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This study takes the Zhouyuan site region, which is the most representative Western Zhou Dynasty (1046 BC-771BC) large city-site in China, as an example. Based on the interpretation results of satellite remote sensing images from 1973 to 2021, the paper systematically analyzed the evolution of landscape patterns in the Zhouyuan site region spanning for about 50 years using 4 methods, including land use classification, land use transfer matrix, landscape pattern distribution gravity center model and landscape pattern index. Additionally, the results show that nowadays Zhouyuan site is still in a period of accelerated invasion and destruction by natural and human factors, which indicates that the protection of the Zhouyuan site has been inadequate or even unsuccessful for a long time. For the purpose of making more accurate and better protection of the Zhouyuan site, four challenges and six protection recommendations have been put forward. Based on remote sensing and geographic information system (GIS), this paper contributed a method combining 4 models to analyze the spatial-temporal evolution characteristics of landscape pattern of ancient large city-sites, in order to provide more basis for the formulation of cultural relic protection strategies. [ABSTRACT FROM AUTHOR]

Urban economic development is crucial to regional economy and people's life, and enhancing the efficiency of urban economic development is of great significance to boost sustainable and healthy economic and social development. In this paper, from the perspective of sustainable development, data of 104 cities in China's Yangtze River Economic Belt (YREB) from 2004 to 2019 are selected, and the urban resource consumption index and urban pollutant emission index are synthesized as new input-output indicators using the Time Series Global Principal Component Analysis (GPCA), combined with the Global Malmquist-Luenberger (GML) Index Model, Standard Deviation Ellipse (SDE) Model to measure the total factor productivity index of urban economic development in China's YREB and analyze its spatial and temporal evolution. The results show that from 2004 to 2019, the total factor productivity index of urban economic development in China's YREB showed an overall fluctuating upward trend with an average annual growth of 5.8%, and the analysis by decomposing indicators shows that the growth of total factor productivity of urban economic development in China's YREB is mainly influenced by the growth of technological progress. Meanwhile, there are obvious regional differences in the efficiency of urban economic development in China's YREB, with the largest difference in the middle reaches of the Yangtze River, the second largest in the upper reaches, and the smallest in the lower reaches. From 2004 to 2019, the efficiency center of gravity of urban economic development efficiency in the YREB has always been located in the middle reaches of the Yangtze River region. The spatial distribution pattern of urban economic development efficiency in the YREB is dominated by the northeast-southwest direction and tends to be concentrated in the study time period. [ABSTRACT FROM AUTHOR]

China is a large country with rapid economic expansion and high energy consumption, which implies that the country's overall carbon emissions are enormous. It is vital to increase urban low-carbon economy efficiency (ULEE) to achieve sustainable development of China's urban economy. Digital finance is a significant tool to boost ULEE by providing a convenient and effective funding channel for urban low-carbon economic transformation. Analyzing the coupled and coordinated relationship between ULEE and digital finance is of vital importance for the sustainable development of the urban economy. This paper selects panel data of 100 cities in China's Yangtze River Economic Belt (YEB) in 2011-2019, and analyzes the research methods such as the Global Malmquist-Luenberger index model, coupling coordination degree (CCD) model, standard deviation ellipse model, gray model, and geographic detector by The spatial and temporal distribution, dynamic evolution characteristics and influencing factors of the CCD between ULEE and digital finance are analyzed. The study shows that: (1) the CCD of ULEE and digital finance grows by 3.42% annually, reflecting the increasingly coordinated development of the two systems; (2) The CCD of ULEE and digital finance shows a distribution pattern of gradient increase from the upstream region of Yangtze River to the downstream region, meanwhile, the spatial center of gravity moves mainly in the midstream region; (3) The spatial center of gravity of CCD of ULEE and digital finance is expected to move 22.17 km to the southwest from 2019 to 2040; (4) In terms of influencing factors, the influence of informatization and industrial structure on the CCD increases over time, while the influence of factors such as population development, greening, transportation, and scientific research decreases over time. Finally, this paper proposes policy recommendations for improving the CCD of ULEE and digital finance based on the empirical results. [ABSTRACT FROM AUTHOR]

Tea (Camellia sinensis L.), as one of the most important cash crops in China, plays an important role in increasing farmers' incomes and guaranteeing a high quality of life. Tea production has been greatly influenced by both climate change and economic development in China. However, without a scientific understanding of the interaction mechanism of climate change and the impetus from rapid economic development on tea production practices in China, it is difficult to take adaptive actions to meet the climate change challenges for the tea industry. In this paper, we firstly assessed the potential impacts of climate change on tea climate suitability by empirical formula calculation using meteorological data; then, the effects from the additional climatic stress due to warming on tea production were detected with the annual statistical tea yield record on a municipal level. The contribution of socioeconomic development to the tea industry was evaluated with the comparison of the movement of China's national economy's and tea industry's gravity center during the period of 1987–2017. Finally, a conceptual adaptation framework was built to demonstrate the interaction mechanisms between climate change, tea production, and the economic development. The results showed that there was a negative impact of climate change on tea production in mainland China, with the percentage of high tea climate suitability (>0.9) areas dropping by 45% to 32%, while opportunities of enlarging the tea cultivating area emerged in the north tea production region where the tea climate suitability increased. We found that the tea planting area expanded northwards from 33° N in 1987 to 35° N in 2017 to take advantage of the favorable climatic resources due to warming, and tea planting decreased at an altitude of 100–400 m while increasing to higher altitude of 400–2000 m to avoid hot temperature damage and seek the optimum environment in high mountainous areas for tea production. In addition, the tea production moved westward along the longitude, decreasing obviously at 117–121° E while increasing significantly at 98–104° E and 107–110° E. Meanwhile, the tea production gravity center showed a westward movement consistent with the national economic gravity center moving trend, which means that tea industry development was driven by multiple socioeconomic factors and climatic forcings. A conceptual framework was built in this paper, aiming to show a robust adaptation mechanism for the tea system to maximize the benefits and minimize the damages from the altered climatic resources under rapid economic development in mainland China. The results in this study would help deepen the understanding of the adaptation process and practices for tea production in mainland China. [ABSTRACT FROM AUTHOR]

The Central Plains has a long history, rich culture, unique geographical advantages, and profound cultural heritage. The occurrence of ancient cities in the Central Plains marks the formation of Chinese state-level societies. The number, size, and distribution of ancient cities have changed greatly from the late Yangshao to the Xia and Shang Dynasties, which reflects the evolution of settlement and social organization. In this study, Geographic Information System (GIS) spatial database technology was used to establish a spatiotemporal database of ancient cities in the late Yangshao, Longshan, as well as Xia and Shang Dynasties in the Central Plains. This paper uses GIS spatial analysis technology to analyze the relationship between the ancient city distribution and the geographical environment, as well as the evolution of ancient city's shapes and sizes. Furthermore, by using the method of the nearest neighbor distance and gravity center analysis, this paper discusses the agglomeration characteristics and gravity center evolution of ancient cities. The results show that: (1) Most of the ancient cities were distributed in areas below 500 m and within 3 km from the river during the time interval from the late Yangshao to Xia and Shang Dynasties; (2) The shape of the ancient cities gradually changed from circles to squares in the Central Plains, which became a unified model for the later ancient city design; (3) The sizes of the 18 ancient cities in the Yangshao period shared high similarity, with an average area of 20 hectares. The sizes of 24 ancient cities in the Longshan period increased significantly, with an average of 39 hectares. During the Xia and Shang Dynasties, there were 22 ancient cities with an average size of 340 hectares, and the grade of sizes became obvious, marking the entrance into Chinese state-level societies; (4) Cities were scattered in the decentralized pattern during the late Yangshao and Longshan periods, whereas they became agglomerative in Xia and Shang Dynasties. This reflects the evolution of the spatial scopes and social organizational forms; and (5) From the late Yangshao to Xia and Shang Dynasties, the gravity center of ancient cities moved around the Songshan Mountain from the northwest to the southeast and again to the northeast. [ABSTRACT FROM AUTHOR]

