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.

Spatiotemporal Evolution of Urban Land Uses in Modern Urbanization of China

Taking social statistic data as basic data,this paper extended the meaning of urban land uses,highlighted the meaning of urban land uses in modern urbanization,which includes direct,indirect and induced land uses,quantitatively simulated the indirect and induced land uses by the substitution method of agricultural consumption and urban carbon emission and then,analyzed the spatiotemporal evolution of urban land uses in China during 1952–2005 by spatial analysis tool of Geographic Information System. The results indicate that the area of urban land use in China had been increasing since 1952,showing an inversed pyramid structure,i.e.,the direct<the indirect<the induced. Specifically,Chinese urban land use has changed from concentrated distribution in Northwest China to balanced spatial distribution,and the eastern coastal area is under great pressure. Moreover,the northeastern region has moved into the induced dominant stage,while the western region remains at the indirect dominant stage. Finally,it is proposed that in order to guarantee the future demand of urban land use in China,ensuring the induced land use in the eastern region should be taken as a priority goal of Chinese developing policy.

The urban land area Change in China from 1820 to 1999

According to the length of city perimeter and the administration systems recorded in the historical literatures of the Qing Dynasty, a set of methods is developed to convert the historical records into the area of urban land use, by which a set of preliminary estimated urban land use data of the 18 provinces during the Emperor Jiaqing (1820AD) in the Qing Dynasty, is achieved. Based on the above achievements, the regional differences of urban land use are analyzed, and the comparison in urban land use between the Qing Dynasty and present (1999) is made.

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.

Spatiotemporal patterns and drivers of cultivated land conversion in Inner Mongolia Autonomous Region,northern China

Protection and optimization of cultivated land resources are of great significance to national food security.Cultivated land conversion in northern China has increased in recent years due to the industrialization and urbanization of society.However,the assessment of cultivated land conversion in this area is insufficient,posing a potential risk to cultivated land resources.This study evaluated the evolution and spatiotemporal patterns of cultivated land conversion in Inner Mongolia Autonomous Region,China,and the driving factors to improve rational utilization and to protect cultivated land resources.The spatiotemporal patterns of cultivated land conversion in Inner Mongolia were analyzed using the cultivated land conversion index,kernel density analysis,a standard deviation ellipse model,and a geographic detector.Results showed that from 2000 to 2020,the trends in cultivated land conversion area and rate in Inner Mongolia exhibited fluctuating growth,with the total area of cultivated land conversion reaching 7307.59 km^(2) at a rate of 6.69%.Spatial distribution of cultivated land conversion was primarily concentrated in the Hetao Plain,Nengjiang Plain,Liaohe Plain,and the Hohhot-Baotou-Ordos urban agglomeration.Moreover,the standard deviational ellipse of cultivated land conversion in Inner Mongolia exhibited a directional southwest-northeast-southwest-northeast distribution,with the northeast-southwest direction identified as the main driving force of spatial change in cultivated land conversion.Meanwhile,cultivated land conversion exhibited an increase-decrease-increase change process,indicating that spatial distribution of cultivated land conversion in Inner Mongolia became gradually apparent within the study period.The geographic detector results further revealed that the main driving factors of cultivated land conversion in Inner Mongolia were the share of secondary and tertiary industries and per-unit area yield of grain,with explanatory rates of 57.00%,55.00%,and 51.00%,respectively.Additionally,improved agricultural production efficiency and the coordinated development of population urbanization and industry resulted in cultivated land conversion.Collectively,the findings of this study indicated that,from 2000 to 2020,the cultivated land conversion in Inner Mongolia was significant and fluctuated in time,and had strong spatial heterogeneity.The primary drivers of these events included the effects of agriculture,population,and social economy.

