How Frequently Will the Persistent Heavy Rainfall over the Middle and Lower Yangtze River Basin in Summer 2020 Happen under Global Warming?

The middle and lower Yangtze River basin(MLYRB)suffered persistent heavy rainfall in summer 2020,with nearly continuous rainfall for about six consecutive weeks.How the likelihood of persistent heavy rainfall resembling that which occurred over the MLYRB in summer 2020(hereafter 2020PHR-like event)would change under global warming is investigated.An index that reflects maximum accumulated precipitation during a consecutive five-week period in summer(Rx35day)is introduced.This accumulated precipitation index in summer 2020 is 60%stronger than the climatology,and a statistical analysis further shows that the 2020 event is a 1-in-70-year event.The model projection results derived from the 50-member ensemble of CanESM2 and the multimodel ensemble(MME)of the CMIP5 and CMIP6 models show that the occurrence probability of the 2020PHR-like event will dramatically increase under global warming.Based on the Kolmogorov-Smirnoff test,one-third of the CMIP5 and CMIP6 models that have reasonable performance in reproducing the 2020PHR-like event in their historical simulations are selected for the future projection study.The CMIP5 and CMIP6 MME results show that the occurrence probability of the 2020PHR-like event under the present-day climate will be double under lower-emission scenarios(CMIP5 RCP4.5,CMIP6 SSP1-2.6,and SSP2-4.5)and 3-5 times greater under higher-emission scenarios(3.0 times for CMIP5 RCP8.5,2.9 times for CMIP6 SSP3-7.0,and 4.8 times for CMIP6 SSP5-8.5).The inter-model spread of the probability change is small,lending confidence to the projection results.The results provide a scientific reference for mitigation of and adaptation to future climate change.

Industrial carbon emissions and influencing factors in the Yangtze River Delta urban agglomeration

This paper calculates the industrial carbon emissions of the Yangtze River Delta urban agglomeration over the period 2006-2013. An empirical analysis is conducted to find out the influencing factors of industrial carbon emissions of the Yangtze River Delta urban agglomeration, using a spatial Durbin panel model. The results show that cities with larger industrial carbon emissions often enjoy low annual growth rates, while the cities with smaller ones enjoy higher annual growth rate; There exists a comparatively strong positive correlation in space in per capita carbon emission; urbanization, and total population. GDP per capita and international trade are the main influencing factors of industrial carbon emissions; There are spatial spillover effects on international trade and urbanization of neighboring cities, which have a significant impact on local industrial carbon emissions.

Analysis on the green development of urban agglomeration in the Yellow River basin

After the ecological protection and high quality development of the Yellow River basin became the national strategy,the new idea of river basin development with urban agglomeration as the main body was clarified.Promoting high-quality development of urban clusters in the Yellow River Basin is not only an important practice of the concept of harmonious coexistence between man and nature,but also conducive to exploring new paths of high-quality development that can be copied and popularized.In the process of promoting development,we should adhere to the principle of overall planning and differentiated development.On the basis of constantly improving cross-regional environmental administrative coordination,strengthening the radiation driving role of central cities,and establishing and improving the cross-regional ecological compensation mechanism,we should adopt different measures according to the requirements of ecological priority and green development,so as to form a new competitive advantage that is both unified and distinctive.

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.

The Effect of Urban Agglomeration Expansion on PM_(2.5) Concentrations: Evidence from a Quasi-natural Experiment

This study constructs a quasi-natural experiment based on the expansion of the Yangtze River Delta urban agglomeration(YRDUA) of China in 2010 to investigate the impact and inner mechanism of urban agglomeration expansion on fine particulate matter(PM_(2.5)) concentrations through propensity scores in difference-in-differences models(PSM-DID) using panel data from 286 prefecturelevel cities in China from 2003 to 2016. The results show that 1) urban agglomeration expansion contributes to an overall decrease in PM_(2.5)concentration, which is mainly achieved from the original cities. For the new cities, on the other hand, the expansion significantly increases the local PM_(2.5)concentration. 2) In the long term, the significant influence of urban agglomeration expansion on PM_(2.5)concentration lasts for three years and gradually decreases. A series of robustness tests confirm the applicability of the PSM-DID model.3) Cities with weaker government regulation, a better educated population and higher per capita income present stronger PM_(2.5)reduction effects. 4) Urban agglomeration expansion affects the PM_(2.5)concentration mainly through industrial transfer and population migration, which cause a decrease in the PM_(2.5)concentration in the original cities and an increase in the PM_(2.5)concentration in the new cities.Corresponding policy suggestions are proposed based on the conclusions.

