Delta Urban Agglomeration Of China Research Articles

Measurement and spatial correlation analysis of high-quality development Level: A case study of the Yangtze River Delta urban agglomeration in China

Against the backdrop of slowing economic growth and increasing environmental pressure, the Yangtze River Delta city cluster, as one of the largest city clusters in the world, has become more driven in its pursuit of high-quality development. We constructed a system of 24 evaluation indexes and used entropy-weighted TOPSIS to calculate and study the high-quality development index of urban agglomerations in the region. First, the level of high quality development (HQD) of the Yangtze River Delta city cluster generally improved from 2010 to 2021, with 2017 was the best year, while 2010 was the worst year. Second, in the multidimensional evaluation of HQD, Jiangsu excels in innovation and people's livelihood with 0.524 and 0.534, respectively; Shanghai (0.531) excels in coordinated development; Zhejiang excels in green and economic development with 0.557 and 0.484, respectively; and Anhui lags behind in all aspects. Third, the development process of HQD in the Yangtze River Delta region is uneven, and the level of HQD development varies greatly among the city clusters in the province. The measurement results show that Shanghai (0.511) has the highest score, followed by Zhejiang (0.484), Jiangsu (0.440) and Anhui (0.435). Fourth, spatial correlation analysis shows that Shanghai and Jiangsu are mainly distributed in the double-high region, Zhejiang is distributed in the high-low region, while Anhui is concentrated in the low-low region. The results of this study help us understand more deeply the characteristics and challenges of high-quality development in the Yangtze River Delta urban agglomerations and provide a scientific basis for more precise urban development policies.

Occurrence and health risk assessment of organic amine pesticides in drinking water of the Yangtze River delta urban agglomeration

Organic amine pesticides (OAPs) are widely used in modern agriculture and these compounds can contaminate drinking water sources in different ways. However, there is a lack of data on the occurrence of OAPs in drinking water and their potential human health risks. In this study, tap water (TW) and bottled water (BW) samples were collected from eight cities in the Yangtze River Delta urban agglomeration in China, and their OAP levels were analyzed using high-throughput organic analysis testing coupled with high-volume solid-phase extraction (Hi- throat/Hi-volume SPE techniques). This study is the first to systematically characterize the trace levels of OAPs in drinking water in China. Our findings indicated that the total concentration of OAPs (∑OAPs) in TW (average 11.06 ± 4.99 ng/L) was 29.4 % higher than in BW (average 8.55 ± 3.98 ng/L) and fewer kinds (7) of OAPs were detected in BW. Furthermore, the long-term intake of TW in some areas was linked to carcinogenic risks even at an acceptable OAP range, particularly in males, with molinate being the major contributor (61.3 %) to OAP exposure. Further analysis revealed that the occurrence and health risks of OAPs in drinking water were mainly influenced by the quality of water sources and the technologies adopted in drinking water treatment plants (DWTPs). Furthermore, our findings demonstrated that advanced treatment technologies such as nanofiltration could more effectively remove OAPs in raw water (up to 87.5 %). Therefore, our findings highlighted the importance of selecting appropriate advanced treatment technologies in DWTPs.

Regional integration policies and urban green innovation: Fresh evidence from urban agglomeration expansion

Climate change is a non-traditional security crisis affecting the global economy and diplomatic progress. In order to curtail carbon emissions and alleviate the perils of climate change at their roots, urban green innovation (UGI) has emerged as a pivotal technological solution. Using the expansion of the Yangtze River Delta urban agglomeration in China as a case study, this paper develops a quasi-experimental model to analyze the effects of regional integration policies on UGI. The main findings are: (1) Regional integration policies significantly enhance UGI and their impact is more pronounced with the expansion of urban agglomerations; (2) Regional integration policies contribute to the advancement of exploitative green innovation while tending to diminish exploratory green innovation; (3) The green innovation effects (GIEs) created by the expansion of regional integration policies are largely influenced by governmental mechanisms on environmental governance as well as residents’ green preferences. Based on these findings, recommendations are put forward to promote UGI from the perspective of policy implementation.

