Social-Ecological System (SES) is a collection of social subsystems, ecological subsystems, and the interactions between them. It is a common difficulty of cross-multidisciplinary fields to predict the changes in human-earth systems and support the relevant management decisions through clarifying the interaction between the ecological environment and human society. The framework of ecosystem service provides a new perspective for revealing the transmission and the role of various elements in SES. Taking ecosystem service as an entry point, this study follows the context of "Ecological System Supply-Ecological Coupling Human Intervention-Promoting Social Development". And the research progress and trends of existing coupling simulation methods related to SES are summarized. This article argues that in the conduction research of the ecosystem services cascade, the academic cognition has emphasized the "impact of natural ecosystem to social-economic system" rather than the "interaction and feedback mechanisms for ecosystems and social systems". In terms of research content, scholars have trsnsformed their focus from "changes in ecosystems and environmental effects" to "social-economic system and the effect on different groups". The focus of research has shifted from the theoretical inquiry of the "internal mechanism and power mechanism" to the applied practice of "optimization and regulation strategy" among the coupling systems. Future research of SES should strengthen the simulation of social-ecological coupling with equal emphasis on nature and humanities. It is the focus of breakthroughs to comprehensively understand the internal interactions and feedback of complex systems.

Urban-rural integrated development is an advanced stage in the evolution of the urban-rural relationship, and it is also the basic path and main goal for the implementation of rural revitalization. Scientifically understanding and identifying the integration stage and its current level of urban-rural development in China is the prerequisite basis for promoting urban-rural integrated development and rural revitalization. Based on the concept connotation, this paper constructed a multi-dimensional evaluation system of urban-rural integrated development at the prefecture level. The process status and spatiotemporal divergent characteristics of urban-rural integrated development in 336 prefecture-level regions in China from 2000-2018 were portrayed and revealed. The results show that: (1) The current state of urban-rural integrated development in China is generally at a low-to-middle level, showing a heterogeneous spatiotemporal pattern with apparent gradient divergence. The integrated development level of the Pearl River Delta, Jiangsu and Zhejiang provinces, and the Shandong Peninsula is high, but the regions distributed to the west of the "Hu Line" develops slowly. (2) According to the level and characteristics of integrated development, the 366 prefecture-level regions can be divided into four types: integrated development, tending integration, imbalanced development, and lagging development, with a more active transformation between the latter three types. (3) The development level of urban-rural economic integration is higher than that of demographic and social integration, while the development process of urban-rural spatial and ecological integration shows some natural zonal divergent characteristics. Finally, we identified the problem areas for different types of integrated development and explored the regional promotion path of urban-rural integrated development, which could provide scientific references for the strategies of regional urban-rural development and rural revitalization.

Global climate change caused by human activities results in frequent extreme climate events, and shifts the physiological processes of plants, and the carbon, water cycle and energy balance of terrestrial ecosystems. Vegetation phenology is the most sensitive biological indicator to climate change. In recent years, the responses of vegetation phenology to climate change mainly focus on the mean state of the climate, while the response mechanisms of vegetation phenology to extreme climate are still unclear. In this paper, the response of vegetation spring and autumn phenology to various extreme climatic events and their mechanisms were reviewed. We found that extreme low temperature and extreme precipitation directly delayed the vegetation green-up date and advanced the leaf senescence, while extreme high temperature and extreme drought led to stomatal closure, inhibited photosynthesis and transpiration, and thus advanced leaf senescence at middle and high latitudes of the Northern Hemisphere. Currently, the studies on the response of vegetation phenology to extreme climate events pay less attention to compound extreme climate events, and there are only few studies on the lag effect of vegetation phenology response to extreme climate events and the recovery process of vegetation after the occurrence of extreme events. Under future climate change scenarios, it is necessary to modify the vegetation phenological models by considering the impact of extreme climate events and couple it into the dynamic global vegetation models to improve the simulation accuracy of the carbon cycle in terrestrial ecosystems.

Deconstructing rural spatial characteristics is the precondition for building rural spatial governance system in the new era, and multi-scale rural spatial characteristics and its governance path would effectively support the modernization of the national governance system. Based on the comprehensive, regional and mobile thinking paradigm of geography, this paper deconstructs the multi-scale rural spatial characteristics, identifies its internal operating logics, summarizes its governance dilemmas, constructs a multi-scale rural spatial governance framework that is based on geographical analysis paradigm, explores feasible governance paths, and constructs a multi-scale rural spatial governance system research plan, namely, "characteristics identification-dilemma analysis-governance framework-governance path". The paper finds that: (1) to analyze the operating logics of the multi-scale rural space through the comprehensive, regional and mobile analytical thinking of geography, it is necessary to understand the mechanism of action of scale synthesis, scale differentiation and scale flow to the multi-scale rural spatial characteristics, highlighting the comprehensive characteristics of rural space, strengthening rural spatial heterogeneity, and integrating rural spatial mobility. (2) The lacking urban-rural spatial overall planning, unsmooth spatial mobile network and not-reflected different types of rural spatial value are the key dilemmas in the rural spatial governance, which need to be addressed. (3) The multi-scale rural spatial governance framework of "comprehensive spatial governance-spatial zoning governance-spatial mobile governance" could effectively solve the problems of urban-rural spatial integration, regional spatial coordination and spatial network blockage. (4) Integrating urban-rural comprehensive governance, innovating regulation control to improve regional governance and balancing the configuration of spatial development right to achieve mobile spatial governance are feasible paths for multi-scale rural space governance. In conclusion, clarifying the multi-scale rural spatial characteristics in the new era and constructing a scientific governance system could provide theoretical support to promote integrated urban-rural development and rural vitalization strategy.

