Enhanced Cooling Efficiency of Urban Trees on Hotter Summer Days in 70 Cities of China

Increasing the urban tree cover percentage(TCP) is widely recognized as an efficient way to mitigate the urban heat island effect. The cooling efficiency of urban trees can be either enhanced or attenuated on hotter days, depending on the physiological response of urban trees to rising ambient temperature. However, the response of urban trees' cooling efficiency to rising urban temperature remains poorly quantified for China's cities. In this study, we quantify the response of urban trees' cooling efficiency to rising urban temperature at noontime [~1330 LT(local time), LT=UTC+8] in 17summers(June, July, and August) from 2003–19 in 70 economically developed cities of China based on satellite observations. The results show that urban trees have stronger cooling efficiency with increasing temperature, suggesting additional cooling benefits provided by urban trees on hotter days. The enhanced cooling efficiency values of urban trees range from 0.002 to 0.055℃ %-1 per 1℃ increase in temperature across the selected cities, with larger values for the lowTCP-level cities. The response is also regulated by background temperature and precipitation, as the additional cooling benefit tends to be larger in warmer and wetter cities at the same TCP level. The positive response of urban trees' cooling efficiency to rising urban temperature is explained mainly by the stronger evapotranspiration of urban trees on hotter days.These results have important implications for alleviating urban heat risk by utilizing urban trees, particularly considering that extreme hot days are becoming more frequent in cities under global warming.

How Does Urban Shrinkage Affect Land Use Efficiency?A Case Study of Shrinking Cities in Northeast China

The effect of urban shrinkage has gradually become a new topic.Theoretically,urban shrinkage may exert great influence on land use efficiency(LUE)through various urban subsystems,but there is currently limited research examining these pathways.Using the Super-SBM-Undesirable model and the Structural Equation Model(SEM),this study calculates the LUE of shrinking cities in Northeast China and simulates the process of urban shrinkage affecting LUE.To quantify the process of urban shrinkage affecting LUE,three mediation variables,namely the economy,public services,and innovation,are used as latent variables to apply SEM.The results show that urban shrinkage will affect LUE through a direct path and indirect paths.In the direct path,urban shrinkage leads to an improvement in LUE.In the indirect paths,the economy and innovation will transmit the negative effect of urban shrinkage on LUE,while public services will reverse this effect.An important contribution of this study is that it quantifies the paths of urban shrinkage affecting LUE,thereby expanding the understanding of urban shrinkage effect and laying a foundation for the sustainable development of shrinking cities.

Carbon efficiency evaluation method for urban energy system with multiple energy complementary

Urban energy systems(UESs)play a pivotal role in the consumption of clean energy and the promotion of energy cascade utilization.In the context of the construction and operation strategy of UESs with multiple complementary energy resources,a comprehensive assessment of the energy efficiency is of paramount importance.First,a multi-dimensional evaluation system with four primary indexes of energy utilization,environmental protection,system operation,and economic efficiency and 21 secondary indexes is constructed to comprehensively portray the UES.Considering that the evaluation system may contain a large number of indexes and that there is overlapping information among them,an energy efficiency evaluation method based on data processing,dimensionality reduction,integration of combined weights,and gray correlation analysis is proposed.This method can effectively reduce the number of calculations and improve the accuracy of energy efficiency assessments.Third,a demonstration project for a UES in China is presented.The energy efficiency of each scenario is assessed using six operational scenarios.The results show that Scenario 5,in which parks operate independently and investors build shared energy-storage equipment,has the best results and is best suited for green and low-carbon development.The results of the comparative assessment methods show that the proposed method provides a good energy efficiency assessment.This study provides a reference for the optimal planning,construction,and operation of UESs with multiple energy sources.

A Study of the Impact of the Digital Economy on the Efficiency of Urban Green Economy--Based on the Yangtze River Delta City Cluster

This paper adopts the non-expected output-super-efficiency SBM(Slacks-Based Model)model and principal component analysis to calculate the green economy efficiency and the digital economy level of 27 prefecture-level cities in China’s Yangtze River Delta urban agglomeration between 2011 and 2019,respectively,and examines the impact of the digital economy on the green economy efficiency by using benchmark regression and mechanism analysis.The findings show that,first,the digital economy has a significant contribution to the green economic efficiency of cities,and this conclusion still holds after robustness tests such as replacing explanatory and interpreted variables and introducing province-fixed effects.Second,through the mechanism test,it is found that the digital economy can indirectly promote urban green economic efficiency through the positive mechanism effect of promoting industrial structure upgrading.