Spatial-temporal evolution of population aging in the yangtze river delta urban agglomeration of China.

The Yangtze River Delta urban agglomeration (YRDUA) is China's most representative region with remarkable economic development vitality. The purpose of this study is to provide valuable data analysis to actively respond to the population aging in China. We mainly focus on the spatial and temporal evolution of population aging in YRDUA from 2000 to 2020 using city-level population data. This study constructs a multi-dimensional index system to measure population aging including population aging degree, speed, and density. It finds out: (1) the elderly population rate (EPR), the elder-child ratio (ECR), and the elderly dependency ratio (EDR) in the YRDUA area are gradually increasing from 2000 to 2020. In addition, the trends of these indicators in various cities and regions are relatively consistent. All 27 cities in YRDUA entered an aging society, from the primary to the moderate aging stage from 2000 to 2010 and from the moderate to the hyper aging stage from 2010 to 2020. (2) the absolute and relative growth rate of EPR is increasing from 2000 to 2020. However, the absolute and relative growth rate of ECR is increasing from 2000 to 2010 and then decreasing from 2010 to 2020. These results indicate that the two-child policy adopted by the Chinese government plays a positive role. (3) the density level of the elderly population in the YRDUA evolved from low in 2000 to middle in 2010 and then to high in 2020. (4) There are remarkable differences in the process of population aging among three provinces and one city. The contribution of this study is mainly reflected in two aspects: firstly, it constructs a multi-dimensional index system to measure population aging; secondly, using this multi-dimensional index system, it systematically observes the spatial and temporal evolution of population aging from 2000 to 2020 in the Yangtze River Delta Urban Agglomeration.

The Effects and Mechanisms of the Rural Homestead System on the Imbalance of Rural Human–Land Relationships: Evidence from the Yangtze River Delta Urban Agglomeration in China

The imbalance of rural human–land relationships has become a notable problem in China’s urbanization process. The dual urban–rural system is widely regarded as the crucial factor contributing to this problem in China. Although the significance of institutional forces has been substantially recognized, the rural homestead system seems to be generally under-evaluated in this issue. Most of the previous literature focuses on the dual household registration system, while the effects and the detailed mechanisms of the rural homestead system on human–land relationships lack depth in research. The objective of this research is to help fill this gap in the literature on the complex effects and the detailed mechanisms of the rural homestead system on rural human–land relationships. In view of this, this paper establishes a conceptual framework on the basis of land function theory and public domain of property rights theory and proposes two mechanism hypotheses: one is the land attachment mechanism of farmers’ rights and interests (LAM), the other is the land finance preference mechanism of local governments (LFPM). Then, this article examines them empirically using the panel model with the data of 41 cities from 2010 to 2021 in the Yangtze River Delta of China. The main conclusions are as follows: (1) LAM promotes the imbalance of rural human–land relationships due to the attachment of farmer’s social security rights and property expectant interests to the rural homesteads; (2) LFPM drives the imbalance of rural human–land relationships, owing to both the preference of land transfer revenue and the exclusion of rural migrants’ citizenship financial cost on local governments; (3) the moderating effects suggest that LFPM can strengthen the effect of LAM, and the spatial Durbin model results show that both LAM and LFPM have spatial spillover effects. It is hoped that the findings will provide a reference for deepening the rural homestead system reform.

Unveiling the impact mechanism of urban resilience on carbon dioxide emissions of the Pearl River Delta urban agglomeration in China