Carrying capacity, a concept entrenched in the natural resources and environmental field for nearly two centuries, has continually evolved to address the conflicts and sustainability of the human-nature relationship. This paper introduces an analytical framework for understanding carrying capacity within the context of the human-nature relationship. It systematically reviews the progression of international carrying capacity studies, analyzes global research trends, and compares these with Chinese studies, highlighting key research directions in China. Historically, carrying capacity traces its roots to (neo)Malthusian theories. Its evolution spans four distinct stages: resource carrying capacity (since the 1800s), environmental carrying capacity (since the 1970s), ecosystem carrying capacity (since the 1990s), and natural system carrying capacity (since the 2010s). The concept of carrying capacity varies widely across global disciplines and even within the same discipline, showcasing diverse applications. Carrying capacity has sparked controversy due to its connection to political economy theories and factors such as technological progress, market mechanisms, and spatial and temporal constraints. Therefore, it is imperative to engage in a restrained and explicit discussion and application of carrying capacity. Presently, China's carrying capacity studies align closely with the international community, capitalizing on regional-scale studies employing a holistic and systematic human-nature relationship approach. However, there is an opportunity for enhancement in terms of global-scale perspectives and the integration of natural and social sciences theories and methodologies. This paper proposes fostering innovation and application in carrying capacity research within the Chinese context. This entails integrating various disciplines and theories, exploring scale effects and mechanisms, utilizing model-data fusion and integration, applying case studies in various spatial units and typical zone types, and improving policy systems and institutions.

Despite the initial development goals achieved, China's macro-economy is still deeply affected by the external environment and stuck in its own structure at the same time. In retrospect, not until 1949 with the founding of the People's Republic of China did China's budding regional economy witness the prominence of a fixed development pattern shifting from a spontaneous to an actuating one. After comparing the three regional economic practices, this paper finds that each development stage has its corresponding development strategy. At the same time, several development patterns, namely, the coastal and inland areas, the three regions, and four plates were formed accordingly. Furthermore, through combing the literature and historical facts, this paper determines the historical starting point, division criteria and division scheme of China's regional economic development before summarizing three main lines and also contradictions therein: the government-market relations against the background of market reform, the coastal-inland relations against the tide of economic zonation, and the urban-rural relations against the trend of urbanization. Based on the above, the paper constructs a three-dimensional model out of the spatio-termporal process of China's regional development before proposing new historical stages from the perspective of economic system modernization. These historical stages are: industrial economy, special zone economy, district economy, regional economy and urban network economy. Finally, from the urbanization angle, this paper concludes that for different urbanization stages, regional policies should be industrial policies, factor policies, fiscal and tax policies sequentially.

As China's urbanization has entered the middle and later stage and the improvement of well-being of residents has become a core goal, the transformation from "top-down" system goals optimization on the supply side to "bottom-up" multi-dimensional goals coordination on the demand side has become a new perspective to understand the connotation of urbanization. Based on the perspective of the human living conditions, the humanities environment, and human-city relationship, this paper constructs a connotation framework and index system of urbanization. Furthermore, Theil index is employed to analyze the spatio-temporal differentiation characteristics of China's urbanization before and after the implementation of the new-type urbanization strategy. Finally, in terms of both direct and indirect effect mechanisms, the mechanism framework of urbanization differentiation is constructed, and its evolution pattern is revealed by using Variance Decomposition and Geodetector. The results show that: since the implementation of the new-type urbanization strategy in 2014, China's urbanization has made remarkable achievements, with a steady improvement in human living conditions and human-city relationship, and there is still much room for improvement in the humanities environment. The high-level areas of urbanization are mainly distributed in coastal areas, and expanding to inland areas along the Yangtze River Basin and Yellow River Basin. The regional differences of urbanization gradually decrease, but the contribution rate of inner-regional differences shows an expanding trend. Differences in human living conditions and human-city relationship are the main factors of urbanization differentiation, but the contribution of differences in humanities environment is gradually expanding after 2014. Opening up and scientific & technological innovation are the main influencing factors of the difference in human living conditions. With the implementation of the new-type urbanization strategy, the impact on differences in humanities environment of the government finance gradually diminishes. Resource endowments have a relatively strong influence on differences in human-city relationship. This study can provide theoretical and empirical support for promoting the development of urbanization in China.

GIScience inherits the spatial analysis tradition of geography. Given that "spatial is special", GIScience needs to highlight spatial effects when constructing methods for geographical analysis. The research presents an explicit definition of spatial effect. By formalizing core GIScience concepts including space, location, field, distance, and region, we identify four types of spatial effects, namely spatial heterogeneity effect, neighbor effect in spatial dependence, distance decay effect in spatial interactions, and scale effect in spatial zoning. A unified framework is constructed to cover the four spatial effects based on the inherent linkages among them. We argue that spatial heterogeneity effect is the most fundamental one. While spatial dependence and spatial interaction are two basic geographical processes that represent the second-order relationships between two locations, neighbor effect and distance decay effect reflect the impacts of space. Scale effect is raised when aggregating attributes using regional units. Hence, the four types of effects form a hierarchical system. From a methodological perspective, this paper summaries related GIScience tools that implement different effects, and emphasizes the value of geospatial artificial intelligence for revealing and quantifying spatial effects.

