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.

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.

According to the Ministry of Water Resources of the People's Republic of China, the number of casualties in flash flood disasters accounts for nearly 70% of flood disaster casualties in recent years and flash flood has become one of the major natural disasters causing casualties in China. Flash flood regionalization is fundamental for implementing the local measures of the flash flood prevention and mitigation according to local conditions. Using results from existing flash flood relevant physiographical regionalization schemes, and in accordance with the principles of comprehensive, dominant factors, the relative consistency within units, the relative difference between units, the integrity of spatial distribution and the hierarchical divisions, this paper firstly constructs an index system of the flash flood trigger factors and its underlying surface environment for the flash flood regionalization in China. In the combination of top-down and bottom-up regionalization, the hybrid self-organizing-map-based spatial clustering algorithm is then built. Finally, nine homogeneous regions at the first-grade and thirty-three subregions at the second-grade are delineated for flash floods in China. The historical flash flood events and the Geodetector method are adopted to evaluate the developed regionalization schemes. Results show that the first-grade and the second-grade flash flood regionalization schemes in China can respectively provide the determinant power of 66.4% and 75.4% for the spatial distribution of historical flash flood events in the whole country, indicating the developed flash flood regionalization has a good spatial consistency with the distribution of historical flash flood events with different densities. The developed flash flood regionalization not only effectively delineates the regional differentiation pattern of flash floods, but also provides a scientific basis for the implementation of localized flash flood prevention and mitigation measures in China, which benefits for the sound development of flash flood disasters prevention and management in China.

The land conversion processes concerning non-agricultural and non-grain production areas have prominently decreased arable land availability, which substantially impacted grain production capacity and threatened national food security. Thus, it is critical to establish a novel scientific approach to identify spatio-temporal evolution patterns of land conversion and its influencing factors in different stages. This study evaluates the evolutionary characteristics of non-agricultural and non-grain fields by constructing a comprehensive index system that considers factors like cultivated land resources, social and economic conditions, and farmers' subjective perspectives, using a county as the basic research unit. For a comprehensive analysis, a geographical detector model was utilized to quantify driving factors in different stages. The results indicated spatial clustering effects for non-agricultural and non-grain fields throughout China, particularly in the eastern region beyond the "Hu Huanyong Line". Further analysis revealed a spatial pattern for non-grain conversion phenomenon was more intense in the southwestern than the northeastern fields. Over the past four decades, non-agricultural fields recorded an area expansion, but the year-wise area increase was gradually reduced, while non-grain areas exhibited a "growth-stable" change pattern. Although progress in non-grain was less in primary producing areas over the last 40 years, an increase of 1.49 times and 1.33 times was recorded from 2010 to 2020 in PSB (production and sales balance area) and Mrt (marketing) areas, respectively. Compared to the period 1980-2000, the rate of non-agricultural conversion in primary producing areas decreased by 77% during 2010-2020, while the rate of non-agricultural conversion increased by 1.63 and 4.65 times for PSB and Mrt regions, respectively. Based on these findings, this paper puts forward suggestions, such as setting control rules and subsidy mechanisms according to area classification, promoting control policies based on regional considerations, strengthening dynamic monitoring and risk warning, as well as enhancing supervision and assessment.

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.

At present, the empirical analysis of regional dual-nuclei structures at the national level is still relatively rare. How to define the provinces with the characteristics of dual-nuclei structures and analyze their impact needs further empirical discussion. In this paper, the spatial Dubin model and the data of 259 prefecture-level cities are used to analyze the distribution characteristics of regional dual-nuclei structure in China and its influence on provincial development. The empirical results show that 11 provincial-level regions (hereafter provinces) in China show the characteristics of dual-nuclei structure. The regional dual-nuclei structure plays a significant role in promoting the economic development of the province, but the northern and southern regions show great differences. The regional dual-nuclei structure has a promoting effect on provincial industrial agglomeration and helps to promote the improvement of local scientific and technological innovation. In general, compared with some single-core provinces with small scale and weak radiation driving force in some provincial capitals, the regional dual-nuclei structure can make up for these shortcomings to a certain extent by virtue of the number of central cities and spatial distribution, which is more conducive to driving local economic development and scientific and technological innovation.