Coordination of Urbanization and Water Ecological Environment in Shayinghe River Basin,China

During the rapid industrialization and urbanization of China,urban agglomeration in river basin areas raises the problems of over-use of water resources and pollution of the water environment.Related research in China has mainly focused on the conflicts among economic growth,urban expansion and water resource shortages within admin-istrative boundaries.However,water environments are much more dependent on their physical boundaries than their administrative boundaries.Consistent with the nature of water environment,this study aims at analyzing coordination relationships between urban development and water environment changes within physical river basin boundaries.We chose the Shayinghe River Basin,China,as our case study area which is facing serious challenges related to water en-vironment protection.Then we classified 35 county-level administrative units into upstream,midstream and down-stream regions based on their physical characteristics;analyzed the coordination degree of urban agglomeration using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method;and constructed cooperative models using the Linear Programming (LP function) to simulate four scenarios of the coordination relationship be-tween urban population increase and water environment protection based on existing water resources and water pollu-tion data.The results show that the present coordinative situation in Shayinghe River Basin is not sustainable.In gen-eral,more than 50% administrative units are in the bad coordinative situation.In particular,the downstream region is under worse condition than the upstream and midstream regions.Cooperative models in scenario analyses indicate that the population scale set in existing urban master plannings is not coordinated with the water environment protection.To reach the goal of regional sustainable development,the total population needs to be controlled such that it will re-main at 4.5×10 7 or below by 2020 given the capacity of water environment.

Understanding the change of land space utilization efficiency with different functions and its coupling coordination: A case study of Urban Agglomeration in the Middle Reaches of the Yangtze River, China

Land spaces function in capacities of urban development,agricultural production,and ecological conservation,among many others.Research of land space utilization efficiency(LSUE)and coupling coordination relationships among its subsystems are significant for sustainable land space development.In this study,taking the Urban Agglomeration in the Middle Reaches of the Yangtze River(UAMRYR)as the study area,we establish a measurement index system to evaluate the LSUE(2000–2018)and analyze its coupling coordination degree by utilizing an improved coupling coordination model.The main results include the following.(1)The average efficiency levels of urban space and agricultural space in the UAMRYR increased 2000–2018,while the average efficiency of ecological space declined.(2)The spatial pattern of the LSUE values varied greatly,with the distributions of high-efficiency and low-efficiency levels significantly different.(3)The coupling degree of LSUE includes three types,i.e.,high-level coupling,break-in,and antagonism.Each coupling degree type was characterized by change over time.(4)The proportion of areas with high coupling coordination and moderate coupling coordination increased from 2000 to 2018,while the proportion of areas with basic coupling coordination,moderate imbalance,and serious imbalance declined during this period.Given that the spatial differentiation of the LSUE and its coupling coordination,it is necessary to implement a differential land space development strategy in the UAMRYR.This study is helpful to promote the efficient utilization and coordinated development of land space utilization systems.

长江中游城市群交通一体化建设存在的问题与推进建议

交通一体化能促进生产要素高效流动与整合,有力推动区域经济与社会一体化发展和经济内循环顺利实现。长江中游城市群在交通一体化方面取得很大进展,不仅建立完备的由铁路、公路、地铁、航空、水运等运输方式组成的综合交通运输网络,而且在交通管理与服务方面实现一定程度的信息化与智能化。但长江中游城市群交通一体化建设存在政府与市场配合度不高,缺乏统一的跨区域整体规划和协调机制,各种交通方式互联互通效率低下,智能交通建设落后等困难与问题。可以通过提高政府一体化建设积极性与市场参与度,破除行政壁垒,建立一体化管理协调机制,发展多式联运促进互联互通,增强交通管理与服务的信息化和智能化建设等,进一步推进长江中游城市群交通一体化建设,以服务区域经济内循环和城市群的整体发展。