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Ensuring food and nutrient supply is a crucial aspect of achieving food safety. With rapid population growth, urbanization, and social and economic development, the challenges related to China's food and nutrient production have become increasingly prominent. This paper analyzed the characteristics of the spatiotemporal pattern evolution of food and nutrient production in China from 1995 to 2020, utilizing the conversion of various food nutrients and the establishment of a gravity center model. The results showed that: (1) Food production exhibited increasing trends in China, six regions, and 90% of the provinces. Notably, the structure of food production underwent significant changes in China, East China, Central-South China, Southwest China, Northwest China, and 60% of the provinces. (2) The output of all categories of food nutrients demonstrated increasing trends in China, six regions, and most provinces. At three different geographical scales, the changes of six food nutrients production structure showed significant differences. (3) Natural, political, social, economic, and technological factors played pivotal roles in influencing the gravity centers of food and nutrient production in China. The gravity centers of cereal production shifted northeast, while those of root and tuber, oil crops, and stimulants production moved westward. Additionally, the gravity centers of sugar crop, pulse, vegetable, fruit, and aquatic product production moved southwest and those of livestock and poultry production shifted northward. (4) Affected by the food production, the gravity centers of food energy, food protein, and food carbohydrate production shifted northward, while those of food fat, food vitamins, and food minerals production shifted northwest, southwest, and westward, respectively. The results of this study are of great significance for policy adjustments pertaining to the distribution pattern of food production, food security stability, and sustainable development in China. [ABSTRACT FROM AUTHOR]

At present, the fault diagnosis of pumping units in major oil fields in China is time-consuming and inefficient, and there is no universal problem for high requirements of hardware resources. In this study, a fault fusion diagnosis method of pumping unit based on improved Fourier descriptor (IDF) and rapid density clustering RBF (RDC-RBF) neural network is proposed. Firstly, the minimum inertia axis of the center of gravity of the indicator diagram is obtained. The farthest point of the intersection of the inertial axis and the contour is determined as the starting point. Then Fourier transform is performed on the contour boundary of the graph to obtain the feature vector. Then, combining with the idea of fast density clustering algorithm, the number of hidden layer neurons of RBF is determined by finding the point with the highest density and using it as the hidden layer neuron. At the same time, the characteristics of Gaussian function are introduced to ensure the activity of hidden layer neurons. Finally, through dynamic adaptive cuckoo search (DACS), the step size is automatically adjusted according to the convergence speed of the objective function of RBF, and the efficiency and accuracy of RBF in different search stages are balanced. The optimal parameters such as the width and weight of RBF are determined, and the optimal RDC-RBF fault diagnosis model is established. The model is applied to the diagnosis of different fault types of pumping units, and compared with the current mainstream models. The average detection accuracy of the fusion RDC-RBF fault diagnosis method proposed in this paper reaches 96.3%. The measured results have high accuracy and short time. At the same time, this method is currently applied to oil production sites such as Shengli Oilfield in China, which greatly reduces the human resources required for fault diagnosis of pumping units in the past. [ABSTRACT FROM AUTHOR]

Based on the research of spatial pattern dynamic evolution algorithm and optimization model construction and driving mechanism of provincial tourism eco-efficiency in China under the background of cloud computing, this paper takes 30 provinces in mainland China (excluding Tibet, Hong Kong, Macao, and Taiwan) as the research object and scientifically constructs the measurement index system of tourism eco-efficiency. The Super-SBM-Undesirable model is used to measure the tourism eco-efficiency of each province from 2004 to 2017, and the algorithm and model are optimized. This paper explores the spatial evolution trajectory and path of tourism eco-efficiency by using the barycentric standard deviation ellipse method and constructs a dynamic panel model to identify the factors affecting the evolution trajectory and their driving mechanisms by using the SYS-GMM method. The results show that China's tourism eco-efficiency is at a high level and the eastern region is higher than the central and western regions. From the moving track of the center of gravity, the center of gravity of China's tourism eco-efficiency is located in Henan province, which has experienced a process of moving from southeast to northwest. From the standard deviation ellipse, the spatial distribution direction of China's tourism eco-efficiency presents a "northeast-southwest" pattern, and there is a further strengthening trend of deviation. There is a significant positive correlation between tourism eco-efficiency and tourism industrial structure upgrading, tourism industrial structure rationalization, tourism technology level, and tourism human capital, as well as a significant negative correlation between tourism eco-efficiency and tourism economic development level, environmental regulation intensity, and the degree of opening to the outside world, while the relationship between urbanization and tourism eco-efficiency is relatively vague. [ABSTRACT FROM AUTHOR]

The combination of knowledge innovation and technology innovation provides vitality for social science and technology innovation. China leaps into the front ranks of the world in the 2021 Global Innovation Index (GII). Therefore, this research takes China's theoretical-application innovation as the research object and empirically analyzes measure the innovation efficiency of knowledge innovation dominated by universities and technological innovation dominated by enterprises in China, as well as the gravity-center migration trajectory. The results show that the ranking of overall efficiency of theoretical innovation-application innovation is eastern region > central region > western region. Knowledge innovation presents a drag on overall efficiency, while technology innovation offers a contribution to overall efficiency. In the analysis of PIE (R&D personnel of industrial enterprises above a designated size) variables, the efficiency value is relatively low. The peak value of kernel density increases in the eastern, central and western regions, namely the concentration degree of theoretical innovation-application innovation effi- ciency in China has risen. The gravity center of each stage migrates to the eastern region, meaning the efficiency value of China's theoretical innovation and application innovation increases more significantly in the eastern region. From the perspective of knowledge innovation and technology innovation, this paper puts forward suggestions for China and provides some references for other developing countries. [ABSTRACT FROM AUTHOR]

The development of green residences is crucial to reducing energy consumption and carbon emissions of the construction industry. However, the study on the spatial distribution characteristics of green residences and its influencing factors has not attracted enough attention in the academic circles. Base on the panel database on the number of each star green residences and their driving factors at the municipal level from 2008 to 2016, this paper employed the Weighted Standard Deviational Ellipse model to reveal the spatial and temporal evolution features of green residences in China, creatively introduced an improved Gini coefficient (G′-score) to measure the green residences development in each city, and utilized the panel Tobit model and average marginal effect to identify the driving mechanisms and key factors of green residences from economy, society, the real estate market, policy and climate. The main conclusions show that: (1) China has formed a relatively stable and clear temporal and spatial evolution path since 2011, such as the center of gravity and coverage having moved to the west, and the direction of development trend having weakened; (2) China's green residence is mainly distributed in the central and eastern regions, and the main direction layout is northeast–southwest; (3) the development of green residences is the result of the interaction of various factors, and the driving force of each factor varies greatly under the single action and the interaction; (4) the driving effects of the same factor on green residences with different star ratings are inconsistent in sign, magnitude, and significance, the same as for each factor under the same star rating. [ABSTRACT FROM AUTHOR]

