Spatio-temporal Evolution Characteristics and Driving Forces of Winter Urban Heat Island:A Case Study of Rapid Urbanization Area of Fuzhou City,China

Under the influence of anthropogenic and climate change,the problems caused by urban heat island(UHI)has become increasingly prominent.In order to promote urban sustainable development and improve the quality of human settlements,it is significant for exploring the evolution characteristics of urban thermal environment and analyzing its driving forces.Taking the Landsat series images as the basic data sources,the winter land surface temperature(LST)of the rapid urbanization area of Fuzhou City in China was quantitatively retrieved from 2001 to 2021.Combing comprehensively the standard deviation ellipse model,profile analysis and GeoDetector model,the spatio-temporal evolution characteristics and influencing factors of the winter urban thermal environment were systematically analyzed.The results showed that the winter LST presented an increasing trend in the study area during 2001–2021,and the winter LST of the central urban regions was significantly higher than the suburbs.There was a strong UHI effect from 2001 to 2021with an expansion trend from the central urban regions to the suburbs and coastal areas in space scale.The LST of green lands and wetlands are significantly lower than croplands,artificial surface and unvegetated lands.Vegetation and water bodies had a significant mitigation effect on UHI,especially in the micro-scale.The winter UHI had been jointly driven by the underlying surface and socio-economic factors in a nonlinear or two-factor interactive enhancement mode,and socio-economic factors had played a leading role.This research could provide data support and decision-making references for rationally planning urban layout and promoting sustainable urban development.

Effects of urbanization and forest type on species composition and diversity,forest characteristics,biomass carbon sink,and their associations in Changchun,Northeast China:implications for urban carbon stock improvement

Differences in forest attributes and carbon sequestration of each organ and layer between broadleaved and conifer forests of central and outer urban areas are not well-defined,hindering the precise management of urban forests and improvement of function.To clarify the effect of two forest types with different urbanization intensities,we determined differences in vegetation composition and diversity,structural traits,and carbon stocks of 152 plots(20 m×20 m)in urban park forests in Changchun,which had the largest green quantity and carbon density effectiveness.We found that 1.1-fold thicker and healthier trees,and 1.6-to 2.0-fold higher,healthier,denser,and more various shrubs but with sparser trees and herbs occurred in the central urban forests(p<0.05)than in the outer forests.The conifer forests exhibited 30–70%obviously higher tree aboveground carbon sequestration(including stem and leaf)and 20%bigger trees,especially in the outer forests(p<0.05).In contrast,1.1-to 1.5-fold higher branch stocks,healthier and more diverse trees were found in broadleaved forests of both the inner and outer forests(p<0.05).Plant size and dominant species had similarly important roles in carbon stock improvement,especially big-sized woody plants and Pinus tabuliformis.In addition,a higher number of deciduous or needle species positively affected the broadleaved forest of the central urban area and conifer forest of the outer urban area,respectively.These findings can be used to guide precise management and accelerate the improvement of urban carbon function in Northeast China in the future.

Long-term dynamics and driving factors of phytoplankton biomass during urbanization, northern China

Understanding the relative impact of nutrients and related environmental variables on phytoplankton biomass changes in urban rivers is important for river management.In this study,we explored the long-term dynamic changes and driving factors of phytoplankton biomass in the process of urbanization from the perspective of time and space,and provided a scientific support to water ecological health assessment and management of urban rivers.From 2012 to 2021,the phytoplankton community composition in Taiyuan section of Fenhe River was found to be dominated by Cyanophyta,Chlorophyta,and Bacillariophyta.Among them,cyanobacteria were the main contributors to the total abundance,green algae ranked second,and diatoms were the least.The biomass of phytoplankton in different groups showed different decreasing trends.Based on 10 environmental factors to explain the changes of three main phytoplankton groups(cyanobacteria,green algae,diatoms),we found that chemical oxygen demand and water temperature had a high explanation rate for the abundance changes of the three main phytoplankton groups,which were important environmental factors affecting their biomass changes.The random forest model was used to analyze the changes in the total biomass of phytoplankton.It was found that the permanganate index had a higher contribution to the total biomass of phytoplankton in time.The contribution of air temperature to the total biomass of phytoplankton was higher in space.