Evaluation and Influencing Factors of Urban Renewal Efficiency Based on SBM Model:A Case Study of the First Batch of Pilot Cities for Urban Renewal

China is already in the second half of the urbanization process,which means that the urbanization path in China needs to shift from“large-scale expansion development”in the past to“comprehensive and refined operation”.To explore how to efficiently carry out urban renewal work,from the perspective of urban renewal efficiency,the first batch of pilot cities for urban renewal released by the Ministry of Housing and Urban Development in 2021 are selected as the objects.And the SBM model and Malmquist index are used to calculate and analyze their urban renewal efficiency.The results indicate that among the 20 pilot cities,Beijing,Tangshan,Suzhou,Tongling,and Jingdezhen are of high grade,and Hohhot,Xiamen,Huangshi,and Yinchuan are of medium grade,while the rest of the cities are of low grade.The regression results of the Tobit model indicate that population density,real estate investment,and regional economic development level are the main influencing factors of urban renewal.Finally,constructive suggestions are proposed for urban renewal from four aspects:concept,technology,real estate,and policy.

Measurement of Digital Economy Development Level in Yangtze River Delta and Its Influence on Ecological Efficiency

Based on the panel data of 41 cities in the Yangtze River Delta from 2007 to 2018,this paper empirically tests the impact of digital economy development on urban ecological efficiency in the Yangtze River Delta.The results show that the development level of digital economy in Yangtze River Delta urban agglomeration is fluctuating and rising;the development of digital economy has a significant positive role in promoting the improvement of urban ecological efficiency;there is significant regional heterogeneity in the promotion of ecological efficiency by digital economy,especially in central cities.

Urban Water Resource Utilization Efficiency in China

The efficient use of water resources directly affects environmental, social, and economic development; therefore, it has a significant impact on urban populations. A slacks-based measure for data envelopment analysis （SBM-DEA） has been widely used in energy efficiency and environmental efficiency analyses in recent years. Based on this model, data from 316 cities were examined and a category method was employed involving three different sorting techniques to empirically evaluate the efficiency of urban water re- source utilization in China between 2000 and 2012. The overall efficiency （OE） of urban water resource utilization in China was initially low, but has improved over the past decade. The scale efficiency （SE） was higher than the pure technological efficiency （PTE）; PTE is a major determining factor of OE, and has had an increasingly significant effect. The efficiency of water resource utilization varied ac- cording to the region, urban scale, and economic function. The OE score for the eastern China was higher than for the rest of the region, and the OE score for the western China was higher than for the central China. The OE score for urban water resource utilization has improved with urban expansion, except in the case of small cities. The SE showed an inverted U-shaped＇ trend with increasing urban expansion. The OE of urban water utilization in comprehensive functional cities was greater than in economic specialization cities, and was greater in heavy industry specialization cities than in other specialization cities. This study contributes to the field of urban water resource management by examining variations in efficiency with urban ~ezle

Urban Land Use Efficiency and Contributing Factors in the Yangtze River Delta Under Increasing Environmental Restrictions in China

Evaluating urban land use efficiency(ULUE) provides insights into the interactions between land use systems and their external environment. Specifically, changes in ULUE are important for monitoring urban transformation in developing countries. In this study, using a traditional input-output index model, we incorporated slack-based measurements and undesirable outputs into a SBM-UN(slack-based measure-undesirable) model to investigate ULUE within the context of increasing environmental restrictions in China. The model was used to estimate the ULUE of 26 cities in the highly developed urban agglomeration of the Yangtze River Delta from 2000 to2018. The average ULUE in the Yangtze River Delta was relatively low compared to that of developed city regions in the European Union(EU) and North America and exhibited a U-shaped curve over the study period. Incorporating undesirable outputs, such as environmental pollution, into the model reduced ULUE by 19.06%. ULUE varied spatially, with the kernel density estimation exhibiting a bimodal distribution. Efficiency decomposition analysis showed that scale efficiency made a greater contribution to ULUE than pure technical efficiency. Based on our findings, recommended approaches to improve ULUE include optimizing factor allocation, reducing undesirable outputs, and increasing the effective output per land unit. The study suggests that ULUE and the SBM-UN model are useful planning tools for sustainable urban development.

Efficiency of Land Utilizationand Urbanization Progress of China

Urbanization is a process that is undergoing all over the world, which will speed up in the forthcoming years, especially in China as the boom of economy. On average, urbanization level is not only depended on the speed, but theefficiency, particularly efficiency of using land resource which affects urbanization directly. This paper provided status quo of land resource utilization efficiency, indictors, methods and factors, and illustrated the reference of well land utilization, aiming at fostering urbanization in China.

