Research on the impact assessment of urbanization on air environment with urban environmental entropy model: a case study

A new concept of urban environmental entropy was introduced to investigate the effect of urbanization on air environment considering the fact that rapid development of urbanization may have negative influence on the whole air environment system. The urban environmental entropies which were built based on the generalized thermodynamic entropy and the generalized statistic entropy, respectively. These two entropy models have been used to analyze the relationship between the development of urbanization and air environment. The negative entropy flow mechanism was proposed to reveal the advantages and approaches of regional cities in improving air environment system. A case study on 17 cities in Shandong Province of China showed that the values of urban environmental entropy were negative in most cities from 2001 to 2008, which implies that there is a positive correlation between the development of urbanization and air environment and that is a negative entropy development level in Shandong Province of China. In 2008, the urbanization of Qingdao city and Jinan city improved their air environments. Moreover, restraints for both cities in air environment improvement were recognized according to the analysis of negative entropy flow mechanism.     

Simulation of urban expansion based on cellular automata and maximum entropy model

Urban expansion is a hot topic in land use/land cover change(LUCC) researches. In this paper, maximum entropy model and cellular automata(CA) model are coupled into a new CA model(Maxent-CA) for urban expansion. This model can help to obtain transition rules from single-period dataset. Moreover, it can be constructed and calibrated easily with several steps.Firstly, Maxent-CA model was built by using remote sensing data of China in 2000(basic data) and spatial variables(such as population density and Euclidean distance to cities). Secondly, the proposed model was calibrated by analyzing training samples,neighborhood structure and spatial scale. Finally, this model was verified by comparing logistic regression CA model and their simulation results. Experiments showed that suitable sampling ratio(sampling ratio equals the proportion of urban land in the whole region) and von Neumann neighborhood structure will help to yield better results. Spatial structure of simulation results becomes simple as spatial resolution decreases. Besides, simulation accuracy is significantly affected by spatial resolution.Compared to simulation results of logistic regression CA model, Maxent-CA model can avoid clusters phenomenon and obtain better results matching actual situation. It is found that the proposed model performs well in simulating urban expansion of China. It will be helpful for simulating even larger study area in the background of global environment changes.     

A method of urban ecological risk assessment: combining the multimedia fugacity model and GIS

Industrial pollution has caused serious human health risk because the pollutants can be accumulated in human body via multi routes in a long term, especially in areas of rapid industrialization. It is of great importance to obtain the pollutants’ information, including the transport routes and spatial distribution in the various environmental media of different sub-regions, to facilitate more accurate risk assessment and more effective risk management in urban ecosystems. In this article, we proposed a research framework of urban ecological risk assessment method, which combines the multimedia fugacity model, the multi-route exposure model, exposure-risk relationships and geographic information system (GIS). An urban ecological risk assessment of a hypothetical region indicates that it is possible and feasible to introduce GIS into the previous method to satisfy the requirements of risk management. The assessment results can be further utilized for industrial pollution emission control.     

地震带城市规划模型设计与仿真

传统三维城市规划模型是利用三维技术通过计算机生成模型对城市进行规划,没有考虑城市地理位置因素,不能保障城市震后应急救灾工作效率。为此,构建一种新的地震带城市规划模型。通过对城市抗震防灾空间及防灾分区定义,并对其规划原则进行分析,从而为城市防灾空间规划提供依据;以此为基础,采用风险评估方法构建出地震带城市抗震防灾空间规划的基本模型。实验结果表明,所设计模型性能极佳,考虑到了城市地理因素,在进行城市规划的同时,能够促进城市震后应急救灾工作的高效运行。     