The rise of global neoliberalism and reflexive governance has driven the political flows at the global level. Policy movements thus have shown new dynamics and characteristics. Political science, within the sphere of rational formalism, whose dependence on traditional frameworks, as well as the neglect of geographic mobility in sociology, have limited the explanatory power of existing concepts. The geographical orientation and spatial correlation of policy mobility offer the possibility of a theoretical breakthrough by introducing human geography in the policy research. Based on the literature in geography, this study traces the process of resembling rolling conversation through transdisciplinary research on policy mobility, and further clarifies the conceptual connotations, commitments, and research starting points of policy mobility. As an effective conceptual tool for understanding how policymaking operates, how policy knowledge and models flow, and how these mobilities shape places in the context of neoliberal globalization, policy mobility seeks to clarify the geographic positions, power relations, spatial characteristics, and social and geographical formation processes that are involved in the movements of policies. Policy mobility thus becomes a core field in the social sciences exploring "ideas in motion" and "production of mobilities". In addition, the theoretical orientation and research elements in the study of policy mobility also enhance the explanatory powers of literature from other disciplines to this subject. To a certain extent, this study compensates for the lack of empirical analyses of ideas and knowledge in mobility studies and insufficient research on power theory in human geography. It provides an important research field for applying geography in transdisciplinary research.

Climbing dunes are important barrier dunes that are widely distributed in highland mountain regions, and their formation is mainly controlled by topography, sand sources and wind regime. Existing researches mainly focus on simulation experiments, distribution patterns, field observations, and morphological characteristics. From a regional scale, there is a lack of research to analyze the variations in sediment characteristics and environmental significance of climbing dunes in different climatic regions. In this study, the wind regime, near-surface airflow, sediment characteristics and material sources of climbing dunes on the Qinghai-Tibet Plateau were comprehensively analyzed from the aspects of aeolian geomorphology, grain-size sedimentology, and geochemistry. The results show that: (1) Due to differences in material sources, the grain-size composition of climbing dunes sediments in different climatic areas varies, primarily fine and medium sands, with good sorting in the semi-humid areas and poor sorting in arid areas. The grain-size difference of sediments in different geomorphic parts is small, and it responds well to near-surface airflow, and in-situ sand accumulation is the basic formation form, with fine sand having the strongest climbing ability. (2) The chemical element content of sediments is influenced by the parent rock characteristics and the climatic environment, and the particle size is also important to its spatial variation, and trace elements are primarily concentrated in river floodplains, with little variation between geomorphic sites. (3) Except for SiO₂ enrichment, all macronutrients in the sediment show varying degrees of leaching or enrichment, and the majority of trace elements are deficient, as leaching and enrichment are closely related to particle size. (4) Climbing dunes sediments are in the early stage of continental weathering, with higher weathering levels in the semi-humid zone. The weathering of sediments in different geomorphic sites varies substantially, which is related to the parent rock, climatic environment, and grain size.

Soil organic carbon (SOC) storage and soil carbon sinks play a crucial role in the global carbon cycle of terrestrial ecosystem. However, many previous studies of soil carbon storage and sinks utilized low-resolution land use dataset, with limited focus on soil carbon sinks from farmland and grassland management. To address this issue, this study employed a series of accounting models to estimate the carbon sink from farmland and grassland management, the carbon sink from forest management, changes in soil carbon storage, changes in carbon storage due to land use conversion from 2000 to 2020, as well as the soil carbon storage in China in 2000 and 2020 using a 30 m-resolution land use dataset. The results showed that the national carbon sink from farmland management in China was approximately 17.918 Tg C a^-1 and the carbon sink from grassland management was approximately 20.171 Tg C a^-1 during 2000-2020. The carbon sink from forest management in China was approximately 81.622 Tg C a^-1 during 2000-2020. The soil carbon storage (0-100 cm) in China increased from 86.074 Pg C in 2000 to 86.771 Pg C in 2020. The soil carbon storage increased by approximately 34.850 Tg C a^-1 from 2000 to 2020. The land use transformation during the study period resulted in a decrease of approximately 17.621 Tg C a^-1 in soil carbon storage. The findings of this study can help researchers understand China's carbon storage and provide scientific data to China's 2060 Carbon Neutrality Target.

The social integration of urban floating population is the key task of the new-type urbanization in China. In view of the deficiencies of existing studies on the spatial characteristics of social integration and the role of destination city (place of inflow) factors, based on the China Migrants Dynamic Survey in 2017, this paper employs spatial analysis and hierarchical linear model to reveal the spatial pattern and influencing mechanism of social integration of migrants in cities above prefecture level in China. The results show that: (1) the overall social integration index of China's urban migrants is 0.43, which has the dimensional characteristics of behavioral integration (0.71) > psychological integration (0.61) > economic integration (0.33). (2) The social integration of migrants has spatial autocorrelation and agglomeration. The high-level social integration areas are mainly distributed in Northeast China, Shandong Peninsula, and Sichuan and Chongqing, and the low-level social integration areas are mainly found in the southeast coastal areas, Guanzhong Plain and North China Plain. These regions have the basic characteristics that the social integration level of migrants in small cities with a population of less than 0.5 million is higher than that in large cities. (3) Both the destination city and migrant individual factors jointly affect and shape the level and spatial pattern of migrants' social integration. Moreover, it is found that the population size, house price level and public services in the destination city regulate the impact of individual factors by four regulatory mechanisms: positive polarization, negative polarization, positive homogenization and negative homogenization. This paper calls for the research on the social integration of migrants from the human-land interaction perspective highlighting the relation of destination-individual factors to reveal the effect of destination factors on individual factors. This approach can provide a place-based policy implication for promoting the construction of new-type urbanization in China.