Examining the Spatiotemporal Dynamics and Determinants of Land Urbanization in Prefecture-level Cities,China

Examining the spatiotemporal dynamics and determinants of land urbanization is critical for promoting healthy urban development and the rational use of land resources.Based on the dataset consisting of land use change data and selected factors in 2010 and2020,this study used visual analysis to reveal the spatiotemporal dynamics of land urbanization across prefecture-level cities in China.Meanwhile,the driving forces underlying land urbanization were examined by using geographical detector technique.Following are the findings:1)we find that there exist notable spatial variances in land urbanization across prefecture-level cities.Currently,the differentiation in land urbanization between the northern and southern cities is more pronounced than that between the coastal and inland cities,or between the eastern and western cities.Prefecture-level cities located in central and western China have experienced the most rapid growth in land urbanization.Conversely,the growth rate in northeastern China is the lowest,while the velocity in eastern China remains relatively stable.By using spatial autocorrelation analysis,this study reveals that the land urbanization level in prefecture-level cities has significant spatial agglomeration.2)We further find that land urbanization in China is influenced by factors related to urban land supply and demand,and urban population growth,economic growth,land financial and political incentive have greater impact on land urbanization than other factors.3)We also find that the impacts of determinants on China’s land urbanization vary over time,the explanatory power of economic development increased,while the explanatory power of state forces declined.We argue that integrating the supply and demand factors of land urbanization can provide a more comprehensive understanding of the driving mechanisms underlying land urbanization in China and other transitional countries,and help decision-makers in these countries formulate more detailed and specific land urbanization policies.

Evolutionary characteristics and influencing factors of agricultural regional system in the Loess Plateau of China under rapid urbanization

The rapid expansion of cities seriously threatens the sustainable development of agriculture in China.Exploring the evolution law and influencing mechanism of agricultural regional system in the process of urbanization is of great significance for promoting sustainable development of agriculture in China.This paper takes the Loess Plateau(LP)as an example,and constructs a research framework to study the effect of urbanization on agricultural regional system through the lens of human-earth interaction,aiming at elucidating the evolutionary characteristics of agricultural regional system and revealing the impact law of urbanization.The results show that:(1)The growth trend of the evolution index of the agricultural regional system in the LP was significant,gradually evolving into a spatial pattern of"high in the north and south,low in the east and west".(2)The hot spot and sub-hot spot zones of the agricultural regional system evolution index in the LP were mainly distributed in the south and north,while the cold spot and sub-cold spot zones were primarily located in the center,east and west.(3)The levels of agricultural mechanization,agricultural land productivity,cropland area,and agricultural labor productivity were the main internal influencing factors of the agricultural regional system in the LP.The obstacle degree of agricultural mechanization level,cropland area,and the proportion of agricultural employees increased over time,while the obstacle degree of agricultural land productivity and grain yield capacity decreased.(4)The impact of population urbanization in the LP showed a spatial pattern of"inhibition in the southeast and promotion in the northwest",the impact of economic urbanization was dominated by inhibition,and the impact of land urbanization showed a spatial pattern of"promotion in the whole and inhibition in the local".This study provides ideas for the comprehensive research on the evolution and influencing factors of agricultural regional system,and offers practical references for achieving sustainable agricultural development in LP.

Anthropogenic nesting materials and reproductive performance of Chinese Bulbuls(Pycnonotus sinensis)along the urbanization gradient in Hangzhou,China

