan, Korea

This article examines whether, and to what extent, the announcement of new urban regeneration plans has influenced residential property values in Ulsan, Korea, where state-led initiatives have recently taken place to revitalize urban core areas in a more incremental and participatory manner. This is accomplished by analyzing data for single-family residential properties sold from January 2014 to December 2016 in the Ulsan Metropolitan area. A sample of 7139 transactions is used for hedonic analysis with consideration of the detailed timing of plan information dissemination from the beginning of the planning process to the release of the final plan. The results showed that the urban regeneration strategic plan's release in December 2015 had a significant influence on the values of residential properties within and around the project sites, but this influence varied across neighborhoods. The effect of the plan release was found to be most significant in/around the project sites where residents showed a high level of willingness to participate. In these areas, price escalations were found to occur even before the release of the final plan, suggesting that appropriate planning interventions are required at early stages of urban regeneration projects to protect vulnerable groups of residents from potential displacement.

Assessing maintenance of urban core areas based on decrease of urban service facilities

Assessing maintenance of urban core areas based on decrease of urban service facilities

Impact of Urbanization and Climate on Vegetation Coverage in the Beijing–Tianjin–Hebei Region of China

Worldwide urbanization leads to ecological changes around urban areas. However, few studies have quantitatively investigated the impacts of urbanization on vegetation coverage so far. As an important indicator measuring regional environment change, fractional vegetation cover (FVC) is widely used to analyze changes in vegetation in urban areas. In this study, on the basis of a partial derivative model, we quantified the effect of temperature, precipitation, radiation, and urbanization represented as nighttime light on vegetation coverage changes in the Beijing–Tianjin–Hebei (BTH) region during its period of rapid resident population growth from 2001 to 2011. The results showed that (1) the FVC of the BTH region varied from 0.20 to 0.26, with significant spatial heterogeneity. The FVC increased in small cities such as Cangzhou and in the Taihang Mountains, while it decreased in megacities with populations greater than 1 million, such as Beijing and Zhangjiakou Bashang. (2) The BTH region experienced rapid urbanization, with the area of artificial surface increasing by 18.42%. From the urban core area to the fringe area, the urbanization intensity decreased, but the urbanization rate increased. (3) Urbanization and precipitation had the greatest effect on FVC changes. Urbanization dominated the FVC changes in the expanded area, while precipitation had the greatest impacts on the FVC changes in the core area. For future studies on the major influencing factors of FVC changes, quantitative analysis of the contribution of urbanization to FVC changes in urban regions is crucial and will provide scientific perspectives for sustainable urban planning.

A multi‐modal transportation data‐driven approach to identify urban functional zones: An exploration based on Hangzhou City, China

AbstractRecent urban studies have used human mobility data such as taxi trajectories and smartcard data as a complementary way to identify the social functions of land use. However, little work has been conducted to reveal how multi‐modal transportation data impact on this identification process. In our study, we propose a data‐driven approach that addresses the relationships between travel behavior and urban structure: first, multi‐modal transportation data are aggregated to extract explicit statistical features; then, topic modeling methods are applied to transform these explicit statistical features into latent semantic features; and finally, a classification method is used to identify functional zones with similar latent topic distributions. Two 10‐day‐long “big” datasets from the 2,370 bicycle stations of the public bicycle‐sharing system, and up to 9,992 taxi cabs within the core urban area of Hangzhou City, China, as well as point‐of‐interest data are tested to reveal the extent to which different travel modes contribute to the detection and understanding of urban land functions. Our results show that: (1) using latent semantic features delineated from the topic modeling process as the classification input outperforms approaches using explicit statistical features; (2) combining multi‐modal data visibly improves the accuracy and consistency of the identified functional zones; and (3) the proposed data‐driven approach is also capable of identifying mixed land use in the urban space. This work presents a novel attempt to uncover the hidden linkages between urban transportation patterns with urban land use and its functions.