Terrestrial recycling of green water, which is created through a continuous cycle of evapotranspiration, atmospheric transport, and terrestrial precipitation, serves as bridges connecting hydrosphere, atmosphere, biosphere, and anthroposphere. Limited knowledge of terrestrial recycling may underestimate the impact of human activities on water and ecology. This study focuses on the structure of China's green water recycling (CGWR) and quantifies the contributions of natural and human ecosystems. Results indicate a high green water recycling ratio (50.4%) and a large recycled amount (2.75 trillion m³/a) over China, with significant south-to-north transport structures over eastern China, southwest-to-northeast transport structures from southwestern China to northern China, and high self-recycling structures in western China. The grassland-dominated Qinghai-Tibet Plateau provides the largest amount of green water (about 800 billion m³/a) and serves as the most critical region for CGWR. The forest-dominated southern hilly region and Yunnan-Guizhou-Sichuan region play a crucial role in supplying green water to a wide area of China. The cropland-dominated Middle-Lower Yangtze Plain and the grassland-dominated Loess Plateau are the key hubs for south-to-north and southwest-to-northeast transport of green water. The structure of CGWR is driven by large-scale geosystems such as ecosystems and atmospheric circulation systems, and has strategic implications in the following three aspects. First, CGWR serves as the "domestic cycle" of water, based on which a general domestic-level water governance framework can be established. Second, CGWR is a representative picture of the water-related processes in the Mountain-River-Forest-Farmland-Lake-Grassland-Desert (MRFFLGD) system and serves as a critical pivot to actualize the conservation and improvement of the MRFFLGD system. Finally, CGWR, together with inter-basin water resources transfer and virtual water transfer, forms a complete picture of China's inter-basin water transfer. The scientific coordination and integration of the three processes present a new approach for achieving spatial equilibrium between China's water resources and economic development.

As the third pole of earth, the Qinghai-Tibet Plateau is an important ecological security barrier in China and an ecologically sensitive area of global climate change. The increasing climate change has posed a major challenge to its ecosystem function and stability. This paper first analyzes the spatiotemporal variation characteristics of the ecosystem pattern of the Qinghai-Tibet Plateau and its key functions including water conservation, soil conservation, windbreak and sand fixation from 2000 to 2020, clarifies the regional differences in ecosystem functions and their importance, and further evaluates the stability of ecosystem functions. And there is no doubt that the stable state will lay a scientific foundation for the plateau to build an ecologically civilized highland and launch protection and restoration projects. The results show that: (1) From 2000 to 2020, the wetland area of the study area increased and the grassland area decreased significantly. The water conservation and windbreak and sand fixation capacity were improved, and the annual change rates were 3.57 m³/(hm²·a) and 0.23 t/(hm²·a), respectively. However, the overall soil conservation showed a downward trend with an annual change rate of -0.16 t/(hm²·a). (2) The core areas of water conservation, soil conservation and windbreak and sand fixation accounted for 12.7%, 13.9% and 14.2%, respectively. The core water conservation barrier areas were mainly located in southeast Tibet, Sanjiangyuan and Ruoergai. The core windbreak and sand fixation areas were concentrated in the central and western parts of the plateau, and the core soil conservation areas surrounded the plateau. (3) From 2000 to 2020, the water conservation, soil conservation, and wind protection and sand-fixation functions have shown relatively high stability in the southeastern and central parts of the plateau, while relatively weak stability in the western part of the plateau. Combining stability assessment and ecological protection and restoration practices, we can divide the Qinghai-Tibet Plateau into three major categories of 16 ecosystem function zones and carry out differentiated ecological protection and restoration for different core ecosystem functions and zones.

The continuous generalization of geographic information poses a huge challenge to the classic geographic information analysis modes. Networked knowledge services will gradually become a new mode for geographic information applications, facilitating to transform the form of geographic computing into social computing. Geographic knowledge services need to connect people, institutions, natural environments, geographical entities, geographical units and social events, so as to promote knowledge assisted data intelligence and computational intelligence. Facing the urgent need for spatiotemporal knowledge acquisition, formal expression and analysis, this paper firstly introduces the concepts and characteristics of spatiotemporal knowledge graph. The spatiotemporal knowledge graph is a directed graph composed of geographic spatiotemporal distribution or geo-locational metaphors of knowledge that is a knowledge graph centered on spatiotemporal distribution characteristics. Secondly we proposes a research framework for spatiotemporal knowledge graph. The framework includes various levels from multimodal spatiotemporal big data to spatiotemporal knowledge services that contain ubiquitous spatiotemporal big data layer, spatiotemporal knowledge acquisition technique layer, spatiotemporal knowledge management layer, spatiotemporal knowledge graph layer, software/tools layer, and industrial application layer. Thirdly this paper introduces relevant research progress from text implied geographic information retrieval, heterogeneous geographic semantic web alignment, spatiotemporal knowledge formalization and representation learning. Combined with application practice, we then enumerate the construction and application approaches of domain oriented spatiotemporal knowledge graph. Finally, it discusses the key scientific issues and technical bottlenecks currently faced in the research of spatiotemporal knowledge graph. It is argued that in the era of large models, constructing explicit spatiotemporal knowledge graph and conducting knowledge reasoning to meet domain needs is still the only way for spatiotemporal knowledge services.