With the increasingly severe global climate change situation, the construction of low-carbon and resilient cities is expected to be an effective means of accelerating the achievement of carbon peak and carbon neutrality goals. As a major global economic and carbon-emitting power, it is necessary to advocate for China to accelerate the construction of low-carbon and resilient cities. We have formulated a comprehensive methodological framework to appraise the effects of urban resilience (UR) on carbon dioxide (CO2) emissions. This study first constructs a “social-economic-institutional-ecological-engineering” UR assessment framework. Based on this framework, we establish an evaluation system for the UR of the urban agglomeration to explore the dynamic evolution of its spatial and temporal patterns. And then this study uses the SBM-DEA method that includes undesirable outputs to measure the carbon emission efficiency of the urban agglomeration. Finally, the spatial Durbin model is used to analyze the spatial spillover effects of UR on CO2 emissions, and the mechanism of CO2 emission spatial effects is theoretically explained by introducing geographical laws. The results show that the overall UR level in the region increased from 0.107 in 2000 to 0.318 in 2020, with an average carbon emission efficiency of 0.82, but still at a relatively low level. Moreover, there are significant differences in the regional level, with Guangzhou and Shenzhen and their surrounding cities showing significantly higher levels compared to other cities. Regarding the spillover effects analysis, CO2 emissions exhibit significant spatial spillover effects between cities. Improving UR can reduce urban CO2 emissions, but it may also have negative spillover effects on surrounding cities. This research can provide a new perspective for improving the study of regional CO2 emissions reduction and its influencing mechanisms while also offering important references for accelerating the construction of UR and achieving regional carbon peak targets.

The driving factors of recreational utilization of ecological space in urban agglomerations: The perspective of urban political ecology

Understanding factors driving the recreational utilization of ecological space in urban agglomerations is crucial for the sustainable management of regional systems. However, existing literature focuses on the provision, distribution, and accessibility of urban green space at small scales, lacking explorations into ecological recreational spaces at an urban agglomeration scale. The current study explores the recreational utilization of ecological space in the Pearl River Delta Urban Agglomeration in China by using panel data regression and field investigations from the perspective of urban political ecology. The results show that the forest area proportion, natural reserve area proportion, fiscal revenue, and tourist numbers all have a positive effect on the recreational utilization rate of ecological space; the fixed assets investment exerts unstable prohibitive impacts on the RUoES rate, and the wetland area proportion presents a negative effect on the RUoES rate; land use rights and regional governance structure exacerbate the imbalanced distribution of the rate across different cities. The research contributes to the existing literature by researching urban ecological space from a recreational perspective and at a broader spatial scale, thereby promoting the theoretical integration of recreational geography and political ecology.

The driving factors and spatial evolution of industrial water pollution governance efficiency in the Yangtze River Delta urban agglomeration in China.

In order to explore the effective path to improve the efficiency of industrial water pollution governance efficiency (WGE), this study takes 27 prefecture-level cities in the Yangtze River Delta urban agglomeration in China as the research object, measures WGE through the improved SBM model, and tests the impact of WGE drivers using the spatial Durbin model (SDM). The study found that environmental pollution governance investment (EPGI) is positively correlated with WGE, and industrial agglomeration status (IAS) has inhibitory effects on the improvement of WGE. By testing IAS2, it was determined that the impact of IAS on WGE has a "U"-shaped relationship. The direct impact of EPGI on WGE is 0.5016, and the indirect impact on WGE is 0.6428; the direct impact of IAS on WGE is -0.3036, and the indirect impact on WGE is -0.5158. Among the other tested impact drivers, per capita GDP (PCG), industrial structure (IS), and level of technological innovation (TIL) are positively correlated with the dependent variable WGE, while energy consumption intensity (ECI), environmental regulation intensity (ERI), and degree of openness to foreign investment (FIR) are negatively correlated with the dependent variable WGE. In addition to the impact of the aforementioned main drivers, IAS and EPGI, these six drivers also largely influence and determine the final impact on WGE.

Resilient urban expansion: Identifying critical conflict patches by integrating flood risk and land use predictions: A case study of Min Delta Urban Agglomerations in China