This EUCROSS working paper analyzes European Union-China trade relations in the context of the current negotiations for a new comprehensive framework agreement between the European Union (EU) and the People's Republic of China. China is a strong economic power with increasingly sophisticated production in its coastal regions and is attempting to establish itself as a gravity center by concluding many bilateral free-trade agreements in the region. Although China has a stronghold in the Far East, there may be specific policy areas in which China's influence ends up being global. The paper concludes that dealing with China was one of the main arguments in favor of ratifying the Treaty of Lisbon because it provides for a permanent president of the European Council and a single foreign affairs post for the entire EU, which facilitates the EU's coherence in its external affairs. Moreover, the paper concludes that the European Commission should negotiate the prospective Partnership and Cooperation Agreement between the EU and China more constructively, without patronizing, and instead accept China as an equal player in the current multipolar framework of global economic governance. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to analyze the characteristics of spatio-temporal dynamics and the evolution of land use change is essential for understanding and assessing the status and transition of ecosystems. Such analysis, when applied to Horqin sandy land, can also provide basic information for appropriate decision-making. Design/methodology/approach: By integrating long time series Landsat imageries and geographic information system (GIS) technology, this paper explored the spatio-temporal dynamics and evolution-induced land use change of the largest sandy land in China from 1983 to 2016. Accurate and consistent land use information and land use change information was first extracted by using the maximum likelihood classifier and the post-classification change detection method, respectively. The spatio-temporal dynamics and evolution were then analyzed using three kinds of index models: the dynamic degree model to analyze the change of regional land resources, the dynamic change transfer matrix and flow direction rate to analyze the change direction, and the barycenter transfer model to analyze the spatial pattern of land use change. Findings: The results indicated that land use in Horqin sandy land during the study period changed dramatically. Vegetation and sandy land showed fluctuating changes, cropland and construction land steadily increased, water body decreased continuously, and the spatial distribution patterns of land use were generally unbalanced. Vegetation, sandy land and cropland were transferred frequently. The amount of vegetation loss was the largest. Water body loss was 473.6 km2, which accounted for 41.7 per cent of the total water body. The loss amount of construction land was only 1.0 km2. Considerable differences were noted in the rate of gravity center migration among the land use types in different periods, and the overall rate of construction land migration was the smallest. Moreover, the gravity center migration rates of the water body and sandy land were relatively high and were related to the fragile ecological environment of Horqin sandy land. Originality/value: The results not only confirmed the applicability and effectiveness of the combined method of remote sensing and GIS technology but also revealed notable spatio-temporal dynamics and evolution-induced land use change throughout the different time periods (1983-1990, 1990-2000, 2000-2010, 2010-2014, 2014-2016 and 1983-2016). [ABSTRACT FROM AUTHOR]

The tourism transformation and upgrading is the essential requirement for high-quality development of tourism. Based on proportional relationship, labor productivity and resource allocation efficiency of tourism industries, this paper constructs an evaluation index system of tourism transformation and upgrading level characterized by rationalization, advancement and high efficiency, takes 30 provinces (autonomous regions and municipalities) in China as the research object, and uses kernel density estimation, Theil index, standard deviation ellipse, spatial autocorrelation and other methods to evaluate the tourism transformation and upgrading level in China from 2010 to 2019, objectively reflecting the characteristics of the tourism transformation and upgrading in China. On this basis, the spatial Dub in model is used to explore the spatial effect of driving force involving tourismconsumption demand, tourism technology progress and government regulation, and further clarify the internal logic of the tourism transformation and upgrading and its driving force spatial effect. The results are shown as follows: ➀ The level of tourism transformation and upgrading of China has increased year by year, and the spatial evolution trend of the tourism transformation and upgrading level in various regions is significantly different, showing a decreasing trend in the order of eastern, western, northeastern and central regions. The region difference of the tourism transformation and upgrading level is fluctuating and increasing, which mainly comes from internal difference. ➁ The tourism transformation and upgrading level continues togather in the northeast-southwest directions, and the trajectory of the center of gravity generally shifts eastward. The spatial correlation shows a positive correlation development trend, and the regional characteristics of the correlation type are obvious. ➂ Tourism technology progress and government regulation have significant positive spatial spillover effect on the tourism transformation and upgrading. Tourism consumption demand can promote tourism transformation and upgrading in neighboring areas, but has negative effect on local tourism transformation and upgrading due to the unreasonable structure of tourism consumption. [ABSTRACT FROM AUTHOR]

Landslide failure near a reservoir generates impulse waves, greatly increasing casualties and property losses. This paper presents a field investigation and potential impulse wave simulation analysis of the Wulipo (WLP) landslide, which deformed after the initial impoundment of the Baihetan Hydropower Station, China. According to geological surveys, the WLP landslide is a weak base-type, weathered, fragmented rockslide with soft rock in the lower portion and hard rock in the upper portion. The deformation and failure mechanism under the action of reservoir water consist of compression, fracturing, and shearing. The periodic fluctuation of reservoir water may cause overall high-speed slip failure of the WLP landslide. According to the inferred failure mode of the WLP landslide, the impulse waves caused by the overall failure of the landslide at the highest (825 m) and lowest (765 m) water levels are predicted. Due to the significant height difference between the center of gravity of the landslide and the reservoir water level, the wave height and fluctuation degree of the overall failure of the WLP landslide for 765 m are significantly greater than those for 825 m. However, the wave flood area for 825 m is larger than that for 765 m. Although the impulse waves triggered by the overall landslide at either water level will not destroy the nearby Menggu community, at 765 m, impulse waves will overflow the bridge deck of Ganhu Road. Therefore, engineering measures such as reducing the landslide volume can lower the secondary disaster risk posed by WLP landslides. This study provides insights into landslide disaster risk in the Baihetan Reservoir region and similar areas worldwide. [ABSTRACT FROM AUTHOR]

Clarifying the sources of the digital finance inclusive development gap helps profoundly understand the regional characteristics of inclusive digital finance and benefits and formulate and implement specific policies scientifically and reasonably. Based on the 2011–2020 "Peking University Digital Finance Inclusive Index," this study explores the regional disparity in digital finance inclusive development and its sources in the Yangtze River Delta economic cluster using the methods of the center of gravity shift, standard deviation ellipse, nested Theil index difference decomposition, and Kernel density. We found that inclusive digital finance shows a rising trend year by year, with evident heterogeneity and spatial agglomeration characteristics; interprovincial differences are the primary sources of the overall differences in inclusive digital finance in the Yangtze River Delta. The spatial effect of digital inclusion finance between the Yangtze River Delta regions has continuity. Because of the significant positive spatial correlation of digital inclusion finance between regions, digital inclusion finance in this region is vulnerable to potential shocks from neighboring regions. Moreover, with or without the spatial lag term, the level of inclusive digital finance in all regions of the Yangtze River Delta shows a leap forward. This paper looks at the regional gap of inclusive digital finance and its structural decomposition in the Yangtze River Delta city cluster from three perspectives: time trend, spatial structure, and dynamic evolution. This gives an empirical basis for the different kinds of digital finance inclusive development policies and a guide for making decisions to speed up the formation of a regional digital finance inclusive synergistic development path. [ABSTRACT FROM AUTHOR]