Spatiotemporal Evolution Characteristics of Urban Land Surface Temperature Based on Local Climate Zones in Xi’an Metropolitan,China

Local climate zones(LCZs)are an effective nexus linking internal urban structures to the local climate and have been widely used to study urban thermal environment.However,few studies considered how much the temperature changed due to LCZs transformation and their synergy.This paper quantified the change of urban land surface temperature(LST)in LCZs transformation process by combining the land use transfer matrix with zonal statistics method during 2000–2019 in the Xi’an metropolitan.The results show that,firstly,both LCZs and LST had significant spatiotemporal variations and synchrony.The period when the most LCZs were converted was also the LST rose the fastest,and the spatial growth of the LST coincided with the spatial expansion of the built type LCZs.Secondly,the LST difference between land cover type LCZs and built type LCZs gradually widened.And LST rose more in both built type LCZs transferred in and out.Finally,the Xi’an-Xianyang profile showed that the maximum temperature difference between the peaks and valleys of the LST increased by 4.39℃,indicating that localized high temperature phenomena and fluctuations in the urban thermal environment became more pronounced from 2000 to 2019.

Spatially Heterogeneous Response of Carbon Storage to Land Use Changes in Pearl River Delta Urban Agglomeration, China

Carbon storage of terrestrial ecosystems plays a vital role in advancing carbon neutrality. Better understanding of how land use changes affect carbon storage in urban agglomeration will provide valuable guidance for policymakers in developing effective regional conservation policies. Taking the Pearl River Delta Urban Agglomeration(PRDUA) in China as an example, we examined the heterogeneous response of carbon storage to land use changes in 1990–2018 from a combined view of administrative units and physical entities. The results indicate that the primary change in land use was due to the expansion of construction land(5897.16 km2). The carbon storage in PRDUA decreased from 767.34 Tg C in 1990 to 725.42 Tg C in 2018 with a spatial pattern of high wings and the low middle. The carbon storage loss was largely attributed to construction land expansion(55.74%), followed by forest degradation(54.81%). Changes in carbon storage showed significant divergences in different sized cities and hierarchical boundaries. The coefficients of geographically weighted regression(GWR) reveal that the alteration in carbon storage in Guangzhou City was more responsive to changes in construction land(-0.11) compared to other cities, while that in Shenzhen was mainly affected by the dynamics of forest land(8.32). The change in carbon storage was primarily influenced by the conversion of farmland within urban extent(5.05) and the degradation of forest land in rural areas(5.82). Carbon storage changes were less sensitive to the expansion of construction land in the urban center, urban built-up area, and ex-urban built-up area, with the corresponding GWR coefficients of 0.19, 0.04, and 0.02. This study necessitates the differentiated protection strategies of carbon storage in urban agglomerations.

Simulation of Urban Land Expansion Under Ecological Constraints in Harbin-Changchun Urban Agglomeration,China

Under the demand of urban expansion and the constraints of China’s’National Main Functional Area Planning’policy,urban agglomerations are facing with a huge contradiction between land utilization and ecological protection,especially for HarbinChangchun urban agglomeration who owns a large number of land used for the protection of agricultural production and ecological function.To alleviate this contradiction and provide insight into future land use patterns under different ecological constraints’scenarios,we introduced the patch-based land use simulation(PLUS)model and simulated urban expansion of the Harbin-Changchun urban agglomeration.After verifying the accuracy of the simulation result in 2018,we predicted future urban expansion under the constraints of three different ecological scenarios in 2026.The morphological spatial pattern analysis(MSPA)method and minimum cumulative resistance(MCR)model were also introduced to identify different levels of ecological security pattern(ESP)as ecological constraints.The predicted result of the optimal protection(OP)scenario showed less proportion of water and forest than those of natural expansion(NE)and basic protection(BP)scenarios in 2026.The conclusions are that the PLUS model can improve the simulation accuracy at urban agglomeration scale compared with other cellular automata(CA)models,and the future urban expansion under OP scenario has the least threat to the ecosystem,while the expansion under the natural expansion(NE)scenario poses the greatest threat to the ecosystem.Combined with the MSPA and MCR methods,PLUS model can also be used in other spatial simulations of urban agglomerations under ecological constraints.