Urbanization induced by human activities presents both challenges and adaptive opportunities for wildlife.One notable impact of urban sprawl is the vast amount of waste it produces,which has discernible effects on wildlife.Interestingly,an emerging trend has been observed that birds are incorporating anthropogenic materials into their nests.However,the relationship between anthropogenic nesting materials(ANMs)and the reproductive performance of urban birds is unclear.In this study,we investigated the relationship between the incorporation of ANMs into nests and the reproductive performance of Chinese Bulbuls(Pycnonotus sinensis)by monitoring and collecting data on 136 breeding nests in Hangzhou,China.We gathered data on seven reproductive traits of Chinese Bulbuls,including laying date,incubation period,nestling period,clutch size,egg volume,hatching success rate,and fledging success rate.We then calculated the urbanization synthetic index as a measure of the level of urbanization and examined its relationship with the proportion and weight of ANMs.Through examination of nest components,we observed significant increase in the proportion and weight of ANMs with the urbanization synthetic index.Notably,we found a higher hatching success rate of Chinese Bulbuls with an increasing proportion of ANMs.However,the inclusion of ANMs in nests was not correlated with other reproductive traits of Chinese Bulbuls.Overall,the use of ANMs by Chinese Bulbuls is consistent with the adaptive hypothesis and the availability hypothesis.Further studies should use controlled experiments to investigate the impact of ANMs on avian reproductive success.

Impact of air pollution on urbanization:evidence at China’s city level

This paper investigates the effect and transmission mechanism of air pollution on urbanization based on data from China’s 107 cities during 2005–2018.In order to identify the impact of air pollution on China’s urbanization,we utilized night light data to represent the level of urbanization and used temperature inversion as an instrumental variable to mitigate endogeneity within the two-stage least squares framework.The results suggest that air pollution significantly slowed China’s urbanization process with economic growth acting as the transmission mechanism.The heterogeneity analyses revealed that air pollution had a greater negative impact on urbanization in northern regions than that in southern regions,and a greater negative impact in resource-oriented cities than that in non-resource-based cities.We also find that air pollution was to the detriment of urbanization in larger cities,which have more than 3 million residents,while it did not have a significant impact on Type II large cities,which have fewer than 3 million residents.

Research on the Digital Economy's Impact on China's Economic Growth:Based on the Variations in Urbanization Levels Across China's Eastern,Central,and Western Regions and Sectoral Heterogeneity

This paper uses inter-provincial panel data from 2011 to 2017,a linear regression model,and a threshold model to conduct empirical analyses of the impact of the digital economy on China's overall economic growth and the three main sectors of industry.The paper then investigates the impact and effects the digital economy has had on the economic growth of the three main sectors of industry in China's eastern,central,and western regions.Finally,the paper investigates the most significant differences among the various regions and the threshold effects of urbanization levels on the relationship between the digital economy and economic growth.The findings indicate a significantly positive correlation between the digital economy and regional economic growth.Moreover,geographical factors notably influence this correlation.The digital economy exerts a positive effect on all sectors of industry.It may not substantially impact industrial development in regions with highly developed infrastructure.Regarding the other regions,the digital economy exhibits varying degrees of impact due to the differences in the specific indicators.The conclusion drawn by the threshold model is that the magnitude of the threshold effect correlates with geographic factors.No threshold effect was observed in the eastern region,while the threshold effect occurred in the central region when the urbanization levels for the provinces were below 0.6645.Similarly,the threshold effect was noted in the western region when the urbanization level was below 0.3931.Considering all of this,the study also offers policy recommendations that will help balance the regional development of digital economies,accelerate the digital transformation of traditional industries,enhance digital infrastructure construction,refine the formulation and implementation of data policy,and establish relevant incentive mechanisms.

The Implications of Urbanization Processes in Developed Countries for Africa

Urbanization is the inevitable path of national economic development,and the level of urbanization development in most African countries is still low.By analyzing five typical developed countries in the United States,Britain,France,Germany,and Japan,this paper discusses the promoting factors and problems of the rapid urbanization development in their specific years,as well as the experiences and lessons that Africa can learn,so as to prevent Africa from taking the detour in the urbanization process of Western developed countries and promote the balanced regional development of various African countries.