The cultivated land-use transition (CLUT) is the morphological result of changes in the cultivated land-use mode over time, and the result of the interaction and mutual restriction of the human land system. This paper applies a "spatial–functional" integrated framework to understand the structure and functioning of CLUTs, and quantitatively evaluates and visualizes CLUTs in the major grain-producing area in southern China. The results show that (1) the comprehensive CLUT index in the middle and lower reaches of the Yangtze River changed from 0.0480 to 0.0711 from 2001 to 2019 and indicated significant differences in the transition index between different regions. (2) The CLUT identified a positive aggregation effect under a 5% significance during the period, and the agglomeration degree of the spatial and functional transitions strengthened, which increased from 0.3776 to 0.4673 and from 0.2127 to 0.2952, respectively. (3) The gravity center of the CLUT demonstrated a pattern of migration from the southwest to the northeast, and the migration speed of the gravity center decreased from 2.9401 km/year to 1.2370 km/year. The migration direction of the gravity center for the spatial transition is opposite to the functional transition, and the migration speed of the gravity center for the spatial and functional transitions decreased from 8.3573 km/year to 1.0814 km/year, and from 3.2398 km/year to 1.0254 km/year, respectively. To address this transition, policymakers should formulate differentiated policies to promote the sustainable use of cultivated land through the spatial and functional transition of major grain-producing areas. [ABSTRACT FROM AUTHOR]

With the ability to detect low-frequency gravitational waves (GWs), space-borne detectors will play an important role in exploring the universe in the future. The TianQin project proposed in China participates in this challenge by aiming to detect millihertz GWs. The TianQin GW detector consists of three spacecraft forming a triangular constellation. Each spacecraft carries a pair of test masses (TM) which, inside shielding cages, are left to free fall along the local geodesic. In this way, a pair of TMs on two separate spacecraft can be each other aligned to become the gravitational references of the GW detector, made by an inter-satellite laser interferometer. Each free-falling TM is limited by parasitic forces to be appropriately bounded. The relevant acceleration bound has been fixed to 10−15 m/s2/ Hz within the TianQin measurement bandwidth (MBW) ranging from 0.1 mHz to 0.1 Hz. In turn, TM to cage fluctuations must be kept below 4nm/ Hz to limit the stiffness coupling with the spacecraft displacement caused by non-gravitational disturbances, such as solar radiations and the thruster noise. Suppression of such disturbances calls for a challenging drag-free control technology, since the center of mass (CoM) of a single spacecraft cannot track the separated CoMs of two TMs simultaneously, and consequently tracking must be limited to three degrees of freedom (DoF): two non-orthogonal sensitive axes (one for each TM) and the perpendicular direction to their plane. Control design and simulated tests of this paper will be restricted to the drag-free control along the sensitive axes. The remaining nine DoFs of the two TMs (position and attitude) are controlled by electrostatic suspensions, not to be treated here, but accounted for in the simulated trials. The design of the two-DoF drag-free control relies on a model-based control methodology, the Embedded Model Control (EMC), capable of predicting and suppressing unknown disturbances within the required bandwidth and of decoupling the TM dynamics along the non-orthogonal sensitive axes. The paper starts with the nonlinear model of the TM to cage dynamics, followed by the relevant EMC design, restricted to the sensitive axes. Numerical simulations are employed to validate closed-loop performance and robust stability. Simulated results show that the residual TM to cage fluctuations can be kept below 3nm/ Hz , which leaves a margin within the required spectral bound. The EMC methodology discussed in the paper can provide a reference for future developments and implementations. • Test mass dynamics can be decoupled by 'thruster coupling' or 'sensor coupling'. • Embedded Model Control predicts and compensates unknow disturbances. • Reference generator smooths test mass centering process. • Test mass to cage displacement has satisfied TianQin requirement. • Monte Carlo trails have validated the closed-loop robust stability. [ABSTRACT FROM AUTHOR]

This paper studies the evolution process of the urbanization and ecological environment level of 28 cities in the city cluster along the middle reaches of the Yangtze River in China from 2007 to 2017 on the scale of city cluster and discusses the coordination relationship between the two. The research found that: (1) During the research period, the urbanization level and the ecological environment level of 28 cities increased significantly. (2) The urbanization is generally at a low level and the spatial imbalance among cities is gradually expanding; the ecological environment is generally at a medium level and the spatial imbalance among cities is gradually decreasing. (3) The center transferring track and the center variation consistency of the urbanization level and the ecological environment level present a changing trend of "reverse direction - same direction", and the overall coordination of the two is gradually enhanced. (4) The spatial coordination between the urbanization level and the ecological environment level is constantly enhanced. The Getis-Ord Gi* index generally shows a spatial distribution feature of "high in the southeast area and low in the northwest area". [ABSTRACT FROM AUTHOR]

Understanding the spatial differentiation and driving mechanisms of ecosystem service value (ESV) is helpful for the protection and sustainable development of the ecological environment. Despite the fact that various studies on ESV have been conducted in various regions, few studies have discussed the spatial differentiation characteristics of ESV in a long time series at a national scale, and even fewer studies have thoroughly examined the driving mechanism of the spatial differentiation of ESV from the perspective of different regions. On the basis of China's land use data from 1990 to 2018, this paper used the methods of land use dynamics, the ESV evaluation model, hot spot analysis, the barycenter model, and the geographical detector model to study the temporal and spatial differentiation characteristics of land use and ESV in the study area. Moreover, it analyzes the driving mechanisms of the spatial differentiation of ESV at the national scale and in different regions of China. Our results showed the following: (1) Other land types have increased overall, with the exception of grassland. Obvious differences were observed in the single land use dynamics of each land type, especially the construction land, where farmland was the primary source of construction land. With the passage of time, the dynamic degree of comprehensive land use increased. (2) During the study period, ESV generally showed a decreasing trend, with distinct characteristics in high and low ESV areas. The center of gravity of ESV was constantly in Dingxi County and Pingliang City, Shaanxi Province, and its trajectory was generally "S"-shaped. (3) From the perspective of national scale and different regions, the dominant factors affecting the spatial differentiation of ESV were different, and the interaction among multiple factors was significantly stronger than that of a single factor. The findings of the study can provide more scientific decision-making services for China in order to promote regional environmental protection and develop ecological civilization. [ABSTRACT FROM AUTHOR]

The act of balancing simultaneous rapid development of urbanization and ecological environmental protection is an increasingly important strategic agenda of national importance. While focusing on the principle of sustainable development, this paper calculates and analyzes the extent of coupling coordination degree (CCD) between the new urbanization quality (NUQ) and eco-environmental carrying capacity (EECC) of 246 prefecture level and above cities in China. The gravity center moving trajectory, Moran's I and LISA are employed to perform exploratory spatial analysis, and the differences among cities are analyzed by variation coefficient (CV) method. Based on simulation by the NUQ and CCD, results obtained show a continuous growth trend at similar rate among the cities. Meanwhile, the mean value of EECC showed a fluctuating growth trend. The coordinated development type cities were largely concentrated in the coastal areas of the east. In comparison, other areas are dominated by disorders recession type cities and the coordination transition type cities. The center of gravity CCD was found moving from the northeast to the southwest. The situation of HH (CDD main city—high, CDD surrounding cities—high) and LL (CDD main city—low, CDD surrounding cities—low) always accounted for more than seventy percent. The cluster locations of HH and LH (CDD main city—low, CDD surrounding cities—high) are largely concentrated around mega-urban agglomerations comprising the following three major urban agglomerations, i.e., (i) the Yangtze River Delta; (ii) the Pearl River Delta; and (iii) the Beijing-Tianjin-Hebei. CV of CCD shows that the gap among cities is gradually narrowing. In summary, the results conclude that most of the evaluated cities have not achieved coordinated development. As such, enhancing ecological environment protection awareness, improving the utilization effectiveness of natural resources and gradual elimination of regional differences should be the way forward in facilitating the process of new urban construction. The significance of this research not only helps increase the focus on ecological environmental governance, but also enrich the theoretical system of urbanization, both of which have important theoretical significance and application values in the building of an ecological civilization. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to use the gravity theory to study the spatial distribution and centers of gravity for the global energy-related CO emissions and to determine how they have changed over time. The main results are as follows: (1) In 2011, global energy-related CO emissions reached 34,032.74 Mt, and Asia was the largest CO emitter, which accounted for 45.25 % of total CO emissions in the world. (2) Since 2006, China has exceeded the USA and become the biggest CO emissions country. (3) In terms of the annual growth speed of CO emissions, China is the fastest, followed by India, Saudi Arabia, Brazil, and South Africa. (4) During the study period, the center of gravity for CO emissions is an overall movement toward the southeast, and Asia has become the center of gravity for CO emissions. [ABSTRACT FROM AUTHOR]