基于城市抗震弹塑性分析的我国主要城市建筑地震风险评估

全国尺度的城市建筑地震风险评估对城市防震减灾工作有着重要意义。本文根据全国人口普查和城市统计年鉴等给出的宏观指标建立城市建筑数据库,通过GEAR1方法(Global earthquake activity rate model 1)和第五代中国地震动参数区划图给出具体场地的地面运动强度,通过地面坡度与剪切波速的对应关系确定的场地类别来考虑地震动输入,采用城市抗震弹塑性分析方法建立建筑分析模型,通过地震经济损失风险指标和建筑严重破坏和倒塌风险作为风险评价指标,给出中国大陆主要城市建筑地震风险分布图。结果分析表明,本文方法可以基于可公开获取的数据预测全国不同城市的建筑震害风险;根据第五代地震动参数区划图给出的地面强度,地震经济损失高风险区主要是设防加速度0.3g以上地区;考虑城市人口、GDP因素后,中、东部城市因人口和财富密度较高,建筑地震风险增加明显;不同地震动选波对经济损失风险影响较小,而对倒塌风险影响较大。本文分析方法可以为城市建筑地震风险分析提供相关参考。     

A gravity-spatial entropy model for the measurement of urban sprawl

Since the mid-twentieth century, most cities worldwide have undergone a rapid expansion in urban land use. Along with the expansion, several problems, such as excessive loss of prime agricultural land and increasing traffic congestion have arisen. Thus, understanding and measurements of the expansion scale and its speed are crucial to planners and officials during urban planning and management processes. To measure such geographic phenomena, Shannon first devised entropy theory, and then Batty developed it into spatial entropy. The recently developed spatial entropy model, which was used to measure urban sprawl, introduced area to represent spatial asymmetry. However, most models did not consider spatial discretization, particularly the impact of distance. This study attempted to construct an integrated gravity-spatial entropy model to delineate distance and spatial diffusion impacts on population distribution. Then, we tested the model using Shanghai’s temporal land use and community statistical data. Application results for the new gravity-spatial model show that it is a useful tool for identifying spatial and temporal variations of urban sprawl.     

Big data and the future of urban ecology: From the concept to results

Urban ecology is experiencing the third paradigm shift. To understand the interactions between the social system and the natural system in the city across time and space, and to provide theories and solutions to sustainable urban development are essential tasks for urban ecology in the next decade. Big data can play a crucial role in future urban ecology studies due to the interdisciplinary nature of urban ecology, the fact that cities are factories of big data, and the new insights gained by using big data in studies. Nevertheless, to translate big data from a concept to research results that can guide planning, policymaking, and management of cities, we need to overcome multiple challenges existing in the theoretical framework, data acquisition, and analytic methods. Urban ecologists should enhance the collaboration with the data scientists to increase the application of big data in studies of urban biodiversity, urban ecosystem services and human wellbeing, and processes of urban ecosystems.     

Biomarkers in environmental and human health risk assessment

Marine pollution is a major threat to human and environmental health. Given the complexity of function of marine and coastal ecosystems, it is unlikely that a balanced view of the nature and extent of risk will easily be achieved if human and environmental risk assessments continue to be conducted in isolation. Here, the integration of assessment protocols is advocated as a holistic means of improving risk management. Biomarkers can provide the common conceptual framework and measurable endpoints necessary for successful integration. Examples are given of the ways in which suites of biomarkers encompassing molecular change, cellular pathology and physiological impairment can be developed and adapted for human and ecological scenarios. By placing a greater emphasis on the health status of impacted biota, it is more likely that risk assessment will develop the efficiency, reliability and predictive power to adapt to the unforeseen environmental threats that are an inevitable consequence of human development and global change.     

Multi-city sustainable regional urban growth simulation—MSRUGS: a case study along the mid-section of Silk Road of China

Urban growth along the middle section of the ancient silk-road of China (so called West Yellow River Corridor—He-Xi Corridor) has taken a unique path deviating from what is commonly seen in the coastal China. Urban growth here has been driven by historical heritage, transportation connection between East and West China, and mineral exploitation. However, it has been constrained by water shortage and harsh natural environment because this region is located in arid and semi-arid climate zones. This paper attempts to construct a multi-city agent-based model to explore possible trajectories of regional urban growth along the entire He-Xi Corridor under a severe environment risk, over urban growth under an extreme threat of water shortage. In contrast with current ABM approaches, our model will simulate urban growth in a large administrative region consisting of a system of cities. It simultaneously considers the spatial variations of these cities in terms of population size, development history, water resource endowment and sustainable development potential. It also explores potential impacts of exogenous inter-city interactions on future urban growth on the basis of urban gravity model. The algorithmic foundations of three types of agents, developers, conservationists and regional-planners, are discussed. Simulations with regard to three different development scenarios are presented and analyzed.     