Local Climate Change Induced by Urbanization on a South China Sea Island

The South China Sea is a hotspot for regional climate research.Over the past 40 years,considerable improvement has been made in the development and utilization of the islands in the South China Sea,leading to a substantial change in the land-use of the islands.However,research on the impact of human development on the local climate of these islands is lacking.This study analyzed the characteristics of local climate changes on the islands in the South China Sea based on data from the Yongxing Island Observation Station and ERA5 re-analysis.Furthermore,the influence of urbanization on the local climate of the South China Sea islands was explored in this study.The findings revealed that the 10-year average temperature in Yongxing Island increased by approximately 1.11℃from 1961 to 2020,and the contribution of island development and urbanization to the local warming rate over 60 years was approximately 36.2%.The linear increasing trend of the annual hot days from 1961–2020 was approximately 14.84 days per decade.The diurnal temperature range exhibited an increasing trend of 0.05℃per decade,whereas the number of cold days decreased by 1.06days per decade.The rapid increase in construction on Yongxing Island from 2005 to 2021 led to a decrease in observed surface wind speed by 0.32 m s^(-1)per decade.Consequently,the number of days with strong winds decreased,whereas the number of days with weak winds increased.Additionally,relative humidity exhibited a rapid decline from 2001 to 2016 and then rebounded.The study also found substantial differences between the ERA5 re-analysis and observation data,particularly in wind speed and relative humidity,indicating that the use of re-analysis data for climate resource assessment and climate change evaluation on island areas may not be feasible.

Recent urbanization increases exposure to humid-heat extreme events over populated regions of China

目前对于高温的研究主要侧重于干热,针对湿热的研究相对较少,但它通常会造成更大的社会影响,尤其对人体健康的威胁.已有研究证实,当环境湿球温度超过35℃时,它会破坏人体正常生理代谢,进而威胁人体健康.本研究指出在过去四十年,中国区域日最高湿球温度几乎没有超过35℃,但部分地区日最高湿球温度超过了30℃,主要集中在中国的人口密集区,包括华东,华南和四川盆地等.进一步分析发现,中国区域近期的快速城市化加剧了极端湿热事件的社会影响,城市地区暴露于极端湿热事件的范围的增加速率明显大于其他地区,这也意味着快速城市化使得人口密集区暴露于极端湿热事件的风险明显增加.初步估算指出,自2000年以来,中国区域暴露于极端湿热事件的人口数以每年每天约3100人次的速率显著增加.

From earthquake resistance structure to earthquake resilience city–urban seismic resilience assessment

Earthquakes pose significant perils to the built environment in urban areas.To avert the calamitous aftermath of earthquakes,it is imperative to construct seismic resilient cities.Due to the intricacy of the concept of urban seismic resilience(USR),its assessment is a large-scale system engineering issue.The assessment of USR should be based on the notion of urban seismic capacity(USC)assessment,which includes casualties,economic loss,and recovery time as criteria.Functionality loss is also included in the assessment of USR in addition to these criteria.The assessment indicator system comprising five dimensions(building and lifeline infrastructure,environment,society,economy,and institution)and 20 indicators has been devised to quantify USR.The analytical hierarchy process(AHP)is utilized to compute the weights of the criteria,dimensions,and indicators in the urban seismic resilience assessment(USRA)indicator system.When the necessary data for a city are obtainable,the seismic resilience of that city can be assessed using this framework.To illustrate the proposed methodology,a moderate-sized city in China was selected as a case study.The assessment results indicate a high level of USR,suggesting that the city possesses strong capabilities to withstand and recover from potential future earthquakes.

Spatiotemporal variation and driving factors of vegetation net primary productivity in the Guan-zhong Plain Urban Agglomeration,China from 2001 to 2020

Studying the spatiotemporal variation and driving mechanisms of vegetation net primary productivity(NPP)in the Guanzhong Plain Urban Agglomeration(GPUA)of China is highly important for regional green and low-carbon development.This study used the Theil-Sen trend analysis,Mann-Kendall trend test,coefficient of variation,Hurst index,and machine learning method(eXtreme Gradient Boosting and SHapley Additive exPlanations(XGBoost-SHAP))to analyze the spatiotemporal variation of NPP in the GPUA from 2001 to 2020 and reveal its response to climate change and human activities.The results found that during 2001-2020,the averageNPP in the GPUA showed a significant upward trend,with an annual growth rate of 10.84 g C/(m^(2)•a).The multi-year average NPP in the GPUA was 484.83 g C/(m^(2)•a),with higher values in the southwestern Qinling Mountains and lower values in the central and northeastern cropland and built-up areas.The average coefficient of variation of NPP in the GPUA was 0.14,indicating a relatively stable state overall,but 72.72%of the study area showed weak anti-persistence,suggesting that NPP in most areas may have declined in the short term.According to XGBoost-SHAP analyses,elevation,land use type and precipitation were identified as the main driving factors of NPP.Appropriate precipitation and higher temperatures promote NPP growth,whereas extreme climates,high population density,and nighttime lighting inhibit NPP.This study has important theoretical and practical significance for achieving regional sustainable development,offers a scientific basis for formulating effective ecological protection and restoration strategies,and promotes green,coordinated,and sustainable development in the GPUA.