According to the strategic direction of urban-rural integration and rural revitalization, the spatial reconstruction of rural settlement system is the spatial organization foundation of future urban-rural integration development. This paper focused on the hierarchical scale and spatial organization characteristics of the rural settlement system. It comprehensively revealed the evolution process and regional characteristics of rural settlement systems of 111 administrative units in Guangdong province from 1990 to 2020, and discussed their evolutionary mechanism and spatial optimizing and reorganizing regional modes. The results show that: (1) There were significant regional differences in the hierarchical scale distribution of the rural settlement system in Guangdong. The patches of rural settlements show the characteristics of concentric aggregation and distribution centered on the geometric barycenter of each administrative unit. The spatial distribution pattern of the rank cumulative size coefficients of rural settlement system was "high in the southwest, but low in the northeast" and "high in coastal areas, and low in the inland". The decreasing region of the rank cumulative size coefficient was concentrated on the east bank of the Pearl River Estuary and coastal areas of eastern Guangdong, while the increasing region was mainly distributed on the west bank of the Pearl River Estuary. (2) The influencing factors such as natural background, economic development, urbanization development, transportation and location, institutions and policies jointly drove the development and evolution of the rural settlement system. Rural settlement system of urban areas is small in scale in the mature stage of urbanization, which will gradually die out and integrate into the city. Driven by urbanization, industrialization and policies, rural settlement system of suburban areas has experienced survival of the fittest and maintains a stable scale, but the mixed distribution of urban and rural land makes the spatial organization of rural settlements increasingly loose. Driven by the continuous outflow of production factors, exurb rural settlements appear to be "hollowing out". The villagers returning to build new houses and the lack of homestead exit mechanism have led to a continuous and stable growth in rural settlement scale, and their spatial distribution is characterized by more peripheral diffusion. Rural settlement system with poor location in mountainous areas develops slowly under the support of policies, and the aggregation characteristic along the transportation line is significant. (3) Facing the integrated development of urban and rural spaces, four models of spatial optimization and reorganization of rural settlement system are proposed: urban-rural integration development, dual-core-driven development, central place hierarchical system development, and pan-center chain-connecting cluster development.

Subsurface stormflow is a special form of subsurface flow in the vadose zone of steep slopes in mountainous and hilly regions, and it is also one of the most important runoff generation mechanisms in the process of flash flood formation. However, the systematic summary on the scientific connotation, mechanisms, and disaster-causing characteristics of the subsurface stormflow in current research is very rare and this limits the development of the theoretical system of runoff generation, routing, and modeling methods of flash floods. Herein, we clarify the scientific connotation and definition of subsurface stormflow based on the division of the development periods of the subsurface stormflow research around the world as well as the analysis of physical processes for the runoff generation. Meanwhile, three physical conditions for the occurrence of subsurface stormflow, together with their influences on the nonlinear response process, are highlighted. The influences of the subsurface stormflow on the dynamic development of flash floods, landslides, and debris flow hazards are analyzed and summarized. Finally, three key research directions are proposed: water transport processes and hydrological connectivity mechanism of the macropores in the vadose zone, processes and mechanisms of water exchange at the geotechnical channel interfaces inside the slopes, and the formation mechanism for flash flood from multiple runoff generation processes with complex slope topography conditions. This work can provide new research perspectives for the formation mechanism and hydrological theoretical framework of flash floods in complex mountainous regions, and better support the national scientific and technological needs for flash flood forecast as well as disaster prevention and mitigation.

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.

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.