Assessing urban flood and drought risks under climate change,China

Risk analysis of urban flood and drought can provide useful guidance for urban rainwater management. Based on an analysis of urban climate characteristics in 2,264 Chinese cities from 1958 to 2017, this study evaluated urban flood and drought risks. The results demonstrated that the annual average values of precipitation, aridity index, frequency and intensity of extreme precipitation and extreme drought events differed significantly in these cities. The values of the above six climatic indicators in the cities ranged from 9.29–2639.30 mm, 0.47–54.73, 1.08–8.79 time, 7.82–107.25 mm, 0.76–2.99 time, and 10.30–131.19 days, respectively. The geographical patterns of urban precipitation, aridity index, intensity and frequency of extreme precipitation and drought events in China fit well to the Hu‐Huanyong Line that was created in 1940s to identify the pattern of population distribution. Extreme precipitation in most cities has upward trends, except for those around the Hu‐Huanyong Line. The extreme drought events had upward trends in the cities east of the Hu‐Huanyong Line, but there were downward trends in the cities west of the line. The risk assessment indicated that 3.80% cities were facing serious flood and 6.01% cities were facing serious drought risks, which are located in the coast of southern China and northwestern China, respectively, and other 90.19% cities were facing different types of drought and flood risks in terms of their intensity and frequency.     

Complexity as a streamflow metric of hydrologic alteration

We explore the potential of using a complexity measure from statistical physics as a streamflow metric of basin-scale hydrologic alteration. The complexity measure that we employ is a non-trivial function of entropy. To determine entropy, we use the so-called permutation entropy (PE) approach. The PE approach is desirable in this case since it accounts for temporal streamflow information and it only requires a weak form of stationarity to be satisfied. To compute the complexity measure and assess hydrologic alteration, we employ daily streamflow records from 22 urban basins, located in the metropolitan areas of the cities of Baltimore, Philadelphia, and Washington DC, in the United States. We use urbanization to represent hydrologic alteration since urban basins are characterized by varied and often pronounced human impacts. Based on our application of the complexity measure to urban basins, we find that complexity tends to decline with increasing hydrologic alteration while entropy rises. According to this evidence, heavily urbanized basins tend to be temporally less complex (less ordered or structured) and more random than basins with low urbanization. This complexity loss may have important implications for stream ecosystems whose ability to provide ecosystem services depend on the flow regime. We also find that the complexity measure performs better in detecting alteration to the streamflow than more conventional metrics (e.g., variance and median of streamflow). We conclude that complexity is a useful streamflow metric for assessing basin-scale hydrologic alteration.     

A method characterizing urban expansion based on land cover map at 30 m resolution

Based on the global land cover data at 30 m resolution (GlobeLand30) in the year 2000 and 2010, the urban expansion process of 320 cities in China was analyzed using lognormal regression, and the expansion model were established. Three metrics were presented for the models, including the peak position, the full width at half maximum, and the skewness. It was found that the three metrics could reveal different patterns of the urban expansion process of cities with different sizes. Specifically, cities with larger size tend to expand outward strongly, and their expansion intensity and influence are likely to be higher. Moreover, most cities’ expansion occurs around the urban core with spatially limited influence. In addition, it was also found that the city’s expansion intensity is related to the city size. These results showed that the lognormal regression model could describe the distribution of urban expansion with effectiveness and robustness.     