Dynamic partition of urban network considering congestion evolution based on random walk

The successful application of perimeter control of urban traffic system strongly depends on the macroscopic fundamental diagram of the targeted region.Despite intensive studies on the partitioning of urban road networks,the dynamic partitioning of urban regions reflecting the propagation of congestion remains an open question.This paper proposes to partition the network into homogeneous sub-regions based on random walk algorithm.Starting from selected random walkers,the road network is partitioned from the early morning when congestion emerges.A modified Akaike information criterion is defined to find the optimal number of partitions.Region boundary adjustment algorithms are adopted to optimize the partitioning results to further ensure the correlation of partitions.The traffic data of Melbourne city are used to verify the effectiveness of the proposed partitioning method.

Environmental Inequality in China’s Urban Expansion:A Case Study of Guangzhou,China

Environmental inequality is a prevalent issue in developing countries undergoing urban expansion.Urban expansion induces the formation and evolution of environmental inequality by creating environmental and structural conditions that lead to the spatial relocation of environmental hazards and the socio-spatial segregation of different groups in developing countries.This study investigated the spatial patterns and temporal trends of environmental inequality under urban expansion in Guangzhou,a megacity in China.It considered how environmental disparities and socio-demographic attributes interact in terms of industrial pollution exposure using additive semiparametric quantile regression,combined with spatial visualisation,on the basis of the economic and population census data from 1990 to 2020.This study revealed that urban expansion sparked the spatial displacement of environmental risks and the social-spatial differentiation,exposing the peripheral regions and disadvantaged groups to higher environmental risks.A reciprocal transformation occurred between central and peripheral regions,as well as a process of redistributing environmental risks across social space.In the context of urban expansion in developing countries,the causes of environmental inequality shifted from individual socio-economic differences to structural factors,such as industrial layout and social division of labour in cities,leading to the spatial displacement and concealment of environmental inequality.This study provides insights and guidance for policymakers to address the issue of environmental inequality in the context of urban expansion.

Territorial Ecological Restoration with a High-carbon Storage Focus in the Beibu Gulf Urban Agglomeration of China:Insights from Carbon Metabolism Spatial Security Patterns

This study focuses on urgent research on restoring and enhancing carbon storage capacity in the Beibu Gulf Urban Agglomer-ation of China,a key area in the‘Belt and Road’Initiative,which aligns with carbon peaking and neutrality goals.This research ana-lyzes the spatial characteristics of carbon metabolism from 2000 to 2020 and uses models to identify stable carbon sink areas,positive carbon flow corridors,and carbon sequestration nodes.The goal is to construct a carbon metabolism spatial security pattern(CMSSP)and propose territorial ecological restoration strategies under different development demand scenarios.The results show the following:1)in 2020,the study area’s carbon sink decreased by 8.29×10^(4) t C/yr compared with that in 2010 and by 10.83×10^(4) t C/yr compared with that in 2000.High-carbon sinks were found mainly in mountainous areas,whereas low-carbon sinks are concentrated in urban con-struction land,rural residential areas,and land margins.2)From 2000 to 2020,the spatial security pattern of carbon metabolism tended to be‘high in the middle of the east and west and low in the gulf.’In 2000,2010,and 2020,16 stable carbon sinks were identified.The carbon energy flow density in Guangxi was greater than that in Guangdong and Hainan,with positive carbon flow corridors located primarily in Guangxi and Guangdong.The number of carbon sequestration nodes remained stable at approximately 15,mainly in Guangxi and Hainan.3)Scenario simulations revealed that under the Nature-based mild restoration scenario,the carbon sink rate will reach 611.85×10^(4) t C/yr by 2030 and increase to 612.45×10^(4) t C/yr by 2060,with stable carbon sinks increasing to 18.In the restora-tion scenario based on Anti-globalization,the carbon sink will decrease from 610.24×10^(4) t C/yr in 2030 to 605.19×10^(4) t C/yr in 2060,with the disappearance of some positive carbon flow corridors and stable carbon sinks.Under the Human-based sustainable restoration scenario,the carbon sink area will decrease from 607.00×10^(4) t C/yr in 2030 to 596.39×10^(4) t C/yr in 2060,with carbon sink areas frag-menting and positive carbon flow corridors becoming less dense.4)On the basis of the current and predicted CMSSPs,this study ex-plores spatial ecological restoration strategies for high-carbon storage areas in bay urban agglomerations at four levels:the land control region,urban agglomeration structure system,carbon sink structure and bay structure control region.