The study of the new economic geography has paid attention to the polarization and balanced development of urban systems. In reality, however, transport accessibility is subject to great uncertainty in explaining the polarization and balance of the urban system. In fact, the polarization or equilibrium of the regional urban system is not only unique in China, but also a general phenomenon in countries with different development outcomes, political systems and degrees of marketization. From the perspective of industrial heterogeneity, this study empirically analyzes the process and mechanism of the industrial structure of regional central cities on the population growth of neighboring cities in China from 1980 to 2020, and examines the influence of industrial structure on the polarization and equilibrium development of the regional urban system. The results show that, firstly, the manufacturing sector strengthens the spillover effect from the core city and promotes the population growth in neighboring cities, while the service sector weakens the spillover effect and hinders the growth in neighboring cities. Secondly, the manufacturing-oriented cities have relatively small city scale, while the service-oriented cities are relatively large. Therefore, the driving effect of manufacturing-oriented central cities on the neighboring cities is larger, which tends to produce a relatively balanced regional city system. Correspondently, the spillover effect of service-oriented central cities on the neighboring cities is smaller, which tends to form a relatively polarized regional city system. Finally, as the share of services in the industrial structure of central cities continues to rise, China's urban system may become more polarized rather than balanced. Certainly, the higher the proportion of manufacturing in the central city, the more balanced the regional urban system is. In fact, the empirical results show that the industrial structure and the spillover effect of the core city have an inverted U-shaped relationship, i.e. a high proportion of manufacturing or services weakens the driving effect of the core city on surrounding cities. The reasons for this vary. The high proportion of manufacturing and the small size of the central city have a limited spillover effect on the neighboring cities and therefore can hardly drive their growth; while the high proportion of service industry and the negative effect of the service industry on the spillover effect lead to the slow development of the neighboring small-and-medium-sized cities. It is worth noting that because of the significant spatial impact of industry on the urban system, the future regional urbanization strategy should be coordinated with the industrial strategy. More importantly, with the gradual liberalization of the household registration system, industry selection can become an effective policy option for macro-control of the regional urban system.

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.

Regional economic resilience is closely related to the state of the regional industrial structure. During the process of the region undergoing and recovering from external shocks, whether and how the spatio-temporal correlation between economic resilience and the evolution of the established industrial structure should be further explored. The micro and mesoscopic views of enterprises and industries, multi-year economic growth data, and enterprise status in the counties of the Beijing-Tianjin-Hebei region were employed to measure regional economic resilience at the county level and divide its economic development stages. In addition, a spatio-temporal correlation between regional economic resilience and industrial structure was appropriately tested, and the main industries affecting regional economic resilience were distinguished. Finally, the coupling mechanism of regional economic resilience and industrial structure evolution was analyzed. The major findings are as follows: (1) The periods of rapid and slow economic growth occur alternately in the study region, and the economic resilience shows a fluctuating growth trend. Meanwhile, central urban areas such as Beijing, Tianjin, and Shijiazhuang exhibited high economic resilience, and a typical center-periphery structure gradually took shape. (2) There was a significant spatial correlation between regional economic resilience and industrial structure. In economically developed regions, such as Beijing and Tianjin, the agglomeration of high economic resilience and high industrial structure was evident. There was a two-way causal correlation and consistency in time-series changes. (3) The industrial structure in the Beijing-Tianjin-Hebei region had gradually improved. Compared to the effect of industrial structure, the effect of competitiveness contributed more to economic resilience. Primary industries as well as those pertinent to consumer services and social services have played a pivotal role in improving regional resisting economic resilience. Besides, the development of consumer services and social services leads to the strengthening of the region's recovering economic resilience. (4) The evolution of the industrial structure achieved the evolution of the development path, which was revealed in the distinction of economic resilience at the county level. In addition, the coupling correlation between regional economic resilience and the evolution of industrial structure in the study region was mainly revealed in the time scale, which had not yet led to the fundamental restructuring of the regional spatial structure, and the center-periphery structure is still relatively significant.

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.