长江中下游城市内涝与雨季污染协同治理对策

针对长江中下游城市内涝与雨季污染协同治理的突出问题,对城市水安全、雨季水体返黑返臭风险和河湖水生态退化三方面存在的问题进行了论述。发现长江中下游城市河网密度高、降水量大、暴雨多发,同时人口密集、经济发展水平高,内涝、污染、生态退化等水问题突出;城市内涝频发,雨季污染造成某些城市水体局部返黑返臭,严重影响城市水环境品质,成为制约长江中下游城市绿色发展的重要瓶颈问题。提出了建立三级内涝协同防治体系、构建城市“绿-灰-蓝”设施耦合工程体系、协同推进水体品质提升与生态修复等建议。

长三角城市群物流业高质量发展水平测度研究及评价

以长三角城市群物流业为研究对象,采用熵权TOPSIS法和核密度估计分析方法,测度2010—2021年长三角城市群物流业高质量发展水平并分析区域发展差异。研究发现:长三角城市群物流业高质量发展水平向好趋势明显,但仍然有待提高。有18个城市的物流业高质量发展水平低于均值。其中上海的物流业高质量发展水平最高,居于第2位的苏州相比于上海还有较大差距。从各区域来看,区域发展不均衡的特征较明显,各区域物流业高质量发展水平存在一定差距,上海物流业高质量发展水平显著高于其他区域,物流业高质量发展水平排名靠后的城市主要集中在安徽,该区域内发展差距呈现缩小趋势。

黄河流域城市群新型城镇化与生态安全协调发展研究

为推进中国式现代化建设,统筹黄河流域生态保护和高质量发展,提升城市群新型城镇化与生态安全协调发展水平,以黄河流域内的7个城市群为研究对象,构建新型城镇化与生态安全评价指标体系,运用耦合协调度模型和相对发展模型,并结合时空演化过程分析了黄河流域城市群新型城镇化与生态安全耦合协调度发展格局,最后通过系统动力学模型模拟未来5年耦合协调发展趋势.结果表明,研究期内,黄河流域城市群新型城镇化与生态安全耦合协调度总体呈上升趋势,部分城市群出现轻度波动,耦合协调特征由失调、濒临协调转化为勉强协调、初级协调;最后通过预测未来5年黄河流域城市群新型城镇化与生态安全耦合协调度发展过程,推断城市群均处于显著提升状态,且逐步达到初级协调阶段.针对目前黄河流域城市群新型城镇化与生态安全协调发展存在的不足,提出了相应的对策建议.

长江中游城市群城市土地利用效率及影响因素——基于非预期超效率SBM模型和空间计量分析

本文以长江中游城市群36个地级市为研究对象,基于2000-2019年统计数据,运用非预期超效率SBM模型,综合计算评估长江中游城市群的土地利用效率和效率分解,并构建空间杜宾模型分析其影响因素。研究结果表明,长江中游城市群土地利用效率并没有实现联动发展,湖北省在地区土地利用中独自领先,湖南省和江西省既没有在内部形成聚集,且与湖北省及其周边城市也缺乏联动。在空间杜宾计量模型分析中,外溢性较小的地区发展因素对土地利用效率推动最大,间接反映出长江中游城市群内部省际要素流动不太通畅,土地利用效率具有高度自我强化特性,现有高效利用的土地会进一步强化土地后续的高效率配置。