The high-quality development of agriculture is closely related to technological innovation, but the evolutionary characteristics of the relationship between agricultural transformation and technological innovation have received little study. This study takes 13 main grain-producing areas of China as the research object. Data collection was from 2004 to 2019. Based on the coupling coordination and responsiveness models, we analyze the spatio-temporal agriculture comprehensive level and the associated response degree of agricultural transformation to technological innovation. The results showed that (1) the comprehensive development of technological innovation showed a growth trend, while the agricultural transformation showed a U-shaped growth trend; (2) the coordinated development of these two systems has been significantly improved, but there are differences in the development speed of each province; (3) the coordinated gravity center moved southward in the spatial pattern, eventually presenting the characteristics of "higher level in the east and lower level in the west, while the higher level in the south and lower level in the north"; (4) the influence of technological innovation on agricultural transformation gradually changed from inhibition to positive promotion. In the end, this paper puts forward suggestions on the high-quality development of agriculture from the relationship of technological innovation and agricultural transformation. [ABSTRACT FROM AUTHOR]

National nature reserves are an important part of classification management on ecological protection in China. Taking the national nature reserves of Jilin Province as examples, this paper introduced the stability index by referring to the intensity model of land-use and land-cover change (LUCC), and analyzed the overall stability of land-use and land-cover (LULC) in the study area from the time interval level and land category level. The stability of LULC in different types of nature reserves was tracked and identified by extracting land-use change trajectory, and the land-use change trajectory was divided into three types: stable type, sub-stable type and unstable type. The impact of LUCC on regional ecosystem services was studied by using hotspot analysis and gravity center analysis. The results showed that: 1) The LULC in the study area was stable on the whole, and the proportion of stable land area reached 86.08%. The intensity of LUCC showed an increasing trend in recent 20 years, and the conversion of cultivated land and construction land was active in continuous time interval. 2) The stability of LULC in forest ecological reserves and wildlife reserves in the eastern part of Jilin Province was the highest, while that in inland wetland reserves and geological relic reserves in the central and western part of Jilin Province was lower. 3) The LUCC in national nature reserves not only changed the value of its own ecosystem service function, but also affected the ecosystem service function of the whole region. The combination of intensity analysis and land-use change trajectory was used to identify the characteristics of stability of LULC in nature reserves, which was conducive to deeply understand the process of LUCC in national nature reserves and provided reasonable suggestions for regional ecological protection. [ABSTRACT FROM AUTHOR]

Since the Ming Dynasty, the flood disaster has been one of the important natural disasters affecting our country. However, relatively few studies on the evolution law of flood disaster at large spatial–temporal scales have been reported. Based on the datasets of flood stations from 1470 to 2000, this paper quantitatively analyzes and discusses the spatial and temporal evolution pattrens of floods in China in the past 500 years by using regional gravity center model, wavelet analysis, Daniel index, and M–K test, and predicts the trend of flood disasters in the future. The results show that: (1) Since 1470, there has been an increasing trend of flood intensity index in China;(2) From 1470 to 2000, there were two high centers of flood disaster in 1560 and 1925, respectively, and one low center appeared in 1745; (3) Flood risk changes from easy occurrence in the eastern coastal area to uniform spatial distribution over the whole study region; (4) In the past 500 years, the graver center of flood disaster is located in Baokang County, Hubei Province, and the gravity center of flood disaster shows a trend of moving to northwest both at time scales of 50-year and 100 year; (5) The flood disaster in the studied area will still show an overall upward trend in the future.The research can provide decision support for the precise prevention and control of flood disasters in China. [ABSTRACT FROM AUTHOR]

This study aims to understand the factors and mechanisms influencing the spatio-temporal changes of fractional vegetation cover (FVC) in the northern slopes of the Tianshan Mountains. The MOD13Q1 product data between June and September (peak of plants growing) during the 2001–2020 period was incorporated into the pixel dichotomy model to calculate the vegetation cover changes. Then, the principal component analysis method was used to identify the primary driving factors affecting the change in vegetation cover from the natural, human, and economic perspectives. Finally, the partial correlation coefficients of FVC with temperature and precipitation were further calculated based on the pixel scale. The findings indicate that (1) FVC in the northern slopes of the Tianshan Mountains ranged from 0.37 to 0.47 during the 2001–2020 period, with an obvious inter-annual variation and an overall upward trend of about 0.4484/10 a. Although the vegetation cover had some changes over time, it was generally stable, and the area of strong variation only accounted for 0.58% of the total. (2) The five grades of vegetation cover were distributed spatially similarly, but the area-weighted gravity center for each vegetation class shifted significantly. The FVC under different land use/land cover types and elevations was obviously different, and as elevation increased, vegetation coverage presented a trend of a "∩"-shape change. (3) According to the results of principal component analysis, human activities, economic growth, and natural climate were the main driving factors that caused the changes in vegetation cover, and the cumulative contribution of the three reached 89.278%. In addition, when it came to climatic factors, precipitation had a greater driving force on the vegetation cover change, followed by temperature and sunshine hours. (4) Overall, precipitation and temperature were correlated positively with FVC, with the average correlation coefficient values of 0.089 and 0.135, respectively. Locally, the correlations vary greatly under different LULC and altitudes. This research can provide some scientific basis and reference for the vegetation evolution pattern and ecological civilization construction in the region. [ABSTRACT FROM AUTHOR]

To begin with, the gravity model is used to study the spatial distribution and centers of gravity for energy-related CO emission at regional level and to determine how they have changed over the period 1995-2010 in this paper. Furthermore, the occurrence of a decoupling of each province region between economic activity and CO emission from energy consumption is examined based on decoupling index method. The main results are as follows: (1) In 1995, there were only seven provinces, each province of which emitted more than 150 Mt CO. However, there were 25 provinces and each province's CO emission was more than 150 Mt in 2010. (2) In terms of the annual growth speed of CO emission, Neimenggu was the fastest. (3) During the study period, the centers of gravity for CO emission are an overall movement toward southwest. (4) During the study period, the decoupling index for 23 provincial regions firstly increased and then decreased; there were six provincial regions whose decoupling index increased continuously; however, the decoupling index for Tianjin firstly decreased and then increased. [ABSTRACT FROM AUTHOR]

With the rapid development of China's economy, air pollution is becoming extremely serious. The spatial-temporal evolution of air pollution is conducive to the management of air pollution. The paper is proceeded into three steps. Firstly, based on the generalization principal component analysis method, the comprehensive air pollution evaluation index is established. Then, the gravity center model is utilized to explore the spatial-temporal evolution of air pollution in Yangtze River Delta from January 2014 to December 2016. Finally, the contribution decomposition method is utilized to explore the contribution to gravity center evolution. The main results are as follows: (1) The air pollution have obvious seasonal and regional differences in Yangtze River Delta. (2) The gravity center of air pollution continues to westward after 2014 with the characteristic of the north-south circular movement. (3) Hefei City and Yangzhou City have huge impact on the gravity center evolution of air pollution. The conclusions could be helpful for Chinese government to control the air pollution in Yangtze River Delta. [ABSTRACT FROM AUTHOR]