The rural human settlement is an indivisible part of the urban-rural human settlements, and it is also the comprehensive embodiment of the rural man-land relationship. Based on the theoretical framework of the formation of rural human settlement resilience and combined independent weight method and regression analysis, this paper builds an index system of the formation of rural human settlement resilience. This system comprehensively measured the rural human settlements in the Dongting Lake area and analyzes the spatial differentiation characteristics of resilience and its formation mechanism. The results show that: (1) There are evident spatial differences in the degree of resilience formation of rural human settlement in the study area. Resilience value varies based on the distance to the lake areas, the nearer the higher, the further the lower, which demonstrated the spatial differentiation characteristics of "inner high and outer low". (2) Based on the measured results of flexibility, adaptability and responsiveness, the resilience formation level in the Dongting Lake is divided into 3 ring belts in space: Huarong-Linxiang ring belt, Lixian-Pingjiang ring belt and Shimen-Heshan ring belt. (3) Rural human settlement is affected by the combination of exogenous and endogenous factors, which, in the form of mutation, continuation and transformation, have positive and negative effects on the resilience formation, so as to facilitate or not to facilitate the formation of rural human settlement resilience. On the basis of the geographical location, resource endowment, economic and social differences of three ring belts in the Dongting Lake, the corresponding strategies are put forward according to the principle of adapting to local conditions. In the process of optimizing rural human settlement, the monitoring, prediction and anti-disturbance capabilities of rural human settlements are enhanced, the resilience is continuously improved and the sustainable development of rural areas is promoted.

With the coming of digital economy era, the development and application of information technology revolution, such as 5G, cloud computing, big data, Internet of Things and artificial intelligence, production and living of human are being deeply affected. The data center is an important new infrastructure that integrates data storage, analysis, processing and application. It is increasingly important in the global data value chain and plays a strong supporting role in the global digital development. In this context, it is of great significance to clarify the multi-spatial scale expansion laws and location selection mechanism of global data centers, and layout them scientifically and reasonably. This paper integrates spatial statistics, spatial analysis, and spatial measurement methods, and conducts empirical research on the spatio-temporal differentiation and influencing factors of global data center expansion from 2005 to 2020. The results show that: (1) The spatial expansion trend of the global data center is obvious, and the growth center and the economic center move eastward, forming three major growth cores in North America, Western Europe, and East Asia. From the perspective of city scale, city clusters and metropolitan areas are the main spatial carriers of expansion, while a few cities such as Beijing, Tokyo, and Shanghai are the central hubs. (2) The spatial expansion characteristics of the data centers can be divided into contact expansion mode, point growth mode and agglomeration growth mode. (3) The location selection of data center spatial expansion is jointly affected by market size, element supply, and operating environment. However, the measurement method and spatial scale factors in selecting a country or a city are not completely consistent. From the perspective of global scale, market size is the most important factor, and the influence of element supply and operating environment show different stage characteristics; city scale is significantly affected by market size, element supply, and security level.

This study focuses on the Lower Yellow River (LYR), which has experienced continuous erosion since the operation of Xiaolangdi Reservoir in 1999, and its complex spatio-temporal variation process. Using the single-step mode of the Delayed Response Model (DRM), we derive a calculation formula for the accumulated erosion and deposition volume in the LYR. The coefficient of determination R² between the simulated and observed values from 2000 to 2020 is 0.99. Currently, the LYR is undergoing continuous erosion, but the erosion rate is gradually slowing down, and the difference between the equilibrium value and the calculated value of accumulated erosion and deposition volume gradually decreases, which means that the riverbed erosion is approaching equilibrium. Additionally, we derive a formula for the spatial distribution of main channel accumulated erosion volume per unit river length in the LYR based on the non-equilibrium suspended sediment transport equation. The coefficient of determination between the fitted value and observed value from 2003 to 2015 is about 0.98-0.99, with a relative error of approximately 6.2%. Our findings suggest that under the current conditions of decreasing sediment inflow and continuous scouring, it takes around 3.0 years for the riverbed to achieve half of the erosion and deposition adjustment and approximately 13.0 years to achieve 95% of the adjustment. Moreover, the spatial distribution of accumulated erosion volume in the LYR tends to become more uniform with the continuous development of erosion. These results provide valuable reference for analyzing the complex spatio-temporal variation process of the LYR.

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.