The increasing occurrence of floods due to global climate change is a challenge to the growth of urban resilience. However, few studies have investigated strategies to avoid flood risks during long-term and comprehensive land use and development. To address this issue, this study proposes a method that integrates flood risk and land use predictions to identify critical conflict patches that impact urban resilience. Further strategies for differential development based on the attributes of these critical conflict patches were formulated. Taking the Min Delta Urban Agglomeration (MDUA) in China as a case study, critical conflict patches for expanded urban resilience were identified based on a multi-source data set, a random forest (RF) algorithm, and a patch-generating land use simulation model (PLUS) combined with cellular automata (CA). These patches were categorized into three levels of risk prediction—low, medium, and high risk—based on flood risk attributes. These risk forecast levels were further divided into seven categories. The best land use approach was determined by assessing the quantity, spatial distribution, and risk-based priority ranking of these conflict patches. The results demonstrated that most conflicting patches were located in bare land within built-up areas, urban-rural intersection zones, and remote suburban areas with high traffic accessibility. The identified conflicting patches were applied to three different land use patterns: intra-city renewal, urban edge expansion, and the creation of derived cities. The total number of conflicting patches for land use decisions in the MDUA was 122 (170.82 km2) in 2025 and 685 (1205.81 km2) in 2035. Approximately 108 km2 of urban land was added for resilience expansion following optimization. In all development scenarios, the optimized land use pattern facilitated resilient growth of urban development while maintaining the stability of the flood disaster environment. Based on our methodology and case study, we proposed a decision-making framework to assist cities or potential urban regions to avoid water-related problems and related issues. This approach could also contribute to decisions involving different geographical areas for resilient land use.

Market Segmentation and Haze Pollution in Yangtze River Delta Urban Agglomeration of China

Haze pollution not only has negative impact on public health and air quality, but also has restricted China’s industrial upgrading and high-quality development, and Chinese urban agglomerations are one of the areas hardest hit of haze pollution. In the process of China’s economic transformation, local governments will adopt local protectionism, leading to market segmentation. This is a phenomenon that refers to the distortion of resource allocation by local governments for the sake of vested interests and the existence of segmentation in commodity markets. This behavior is considered to be one of the important factors causing haze pollution. As Yangtze River Delta urban agglomerations are considered to be one of the earliest, fastest growing, and most mature for market integration in China, there is a lack of empirical testing on the impact of market segmentation on haze pollution in this urban agglomeration. Based on urban panel data from the period of 1998–2018 and the market segmentation index calculated by the relative price method, we use the dynamic spatial Durbin model and generalized space two-stage least squares method to explore the effect of market segmentation in urban agglomeration on haze pollution; the results are as follows: (1) Market segmentation significantly exacerbates haze pollution, in other words, haze pollution will increase by 2.14% when market segmentation increases by 1%. (2) Cities with a high degree of market segmentation and high levels of haze pollution have the potential to reduce pollution through market integration in the future. (3) Market segmentation in surrounding regions also has a significant worsening effect on haze pollution in the region. The indirect effect of market segmentation is 3.67 times that direct effect, indicating that the spatial spillover effect of market segmentation on haze pollution is greater than its own impact. (4) Mechanism analysis finds that it will aggravate haze pollution by hindering economic scale, industrial structure, and technological progress when the degree of market segmentation is high.

Collaborative governance on SO2 pollution from thermal power energy consumption: Evidence from Yangtze River Delta urban agglomeration in China

In order to explore an effective method for the effect of collaborative governance on SO2 pollution from thermal power energy consumption in the Yangtze River Delta (YRD) urban agglomeration, the spatiotemporal evolution of SO2 pollution from thermal power energy consumption was empirically studied by Moran's I first; then the revised Difference-in-Difference-in-Differences model was constructed to examine the effect of collaborative governance on SO2 emission intensity from thermal power energy consumption, and the time effect of collaborative governance was also examined; finally, the Grey System Prediction Model was used to forecast the SO2 emission intensity from thermal power energy consumption in YRD urban agglomeration from 2021 to 2025. The results show that SO2 emissions from thermal power energy consumption in YRD urban agglomeration have positive spatial autocorrelations, and high-high spatial clusters have the tendency of moving to inland cities from coastal cities. Moreover, SO2 pollution from thermal power energy consumption in YRD urban agglomeration has improved year-by-year after the implementation of collaborative governance and the predicted SO2 emission intensity from thermal power energy consumption in YRD urban agglomeration generally shows a downward trend.