Input and output efficiency of urban agglomerations in China using DEA multi-stage model

In this study, we apply the data envelopment analysis(DEA) model to quantitatively measure the input and output efficiency of 19 urban agglomerations in China from 2011 to 2016. The results show that the input and output efficiency of urban agglomerations is relatively not high, only a small number of that reach the optimal DEA efficiency. It is clearly revealed that there are the regions from the east that presents the better performance, followed by regions from the central and the west. The peer counts show that Zhusanjiao is taken into account 12 times which shows the importance here of the Zhusanjiao model.Considering the values for radial movements and the slack movements, respective urban agglomeration has their improving orientation towards the capital slack, the labor slack or the land slack. It offers a scientific decision-making of for healthy urbanization and high quality development.

County urbanization,agricultural servitization,and agricultural eco-efficiency:Statistical verification based on Chongqing

Agricultural ecologicalization is an important starting point to promote sustainable and high-quality development of agriculture.Based on the panel data of 37 districts(counties)in Chongqing from 2004 to 2019,the DDF-GML index method is used to measure the agricultural ecological efficiency of Chongqing.Based on the analysis of the interaction mechanism of urbanization,agricultural service,and agricultural ecological efficiency,with the help of the PVAR model verifies the relationship between the three.The study found that urbanization,agricultural service,and agricultural ecological efficiency have significant inertia effects and path dependence,especially agricultural ecological efficiency can provide more than 90%of its variance contribution,while urbanization and agricultural ecological efficiency have a significant impact on agricultural ecological efficiency.The influence will become weaker and weaker over time,obeying the law of diminishing margins.Therefore,to promote the development of agricultural ecologicalization,we must rely on the clean,green,and ecological development of agricultural production itself.At the same time,we also need to further improve the urbanization and agricultural service modernization system to maximize the benefits of agriculture.

Evaluation of the efficiency of urban solid waste management in Brazil by data envelopment analysis and possible variables of influence

This article has the general objective of estimating the efficiency of urban solid waste management in 940 Brazilian munici-palities through Data Envelopment Analysis(DEA)technique and has specific objectives:(i)to estimate efficiency scores;(ii)to compare the performance between different groups of municipalities;and(ii)to analyze the profile of efficient munici-palities from the perspective of the guidelines of Law 12,305/2010 and socio-economic and environmental indicators.The technique used was DEA with output-oriented and variable scale to return modeling.The results showed higher efficiency scores in the municipalities with populations above 500,000 inhabitants.The score variation ranged from 0.5(municipalities with populations<10,000 inhabitants)to 0.9(municipalities with more than 500,000 inhabitants).Of the sample set,only 12.34%of the municipalities were considered efficient,and when analyzing the efficient group,it was found that adherence to legislation was not a major factor in achieving efficiency.

Beyond skyline and borders: Unraveling the evolution and drivers of tourism green development efficiency in the Beijing-Tianjin-Hebei urban agglomeration, China

Green development is a critical component of sustainable tourism, which prioritizes a comprehensive, ecologically-friendly, and people-oriented approach to development. This study presents a case study of the Beijing–Tianjin–Hebei(BTH) urban agglomeration from 2001 to 2021 to analyze the spatio-temporal evolution characteristics and influencing factors of tourism green development efficiency(TGDE). The study defines the concept of tourism green development and constructs an evaluation system, which is used to explore the internal differences and spatial patterns of TGDE within the urban agglomeration. The methodological approach includes the SBM–Undesirable model, kernel density estimation, Markov chain, and spatial gravity model. The findings indicate that the TGDE in the BTH urban agglomeration is generally favorable, displaying a temporal phase of “rising–declining–rising.” However, the study observes lower TGDE in tourism node cities compared to tourism regional center cities and tourism core hub cities. The non-equilibrium degree of each region indicates significant spatio-temporal evolution patterns and internal differences among the three regions, with a spatially decreasing distribution of “core hub-regional center-node city.” The TGDE in the urban agglomeration experienced an evolutionary trend of “first decreasing and then increasing” with apparent endogenous evolution characteristics. The linkage pattern of green development efficiency in the tourism industry between cities is relatively stable. Furthermore,neighboring cities generally exhibit a higher spatial connectivity strength of green development efficiency in the tourism industry compared to non-neighboring cities. Economic development level, industrial structure, and science and education level are identified as key factors that affect TGDE. However, the study finds that the factors influencing TGDE in tourism core hub cities, tourism regional center cities, and tourism node cities differ somewhat. Economic development level, industrial structure, science and education level, openness, and government regulation impact TGDE in tourism core hub cities and tourism regional center cities, while economic development level, industrial structure, and tourism resource endowment are the primary factors affecting TGDE in tourism node cities. The study provides policymakers and tourism practitioners with valuable insights into enhancing the green development of the tourism industry in the BTH urban agglomeration and other similar regions.Corresponding policy recommendations based on the results are proposed to improve the TGDE of the tourism industry in these regions, promote sustainable tourism development,improve the quality of life of local residents, and protect the ecological environment.