There are important changes in urban-rural structure of population mobility at the late-intermediate stage of urbanization in China, which will have a significant impact on population redistribution, urbanization and regional development. This paper divides the interprovincial urban and rural floating population into four mobility types by using the 2010 and 2020 censuses data, and on the basis of identifying the mainstream types, their spatial patterns evolution and the relationship with regional economic development are investigated through the mobility ratio indexes and regression models. The study results can be summarized as follows. (1) The urban and rural floating population is large and grows rapidly. Meanwhile, rural-urban mobility keeps the dominant position, and urban-urban mobility rises rapidly, these two population mobility types have become the mainstream ones of interprovincial urban and rural floating population in China. (2) In terms of the net mobility pattern of urban-urban floating population, the net-inflow areas are further concentrated in the three major coastal centers of Beijing, Shanghai and Guangdong, and Liaoning, Xinjiang and Yunnan are also maintained at a certain net-inflow rate, but most of the provincial-level regions are in the net-outflow areas. The major changes of the net mobility pattern of urban-urban floating population have shaped a spatial connection network. The main features of this network can be described as three cross-regional flow circles of Beijing-Tianjin-Hebei, Yangtze River Delta, and Pearl River Delta in coastal China. At the same time, the space connections within the regions are strengthening in northeast China, northwest China and southwest China. (3) The net mobility pattern of rural-urban floating population shows that in coastal areas, the net-inflow rate rises or decreases during the study period, while in inland areas, the increase in the net-inflow rate of Liaoning and Xinjiang leads to the decline in the net-outflow rate of their neighboring provinces. The changes of the net mobility pattern of rural-urban floating population depict the dual characteristics of continuous formation and different changes of the coastal flow circle, and the development of the inland flow circle in Xinjiang and Liaoning. (4) There is a mutual relationship between urban-urban and rural-urban population mobility and regional economic development. For regional economic development of both population mobility types, the impact is significantly positive and has been increasing. When we add the floating stock into the models, the positive effect of this variable has decreased in urban-urban mobility's model, while it still plays the first-place positive effect in rural-urban mobility's model. The two population mobility types have a positive effect on the national economic development and the inflow areas' economic development.

Economic globalization has reshaped the world economy's spatial pattern while simultaneously changing the context for developing economic geography theories. This study revisited the changing features of economic globalization and investigated its geographical implications. Next, it summarized the new trends in economic geography studies in response to the changing economic globalization. Lastly, this study proposed a research agenda for domestic economic geography studies by combining the requirements of global trends and national strategies. The main findings include the following: The scale of geographical integration during economic globalization keeps shrinking, leading to a pattern of regionalization. The driving forces of economic globalization have gradually shifted from cost-saving to innovation. Accordingly, the benefits of economic globalization will be reallocated between developed and developing countries. The trade-offs between efficiency and resilience alter the global value chain, shifting outsourcing from off-shoring to re-shoring or near-shoring. The changing economic globalization has witnessed the rising effects of geographical distances, institutions, and resilience on increasing the inequality of the global economic geography. In economic geography, the scalar structures shifted from the global-local to the global-national-local. The relational networks evolved toward a multi-level, multi-agent, and multi-scale one. The role of the nation has been revisited. More attention has been paid to geopolitical hotspots. Overall, economic geography's institutional, cultural, relational, and evolutionary turns exhibit an emerging trend to convergence. In such a setting, domestic economic geography should find a new balance between global trends and national strategies. This study proposed seven research issues, including: (1) the practice of the Belt and Road and the pattern of inclusive globalization; (2) the economic geography of dual circulation; (3) the paths and resilience of regional development in response to the global production network restructuring; (4) the evolution and competitiveness of industrial clusters; (5) the building of multi-level innovation systems; (6) the regional sustainable development within the global environmental governance system; and (7) the impact of geo-economics on national economic security and interests.

Remote sensing in hydrology is a crossing field of hydrology and remote sensing. It not only includes remote sensing retrieval models for water cycle factors, but also covers remote sensing hydrological models which serve for calculating the process of hydrology. This review focuses on the past, present and future development of remote sensing hydrological model by using the meta-analysis method and collecting related research in the past 40 years. The results show that remote sensing hydrological model has played a key role in remote sensing hydrology since the 1970s in the world. In China, the researchers of remote sensing in hydrology keep pace with global scientists, and prominent achievements include the concept generation about the remote sensing hydrology, promotion of the combination between remote sensing and hydrology and development of remote sensing hydrological models. In the future, by the help of enhanced information technology, the remote sensing hydrological models will pay more attention to the runoff monitoring by using remote sensing, the intelligent web of hydrological sensors, hydrological analysis in the data scarce watersheds, and the precise simulation of the water flow, water quality as well as the water ecology.

Senior residential tourism is the product of upgrading demand for elderly care, and thus effectively fits the national development strategy of rural revitalization. Based on grasping the connotation of senior residential tourism, the paper constructs a framework to analyze the development of senior residential tourism with the push-pull theory. This paper uses various analytical methods to discuss senior rural residential tourism's spatial and temporal evolution pattern and formation mechanism, and further reveals and analyzes the typical development mode. The findings are as follows: (1) Senior residential tourism is a lifestyle in which the elderly live continuously in the sojourning place for the dual purpose of deep experience and living. To grasp its connotation, it is necessary to clarify the key issues, such as the subject of action, the motive of action, the time limit, and the moving distance. (2) In terms of temporal dimension, China's senior rural residential tourism has experienced three stages, namely, the budding stage, the slow development stage, and the high-speed development stage, which show a trend of structure type optimization, increased participation of social capital, and market development segmentation. (3) In terms of spatial dimension, senior rural residential tourism development strongly correlates with the "Hu Huanyong Line." During the study period, the high-density core area evolved from the "single-level core" of the Yangtze River Delta to the "three-pillar" situation of the Yangtze River Delta, Beijing-Tianjin-Hebei region, and Pearl River Delta. (4) Under the framework of "push, pull, and intermediate barrier", the development of China takes the pulling force as the dominant driving force, which mainly includes the number of intangible cultural heritages, the number of tourist resorts, and other factors. (5) Finally, based on the comprehensive analysis of regional development factors, this paper classifies senior rural residential tourism into four typical development modes: natural support, cultural tourism support, health support, and mixed type, and thus puts forward a development path according to local conditions and classification.