基于碳汇潜力的碳排放空间关联网络结构特征及影响因素——以长江中游城市群为例

考虑碳汇潜力的碳排放空间关联是促进城市群协同减排的重要基础,更是实现碳中和的有力抓手。以长江中游城市群为研究区,对传统引力模型进行修正,构建兼具碳汇潜力的碳排放空间关联网络,采用社会网络分析(SNA)和二次指派程序方法(QAP)探究长江中游城市群碳排放空间关联网络的时空特征与影响因素。结果表明:①研究期间长江中游城市群碳排放网络关联关系数、网络密度和网络关联度呈增长趋势,网络效率和网络等级度不断下降,且网络等级度在2010年后始终为0,表明碳排放空间关联网络日益稠密、网络通达性较强,存在多重叠加的溢出渠道,但等级结构并不森严。基于碳汇潜力的长江中游城市群碳排放空间关联网络从“双核化”向“多极化、多线程”网络形态发展,核心城市的扩散作用不断增强。此外,以抚州、宜昌、鹰潭、上饶和吉安等为代表的高碳生态承载力地区,在碳排放空间关联网络中的受益关联性大于溢出关联性。②2020年,长江中游城市群碳排放空间关联网络形成四大板块,相较于板块内部成员间的碳排放空间关联效应,板块间的碳排放空间关联效应更为明显,即板块间的“碳排放转移”效应较为普遍。净溢出板块主要分布在武汉都市圈、宜荆荆都市圈和长株潭城市群外围城市,处于网络核心圈层位置;净受益板块主要分布在环鄱阳湖城市群东部,“碳排放避难所”效应显著。经纪人板块集中在环鄱阳湖城市群西部,板块间表现出“净溢出板块→经纪人板块→净受益板块”的碳排放传递路径,呈现出明显的“梯度转移”特征。双向溢出板块主要位于长江中游城市群西部,对净溢出和净受益板块都存在碳排放的空间溢出。研究期内,净溢出板块的成员虽然有所变化但总数保持不变,经纪人板块的成员有所增加,而净受益和双向溢出板块的成员均减少,环鄱阳湖城市群的“碳排放避难所”效应有所弱化。③地理邻近关系能够促进城市间碳排放关联关系的建立,而城市间的经济集聚程度、土地利用强度和经济发展水平上的互补性,促使碳排放空间关联网络随着城市间分工与协作的加强而呈现出千里“碳缘”一线牵的特点。

城市蔓延对生态系统服务流的影响研究进展及对长江流域的启示

全面梳理城市蔓延对生态系统服务流的影响研究现状,有利于促进区域社会经济可持续发展。综述了城市蔓延对生态系统服务流的影响研究,结果表明:城市蔓延对生态系统服务流的影响研究仍处于起步阶段。城市蔓延通过载体传递和流动路径两方面改变了生态系统服务流的流量、流速和流向,导致生态系统服务流总量的减少和空间异质性的增加;城市蔓延的单项指标变化、城市蔓延的尺度以及城市蔓延的多情景模拟是探索城市蔓延对生态系统服务流影响过程的主要切入点;城市蔓延过程中引起的生态系统服务流扩散效应主要源于土地利用类型的变化和人类居住模式的改变。已有研究在一定程度上解释了城市蔓延对生态系统服务流的影响,但在揭示影响机理、剖析影响过程、评估影响效应以及探索生态系统服务流合理分配以促进城市可持续发展等方面的研究还存在较大空白。在此前提下,未来应基于“机理揭示-影响模拟-效应评估”的研究思路,建立长江流域城市蔓延对生态系统服务流影响研究框架,探索长江流域城市可持续发展与生态系统服务流的合理分配方案,实现长江流域生态保护与社会发展的协同共进。

长江中游城市群创新网络演化及影响因素研究

区域一体化背景下,城市群成为推动区域创新协调发展的重要空间载体和增长极,创新活动由单一合作向网络化创新发展。研究利用长江中游城市群28个城市的发明专利合作数据构建创新网络,采用社会网络分析和QAP回归分析对2008—2019年长江中游城市群创新网络的演化进程和驱动机制进行了分析。研究表明:创新网络的规模持续扩张,创新联系增长迅速,创新网络结构从以武汉、长沙为中心的“双核心”结构发展为以武汉、长沙、南昌为中心的“三核心”结构;QAP回归分析发现,地理邻近性、制度邻近性、组织邻近性和地理邻近性对创新网络有显著的推动作用,产业邻近性对创新网络表现出抑制性。