城市活动断裂探测和地震危险性评价问题

城市范围内直下型活动断裂突发错动产生的直下型大地震 ,直接威胁城市和人民生命财产的安全。城市活动断裂探测和地震危险性评价是为城市减灾服务的一项系统工程 ,也是活动构造研究面临的一项新的工作。这一工作的核心是要解决城市范围内的断裂定位、断裂最新活动、断裂的深部背景、断裂的地震危险性和地面错动危险性及减灾对策。为了更好地理解这一问题 ,作者用“有没有、活不活、深不深 ,震不震 ,错不错 ,好对策”这 6句话来表示其核心内容。文中对这些问题作了具体的说明     

Rainwater and reclaimed wastewater for sustainable urban water use

Concern about the sustainability of urban water use is the strong motivation to understand the potential of rainwater use and water recycling in urbanized cities. The history of water supply in Tokyo and its experience may provide useful information to develop sustainable urban water use and find future possible tasks in rapidly growing cities. Besides, various innovative strategies to meet the current and future water demand in Tokyo may help us to consider new approaches adjusting to the developing mega cities in Asia. In this paper, the past and current practices on utilization of latent water resources such as rainwater and reclaimed wastewater in Tokyo are summarized from the viewpoint of sustainable water use.The storage of rainwater is a useful measure for water demand in emergency cases. In addition, the rainwater use can work as a kind of environmental education to make citizens aware of sustainable urban water use. There are 850 facilities for rainwater use in Tokyo. Since reclaimed wastewater use has several benefits, a huge water volume has been utilized for various purposes such as washing, water-cooling, toilet flushing, waterway restoration and creation of recreational waterfront. From the viewpoint of human health risk, new micropollutants such as estrogens, endocrine disrupters and surfactants should be considered as quality guideline parameter besides the conventional ones. Importance of infiltration facilities should be also highlighted to secure the sound water cycle. Groundwater recharge through the infiltration facilities provide a potential storage of water resource which can be withdrawn in the future if necessary.     

A web-based system for public–private sector collaborative ecosystem management

 To preserve biodiversity over centuries, ecosystem management will need to be accepted and practiced by individuals from a broad spectrum of society's strata. Also, management decisions will need to be based on reliable judgments of the cause and effect relationships that govern an ecosystem's dynamics. This article describes an extant, web-based ecosystem management system (EMS) that allows (a) wide participation in ecosystem assessment and policy impact predictions, (b) convenient construction of probabilistic models of ecosystem processes through an influence diagram, and (c) automatic creation of ecosystem assessment reports. For illustration, the system is used to first model the cheetah population in Kenya, and then to assess the impact on this population of different management options. The influence diagram used herein extends standard influence diagram theory to allow representation of variables governed by stochastic differential equations, birth–death processes, and other nongaussian, continuous probability distributions. For many ecosystems, data sets on ecosystem health indicators can be incomplete, small, and contain unknown measurement errors. Some amount of knowledge of an ecosystem's dynamics however, may exist in the form of expert opinion derived from ecological theory. The proposed EMS uses a nonbayesian parameter estimation method, called consistency analysis that finds parameter estimates such that the fitted ecosystem model is as faithful as possible to both the available data and the collected body of expert opinion. For illustration, consistency analysis is used to estimate the cheetah viability influence diagram using all known cheetah surveys in the country of Kenya plus current understanding of factors such as habitat and prey availability that affect cheetah population dynamics.     

中国城市地震小区划实施进展及其问题讨论

城市是人口密集、财富集中的区域,也是需要采取特别抗震设防措施的重点地区。地震小区划是精细划分城市抗震设防单元的重要技术途径,可以帮助摸清城市所面临的潜在地震灾害风险,并为城市规划和建设提供更加科学的抗震设防要求。1986—2022年6月,中国共完成城市地震小区划项目369个,地震小区划总面积22856.6km²,涉及61.3%的省会城市和直辖市、33%的设区的市和地(州、盟)驻地城市以及14.1%的县(市、区、旗)所在城市。本文利用文献调研和统计学方法,系统总结了中国城市地震小区划工作开展情况,分析存在的问题,并对今后推进地震小区划工作提出了建议。     

