As the world’s largest developing country, the ability of China’s agricultural resource utilization to effectively support the current and future food security goals has been affected by a variety of factors (e.g., transformed supply channels, tightening international situation and frequent emergencies) in recent years and has attracted extensive attention from the academic community subject to multiple factors. This study uses literature review, statistical analysis, and spatial analysis methods to systematically explore China’s food security situation in the context of farmland resource constraints. It is found that the demand-side pressures such as demographic changes, social class differentiation, and dietary structure adjustments derived from economic growth and rapid urbanization have placed extremely high expectations on food supply. However, the quantitative restrictions, utilization ways, and health risks of farmland resources on the supply side constitute a huge hidden concern that affects the stability of food production. Although China’s farmland protection system is undergoing a transition from focusing on quantity management to sustainable use, the matching and coordinating demand pressure and supply capacity for food security is unbalanced. Therefore, facing uncertain future development scenarios, policymakers should focus on building a resilient space for China’s farmland protection to withstand the interference of major emergencies. The existing farmland protection space policy can be integrated by establishing a national farmland strategic reserve system (based on resilient space), and further development of targeted use control measures for zoning, grading, and classification will help realize sustainable China’s farmland resources use.

Exploring the spatio-temporal variations of farmland landscape patterns in a traditional agricultural region can provide scientific support for decision-making on sustainable rural land use and rural vitalization development. This study established a comprehensive evaluation index for farmland fragmentation with multiple aspects (dominance, integrity, aggregation, regularity, and connectivity) at the county scale. The goal was to identify the evolution of farmland fragmentation in the traditional agricultural region of the Huang-Huai-Hai Plain during 2000-2015 and investigate underlying drivers using panel data of 359 counties. Results showed an accelerating but fluctuating fragmentation pattern of the farmland landscape. The indexes of dominance, integrity, and aggregation of farmland decreased most sharply, while the index of connectivity increased. Furthermore, the evolution of the farmland fragmentation pattern showed significant spatio-temporal heterogeneity, which is similar to the trajectory of urbanization and land use transition. Farmland fragmentation in municipal districts also emerged earlier and was more severe than in county-level cities and counties. Factors influenced by advancing urbanization include the proportion of artificial land, population density, and proportion of primary industry; these factors drove the evolution of farmland fragmentation. In contrast, the increase in income of rural residents and production efficiency of farmland were the key factors contributing to the improvement in farmland connectivity.

Since the implementation of the Development of Western Regions in 2000, a series of major ecological construction projects have been implemented, leading to a series of changes in the ecological conditions and ecological services of western China. This study calculated the amount of ecosystem services in total in the western region from 2000 to 2019, and analyzed ecological changes and the characteristics of spatio-temporal variations in ecological services. A relevant analysis method was applied to explore the tradeoff and synergy of service. It was found that the area of settlements and wetland ecosystems in the western region increased significantly from 2000 to 2015, whereas grassland showed a downward trend year by year. The vegetation fraction showed a decreasing belt-like distribution from south to north. It showed a fluctuating increase during 2000 to 2019, with inter-annual and large spatial differences. The water conservation service (WCS) had a slight downward trend from 2000 to 2019, and the main decreasing areas were distributed in southeastern Tibet, the western part of the Three Rivers Source region, and the karst rocky desertification area. The soil conservation service (SCS) showed an increasing but fluctuating trend, with the greatest increases observed in the Loess Plateau region, western Sichuan and Yunnan, northwest Tibet, and southeast Tibet. The windbreak and sand fixation service (SFS) showed a downward trend, and the sharp decline was mainly in the central and western parts of Inner Mongolia, Tibet and parts of northern Xinjiang. Ecosystem supply and WCS, and SCS were mainly synergistic, which were found in areas north of the Qinling Mountains-Huaihe River (QM-HR) line, especially in Ningxia and Inner Mongolia. Ecosystem supply was mainly tradeoffs with SFS, and it was found in the agriculture-pastoral transition zone. The synergistic degree of ecosystem services in areas subjected to ecological engineering policy was greater than that in non-engineering areas. Quantitative assessment of ecosystem service changes and their tradeoffs is helpful for scientific ecological management and maximizing ecological benefits.