Spatial and temporal driving mechanisms of ecosystem service trade-off/synergy in national key urban agglomerations: A case study of the Yangtze River Delta urban agglomeration in China

Clarifying the ecosystem service (ES) trade-off/synergy is a prerequisite for scientific implementation and optimization of integrated ecological system management strategies, especially in highly urbanized areas with declining eco-environmental carrying capacity. This study took China's Yangtze River Delta urban agglomeration (YRDUA) as an example. First, we used a pixel-by-pixel analysis based on dynamic spatial correlation to quantify the trade-off/synergy among the 6 primary ESs' change amounts from 2005 to 2020 (habitat quality, soil retention, carbon sequestration, water yield, food production, leisure and recreation). Then, we integrated the multiple ES trade-off/synergy and explored their driving factors by spatial cluster analysis and geographically and temporally weighted regression (GTWR). The results showed synergy between supporting and regulating services predominated while regulating services were mostly trade-offs with regulating and cultural services. The trade-off/synergy of the 15 ES functional pairs within YRDUA can be downscaled into 4 ES trade-off and synergy bundles. Furthermore, the climate drivers (annual highest temperature (TH), annual total precipitation (PRE), annual total solar radiation (SRT)) significantly influenced the spatial heterogeneity of the 6 ESs in the YRDUA. The socio-economic drivers (night light index (NLI), gross domestic product (GDP)) and land use drivers (proportion of arable land (ALP), proportion of construction land (CLP), proportion of woodland (WLP)) had a more remarkable power of explanation for the ES temporal variation and ES trade-off/synergy. YRDUA and other urban agglomerations can use the study's findings to develop differentiated integrated ecological management strategies.

Research on the Influence of Spatial Structure on Carbon Emission Synergy of Urban Agglomeration—Based on the Development Process of Yangtze River Delta Urban Agglomeration in China

Carbon emissions, as an indicator of green economic development in urban agglomerations, are closely related to the degree of coordinated development between cities. Additionally, urban agglomerations, as a highly developed form of urban space, are widely regarded as a more efficient, energy-saving, and land-saving urbanization method. This article constructs an urban agglomeration network based on relevant data from listed companies in the Yangtze River Delta urban agglomeration with practical connections between cities and uses social network analysis methods and a fixed effects model to calculate the impact of overall and individual network indicators of urban agglomerations on urban carbon emissions and collaborative emission reduction of urban agglomerations. The regression results indicate that the centrality of individual cities has a significant negative correlation with the intensity of urban carbon emissions, with a coefficient of −0.067. The centrality of core cities has a significant positive impact on the collaborative emission reduction of urban agglomerations, with a coefficient of 0.0138. The impact of network density on the collaborative emission reduction of urban agglomerations shows an inverted U-shaped curve. Based on the analysis results, the paper explores the spatial structure construction method and industrial development control strategy based on urban agglomeration collaborative emission reduction.

Spatial Impact of Government Venture Capital on Urbanization and Its Path—Evidence from the Yangtze River Delta Urban Agglomeration in China

Despite being the world’s largest developing country and experiencing rapid economic growth, China’s urbanization process lags behind the global standard. The comprehensive promotion of urbanization development is a critical issue for the Chinese government, with government venture capital playing a significant role in promoting regional economic development. Using urbanization dimension levels extracted through factor analysis, this study analyzes the impact of government venture capital on the urbanization development of the Yangtze River Delta region of China and explores its path to determine its spatial spillover effect on surrounding areas. The results show that government venture capital funds can significantly promote urbanization development in this region, primarily by influencing the residents’ standard of living and urban construction levels. In addition, the spatial spillover effect of urbanization can be realized through the promotion of the urban construction level and the ecological health level of surrounding areas. While previous literature has examined government venture capital from multiple perspectives and dimensions, few scholars have investigated the impact of government venture capital on the critical issue of urbanization development. This study fills that research gap and serves as a reference for the Chinese government to promote high−quality urbanization development.