With the rapid development of urbanization construction in China, population and industries are rapidly gathering in cities, bringing about economic development and also causing a large number of environmental problems, among which PM2 s is the most concerned. In this paper, a spatial gravity center model was used to systematically analyze the spatiotemporal distribution characteristics of PM, s and population scale in China from 1999 to 2016. Conclusions were as below; (1) there were significant regional differences in PM2 s pollution from 1999 to 2016, characterized by a spatial distribution of "high in the north and low in the south, and high in the inland and low in the coastal areas". (2) Nationwide, there was a significant spatial mismatch between the gravity center of PM2 s pollution and the gravity center of population scale, with the two centers showing a trend of reverse dislocation development. [ABSTRACT FROM AUTHOR]

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As a major carbon emitter in China, the emission mitigation in industrial sector performs great significance for China to achieve its emission reduction targets. Using the provincial panel data during 2000–2016 of China's industrial sector, this paper first used a gravity model to study the spatial distribution and center of gravity of industrial CO2 emissions. Then, an integrated decomposition approach based on Shephard distance functions was adopted to study the driving factors of industrial carbon intensity. Results indicate that during 2000–2016, industrial CO2 emissions center of gravity gradually moved to the west. China's industrial carbon intensity achieved considerable decline, with the annual change rate of 8.27%. The energy intensity decline, technology progresses of both production and energy saving were the most important factors facilitating carbon intensity decline. However, energy structure adjustment exerted positive effects in carbon intensity increase, although its effects were minor. Industrial carbon intensity witnessed decrease in almost all provinces except Xinjiang. The effects resulted from various factors were also different across provinces. Finally, suggestions were proposed to further decrease industrial carbon intensity. [ABSTRACT FROM AUTHOR]

The Hengduan mountain area, located in the upper reaches of the Yangtze River of China, is an important ecological barrier that significantly impacts the climate and ecological environment of the surrounding region and western China as a whole. This paper introduces the gravity center model used to analyze the spatial-temporal variation patterns of vegetation Net Primary Productivity (NPP) from 2000 to 2015, which were determined by the use of MOD17A3 NPP products. Additionally, the dominant driving factors of the spatial—temporal changes of vegetation NPP of the Hengduan Mountain area were quantitatively determined with a geographical detector over 2000–2015. The results revealed that: (1) From 2000 to 2015, there was an increasing trend of vegetation NPP in the Hengduan mountain area. Throughout the whole study region, the vegetation NPP with a mean value of 611.37 gC·m−2·a−1 indicated a decreasing trend from southeast to northwest in terms of spatial distribution. (2) The gravity centers of vegetation NPP in 2000–2015 were mainly concentrated in Zhongdian County. During the study period, the gravity center of vegetation NPP moved northward, which indicated that the increment and increasing rate of vegetation NPP in the northern parts were greater than that of the southern areas. (3) The vegetation NPP showed a moderately positive correlation with temperature, accumulated temperature (>10°C), and sunshine, while there was an overall negative relationship between NPP and precipitation. (4) The dominant factors and interactive dominant factors changed in different sub-regions over different segments of the study period. The dominant factors of most sub-regions in Hengduan mountain were natural factors, and the climate change factors played an increasingly greater role over the 16 years of the study period. [ABSTRACT FROM AUTHOR]

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Copyright of Geography & Geographic Information Science is the property of Geography & Geo-Information Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Accelerating the promotion of high-quality development of tourism (HQDT) is of great significance to the sustainable development of tourism. This paper defined the concept of HQDT, and then built an evaluation system for HQDT measurement to analyze the spatio-temporal evolution characteristics of China's HQDT based on provincial panel data from 2010 to 2019, using Geodetector to explore the similarities and differences between driving factors of HQDT and tourism development scale (TDS). The results show that: 1) Taking the development concepts of innovation, coordination, green, openness and sharing as the guidance, and considering the organic unity of quantity and quality, the evaluation index system of the HQDT consists of six dimensions of economic stability, innovation driving, coordination and linkage, green and sustainability, openness and cooperation, and sharing and harmony, which respectively represent the basis, momentum, means, orientation, direction and purpose of the HQDT; 2) The level of China's HQDT shows an upward trend, presenting the characteristics of eastern region > central region > western region > northeastern region in 2019. The regional differences in China's HQDT show a downward trend, and the intra-regional differences have replaced the inter-regional differences as the main source of regional differences; 3) China's HQDT shows the characteristics of higher in the east and lower in the west along the Hu line, while the improvement speed of HQDT shows the characteristics of faster in the west and slower in the east, making the decline of east-west differentiation of China's HQDT and the movement of the gravity center towards southwest; 4) Both HQDT and TDS are obviously driven by tourism capital investment and regional consumption. In terms of differences, the HQDT is more driven by government guidance, innovation driving force, and opening up, while the main driving factors of TDS are more biased toward capital elements and hardware facilities, including informatization, tourism resource, traffic, and eco-environment. [ABSTRACT FROM AUTHOR]

In the information age, digital information technology has gradually become a new quality of productivity to improve international competitiveness, and the status and importance of the pseudo human settlements(PHS) constructed by digital and information has been increasing in the human settlements(HS) system. In this context, exploring the coupling coordination of the internal systems of the PHS provides a theoretical basis for promoting the comprehensive improvement of the quality of the HS in the urban agglomerations, provides a theoretical reference for rationally interpreting the new type of human-land relationship in the information age, and provide a new perspective for the study of the human settlements geography. Currently, research on PHS is in its nascent stages, therefore, we construct a theoretical framework for the coupling coordination of the "three states" of the HS, takes the internal system of PHS as the entry point, empirically analyze the spatiotemporal characteristics of the PHS coupling coordination degree within urban agglomerations in eastern China and the driving factors by using the coupling coordination degree, spatial autocorrelation, the center of gravity and the ellipse of the standard deviation, and geo-detector models. Research shows: (1) Time course: exhibits an upward "inverted L" trend. (2) Spatial pattern: exhibits a general spatial pattern of "high in the north and low in the south". (3) Spatial correlation: shows a spatially positively correlated clustering trend. (4) Spatial evolution: demonstrates a decentralized pattern of migration from the northeast to the southwest, indicating that the coupling coordination grows faster in the southwest than in the northeast. (5) Driving factor: the development of coupling coordination degree of PHS results from multiple factors and systems. This research provides theoretical support for promoting the comprehensive improvement of the quality of PHS in the urban agglomerations in eastern China, and offers scientific reference for the construction of PHS in other regions of China. [ABSTRACT FROM AUTHOR]

Confronted with China's burgeoning population and finite arable land resources, the enhancement of sustainable arable land efficiency is of paramount importance. This study, grounded in the United Nations Sustainable Development Goals (SDGs), introduces a robust framework for assessing sustainable arable land use. Utilizing the Sustainable Utilization of Arable Land (SUA) indicator system, the DGA–Super-SBM model, the Malmquist–Luenberger production index, and the TO–Fisher–OSM algorithm, we evaluated the efficiency of sustainable utilization of arable land (ESUA) in 52 prefecture-level cities within China's major grain-producing regions of the Yellow and Huaihai Seas. We analyzed the cropland utilization patterns from 2010 to 2020, examining the influence of these patterns on sustainable utilization efficiency. Our findings indicate that between 2010 and 2020, the arable land usage in these regions exhibited minimal transformation, primarily shifting towards construction land and conversely from grassland and water systems. Notably, the ESUA of arable land demonstrated an upward trend, characterized by pronounced spatial clustering, enduring high efficiency in the northern regions, and a significant surge in the southern sectors. The declining ESUA (D-ESUA) trend was general but increased in half of the cities. The change in the center of gravity of ESUA correlated with the north–south movement of the proportion of cultivated land area, the turn-in rate, and the turn-out rate, yet moved in the opposite direction to that of cultivated land density and yield per unit area. Variables such as the replanting index, cropland density, yield per unit area, and cropland turn-in rate significantly affected ESUA. These findings offer a scientific basis and decision-making support for optimizing the utilization pattern of arable land and achieving a rational allocation of arable land resources. [ABSTRACT FROM AUTHOR]