Based on the quasi-natural experiment, this paper uses the method of time double difference (DID) to empirically test the differential impact and mechanism of the opening of China Railway Express on the export trade of cities along the rail line by using the panel data of 279 prefecture-level cities in China from 2004 to 2019. The results show that: (1) The opening of China Railway Express has significantly promoted the export trade growth of cities along the rail line in China. The better the local transportation infrastructure conditions, the stronger the driving effect on the growth of local export trade. Exports are also positively regulated by the number of countries passing through and the logistics transportation capacity of the destination country. (2) Heterogeneity analysis found that the opening of the train has a significant positive impact on the export trade of the node cities of the supply hub, but it has no significant impact on the railway hub cities, and has a certain inhibitory effect on the export of the port cities. From the perspective of city size, the positive promotion effect of trade mainly occurs in small and medium-sized cities. Based on the analysis of different geographical location train channels, it is found that the promotion effect on the export trade growth of cities along the western channel is obvious. (3) The organization and operation of China Railway Express follow the "axle-spoke" mode, and their radiating space to the surrounding areas is roughly within 150 kilometers. The intermediary mechanism test shows that the opening of China Railway Express can promote the growth of export trade by improving the regional marketization level, and the positive intermediary effect of marketization level is more significant for cities in peripheral regions. The intermediary effect of transportation time cost saving is not significant, and the saving of time required by traditional shipping is not the main reason to promote the growth of export trade.

Yangtze River Delta, as a pivotal region where the coastal axis and the riverside axis intersect, is characterized by complexity, diversity and typicality of the spatial structural evolution. Therefore, understanding its evolutionary pattern and constructing a theoretical model has important theoretical significance and application value. According to the core-periphery structure theory, the Yangtze River Delta can be divided into a core area that is centered on the Taihu Lake Basin and remaining periphery areas. However, due to its location at the junction of the river and the sea, a gateway area has emerged within the periphery area, thus forming a spatial structure that is composed of the core area and the gateway area. In the early period, the core area was centered on Suzhou, and a five-tier central place structure became well established since ancient times. However, the gateway area kept evolving and underwent three main changes: in ancient times, the gateway area was centered on Yangzhou, forming the canal gateway cluster; in the modern age, the gateway area became centered on Shanghai, forming an offshore gateway cluster; and in the contemporary era, the gateway area became centered on Ningbo, forming an oceanic gateway cluster. Their corresponding navigation capacities were 500 t, 10,000 t, and 200,000 t, respectively. Therefore, in addition to the existing central place theory and seaport spatial structure theory, the spatial structure evolution of the Yangtze River Delta presents a new evolutionary model: namely, the fusion evolutionary model of central places and port gateways. According to this model, in the early period, it was an endogenous evolution of the core area's spatial structure, which was in line with Christaller's hexagonal structure; while in modern times, the evolution of the spatial structure of the Yangtze River Delta was no longer dominated by central places, but rather, it became dominated by the gateway areas, making the k = 3 market principle turn into the k = 4 transportation principle. In this way, the Yangtze River Delta provides a globally exemplary empirical case for validating the process test of the central place theory, analyzing functional attributes of urban centrality and gateway, and refining the relevant theoretical model.

Most of Asian major international rivers originate from China. Their abundant transboundary water resources play an important role in regional "water-energy-food-ecology" security. In recent decades, influenced by global change, especially by the construction of large hydraulic and hydroelectric engineering, the changes in hydrological and ecological processes and their transboundary impacts in the international river regions have attracted more and more attention. The research on these issues in China has achieved prominent results in several aspects, including the changes in hydrological and ecological processes and their attributions, the transboundary impacts and risk regulation, the "water-energy-food-ecology" nexus in transboundary watersheds, and the construction of transboundary water resources coordination mechanism to adapt to global changes. In the face of the increasing risks of transboundary water security and ecological security under global change, the hydro-geographical research on international rivers needs to make use of space-air-ground integrated monitoring technology, modern spatial geographic information technology, intelligent technology, and so on. By providing quantifiable, participatory, and public results, these researches can better provide scientific basis and decision support for the rational utilization of international rivers and geopolitical cooperation, health maintenance and risk control, transboundary water diplomacy and environmental diplomacy.

With the increasing global warming over the past three decades, the climatic zones and eco-geographical regions characteristics in China have changed. This study used the climatic data of 641 meteorological stations over the past three decades (1991-2020), as well as the high-precision data of eco-geographical elements to optimize the eco-geographical regions in China. The study updated the map of eco-geographical regionalization in China (2023) and increased the scale to 1:4000000. The new map divided China into 11 temperature zones, 22 dry and wet regions, and 50 natural regions. The results show that compared with eco-geographical regionalization in 2007, the overall pattern of eco-geographical regions in China has not changed significantly over the past three decades, but the boundaries of temperature zones, dry and wet regions, and eco-geographical regions (natural regions) in some areas have changed to some extent. Firstly, the boundary change of temperature zones is more obvious in the east. Particularly, in the middle and lower reaches of the Yangtze River, the northward shift of the temperature zone boundary between the northern subtropical and the mid-subtropical zones is obvious. Secondly, the boundary between dry and wet regions has changed, and that between semi-arid and arid regions in the north of the second-order landform step has shifted slightly to the west. In addition, the boundary between semi-arid and sub-humid regions in the Qinghai-Tibet Plateau has shifted slightly to the southeast, reflecting a slight expansion of the scope of semi-arid regions. Finally, boundary changes in natural regions in some areas vary greatly. This study can provide a macro-regional framework for guiding ecological conservation and restoration in different regions.