Assessment of spatiotemporal changes of ecological environment quality of the Yangtze River Delta urban agglomeration in China based on MRSEI

The Ecological Environment Quality (EEQ) is an important foundation for the sustainable development of society and economy. To assess the spatiotemporal changes of the EEQ in the Yangtze River Delta Urban Agglomeration (YRDUA), we selected MODIS images of 2001, 2006, 2011, 2016 and 2021 to construct the Modified Remote Sensing Ecological Index (MRSEI) based on Google Earth Engine (GEE) platform and Principal Component Analysis (PCA). Then, we evaluated the spatiotemporal changes and spatial autocorrelation of the EEQ in the YRDUA. The results showed that: the EEQ of the YRDUA was improved from 2001 to 2011, deteriorated from 2011 to 2016, and improved from 2016 to 2021. The overall EEQ of the YRDUA was at moderate or excellent level, and the EEQ in the south was better than that in the north. The EEQ of the southern cities in the study area was better and more stable, while that of the northern cities was relatively poor and changes relatively drastic. The EEQ of the YRDUA was mainly unchanged and improved from 2001 to 2021. The regions with improved EEQ were mainly distributed in the north and west, while those with deteriorated EEQ were mainly distributed in the east and south. The EEQ of the YRDUA was improved gradually from 2001 to 2006, and relatively stable from 2006 to 2011. From 2011 to 2016, the changes were drastic and the EEQ deteriorated greatly; while from 2016 to 2021, the EEQ of the YRDUA was improved, and the area of ecological deterioration was significantly reduced. From 2001 to 2021, the Globalmoran’s I value ranged from 0.838 ~ 0.918. In the past 20 years, NS area in the YRDUA accounted for the highest proportion, while the HH aggregation was mainly distributed in the southern part of the YRDUA, while LL aggregation was mainly distributed in the northern part, indicated that the EEQ in the southern part was better than that in the northern part. This study provides a promising approach to assess the spatiotemporal changes of EEQ in urban areas, which is crucial to formulate the ecosystem protection policies and sustainable development strategies of YRDUA.

Study on treatment effect assessment of heavy metal pollution in Taihu Lake Sediments Based on the rapid development of Yangtze River Delta Urban Agglomeration in China

<p>In order to explore an effective assessment method for the treatment effect of heavy metal pollution in the sediment of Taihu Lake in China, based on the research background analysis and literature review, this paper reconstructs the spatial niche suitability model and applies it to the effect assessment of heavy metal pollution treatment in Taihu Lake sediment. The study found that the pollution degree of heavy metals in Taihu Lake sediment is as follows: North water area, West water area, South water area and East water area. The assessment results of the effect of heavy metal pollution treatment in Taihu Lake sediment by using SNSM are as follows: As > Cd > Hg > Ni > Mn > Zn > Pb > Cr > Cu. The four heavy metals that pose the greatest threat to the effect of Taihu Lake sediment are As, Cd, Hg and Ni; in particular, As and Cd are carcinogenic heavy metals, which the management authorities should pay special attention to. The research results of this paper are of great significance in supporting the government to formulate relevant policies for treating Taihu Lake and helping the management departments improve the treatment effect of heavy metal pollution in Taihu Lake sediments.</p>

The Effects of Tourism Industry Agglomeration on Tourism Environmental Carrying Capacity: Evidence from a Panel Threshold Model

By utilizing the panel data of 26 cities in the Yangtze River Delta urban agglomeration of China from 2000 to 2018, this study constructs a panel threshold model to examine the nonlinear relationship between Tourism Environmental Carrying Capacity (TECC) and Tourism Industry Agglomeration (TIA). TECC is evaluated based on the Driver-Pressure-State-Impact-Response (DPSIR) model, and TIA is estimated by the location quotient index. The analysis reveals that TIA and TECC both show growth trends and significant regional differences among the 26 cities, but the latter fluctuates at certain stages. Moreover, TIA has a significant double threshold effect on TECC, which shows that the positive impact of TIA is enhanced initially but then weakens afterwards. Theoretically, this study contributes to enriching the current literature on TECC from the perspective of TIA. Practically, it could help local governments effectively arrange agglomerations to promote the sustainable development of the tourism industry in China.