Urban expansion and intra-urban land evolution as well as their natural environmental constraints in arid/semiarid regions of China from 2000–2018

Rapid urbanization has occurred in arid/semiarid China,threatening the sustainability of fragile dryland ecosystems;however,our knowledge of natural environmental constraints on multiscale urban lands in this region is still lacking.To solve this issue,this study retrieved 15-m multiscale urban lands.Results indicated that urban area increased by 68%during 2000–2018,and one-third of the increase was contributed by only three large cities.The coverage of impervious surface area(ISA) and vegetated area(VA) increased by 16.6%and 1.38%,respectively.Such land-cover change may be helpful in suppressing wind erosion and sand storms.We also found that the newly urban lands had relatively lower ISA and higher VA than the old urban lands,indicating an improved human settlement environment.Strong environmental constraints on urban expansion were identified,with cities in oasis urban environments(OUEs) that had water supply expanding 150% faster than cities in desert urban environments(DUEs).Urban development was also constrained by terrain,with 73% of the ISA expansion occurring in relatively flat areas.Overall,the aggregated pattern of urbanization and the increase in ISA and VA in the newly urbanized lands have improved water-use efficiency and ecological services and benefited desert ecosystem protection in arid/semiarid China.

Monitoring Intra-annual Spatiotemporal Changes in Urban Heat Islands in 1449 Cities in China Based on Remote Sensing

This study aimed to accurately study the intra-annual spatiotemporal variation in the surface urban heat island intensities(SUHIIs) in 1449 cities in China.First, China was divided into five environmental regions.Then, the SUHIIs were accurately calculated based on the modified definitions of the city extents and their corresponding nearby rural areas.Finally, we explored the spatiotemporal variation of the mean, maximum, and minimum values, and ranges of SUHIIs from several aspects.The results showed that larger annual mean daytime SUHIIs occurred in hot-humid South China and cold-humid northeastern China, and the smallest occurred in arid and semiarid west China.The seasonal order of the SUHIIs was summer > spring > autumn > winter in all the temperate regions except west China.The SUHIIs were obviously larger during the rainy season than the dry season in the tropical region.Nevertheless, significant differences were not observed between the two seasons within the rainy or dry periods.During the daytime, the maximum SUHIIs mostly occurred in summer in each region, while the minimum occurred in winter.A few cold island phenomena existed during the nighttime.The maximum SUHIIs were generally significantly positively correlated with the minimum SUHIIs during the daytime, nighttime and all-day in all environmental regions throughout the year and the four seasons.Moreover, significant correlation scarcely existed between the daytime and nighttime ranges of the SUHIIs.In addition, the daytime SUHIIs were also insignificantly correlated with the nighttime SUHIIs in half of the cases.

Agricultural land loss in China's urbanization process

In China, urbanization of agricultural land around city agglomerations increases rapidly. Rapid urbanization of agricultoral land affects food supply, land value and ecological balance in the society. In China, the urban built-up area had increased by 40% from 1996 to 2003. This increase came predominantly from farmland surrounding the cities. How the ongoing urbanization of China affects its agricultural land is the focus of this paper. In current studies, we have found that population density; urbanization degree and personal income are key factors that influence the urbanization process. Based on this, relation model has been established and to predict the general trends of the urban area expansion in China in 2020.In 2020, the constructed urban area of China would be increased by 1.3 times compared wtth 2003. In 2020, this study anticipates the conversion of about 32,562 sq. kin. agricultural land of China for urban use.

A study on the evolution of land use for modern urbanization in China:1952-2005

Modern cities and towns play as the central places of wealth accumulation for human-being, not only in the ways of settlement and material consumption as they were traditionally in ancient time, but also in the ways of social production and environmental pollution as they are mostly today. With such a transition, the meaning of land use for urbanization has broadened. According to the rule of human ecosystem, land use for modern urbanization can be divided into three types: namely, the direct, the indirect and the induced. However, its structure follows its own way of the direct < the indirect < the induced, rather different from what it normally happens in the natural ecosystem. This paper takes China as an example, calculates the evolution of the land used by cities and towns during 1952-2005 according to statistics, and then analyzes the evolvement of the structure. At last, it puts forward several countermeasures to ensure land resource requirement for urbanization in future.