To Improve Energy Efficiency via Car Driving Deduction by Land Use Planning

Urban area consumes about main percentage of used energy. Cities need basic review in land management, structure and form to minimize the use of energy which creating environmental pollution. Urban planners and designers are looking for a solution and essential agreement in urban planning and designing principles that can decrease the pollution from rapid urbanization. Travelling is essential for daily needs of most people in urban area. Issues arise when one considers the amount of necessary fossil fuels used in the majority of daily commuting for accessibility to services. It is necessary to design a city to minimize the use of energy which creating environmental pollution. Research conducted in Subang Jaya in Malaysia in 2012 finds a variable which influences on use of car, propose of use of car and commuting distance by car. However it tried to find effect of train station and density on use of car for accessibility to this services and facilities. Findings illustrate neighbourhood distance from train station influences distance to facilities and services in neighbourhoods. However it illustrates derived distance by car was affected by residential lots distance from restaurant, work place, school, park, house area per person, and car ownership.

Urban economic efficiency under the interactive effect of urban hierarchy and connection networks in China

The efficient development of the urban economy is a major concern of scholars in the fields of geography and urban science.In the context of globalization,informatization,industrialization,and urbanization,the external relationships of China's cities are experiencing the joint action of urban scale hierarchies and connection networks(“hierarchy-network”).However,under the interactive effect of the two,the mechanism of urban economic efficiency(UEE)is unclear.Therefore,based on Baidu migration data,the regionalization with dynamically constrained agglomerative clustering and partitioning(REDCAP)method,and a spatial simultaneous equation model,this paper analyzes the UEE spatial pattern and mechanism in China.The results indicate that:(1)the urban economy has a superlinear relationship with the population size.However,the benefit of this superlinear growth is in marginal decline.(2)The UEE shows a pattern of differentiation between China's eastern,then central,and then western region.Also,local differences are found within the three major sub-regions.(3)The increase of urban network centrality can promote UEE,while the impact of urban scale is negative.(4)There is regional heterogeneity of the interactive effect of“hierarchy-network”on UEE.This study reveals the influencing mechanism of UEE and also provides policy implications for the development of UEE.

基于车车通信列控系统的城市轨道交通列车运行效率分析

[目的]城市轨道交通T2T(车车通信)列控系统是一种新型的信号系统,其通过资源化管理方式对轨旁设备进行管控。为了验证该系统的优越性,需对该系统下的列车运行效率进行分析。[方法]针对T2T列控系统,基于资源管理层面和安全防护原理的特点,在折返工况下,将原本由联锁控制的双动道岔转变为两个单动道岔,并基于列车精确自定位实现ATP(列车自动防护),提高了岔区线路资源的使用能力;在区间和车站追踪工况下,通过前后车对于车速、加速度、所处线路位置等信息的实时互传,利用相对速度安全防护原理进一步缩小了列车的追踪间隔。通过上述两方面的技术革新,结合城市轨道交通线路的实际数据,对站后交叉渡线折返、站前单渡线折返、区间与车站追踪等运营场景进行了模拟仿真计算,确定了T2T列控系统的折返能力和区间追踪能力。[结果及结论]相较传统的CBTC(基于通信的列车控制系统),T2T列控系统在折返能力、追踪能力等方面均有着显著提升,更加适应于超大运量的城市轨道交通线路;T2T列控系统架构简单,轨旁设备少,尤其适合城市轨道交通的大修改造项目。