Analysis of the Effects of the River Network Structure and Urbanization on Waterlogging in High-Density Urban Areas—A Case Study of the Pudong New Area in Shanghai

In the process of urbanization, high-intensity human activities have seriously disturbed the river networks, especially in the core urban areas of large cities. At present, a series of urban water environmental problems, such as urban waterlogging and non-point pollution, caused by damage to the river network structure and the decrease in surface permeability conditions in high-density urban areas have received widespread attention. In this study, the effects of the river network structure and urbanization on urban waterlogging were analyzed in the Pudong New Area by using the data of waterlogging sites on the Amap. The results showed that the average water surface ratio is 10.9%, the average river network density is 4.59 km/km2, and the comprehensive impervious ratio is 42.8%. From northwest to southeast, the impervious ratio of the Pudong New Area decreases gradually, and the water surface ratio and the river density increase gradually, while the areas with high waterlogging density are mainly concentrated in the northwest districts. The correlation coefficients indicate that the river network structure (−0.710 and −0.716) has a greater impact on waterlogging than urbanization (0.608) does. The current water surface ratio (10.9%) of the study area generally meets the requirements of the suitable water surface ratio (10.0%) in a rainfall return period of 50 years. However, the water surface ratio and the river density in about half of the districts did not meet the requirements of the suitable river network structure.

Study of the School–Residence Spatial Relationship and the Characteristics of Travel-to-School Distance in Shenyang

The school–residence spatial relationship is a key factor in understanding urban spatial structure and travel-to-school behavior of students. Analyzing the change law and the spatial characteristics of travel-to-school distance can provide a basis for improved accessibility of urban educational facilities and enable enrolment of students from the neighborhood. Based on one complete month of mobile phone signaling data for May 2018, the changes in student density with the travel-to-school distance was analyzed using MATLAB and Mann–Kendall Trend Test, and the pattern and the spatial structure of travel-to-school were explored. The results revealed that: (1) With increase in travel-to-school distance, the student density showed a decrease in truncated power law distribution, and it is concentrated within the travel-to-school distance of 5.0 km; (2) According to the sudden change points of the student density growth rate, the threshold distance for travel to kindergartens is 1.30 km, and for primary schools and secondary schools is 1.50 km. The school–residence spatial structure is divided according to the threshold of travel-to-school distance and the scope of attendance; (3) The dominant flow of travel-to-school is generally from urban peripheral and marginal areas to the urban core area, and partly from marginal areas to peripheral areas; (4) The pattern of travel-to-school is polycentric, and the study centers are mainly located in the urban central district north of the Hun River. The urban core area has the strongest attraction of students, while the marginal area has the weakest.

Spatial and dynamic perspectives on surface urban heat island and their relationships with vegetation activity in Beijing, China, based on Moderate Resolution Imaging Spectroradiometer data

ABSTRACTSystematically investigating the spatial and dynamic variations in surface urban heat island (SUHI) and their relationships with vegetation is needed in the context of sustainable urban development. In this study, the regional differences in the spatial and temporal variations in SUHI intensity (SUHII) were quantified, and their correlations with vegetation activity were analyzed in Beijing during 2001–2013, based on Moderate Resolution Imaging Spectroradiometer land cover/land use, land surface temperature, normalized difference vegetation index and digital elevation model. The results show that the 13-year averaged daytime SUHII presenting obvious seasonal variations was the highest (2.61°C) in urban core area and the lowest (−2.09°C) in rural area. The night-time SUHII was relatively stable in season, showing the highest SUHII (2.47°C) in urban core area and the lowest SUHII (−1.25°C) in rural area. The annual daytime SUHII decreased apparently in urban core (−0.28°C), urban (−0.10°C) and rural (−0.58°C) areas. The annual night-time SUHII increased weakly in urban core (0.20°C), urban (0.02°C) and suburban (0.08°C) areas. Correlation analyses indicate that the SUHII was negatively and significantly correlated with vegetation activity except in winter days. In addition, the significant negative correlations between daytime SUHII change and vegetation change were observed except in winter. In contrast, the correlation between night-time SUHII change and vegetation change was not observed.