Integration and Symbiosis between Traditional Folk Culture and Urban Space during Urbanization in China

By taking the residential environment change in Tai'an City of Shandong Province over the past 30 years for example, the paper had introduced characteristics of traditional residential culture and their influence on the urban residential spatial pattern, and explained the mutual effect and guidance between the establishment of new residential concepts and the extension of city context. It had pointed out that the government planning and development should be considered from historical and cultural perspective rather than economic perspective. Through the analysis of problems at each level, it had proposed that urban construction should pay attention to historical inheritance, and characteristic livable city construction should lay stress on the coordinated development between urban economy and historical culture.

Study on the Urbanization-based Restructuring of Urban Spaces in Meizhou City of China

By introducing the urbanization history of Meizhou City,major problems of its spatial structure were summarized as small scale of urban areas and incomplete hierarchical structure;poor cohesive force of central city,imbalanced regional spatial ratio;disorderly development of urban spaces;and fierce competition for space.Then spatial restructuring of Meizhou City was discussed from the following 3 perspectives:optimizing hierarchical structure of space,planning in advance to construct a central city with more than 1 million residents;establishing the traffic hub of Guangdong,Fujian and Jiangxi;improving spatial structure of industries.It was to enhance sustainable social and economic development of the local area,break the dualistic structure and realize the overall development of urban and rural areas,and also narrow the urban-rural gap.

Urbanization Level Analysis of Chongqing 1 Hour Economic Circle Based on AHP and GIS

With Chongqing 1 Hour Economic Center as an example, AHP was adopted to comprehensively analyze factors influencing the economic development of all districts and counties of Chongqing City, economic development scores were calculated and urbanization level of each district and county was comparatively analyzed. The results showed that the economic development level and the urbanization level of almost all districts and counties were not coordinated, then the reasons were briefly elaborated and corresponding countermeasures and suggestions were proposed.

Analysis of the Response and Driving Forces of Urban Landscape Pattern during Urbanization of Zhangjiagang City in China

By taking Zhangjiagang City as the research object, with the guidance of 3S (GIS, GPS and RS) and the theory of landscape ecology, based on the remote sensing images from 1991 to 2006, land use maps and social-economic statistical data, by combining with gradient analytical method, eight landscape pattern metrics had been selected to analyze the urbanization of Zhangjiagang City and urban landscape pattern change characteristics at different stages of urbanization. The results showed that the urbanization of Zhangjiagang City could be divided into two stages which were the urbanization of Zhangjiagang City from 1991 to 2001 and the suburbanization of Zhangjiagang City from 2001 to 2006 based on landscape metrics' change characteristics. During urbanization, the response was obvious in the urban center of Zhangjiagang City, and urban landscape pattern changed greatly. During suburbanization, the response was obvious in the rural area of Zhangjiagang City and rural landscape pattern changed greatly. The urbanization of Zhangjiagang City conformed to the urbanization mode based on population theory and extension theory. Urbanization firstly affected the urban center, and then extended to its surrounding areas, and further influenced widespread rural areas. During suburbanization, agricultural land had decreased and been seriously destroyed; thus, it should strengthen the protection of agricultural land.