Rural area has abundant ecological resources. Ecological industrialization has become the emerging trends in rural areas and the new driving forces for rural revitalization. This study summarized the evolution of China's ecological environmental policies, and clarified the promotion mechanisms of regional ecological industrialization development to rural revitalization from the perspectives of ecosystem and human society, ecological products and economic development, ecological industrialization and rural revitalization, and discussed the models and pathways of poverty alleviation and rural revitalization by developing modern organic industry based on the regional ecological resources from the case study of Yangxian county in southern Shaanxi province. Three stages of China's ecological environmental policies were summarized, including "Focus on economy and light on environmental protection", "Environmental protection and scientific development" and "ecological civilization construction". Relationship between natural ecosystem and human social welfare reflects the objective needs of social and economic development and subjective initiative of human utilization of nature. The crucial ecological products and economic development was the engine of "nature-ecology-society-economy" in the core of benefits. The core of ecological industrialization and rural revitalization is the guarantee mechanism of "human-land-industry-right". Organic industry development is the typical model and important direction of ecological industrialization. In Yangxian county, the organic production paradigm of "product-industry-production area" promotes the transformation of organic practitioners from single subject management to multi-agent operation, and the transformation of land use type from resource optimal allocation to man-land coordination. In the future, coupling of ecological protection and socio-economic development can be realized by the model construction of modern organic agriculture and rural revitalization in Hanjiang River basin from the aspects of improving organic products quality and yield, enhancing organic industrial integration and value, reducing consumption and increasing efficiency in production areas.

Selecting 887 inter-provincial border counties in China as a research area, this paper constructs an evaluation index system incorporating five dimensions to measure the degree of urbanization that each county experienced from 2000 to 2019, describes characteristics of the evolution of urbanized spatial patterns combined with spatial autocorrelation analysis, uses geodetectors to identify the main factors influencing urbanization and interactive relationships, divides driving areas into types on the above basis, and proposes targeted suggestions. The results show that: (1) From 2000 to 2019, the urbanization level of China's inter-provincial border areas continued to increase, but the overall level remained low, and displayed a spatial distribution pattern of stepwise decline from east to central to west. (2) The urbanization level of counties on the inter-provincial border showed a significant positive spatial correlation. In terms of spatial distribution, HH-clustering counties formed a "T" pattern, and LL-clustering counties concentrated in the inter-provincial border areas of the northwest, northeast, and southwest. (3) Economic development and traffic level are the leading factors affecting the spatial pattern of urbanization in the inter-provincial border areas. (4) The spatial pattern of urbanization in the inter-provincial border areas results from the main factors directly driving economic development and determining transportation levels. In addition, medical care, social investment, and natural conditions also directly impact the spatial pattern of urbanization. Government behavior and educational services exert indirect effects. (5) Inter-provincial border areas are divided into six types with distinct patterns of leading driving factors: terrain element restriction, location traffic leading, economic development driving, social investment driving, public service lagging, and government leading. (6) Urbanization of inter-provincial border areas exerts a spatial nearest neighbor effect, and the urbanization level of counties close to urban agglomerations of developed regions is high. The marginality of urbanization space of counties in the inter-provincial border areas is prominent. In areas with more county borders in the inter-provincial areas, urbanization levels tend to be lower.

Ladakh is located in the northwest of the Qinghai-Tibet Plateau, the western section of the Himalayas, and the upper reaches of the Indus River valley. It is now part of Indian-controlled Kashmir. Since ancient times, Ladakh has been the "key point" from northwest South Asia to the Ngari Prefecture of Xizang and southern Xinjiang. However, most existing research on Ladakh focuses on its local history and culture. Although there are some related works on geopolitical relations, few have studied the historical changes of this region and its subordinate relationship and geographical value with China over a long time scale and analyzed the geographical significance of Ladakh. At the same time, some erroneous views and geographical maps have been disseminated on the Internet at home and abroad, which urgently needs a comprehensive correction from the academic level. Based on a variety of historical documents, map data, and a detailed review of previous research results, this paper demonstrates the changes in place names, historical evolution, and regional scope of Ladakh from the 1st to the 21st century and analyzes its significance in the homeland security of western China. The results show that: (1) As the native land of China's Xizang Ladakh was part of the Tubo Dynasty until the 9th century. After the collapse of the Tubo Dynasty in the middle of the 9th century, Ladakh was an essential part of the Ngari local administration established by the descendants of the Tubo Royal family. In the 13th century, Ladakh was again united within the territory of China's Yuan Dynasty and continued through the Ming and Qing dynasties. It remained until the mid-19th century when the Prince-state of Jammu in southern Kashmir invaded it and incorporated it into the British Indian colony. It was then occupied by the Indian army in 1947. (2) Ladakh region has a tortuous history with many changes in place names. However, when Jammu annexed it in modern times, Ladakh only referred to the upper reaches of Indus Valley between the Western Himalayas and the Karakoram Mountains, with Leh as the center. (3) The complexity of the historical and geographical processes in the Ladakh region makes it the central area of conflicts created by India in the western section of the China-India border. Therefore, China should adopt active strategies to avoid India's continuous "assimilation" policy.