Revealing Urban Public Space Patterns through Quantitative Comparison between the Old City of Nanjing and Zurich

Urban public space is indispensable in a metropolitan environment. In recent years, green space, as an important part of that public space, has been studied in terms of its pattern and equity of accessibility. However, the pattern of urban public space, including streets, has not yet been studied, nor has it been studied among different countries. To resolve this gap in information, this study conducted a quantitative comparison on the general pattern, type pattern, and scale pattern of urban public space between Zurich in Switzerland and the old city of Nanjing in China. This study also explored using the location quotient method to quantify the pattern of urban public space and its physical structure characteristics. The results show the difference between urban public space in China and Europe exists not only in quantity, scale or type, but also in the pattern of the urban public space system, including the choice of location, distribution status, and service level of that public space. The maximum location quotient of Zurich’s public space is 9.5 for the areas located in the urban core area. Meanwhile, it is 8.5 for Nanjing for areas located in the periphery of the old city. Areas with a location quotient of greater than one cover 63.3% of the urban construction land in Zurich, while only 30.8% of the corresponding urban construction land is covered in Nanjing. The area and quantity of streets are quite different as well. The street areas of Zurich account for 51.5% of the total area of public space and the number of streets account for 51.2% of the total number of public space sites, while those numbers are only 22.6% and 17.5% for Nanjing, respectively. In addition, the scale gradient of public space is polarized. Both the area ratio and quantity ratio of medium, medium-large, and large public space in Zurich exceed 92%, while the area ratio and quantity ratio of Nanjing are less than 77% and 68%, respectively. This study provides important insights for revealing urban public space patterns to facilitate the sustainability development of urban public space.

Urban Expansion and Drying Climate in an Urban Agglomeration of East China

AbstractUrban land expansion is one of the most conspicuous aspects of urbanization and has profound impacts on regional climate change. Most studies, however, focus on its impacts on surface temperature, and possible effects on atmospheric humidity are less known. By examining the humidity changes in the Yangtze River Delta urban agglomeration of China during 1961–2014, we find a prominent urban dry island (UDI) effect in this urban agglomeration, as characterized by reduced humidity and increased vapor pressure deficit in the urban core area. In the past decades, the UDI effect has been significantly intensified by rapid urban land expansion. Urban expansion contributes to around half of the decrease in atmospheric humidity and the increase in vapor pressure deficit in urban areas. These effects are particularly stronger in wet hot summer and relatively weaker in cold dry winter. We suggest that the UDI effect should be considered in future urban planning, landscape design, and climate change assessment and mitigation.

Region-county characteristic of spatial-temporal evolution and influencing factor on land use-related CO2 emissions in Chongqing of China, 1997–2015

The dependence of county industry on high CO2 emission industries makes it difficult to balance the development of county economy and CO2 emission reduction. Therefore, this article attempts to study on the spatial-temporal evolution and influencing factor on land use-related CO2 emissions at region-county level to promote county economy from CO2 source to CO2 sink. 9 regions and 38 counties in Chongqing of China were thus selected as study objects. Based on land use data, land use-related CO2 emissions were estimated using direct and indirect CO2 emission models for the period 1997–2015. On this basis, the space-time patterns were revealed from two scales of region and county. And the main factors influencing CO2 emissions according to land use were revealed based on Logarithmic Mean Divisia Index (LMDI) and geographic detector analysis (GDA), respectively. The results show that: 1) at regional scale, CO2 emissions of different regions all greatly improve in which southeastern ecological protection and development area showed the largest increase. Increases in per capita CO2 emissions in two-wing (suburban) areas are higher than those in downtown and surrounding-downtown areas. 2) at regional scale, the influences of various decomposed factors on the change of CO2 emissions fluctuate. The effect of population shows an insignificant influence on CO2 emissions. Economic development greatly influences CO2 emissions. Additionally, energy consumption shows a significant inhibitory effect on CO2 emissions while energy mix exhibits significant hysteresis. 3) at county scale, heavy CO2 emissions are concentrated in core urban areas; moderate and mild emissions occur mainly in the main urban expansion area, the region around the main urban areas, and in regional hub cities; low emissions are mainly concentrated in the Wuling mountainous area in southeast Chongqing and the Three Gorges Reservoir area in northeast Chongqing. 4) at county scale, the main influences on land use-related CO2 emissions are total energy consumption, per capita GDP, and urbanization rate. Minor influences include population size, proportion of secondary and tertiary industries, and proportion of land used for construction.