Does High-Speed Railway Promote the Level of Human Capital? An Empirical Analysis Based on Three Urban Agglomerations in China

This paper analyzed the impact of high-speed railway (HSR) construction on human capital and its mechanism by establishing high-speed railway-city level panel data from 2003 to 2019 and constructing a multiperiod difference- in-differences (DID) DID model in China. The results showed that HSR has significantly promoted the level of human capital in Beijing–Tianjin–Hebei urban agglomeration, Yangtze River Delta urban agglomeration, and Pearl River Delta urban agglomeration in China, with the overall effect value of 20.8%. The conclusion that HSR promotes the level of human capital is still valid through endogenous treatment of the instrumental variable method and robustness test. Further analysis showed that the impact of HSR construction on the level of human capital in urban agglomerations is mainly through the labor mobility and education investment potential, with the effect values of 3.65% and 4.44%, respectively. The findings of this paper highlight the importance of exploiting the external utility of HSR, improving the level of regional human capital, and promoting high-quality economic development of urban agglomerations.

Sustainability assessment of the Yangtze River Delta Urban agglomeration in China based on stochastic simulation techniques

ABSTRACT The economy, society, and environment of the world are undergoing profound changes. Achieving sustainable development has become the common aspiration of the international communities. In recent years, sustainability issues are gaining increasing prominence for cities to formulate long-term development strategies. The Yangtze River Delta (YRD) urban agglomeration, one of China’s most developed and densely populated industrial areas, has encountered environmental problems. Assessment of city sustainability of the YRD is a prominent issue in the process of urban construction. The paper used multi-criteria decision making (MCDM) framework to evaluate the sustainability level of 26 cities in the YRD by selecting 24 indicators from the economic, social, and environmental dimensions. In the weighting process, the paper proposed a new subjective and objective integrated weighting method based on stochastic simulation techniques. Relative results including pairwise priority matrix (PPM), comprehensive priority index (CPI), and the most likely ranking were obtained to reflect the superiority degree between two cities by adequate comparisons. The assessment results indicate that all the cities showed an upward trend from 2015 to 2019. Shanghai had overwhelming advantages over the other cities. The CPIs of Suzhou, Nanjing, Wuxi, Changzhou in Jiangsu province, and Hangzhou, Ningbo, Zhoushan in Zhejiang province were above 50 in 2015 and increased to over 85 in 2019. Additionally, most cities had unbalanced development on the three dimensions. Each city should firstly pay more attention to their own weak points, and then achieve balanced development and long-term sustainability.

Examining supply and demand of cooling effect of blue and green spaces in mitigating urban heat island effects: A case study of the Fujian Delta urban agglomeration (FDUA), China

Blue and green spaces (BGSs) are used as the important resource to mitigate urban heat island (UHI) effect through their cooling effect. However, research on the supply and demand of cooling effect of BGSs is limited. This study used the Fujian Delta urban agglomeration of China as the study area. Based on multi-source data, we constructed the evaluation indicator system to quantify the supply capacity of cooling effect (CESC) and the demand level of cooling effect (CEDL), and revealed the law of spatial distribution and changes in the CESC and the CEDL. Moreover, we further analyzed the correlation, matching state and coupling coordination degree (CCD) between the CESC and the CEDL. The results showed that (1) in the study area, the CESC has a spatial distribution with a decreasing gradient from the inland BGSs with high elevations to the coastal urban areas, while the CEDL exists the opposite trend. The CESC is negatively correlated with the CEDL, and there is a clear spatial spillover effect. (2) The matching state between the CESC and the CEDL exhibits obvious polarization. An increasing number of areas might face shortage of cooling effect supply. (3) The CCD between the CESC and the CEDL is in a state of low coordination level. In eastern coastal urban areas, the incoordination of the CESC and the CEDL become serious increasingly. (4) In areas with ‘low supply-high demand’ and incoordination, the intensity of urban construction and the size of population should be controlled, and the BGSs should be improved to enhance the CESC. Meanwhile, in areas with ‘high supply-low demand’ and incoordination, spatial structure of land-use/land-cover should be optimized to improve the efficiency of cooling effect utilization. This research can provide a new perspective and scientific basis for the BGSs layout in order to achieve the mitigation of UHI effect.