Spatio-temporal analysis of land-use conversion in the eastern coastal China during 1996-2005

Based on the acquaintance of the regional background of urban-rural transformational development and investigations on the spot,this paper discusses the holistic situation, dominant factors and mechanism of arable land loss and land for construction occupation in the coastal area of China over the last decade,with the aid of GIS technology.Conclusions of the research are summarized as follows：（1）the arable land had been continuously decreasing from 1996 to 2005,with a loss of 1,708,700 hm^2 and an average decrement of 170,900 hm^2 per year;（2）land for construction increased 1,373,700 hm^2 ,with an average increment of 153,200 hm^2 per year;（3）total area of encroachment on arable land for construction between 1996 and 2005 was 1,053,100 hm^2 ,accounting for 34.03%of the arable land loss in the same period,the percentages of which used for industrial land（INL）,transportation land（TRL）,rural construction land（RUL）and town construction land（TOL）are 45.03%,15.8%,15.47%and 11.5%,respectively;and（4）the fluctuation of the increase of construction land and encroachment on arable land in the area were deeply influenced by the nation＇s macroscopic land-use policies and development level of regional economy.The growth of population and advancement of technology promoted the rapid industrialization, construction of transportation infrastructures,rural urbanization and expansion of rural settlements in the eastern coastal area,and therefore were the primary driving forces of land-use conversion.

Comparing Land Degradation and Regeneration Trends in China Drylands

The aim of this paper is to offer a statistically sound method to make a precise account of the speed of land degradation and regeneration processes.Most common analyses of land degradation focus instead on the extent of degraded areas,rather than on the intensity of degradation processes.The study was implemented for the Potential Extent of Desertification in China(PEDC),composed by arid,semi-arid,and dry sub-humid regions and refers to the period 2002 to 2012.The metrics were standard partial regression coefficients from stepwise regressions,fitted using Net Primary Productivity as the dependent variable,and year number and aridity as predictors.The results indicate that:①the extension of degrading lands(292896 km 2 or 9.12%of PEDC)overcomes the area that is recovering(194560 km 2 or 6.06%of PEDC);and②the intensity of degrading trends is lower than that of increasing trends in three land cover types(grassland,desert,and crops)and in two aridity levels(semi-arid and dry sub-humid).Such an outcome might pinpoint restoration policies by the Chinese government,and document a possible case of hysteresis.

Study on the Spatial Distribution of Resource-based Urban Land Based on Suitability Evaluation——A Case Study of Datong City in Shanxi Province

[ Objective] The study aimed at analyzing the spatial distribution of urban land based on the suitability evaluation of construction land in a resource-based city. [Methed] Firstly, the suitability of construction land in the center of Datong City was assessed; afterwards, according to the urban scale and spatial expansion mode in target years in the General Land Use Planning for Datong City （2006 -2020）, the spatial layout of new- ly-increased urban land and flexible construction land was carried out to determine the development boundary of Datong City in 2020. [ Result] In the evaluation area of Datong City, the most suitable construction land had an area of only 66.18 hm2, accounting for 10.40% of total area of evalu- ation region; the area of more suitable construction land was 117.51 hm2 and make up 18.47% of total area; moderately suitable land covered an area of 149.49 hm2, which took up 23.49% of total area; the area of unsuitable construction land （89.31 hm2 ） only made up 14.04% of total area. In the newly-increased urban construction land, the area of the most suitable and more suitable land accounted for 73.58%, while there was no un- suitable land. Meanwhile, in flexible construction land, the area of the most suitable and more suitable land made up 66.85%. In a word, the spa- tial layout of urban land was reasonable in Datong City. [Conclusion] The research could provide theoretical references for the spatial expansion and layout of urban land.