As a product of certain type of social interaction, urban scaling laws assume that urban attributes such as urban economic outputs are largely determined by urban population size (internal interactions), implying the assumption of agglomeration economies. Urban population agglomeration represents a local network effect, while the global network effect on a larger spatial scale between cities should also be considered in terms of the improvement of social productivity. Taking 275 Chinese cities at prefecture level and above as the research object, we constructed an urban human mobility network by Baidu migration data and portraied the degree of external interaction by human mobility between cities. We comparatively analysed the non-linear relationship between population size within cities and external interaction and urban economic outputs under the urban scaling framework. Results show that there is a significant super-linear scaling relationship between urban economic output and external interaction, revealing the higher multiplier effect of external interaction on urban economic outputs. The role of network spatial interaction cannot be ignored and it has become an important complement to agglomeration economies. Further, indicators such as urban population density, agglomeration and network externalities are introduced to quantitatively and comprehensively measure the effects of urban population agglomeration and interurban population mobility and their synergistic effects on urban economic outputs. The agglomeration effect brought about by urban population size remains the main driver of regional economic development, and the ability of cities to benefit from exchange and cooperation on a larger spatial scale has yet to be enhanced. This study contributes to fully understanding the origins of urban scaling laws from taking both internal and external interaction into consideration, deepening the recognization of the agglomeration effect and network effect of regional economic growth. This paper is supposed to support for promoting high-quality integrated urban development and deepening the practice of coordinated regional development.

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.

Danxia landscapes are a landscape feature with the Danxia landform as the main body, and are widely distributed in China. An in-depth understanding of the landscape differentiation on a national scale is essential for the protection and utilization of Danxia landscapes as tourism resource. Based on data such as lithology, cliff height, stratum attitude, rock strength, and other data, this study quantitatively analyzes the spatial pattern of Danxia landscapes. Combining these data with the understanding from an on-site survey of more than 200 Danxia landforms across the country, the differentiation of Chinese Danxia landscapes is semi-quantitatively determined. Based on multiple geologic and geomorphologic factors, the Danxia landscape in China is divided into six distinctive regions: Southeast China, the Sichuan-Chongqing-Guizhou junction, the Ordos Plateau, the southwestern Ordos Basin, "Tianshan-Qilian", and the Qinghai-Tibet Plateau. Through the national-scale comparison of Danxia landscapes, six key characteristics are noted. The basin size of red-bed deposits and the crustal uplift and subsidence during the Himalayan movement jointly controlled the spatial distribution of the Danxia landforms, while the tectonic deformation characteristics in different regions controlled the inclination of strata. The spatial lithological differences among different types of the basins affect the slope morphology. Rock strength has little effect on cliff height, but the difference in vertical rock strength affects the slope shape, which in turn affects the geomorphological process. The landform evolution stages affect the richness of individual and group landscapes. Finally, climate influences the currently active geomorphic processes, and the combination of vegetation and landforms in different climate zones shapes different Danxia landscape features and aesthetics. Nationally, the spatial distribution of Danxia characteristics is a regional manifestation of tectonic evolution, Earth's surface environment, and other factors.

China has entered the stage of transformation from a "demographic dividend" to a "talent dividend", and talent has increasingly become the key driver of national and regional development in the era of a knowledge economy. As the reserve of talents, university graduates are the main target of the "war for talent" among Chinses cities. Based on the 2019 Graduate Employment Quality Reports of China's "double first-class" universities, adopting the Gini coefficient, spatial autocorrelation, and spatial econometric interaction model, this paper demonstrates the migration pattern of "double first-class" university graduates upon their graduation and investigates its underlying influencing factors. The results reveal that the destination areas of university graduates from "first-class universities" and "first-class disciplines" are highly concentrated in eastern China, with the former showing a higher concentration level. While economic factors still play a vital role in determining the migration of university graduates, the influence of quality of place is also significant, especially for graduates from "first-class universities". In addition, the policy factors also significantly influence the migration pattern of graduates from both types of universities. There are significant network autocorrelation effects among graduates' employment migration flows. The network autocorrelation effects based on places of study and places of employment are significantly positive. These network autocorrection effects reinforce the uneven distribution pattern of university graduates' migration. This study highlights the importance of employing a regional coordination perspective rather than a single-region perspective in terms of the formation and further optimization of regional talent policies.

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.