Based on the ArcGIS geostatistical analysis method, this study offers a visualization of the spatial distribution pattern and spatial trend of vegetable production in China. The research also examines the degree of spatial agglomeration patterns of vegetable production by using the standard deviation ellipse technique and exploratory spatial data analysis method. In addition, we employ the spatial regression model partial differential method to explore the driving factors leading to the changing layout of vegetable production. The findings unveil that vegetable production in China exhibit strong spatial non-equilibrium characteristics, with "high-high" and "low-low" types as the main agglomeration patterns. Furthermore, the location distribution shows a northeast–southwest orientation with the center of gravity of distribution gradually directed toward the southwest. Regarding driving factors, the results show that the effective irrigated area of natural factors had a facilitating effect on the layout of vegetable production, while the affected area had an inhibiting effect on it. Climate indicators such as temperature, precipitation and light show different degrees of influence on the layout of vegetable production. The level of urbanization and transportation conditions have a negative impact on the layout of production in the region. Market demand has a positive spillover effect on the layout of local vegetable production, while it has a negative spillover effect on other regions. Technological progress shows positive spillover effects on the layout of vegetable production in the region and other regions. Financial support policy also shows positive effects from an overall perspective. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Central China Normal University is the property of Huazhong Normal University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• A conceptual framework and model of microagroecosystems were constructed. • Assessed the degree of landscape ecological risk in microagroecosystems. • The human activity gravity of microagroecosystems shifted to lower altitudes. • The ecological vitality of microagroecosystems is increasing. • Clarified micro-spatial human-land relations and development directions. Micro-spatial agroecosystem (AES) changes in karst mountain areas are a response to the human-land relationship of the human activity center. However, the changes and linkages between AESs and landscape ecological risks (LER) from a micro perspective in karst mountain areas (KMA) have not yet attracted in-depth attention from the academic community. This paper proposes the concept of microagroecosystems (MAESs) and constructs the MAES model based on the landscape development intensity (LDI) to evaluate the systematic landscape evolution rules and the LER intensity, which reflects the human-land relationship in KMA. We used the buffer ring with a 200 m cultivation range interval to categorize the MAES model into six models, namely, High-Mid-Low, High-Low-Medium, Medium-High-Low, Medium-Low-High, Medium-High-High, Low-Medium-High and Low-Medium-High, and the different models not only reflect the regional conditions but also represent the different stages of the evolution of AESs in KMAs. We found that AESs in karst mountainous areas are transforming from traditional food crop systems to economic fruit forest ecosystems, and at the same time, the gravity center of human activities is migrating from high to low altitude areas, and the ecological vitality of MAESs is showing a trend of enhancement. In addition, the regions with high altitudes and steep slopes in karst mountainous areas have a single landscape structure and are dominated by traditional food cultivation, while the regions with low altitudes and gentle slopes have a diverse landscape structure and are dominated by modern and sustainable agricultural development. Finally, we reveal that the LER in KMAs shows a trend of initial increase followed by subsequent decrease, the influence of the human-land relationship on the LER in the micro perspective is significant, and the coordination and trade-off between agricultural development and environmental protection is the key direction of development in the future. The study results can provide a reference for the rational allocation of landscape, ecological environment restoration, and optimization of regional human-land relationships in KMAs worldwide. [ABSTRACT FROM AUTHOR]

Investigating the ecological and environmental impacts stemming from historical land use and land cover change (LUCC) holds paramount importance in systematically comprehending the fundamental human-land relationship, a pivotal focus within geographical research. The Yellow River Basin (YRB), often referred to as the cradle of Chinese civilization, ranks as the fifth-largest river basin globally. Early inhabitants made significant alterations to the landscape, resulting in substantial damage to natural vegetation, giving rise to prominent regional ecological challenges. By now, the examination of historical LUCC in the YRB over the past millennium remains in the qualitative research stage, primarily due to the limited availability of high-confidence gridded historical LUCC data. This study aims to advance the current historical LUCC research in the YRB from primarily qualitative analysis to an exploration incorporating timing, positioning, and quantification. Based on reconstructed historical cropland, forest, and grassland grid data of 10 km × 10 km from 1000 AD to 2000 AD, the degree of cropland development and the depletion of forests and grasslands were calculated, respectively. Then, the kernel density method was employed for spatiotemporal analysis and interpretation of dynamic changes in land cover. Subsequently, a cartographic visualization depicting the migration trajectories of the land cover gravity centers was generated, allowing for an assessment of the distance and direction of the centroids' movement of cropland, forest, and grassland. The results indicate that the cropland coverage in the YRB escalated from the initial 11.65% to 29.97%, while the forest and grassland coverage dropped from 63.36% to 44.49%. The distribution of cultivated land continually expanded outward from the southeast of the Loess Plateau and the southwest of the North China Plain. All three types of land cover experienced a westward shift in their gravity centers between 1000 and 2000 AD. Besides the population growth and technological advancements, the regime shifts induced by wars, along with land use policies in distinct periods, always served as the predominant factors influencing the conversion between different land covers. This research will present a paradigmatic regional case study contributing to the investigation of historical changes in land use and land cover. Additionally, it will offer historical perspectives beneficial for the advancement of China's objectives in "Ecological Conservation and High-Quality Development of the Yellow River Basin". [ABSTRACT FROM AUTHOR]

The intensification of the regional water cycle resulting from climate change, coupled with the influence of human activities, has brought about alterations in the frequency, scale, and intensity of droughts. In this study, based on hydrological big data and the standardized runoff drought index (SRI), the multi-scale spatiotemporal evolution of hydrological drought in China from 1948 to 2014 was analyzed using the run-length theory and gravity center model. Meanwhile, the hydrological drought hazard index was constructed to analyze the distribution of the hazard levels of drought in China. The results showed that, during 1948~2014, there was an opposite spatial distribution between the average intensity and the average coverage–duration–frequency of drought in the Yellow River Basin, Haihe River Basin and southeastern river basins. The drought situation in most river basins in China has shown an aggravating trend, among which the southeastern river basins, Haihe River Basin, Songliao River Basin and Pearl River Basin have generally shown an aggravating trend. The drought situation in China was severe in the 1950s and 1960s, gradually reduced in the 1970s, 1980s, and 1990s, and the drought situation was the mildest in the 1990s. After entering the 21st century, the drought situation began to worsen sharply. Meanwhile, from 1948 to 2014, the hazard level of drought generally presented a pattern of high in the west and north, and low in the east and south. The hazard levels of drought in the northwest and northeast were generally higher, and those in the southwest and southeast regions were generally lower. In general, the hazard levels of drought were relatively high in most areas of China. [ABSTRACT FROM AUTHOR]