Establishment of Rural Housing Land Standard in China

On the basis of rural household survey in 12 provinces of China in 2005,this research built an econometrical model to find the area standard for rural housing land.This standard is expected to facilitate rural housing land administration,efficient and intensive housing land use and policy making.This research concludes:1) according to the household survey data,the average area for rural housing land in China is about 235.26 m 2,and the rural housing land mainly includes unused land(42.89%) and house construction land(37.76%) with the average floor-area ratio of 0.42;2) the indexes in the standard concern the factors such as location,landform,house form,household population and cultivated land area per farmer,which all have significant effects on rural housing land use;3) the reasonable area for rural housing land may be 150 m 2 in average before 2020,and the referential standards in different provinces are 120 m 2,130 m 2,140m 2,150 m 2,160 m 2,170 m 2,190 m 2,200 m 2,210 m 2,220 m 2,230 m 2 and 250 m 2 respectively;and 4) if there are less than two persons or more than five persons in a family,these standards need to be decreased or increased by 7%.When the cultivated land area per farmer is lower than the provincial average,the standards have to reduce by 3.5%.

Spatio-temporal Evolution of Urban Expansion Based on a Novel Adjusted Index and GEE: A Case Study of Central Plains Urban Agglomeration, China

It is crucial to investigate the urban agglomerations spatio-temporal evolution patterns and driving factors for analyzing the urban spatial structure-functional division and promoting the coordinated development of urban agglomerations.In this study,a novel vegetation-building-nighttime light-adjusted index(VBNAI)was established for rapid and effective mapping of urban construction land(UCL)in Central Plains Urban Agglomeration(CPUA),China during 2000–2020 based on Google Earth Engine(GEE)platform.Compared with traditional indices,VBNAI can significantly decrease the blooming effect,Normalized Difference Vegetation Index(NDVI)saturation,and soil background of nighttime light data.In addition,the urban expansion indices and standard deviation ellipse model were synthetically adopted to analyze the spatio-temporal evolution pattern of urban expansion.The gravity model and the geographically weighted regression model were employed to determine the spatial interaction forces and drivers of urban expansion,respectively.The results showed that the VBNAI index has obvious advantages in efficiency and accuracy to extract UCL with the overall accuracy of more than 91%.The UCL of CPUA had increased by 4489.84 km2 during 2000–2020 with the gravity center moving towards southeast continuously.From 2000 to 2010,the urban expansion was in a‘center-hinterland’pattern which had benefit from the favorable effect of the traffic shaft belt.During 2010–2020,the urban network structure had basically established.Urban expansion had been influenced by a variety of socio-economic and demographic factors,and the impact degree varied from region to region.This study could provide scientific references for facilitating the intensive utilization of urban resources and optimizing the spatial development pattern of urban agglomeration.

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.

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.

Influences of Different Transport Routes and Road Nodes on Industrial Land Conversion: A Case Study of Changchun City of Jilin Province, China

Nowadays, urban transit system has become one of the major forces underlying urban pace transformation via changing accessibility of related land parcels, which leads to the changes of land value and land use structure. This paper studied the interaction between land use changes and related transport routes, particular about how different transport routes and road nodes influence the conversion of industrial lands to residential and commercial uses respectively. Taking Changchun, an old industrial city in the rust belt of China as a case of study, we explored and compared the influences of different transport routes and road nodes on industrial land conversion. We found that surrounding the studied transport routes, more industrial lands were replaced by residential lands than by commercial lands. Also, apparent differences exist in the corridor effects of different transport routes(i.e., light rail, expressway and trunk road) and road nodes(i.e., expressway nodes and trunk road nodes) while the industrial lands convert to residential and commercial uses. Our research findings help us to illuminate the interactive relationships between transportation and industrial land conversion in old industrial cities which are undergoing social, economic and the related urban transition in Northeast China.