The study of influencing mechanisms of intercity knowledge collaboration networks is an important research topic of innovative geography. Most existing research focuses on the influence of exogenous forces (e.g., urban resources endowment, multidimensional proximity), whereas less attention has been paid to endogenous factors (e.g., preferential attachment, transitivity). This research constructs an intercity knowledge collaboration network of Chinese cities based on the co-publication data from the Web of Science, analyzes its evolving characteristics of spatial and topological structures from 2006 to 2016, and quantitatively explores the endogenous and exogenous forces underlying the network formation through exponential random graph modelling. The results show that: (1) From the spatial structure perspective, the intercity knowledge flows are dense in the eastern region but spare in the western region, which is stable during 2006-2016. The overall network has developed from a dual-core structure of Beijing and Shanghai to a polycentric structure, in which five national-level urban agglomerations have become important bases for nurturing multiple centers. The nodal regions centered on highly administrative cities have become increasingly consistent with the planned urban agglomeration, which plays the dual role of proximal spillover and remote interaction of knowledge resources. (2) From the topological structure perspective, the scale and density of intercity knowledge flows have increased significantly, and the preferential attachment to big cities is obvious. However, with the rise of multiple centers, the network polarization and disassortativity have been weakened. With the optimization of intercity knowledge collaboration paths, the network cohesion has improved, thus becoming a small-world network. (3) From the influencing mechanism perspective, self-evolution and preferential attachment are important driving forces of knowledge collaboration networks, showing an overlapping effect with urban hierarchy. The positive impact of urban knowledge-related attributes on intercity flows is weaker than multidimensional proximity and path dependence. The presence of high-speed railways promotes knowledge collaboration, while the influence of geographic distance is not significant.

Under the background of promoting more balanced and fuller regional development in the new era, standing at the strategic height of national regional coordinated and balanced development, it is necessary to comprehensively consider the natural environment, the unbalanced situation of economic and social development and the reality of widening gap on both sides of the Hu Huanyong Line, and put forward the basic idea of the Hu Huanyong Line to achieve micro-breakthrough along the Bole-Taipei Line. The Hu Huanyong Line is an important dividing line of population geography, natural geography and ecological environment in China, the dividing line of national main function area and national ecological function area, the dividing line of new urbanization main area and non-main area in China, and the dividing line of unbalanced and inadequate economic and social development in China. In the past 40 years, the gap of economic and social development between the two sides of the Hu Huanyong Line has been widening at an accelerating speed. In the next 30 years, the gap can be narrowed to achieve micro-breakthroughs, focusing on achieving "ten 10%", namely, the proportion of population in the northwest half of China will be 10%, the proportion of total economy will be 10%, with the economic growth rate being more than 10%, the proportion of fixed asset investment in the whole society will be more than 10%, the proportion of local fiscal revenue will be more than 10%, the proportion of actual use of foreign capital will be 10%, the growth rate of per capita GDP will be more than 10%, the rate of increase in the absolute difference in the per capita disposable income of urban residents will be controlled within 10%, the rate of increase in the absolute difference in the per capita disposable income of rural residents will be controlled within 10%, and the absolute gap in education resources will be narrowing at an average annual rate of 10%. In order to achieve the strategic goal of micro-breakthrough, this paper puts forward the main paths and countermeasures to narrow the development gap between the east and the west of the Hu Huanyong Line and attain the micro-breakthrough from the aspects of population micro-layout, economic micro-layout, urbanization micro-layout, industrial micro-layout, moderate water diversion nearby, improvement of ecological compensation and transfer mechanism, construction of the Bole-Taipei Line and implementation of the strategy of further development in the western region.

The rational flow of urban-rural factors is conducive to optimize the urban-rural relationship and promote rural revitalization and urban-rural integrated development. Based on the theory of social reproduction, this study defined the connotation and flow types of urban-rural factors, proposed the measurement method of urban-rural factor flow, and quantitatively analyzed the spatial pattern and evolution characteristics of urban-rural factor flow in China. The results showed that urban-rural factor flow referring to the changes of factors affecting urban and rural development can be divided into three types of internal flow, mutual flow, and inter-regional flow. Significant spatial differences and a gradual increase of flow intensity existed in the mutual flow of population, capital, technology, and agricultural products between urban and rural China, while great spatial differences were found in the inter-regional flow of population, capital, technology, and agricultural products without conspicuously increased flow intensity. The intensity and structure of urban-rural factor flow were comprehensively affected by adjusting the scale and structure of social reproduction under the regulation of natural resource endowment and human regulation. The free two-way flow between urban and rural areas can be realized from the aspects of selecting reasonable human intervention means and optimizing the allocation of factors in the social reproduction process, according to regional factor endowment differences and factor flow characteristics at different scales.