As the main expenditure item in water balance, evapotranspiration has an important impact on the surface ecosystem. Assessing the impact of changes in meteorological elements on evapotranspiration is essential to identify the spatiotemporal heterogeneity of hydrographic responses to climate changes. Based on the actual evapotranspiration (ETa) product (GPR-ET) generated by Gaussian process regression (GPR), as well as temperature and precipitation datasets, our study employed various statistical analysis methods, including geographic detector, the center of gravity migration model, spatial variation coefficients, and partial differential models, to investigate the spatiotemporal variation in ETa in China from 2000 to 2018. The analysis covered future trends in ETa changes and the contribution of meteorological factors. Our results showed that the ETa in northwest China had stronger spatial heterogeneity and the mean value was generally lower than that in the southeast. But the center of gravity of ETa was shifting towards the northwest. In most areas, the future trend was expected to be inconsistent with the current stage. ETa in the regions of north and west was mainly driven by precipitation, while its increase in southeast China was largely attributed to temperature. In addition to spatial variations, the joint enhancement effect of temperature and precipitation on ETa exists. According to the contribution analysis, precipitation contributed more to the change in ETa than temperature. These findings have enhanced our comprehension of the contribution of climate variability to ETa changes, providing scientific proof for the optimization apportion of future water resources. [ABSTRACT FROM AUTHOR]

Under the combined impact of climatic, socioeconomic, and environmental factors, the vegetation NPP change process and its responses to drive factors in the sub-regions of Mainland China are not clear. This study analyzes the changing pattern of vegetation NPP in China from 2000 to 2022 from the perspective of zoning and clarifies its response mechanism to climate-human interaction based on the gravity center model, third-order partial correlation coefficient and geographical detector. The results showed that: (1) There was an overall decreasing trend of vegetation NPP in China from the southeast to the northwest; (2) The vegetation NPP gravity center in Northeast, Northwest, and North China migrated southwards, while that of Southwest, Central South, and East China showed northward migration.;(3) Human activities played a dominant role in zones with increasing vegetation NPP from 2000 to 2010, while climate change greatly contributed to the increase in vegetation NPP during 2011–2022; (4) Human activities, such as deforestation and overgrazing, in Northeast and North China should be reduced to prevent vegetation ecosystem degradation, and the negative impact of human activities should be reduced to maintain the growth of vegetation NPP. This study was conducted to support decision-making for the precise restoration of ecosystems. [ABSTRACT FROM AUTHOR]

Arable land is the lifeblood of food production, it is of great significance to promote the protection of arable land and ensure national food security by accurately understanding the change law of cultivated land and its driving mechanism. This study takes the Weibei dry plateau region of China as an example, explores its spatial and temporal change characteristics through the center of gravity shift and land use shift matrix, and couples the geographic probe model to reveal the driving mechanisms affecting arable land change. The results show that in the past 25 years, the total arable land area in the Weibei Dry Plateau Region of China has decreased by 5.58%, and the stability of arable land resources in the whole region has weakened. The center of gravity of arable land shifts to the northeast, and the standard deviation ellipse of arable land mainly undergoes the change process of "increase (1995–2015)-decrease (2015–2020)", and the spatial distribution of arable land tends to be dispersed. In the LISA frequency mapping, the proportion of stable constant and low-frequency areas is as high as 89.58%, and the spatial pattern of cultivated land is relatively stable. Medium and high frequency areas. The transformation mode is mainly "low-low" aggregation, "low–high" aggregation is not significant, and the decline of cultivated land in the study area is more obvious. In the past 25 years, a total of 1017.26 km2 of arable land was converted to construction land. The explanatory power of the influencing factors varies in each period (0.299 to 0.731), with total agricultural machinery power has the strongest explanatory power of 0.694, 0.592, and 0.731, respectively. The interaction between slope and annual average temperature and other factors being the highest, both greater than 0.8. Through the construction of LISA frequency mapping, combined with the center of gravity model and standard deviation ellipse, the spatial evolution trend of regional arable land is more comprehensively and dynamically grasped. By using the geodetector model, the driving mechanism of the changes of arable land is revealed comprehensively, which provides a theoretical basis for the scientific management and effective protection of arable land resources and a basis for decision-making. [ABSTRACT FROM AUTHOR]

The Yellow River Basin is an important energy base and economic belt in China, but its water resources are scarce, its ecology is fragile, and the task of achieving the goal of carbon peak and carbon neutrality is arduous. Carbon compensation potential can also be used to study the path to achieving carbon neutrality, which can clarify the potential of one region's carbon sink surplus to be compensated to the other areas. Still, there needs to be more research on the carbon compensation potential of the Yellow River Basin. Therefore, this study calculated the carbon compensation potential using the β convergence test and parameter comparison method. With the help of spatial measurement tools such as GIS, GeoDa, Stata, and social network analysis methods, the spatiotemporal pattern and network structure of the carbon compensation potential in the Yellow River Basin were studied from the perspective of urban agglomeration. The results demonstrate the following: (1) The overall carbon compensation rate of the YRB showed a downward trend from 2005 to 2019, falling by 0.94, and the specific pattern was "high in the northwest and low in the southeast". The spatial distribution is roughly spread along the east–west axis, and the distribution axis and the center of gravity keep shifting to the northwest. It also showed a weak divergence and a bifurcation trend. (2) The carbon compensation rate in the YRB passed the spatial correlation and β convergence tests, demonstrating the existence of spatial correlation and a "catch-up effect" among cities. (3) The overall distribution pattern of the carbon compensation potential in the YRB is a "low in the west and high in the east" pattern, and its value increased by 8.86% during the sampled period. (4) The network correlation of carbon compensation potential in the YRB has been significantly enhanced, with the downstream region being more connected than the upstream region. (5) The Shandong Peninsula Urban Agglomeration has the largest network center, followed by the Central Plains Urban Agglomeration, and the Ningxia along the Yellow River Urban Agglomeration has the fewest linked conduction paths. According to the research results, accurate and efficient planning and development suggestions are proposed for urban agglomeration in the Yellow River Basin. [ABSTRACT FROM AUTHOR]

Water, energy, and food (WEF) are essential material bases for mankind's survival and development. At the same time, water and energy, as necessary inputs for food production, are of great significance to food security. Scientific understanding of the water-energy-food nexus (WEF Nexus) in food production is conducive to ensuring food security and sustainable utilization of basic resources. However, current research linking the WEF Nexus with food production is lacking. Therefore, we took the WEF Nexus as an entry point to quantify China's food production efficiency and considered the direct and indirect inputs of water and energy in food production in this paper. First, we constructed an evaluation index system of food production efficiency based on the perspective of input-output and used the stochastic frontier production function model to measure the absolute efficiency values of food production. Then, GIS spatial analysis, spatial autocorrelation analysis, and the gravity center model were used to reveal the spatial-temporal pattern, spatial autocorrelation characteristics and barycenter trajectory, respectively. Finally, the Tobit model was applied to analyze the main factors which influenced the spatial pattern changes of food production efficiency. The research results indicated that China's food production efficiency was on the rise and there were spatial differences between provinces. Per capita GDP, natural disaster losses and irrigated areas of food crops were the main factors influencing China's food production efficiency. This paper contributed a new theoretical reference to the study of food production efficiency, and provided a decision-making reference for regional resource management to ensure basic resource security and sustainable development in the future. [Display omitted] • Taking WEF Nexus as an entry point to quantify China's food production efficiency based on SFA model. • Analyzing the temporal and spatial characteristics and influencing factors of China's food production efficiency. • China's food production efficiency was on the rise and there are spatial differences between provinces from 2000 to 2018. • The paper made reasonable policy recommendations in view of China's food production efficiency current situation. [ABSTRACT FROM AUTHOR]