基于Landsat-8与ZY3多源遥感影像的城镇居民地识别与再分类研究

精细的居民地数据对地震灾害风险分析具有重要意义。 为得到具有较高时效性与精细度的居民地数据, 充分发挥其对人口、 建筑物空间展布的指示作用, 本文综合利用多源遥感影像的优势, 基于分层分类思想开展城镇居民地识别与再分类研究。 以甘肃天水秦州区的主城区为例, 采用具有较高时效性的Landsat-8 OLI影像, 建立决策树分类模型识别出居民地轮廓; 在居民地轮廓内部, 进一步采用资源三号卫星(ZY3)高分影像, 利用面向对象方法进行居民地内部的建筑群再分类, 最后得到了具有不同精细程度的居民地数据。 实验结果中Landsat-8土地覆盖分类总体精度为92%(其中居民地识别率达86%), 城镇居民地再分类的总体精度为81%, 说明了本文研究方案的可行性。     

地震动参数区划中的不确定性分析

基于《中国地震动参数区划图》(GB18306-2001)中的5套潜在震源区划分及地震活动性参数方案,计算了中国大陆地区所对应的50年超越概率10%和2%的基岩峰值加速度标准差和变异系数.分析了峰值加速度标准差和变异系数的空间分布特征,统计了省级、地级及县级城市峰值加速度的不确定性.结果表明,潜在震源区划分及地震活动性参数方案的不确定性对峰值加速度影响显著.标准差较大的地区与7.0级以上地震及大型活动断裂具有很强的相关性;峰值加速度变异系数较大的地区主要集中分布在我国的弱震活动地区,其次在塔克拉玛干沙漠及阿拉善高原地区.我国绝大部分城市峰值加速度标准差小于80×10-2m/s2;峰值加速度变异系数小于0.4.此外,经分析,峰值加速度的变异系数比标准差更适合表达区划图的不确定性.这些研究结果可为下一代区划图的编制工作提供一些有价值的参考.     

Urban expansion in China and its effect on cultivated land before and after initiating “Reform and Open Policy”

Urbanization in China has expanded at an unprecedented speed since the declaration of "Reform and Open Policy"and presented many challenges. Unbalanced regional development, appearance of super megacities and concomitant problems,and conflicts between urbanization and cultivated land protection are three critical problems that Chinese urbanization has to face. To develop new plans for foreseeable future urbanization in China, it is critical to understand the evolving history of cities across China. This study maps urban expansion of 60 typical Chinese cities based on large amount of remote sensing data and the labor-intensive image interpretation method, in order to understand the history of urban expansion from the 1970 s to 2013.Results showed that area of cities expanded 5.23 times compared to their area in the 1970 s. Urban expansion in China accelerated three times(1988–1996, 1999–2006, and 2009–2011) and decelerated three times(1997–1998, 2007–2008, and 2012–2013) over the 40 years. The urban area of South China expanded most significantly 9.42 times, while the urban area in Northeast China expanded only 2.37 times. The disparity among different administrative ranks of cities was even greater than(3.81 times) the differences among different regions. Super megacities have been continuously expanding at a fast rate(8.60-fold), and have not shown obvious signs of slowing down. The proportion of cultivated land among the land sources for urban expansion decreased to a small extent in the 1990 s, but cultivated land continues to be the major land source for urban expansion. Effective future urbanization needs controlling the expansion scale of large cities and reasonably developing medium and small cities, as well as balancing regional development.     

韧性城市的研究进展和韧性城乡建设的建议

城市的安全稳定、美丽宜居和可持续发展是人类对城市发展的美好追求。韧性城市理念的孕育和产生是城市在漫长发展的历史中,逐步产生和形成的城市公共安全治理的重要途径和全新理念,对城市的建设和发展至关重要,近年来受到科技界的广泛关注。本文系统地梳理了当前有关韧性城市的研究成果;追溯了韧性城市理念的起源;全面地总结了不同学者和有关国际组织关于韧性城市定义和内涵的研究成果,给出了韧性城市新的定义;总结并归纳了韧性城市的主要特征、评价指标及方法;评述了韧性城市研究领域的最新研究进展;提出了我国开展韧性城乡建设的建议。本文的工作对从事韧性城市研究的科技工作者具有参考价值,对推动韧性城市建设及理论研究有重要意义。