中国城市数字经济发展的资源配置效应

优化资源配置是建设全国统一大市场的基本目标,基于市场价格、竞争与风险机制的市场化视角,以中国城市数字经济发展实践为基础,构建“数字经济—市场化—资源配置”的理论分析框架,并运用全国地级市样本数据,在测算城市数字经济和资源配置效率指数的基础上实证分析。实证发现:中国城市数字经济发展显著改善了资源配置扭曲,这一结论在考虑指数测度误差、内生性问题以及外生政策冲击等因素后依然成立;市场化是数字经济提高资源配置效率的有效途径;数字经济对资源配置扭曲的优化效应存在边际递减的非线性特征,且在优化效应的结构差异上存在“资本—产品—劳动力”的递进逻辑;中国城市数字经济发展能够改善城市间产品和资本配置扭曲相互强化的内生交互循环,但也可能因城市间的“虹吸效应”导致劳动力配置在空间上产生“新扭曲”现象。

数字经济提升城市经济效率:理论机制与路径选择--以长三角区域城市为例

数字经济重组要素资源,重塑经济发展结构,促进产业融合和创新效率,驱动城市经济高质量发展。本文构建了数字经济发展水平指标与城市经济效率指数,实证研究了数字经济对城市经济效率的空间影响,并基于因果渠道检验对数字经济通过技术创新与产业结构升级影响城市经济效率的机制进行了检验。研究结果表明:首先,数字经济能够直接驱动城市经济效率提升;其次,数字经济本身具备提升城市经济效率的空间效应;最后,数字经济可以通过产业结构优化与技术进步改善城市经济效率,但技术效率改善的机制作用却不显著。因此,应立足城市实际情况,制定更具空间指向的城市发展政策,把握数字经济发展契机,充分发挥数字经济的辐射带动作用,推进产业数字化与数字产业化融合,破除行政壁垒,构建长三角高质量协同发展网络,精准助力城市经济效率提升。

北京市主城区高分辨率的城市水碳通量模拟研究

城市化通过影响地表蒸散发(ET)过程改变了区域水热平衡等水文和生态过程,进而改变了陆地生态系统的结构与功能。为科学评估城市水碳过程,基于哨兵二号卫星数据的植被信息,估算了2016—2021年逐月北京市主城区10 m×10 m空间分辨率的植被指数,进一步结合PT-JPLim四源蒸散发模型、InVEST模型以及解析型生态系统水分利用效率(WUE)模型,模拟了2016—2021年北京市主城区10 m×10 m空间分辨率的蒸散发、蒸散发分量(植被蒸腾E t、土壤蒸发E b、截留蒸发E i和不透水面蒸发E u)、总初级生产力(GPP)、碳储量以及WUE的月值,并分析了其相关关系。植被指数较大值集中在西部山区,其次为北京市的公园区域,归一化植被指数NDVI最大值为0.65。主城区多年平均蒸散发量为497 mm,ET随着叶面积植被指数LAI和增强植被指数EVI的增加而增加。2016—2021年期间,NDVI、LAI和EVI分别以每年0.0048、0.016 m^(2)·m-2和0.0047的速度增加。区域平均E t为141.51 mm,E i为50.77 mm,E b为272 mm,不透水面上的E u ET为18.2%。碳储量较高的区域主要分布在西部山区,该区域海拔相对较高,植被覆盖率较高,总碳储量密度高值超过5 t hm^(2)。研究区GPP的平均值为2.7 g·m^(-2)·d^(-1),多年平均WUE为0.63 g·mm^(-1)。WUE和E t ET呈显著负相关(R=-0.44,p<0.001),WUE随GPP的增加呈现显著的上升趋势。精细化的城市水碳模拟能够为海绵城市的建设和评估提供理论基础,对“双碳”目标的实现具有重要意义。

政府干预视角下长三角城市群科技创新资源配置效率及影响因素分析

科技创新资源优化配置是贯彻落实创新驱动发展战略的必然要求。长三角城市群作为我国经济社会运行和科技事业发展的先行区,明确其科技创新资源配置效率差异及影响因素,对于打造创新型国家具有重要的推动作用。以政府干预为研究视角,运用超效率DEA模型和DEA-Malmquist模型对2011—2020年长三角城市群26个城市科技创新资源配置效率进行测算,并采用Tobit模型以政府干预为核心解释变量实证分析其影响因素。结果发现:长三角城市群科技创新资源配置效率整体呈现递增趋势,上海、宁波、苏州、杭州、南京的效率值排在前5位,但是城市群内部科技创新资源配置效率差异悬殊,区域空间格局极不平衡,其中政府干预、产业结构调整和城市化水平均对提高科技创新资源配置具有显著正向影响。因此,建议长三角各地政府围绕从科技创新资源投入至产出的各个环节制定相关法律法规,进一步规范科技创新资源配置方式,并加强城市之间的交流与合作。