The orderly development of county urbanization, as an effective driving force for the integrated development of urban and rural areas in the new era, promotes the interaction and flow of elements between urban and rural territorial system, the optimization and adjustment of industrial structures, the optimal allocation of resources and markets, and the organic integration of urban and rural territorial system. The results show that: (1) From 2000 to 2020, the county urbanization in China developed rapidly, and the regional differences in spatial and temporal dynamics were significant. The county urbanization rate in the eastern coastal, central suburbs and northern border areas was high, while it is low in southwest China, rural areas of the central region and most parts of Tibet and Xinjiang. In 2020, to the east of the Hu Huanyong Line, the northeastern region, northern Hebei, Shanxi-Shaanxi-Henan region, eastern Sichuan, and Yunnan-Guizhou region became high-value areas for urbanization rates at the county level. There are 716 counties with urbanization rates exceeding 50%, including the Pearl River Delta, the Yangtze River Delta, the Beijing-Tianjin-Hebei region, the Chengdu-Chongqing region, the middle and lower reaches of the Yangtze River, the border areas of Inner Mongolia, and the southeastern coastal areas of Jiangsu, Zhejiang and Fujian, accounting for 38.3% of the country's total. (2) The county urbanization in China is the result of the combined effects of factors such as population, economy, society, and culture. The level of economic development, natural environment conditions, infrastructure construction, geographic locations, public resource supply, professional entrepreneurial clusters, and macro policies affect the direction, scope and depth of county urbanization. It is predicted that by 2035, the urbanization rate of China will reach about 76.04%, and that of counties will be about 64.38%. In the future, we should strengthen the adjustment and optimization of county population, economy, society and spatial organizational structure. (3) There are five types of county urbanization in China, including factor agglomeration urbanization in counties around big cities, industrial agglomeration-driven urbanization in counties with specialized function, agricultural modernization-led urbanization in counties with main agricultural production areas, ecological conservation urbanization in counties with ecological function areas, and concentrated urbanization in counties with population loss. (4) County urbanization takes county and key towns as important spatial carriers for the agglomeration of urbanization elements, and forms a multi-level system of residence-industry and industry-city coordination. The rational spatial distribution of factors such as the development of industrial integration and population resources will further promote the interactive flow of urban and rural elements, the integration of urban and rural industries, the equalization of urban and rural residents, and the equalization of urban and rural infrastructure, and enhance urban-rural integration and network development.

The continuous remote sensing monitoring of land use/cover change at the national scale is of great scientific significance for land spatial planning and blueprint drawing of "Beautiful China" in the new era. Landsat 8 OLI, GF-2 and other satellite remote sensing data were used to develop the data of land use change across China during 2015-2020 and China Land Use/Cover Dataset in 2020 (CLUD 2020) by integrating remote sensing big data and expert knowledge-assisted human-computer interaction interpretation methods. Long time series land use dynamic database at a 30-m resolution in China was established at 5-year interval in the end of 1980s-2020. On this basis, the general trend, regional differences and main characteristics of land use change in 2015-2020 were revealed from national and regional scales. The research indicated that integrating vegetation cover change at a 30-m resolution and land change information generated by remotely sensed big-data cloud calculation into the expert human-computer interaction interpretation can effectively improve the efficiency of mapping and the accuracy of land use change detection. The overall accuracy of CLUD 2020 first-level type mapping reaches 95%. In general, the intensity of territorial development entered a stable state compared with 2010-2015. During the period, the cropland continued to decrease. Nationwide farmland was encroached by urban development and construction, paddy fields in Northeast China continued to decrease, and cultivated land in Xinjiang was reclaimed in the south and abandoned in the north. The built-up land continued to increase, showing a spatial pattern that "the expansion of built-up land changed from the agglomeration of coastal areas and mega and large cities in 2010-2015 to the surrounding sprawl of large, medium and small towns in the central and western regions in 2015-2020". Although the area of natural ecological land for forest and grass continued to decrease nationwide, the intensity decreased compared with 2010-2015. Under the continuous impact of climate change, the area of water in the Qinghai-Tibet Plateau increased significantly. The pattern of land use change is closely related to the national macro strategy for high-quality development during the "13^th Five-Year Plan" period (2016-2020) and ecological civilization construction, as well as the impact of climate change.

Mountain altitudinal belts are the miniature of horizontal differentiation and succession of climatic and vegetational zonation. However, altitudinal belts' vertical range, transition model, inner structure and combining pattern vary from place to place. In Mt. Taibai of the central section of China's north-south transitional zone, we have found an altitudinal belt with the largest range in the world, namely, the montane deciduous broad-leaved forest, which extends continuously from the mountain base to about 2800 m, including basal oak belt, typical oak belt of two sub-belts and cold-tolerant pioneer birch belt of two sub-belts, which could otherwise develop independently. Characterized by a "three layers and five sub-belts" structure, this "super altitudinal belt" is much vertically broader than the threshold of 1000 m for normal altitudinal belts. Its formation is closely related with its transitional geographic location, integral spectrum of altitudinal belts in central Qinling Mountains, rich and diverse species of deciduous woody plants, and their strong competitiveness. The finding of the super altitudinal belt has multiple significance: Its existence is another significant physio-geographic feature of China's north-south transitional zone; it shows that an altitudinal belt may have rather complex inner structure and broad vertical range in some special mountain environment. This broadens our understanding of altitudinal belt structures and their mechanisms, and is of great significance for developing structural theory for montane altitudinal belts. This finding also demonstrates that there are many big questions for us to explore and study in the north-south transitional zone, and it is expected that our finding could trigger in-depth study of local climate and biodiversity responsible for the formation of this super belt, and of the complex structure and ecological effect of China's north-south transitional zone.