可持续发展目标6视角下黄河流域城市群水足迹时空演变及驱动因素

本研究以黄河流域5座国家级城市群为研究对象,探索性地采用水足迹及其相关评价指标构建面向可持续发展目标6的水资源利用水平评价框架。在描述2010―2019年城市群水足迹时空演变特征的基础上分别建立流域整体、上中游和下游城市群的空间计量模型,探讨驱动水足迹变化的因素。结果表明,城市群水足迹及相关指标均有所下降,自上游至下游呈梯级分布格局,上中游和下游城市群水足迹表现出两极分化的集聚状态,整体向“低−低”集聚跃迁。驱动因素在不同城市群之间存在着显著的差异性和空间交互效应。为此,提出强化中心城市辐射带动作用、提升城市群水资源生态系统韧性、根据不同城市群的比较优势实施差异性水资源系统治理等对策建议。

产业空间关联网络对城市群经济韧性的影响——基于长江中游城市群数据的实证分析

近年来,国内外各式冲击频繁加剧,各区域所面临的内外部环境不确定性与日俱增,因而提高经济系统的抵御、调整和转型能力,即增强经济韧性成为把握新发展阶段、贯彻新发展理念和构建新发展格局的题中之义。选取长江中游城市群内27个主要城市为研究对象,应用改进的引力模型构建2010—2019年长江中游城市群产业空间关联网络,并从社会网络分析的角度测算产业空间关联网络中心度特征,实证检验长江中游城市群产业空间关联网络的三大中心度特征对城市群经济韧性的影响。结果表明:产业空间关联促进了城市群经济韧性的提升,并且在金融环境好、市场化程度高的城市以及非工业城市中,产业空间关联对经济韧性的提升作用更加显著。进而提出有助于长江中游城市群产业高质量发展、经济韧性水平攀升的政策建议。

金融集聚与城市绿色发展的时空耦合分析——以长三角城市群为例

基于2011-2021年长三角27个城市的面板数据,利用区位熵和超效率SBM模型测算长三角各城市金融集聚和城市绿色发展水平,构建两系统耦合协调度模型,分析两系统之间时空耦合特征。结果表明,长三角城市群金融集聚水平呈稳定上升态势,且差距逐渐缩小;城市绿色发展水平空间分布不均衡,随时间推移城市间差距愈发显著;两系统之间呈现高耦合、低协调的局面,形成了以上海、南京、杭州、合肥为高值中心,由高到低向四周扩散的发展格局,两系统协调值差异呈现先减后增的“U”型的趋势,且差异愈发明显。因此,需要加强长三角中心城市与周边城市信息互通,充分发挥中心城市的空间溢出效应带动周边区域发展,进而推动长三角城市群两系统协调发展。

基于DPSIR模型的城市旅游经济韧性评价与影响因素——以长三角城市群为例

基于DPSIR模型构建旅游经济韧性指标体系,对2009—2021年长三角城市群旅游经济韧性水平进行测度,并分析其演化特征与影响因素,以期为旅游经济韧性提升提供一定决策依据.结果表明:长三角城市群旅游经济韧性呈现“先升后降”的变化趋势,各城市韧性水平整体上呈上升趋势.韧性较高城市主要分布在中东部地区,各城市旅游经济韧性水平间具有一定空间集聚特征.旅游经济韧性受经济发展水平、经济发展结构、旅游发展速度、游客承载量、教育水平、基础设施和政府干预等因素的综合影响,其中旅游发展速度对旅游经济韧性具有明显负面影响,其他因素均具有显著促进作用.

数字经济与绿色全要素生产率:来自黄河流域“五极”城市群的证据

数字经济发展是推动黄河流域高质量发展的重要动力。论文基于2011—2019年黄河流域“五极”城市群的面板数据,在城市群视角下实证检验数字经济发展如何影响绿色全要素生产率(GTFP)。研究发现:黄河流域城市群数字经济能够显著提升绿色全要素生产率,且在空间维度具有正向溢出特征。克服潜在的内生性问题后,这一结论依然稳健;黄河流域数字经济发展对绿色全要素生产率的提升效应在不同的城市群维度、核心城市与非核心城市之间具有典型的异质性特征;机制分析表明,黄河流域城市群绿色全要素生产率提升主要源于数字经济所诱发的创新要素集聚。