Governing the country is a matter of routine and people-oriented strategy, and improving the people's well-being is "the greatest thing in the country". At present, China is facing the challenge that the national well-being declines with the economic development. This study is based on the national large-scale regional space and adopts the survey data collected in 2020 by the "China People's Livelihood Survey" research group of the Development Research Center of the State Council. The data cover 31 provincial-level regions (hereafter provinces) across the country, including 164 cities at prefecture-level and above, and the number of valid samples is 26370. The research adopts the methods such as the trend surface analysis and spatial analysis of hotspots and coldspots to construct the spatial differentiation and agglomeration pattern of urban residents' perceptions of living conditions in the 31 provinces; the multi-level regression model is used to explore the multi-dimensional influencing factors of perceptions of living conditions at the individual and city levels. The findings are as follows: (1) The differentiation of the living improvement, living condition evaluation, future life confidence and perceptions of living conditions of urban residents in China shows a pattern of high in the west and low in the east, and high in the south and low in the north. (2) The living conditions of urban residents show the characteristics of "continuous agglomeration", and the evaluation of living conditions shows the characteristics of "coexistence of massive agglomeration and scattered distribution", and shows the characteristics of high in the south and west and low in the north and east together with the future life confidence and overall perceptions of living conditions. (3) On average, the highest and lowest values of life improvement, urban residents' living condition evaluation, future life confidence and perceptions of living conditions are also located in the west and east respectively. (4) The influencing factors at the individual level are reflected in gender, age, education level, employment status, household registration status and satisfaction evaluation of urban public services. Among them, satisfaction evaluation of urban public services is reflected in government services, social security status, fair law enforcement status, food safety status, housing status, education status, medical services, transportation status, environmental status, etc. (5) The city size has a significant impact on the perceptions of living conditions of urban residents. Compared with large cities, the perceptions of living conditions of residents in small and medium-sized cities is higher, while that of residents in megacities is lower. In addition, the positive impact of satisfaction evaluation of public services in megacities on the perceptions of living conditions of urban residents has been weakened. Specifically, it mainly weakens the positive correlation strength of medical status evaluation and traffic status evaluation on the well-being effect. The research provides a practical and theoretical reference for the research, judgment and governance direction of China's national perceptions of living conditions.

Understanding the geographical pattern and driving factors of China's population migration in the first 20 years of the 21st century has become a pivotal issue in promoting the construction of the new-type urbanization and interaction development between regions during the 14th Five-Year Plan period (2021-2025). Supported by the data of the sixth and seventh national population censuses and 2005 and 2015 national 1% population sample surveys, this paper aims to investigate the spatiotemporal evolution characteristics and influencing factors of interprovincial migration in China from 2000 to 2020. Relevant population geospatial analysis and the eigenvector spatial filtering Poisson pseudo-maximum likelihood estimation (ESF PPML) gravity model are employed. The following conclusions are drawn: (1) China's population migration patterns were generally stable from 2000 to 2020, where notable imbalance and network spillover effects were also detected. A large number of migrants from central, western and northeast parts of China tended to move to the eastern region. (2) The overall migration patterns between 2000 and 2020 revealed several changing characteristics. The degree of imbalance and spatial agglomeration of migration patterns gradually weakened. Yet, a north-south differentiation emerged. It is also found that the out-migration trend of the northeast region increased with the elaspe of time. (3) The ESF PPML model indicated that gravity factors (population scale, geographical distance), regional socio-economic factors (wage disparity, proportion of investment in science and technology and education, medical care), social network factors, environmental comfort (PM_2.5 concentration) and living costs (proportion of housing price) drove the interprovincial migration pattern between 2000 and 2020. (4) The influence of regional economic differences on interprovincial migration reflected a weakening trend. The pattern of population migration gradually turned into the decision-making of diversified demands for the economy, public services and urban amenities, while the living cost factor represented by housing price had played a gradually significant part. The conclusion of this paper provides policy references for the construction of the new-type urbanization and coordinated development between regions during the 14th Five-Year Plan period in China.

Geographic big data enables a fine-grained depiction of regional human-terrestrial systems and provides new data for the study of human-terrestrial relations and regional development. At present, geographic big data research has entered the stage of widespread application, but the examination of its quality and the corresponding evaluation methods have been lacking to guarantee the widespread and efficient application of the data. POI is an important part of geographic big data and plays an important role in location-based services and an understanding of regional scenarios. This paper proposes a method to assess and enhance POI-type big data, and realize quality evaluation based on site research, GIS and other methods from three dimensions: feature identification completeness, data redundancy rate and spatial location accuracy; discover and summarize possible influencing factors of data quality based on data production process, and prove that multi-source data fusion is an effective means to enhance POI data quality. We found that: the volume of Amap data acquired based on API interface is slightly higher than that of Baidu, the accuracy rate of spatial location is comparable and the redundancy rate is lower; Amap focuses on identifying the entrance of features, which is suitable for analysis such as accessibility; Baidu focuses on discovering non-significant features, which is suitable for analysis such as spatial planning; the discovery, acquisition and processing stages are possible links to reduce data quality, which is influenced by data protection mechanism, and the data quality is inversely proportional to the acquisition volume and area. The quality assessment, enhancement and integration of multi-source heterogeneous geographic data is one of the key ways to enhance the "emergent value" of data, promote trans- and cross-multidisciplinary and solve geographic problems in the new era.

With urbanization and industrialization, cultivated land in hilly regions of China has been gradually marginalized. Abandoned cultivated lands have ranged from inferior sloping land and extended to high-quality terraces. The abandonment of terraces will lead to a series of social and ecological problems, especially with large-scale abandonment. Therefore, the degree and spatial distribution of terrace abandonment should be evaluated scientifically to address the issue of abandonment as well as its effects. This study investigated the extent of terrace abandonment in China via a questionnaire sampling method. Based on 560 village questionnaires from 329 counties in China, the scale of terrace abandonment was calculated and the spatial heterogeneity characteristics and primary reasons for terrace abandonment were further analyzed. Study results showed that: (1) The phenomenon of terrace abandonment was observed throughout China, occurring in 54% of all the villages investigated; 9.79% of the total terraced areas have been abandoned. (2) The degree of terrace abandonment showed a spatial pattern of "high in the south and low in the north". The degree of terrace abandonment was higher in the southern hilly mountains, and the middle and lower reaches of the Yangtze River was the most serious. (3) The primary factors related to terrace abandonment were found to be labor migration, the degree to which terraces have been mechanized, irrigation conditions, and farming traffic conditions. Measures that include improving the degree of terrace mechanization should be enacted to address the problem of terrace abandonment. An orderly "conversion of cropland" could be applied to poor-quality terraces. Changing the planting structure, strengthening new agricultural infrastructure, and encouraging circulation and large-scale operations are options that could be applied to good-quality terraces.