Spatial models are effective in obtaining local details on grassland biomass, and their accuracy has important practical significance for the stable management of grasses and livestock. To this end, the present study utilized measured quadrat data of grass yield across different regions in the main growing season of temperate grasslands in Ningxia of China (August 2020), combined with hydrometeorology, elevation, net primary productivity (NPP), and other auxiliary data over the same period. Accordingly, non-stationary characteristics of the spatial scale, and the effects of influencing factors on grass yield were analyzed using a mixed geographically weighted regression (MGWR) model. The results showed that the model was suitable for correlation analysis. The spatial scale of ratio resident-area index (PRI) was the largest, followed by the digital elevation model, NPP, distance from gully, distance from river, average July rainfall, and daily temperature range; whereas the spatial scales of night light, distance from roads, and relative humidity (RH) were the most limited. All influencing factors maintained positive and negative effects on grass yield, save for the strictly negative effect of RH. The regression results revealed a multiscale differential spatial response regularity of different influencing factors on grass yield. Regression parameters revealed that the results of Ordinary least squares (OLS) (Adjusted R² = 0.642) and geographically weighted regression (GWR) (Adjusted R² = 0.797) models were worse than those of MGWR (Adjusted R² = 0.889) models. Based on the results of the RMSE and radius index, the simulation effect also was MGWR > GWR > OLS models. Ultimately, the MGWR model held the strongest prediction performance (R² = 0.8306). Spatially, the grass yield was high in the south and west, and low in the north and east of the study area. The results of this study provide a new technical support for rapid and accurate estimation of grassland yield to dynamically adjust grazing decision in the semi-arid loess hilly region.

In arid and semi-arid environments, desert vegetation plays an important role in preventing soil erosion by wind and helps maintain the stability of desert and oasis ecosystems. Four types of typical desert vegetation, namely Populus euphratica, Haloxylon ammodendron, Nitraria sibirica, and Halostachs caspica, corresponding to different habitats (i.e., river bank, sand dune, desert, and salt marsh) were chosen as the model vegetation in this research. The δ²H and δ¹⁸O for rainwater, soil water, and plant water were applied to identify the water sources and quantify the proportions of different water sources used over the entire plant growth period (from March to October). The results showed that the precipitation δ²H and δ¹⁸O in the Ebinur Lake basin varied from -142.5‰ to -0.6‰ and from -20.16‰ to 1.20‰, respectively. The largest δ²H and δ¹⁸O values occurred in summer and the smallest in winter. The soil water δ²H and δ¹⁸O of the four habitats decreased gradually with increasing depth. The δ²H and δ¹⁸O values of water extracted from the stems of the four plants had similar variation trends, that is, the maximum was observed in spring and the minimum in summer. Among the four plants, H. caspica had the highest stable isotopic values in the stem water, followed by N. sibirica, H. ammodendron, and P. euphratica. The water sources and utilization ratios of desert vegetation varied across different growth stages. Throughout the growing period, H. ammodendron mainly used groundwater, whereas the water source proportions used by N. sibirica varied greatly throughout the growing season. In spring, plants mainly relied on surface soil water, with a contribution rate of 80%-94%. However, in summer, the proportion of deep soil water used was 31%-36%; and in autumn, the proportion of middle soil water used was 33%-36%. H. caspica mainly relied on topsoil water in spring and autumn, and the proportion of soil water in the middle layer slightly increased to 20%-36% in summer. P. euphratica mainly used intermediate soil water in spring with a utilization rate of 53%-54%. In summer, groundwater was the main source, with a utilization rate of 72%-88%, and only 2%-5% came from river water, whereas in autumn, the river water utilization rate rose to 11%-21%. The results indicated that there were significant differences in water use sources during the growing period for desert vegetation in arid areas. This research provides a theoretical basis for understanding water use mechanisms, water adaptation strategies, and vegetation restoration and management in arid areas.

A scientific delineation of geographical boundaries reflects the cognitive level of scientific abstraction and systematic analysis of the spatial variation of geographical objects and is a basic scientific issue of geography. From the perspective of earth system science, this study first explicates the core issues (e.g., basic concepts, scientific contents, and basic properties) of geographical boundaries. Based on the principles of scientificity and systematicness, we then classify geographical boundaries in terms of intrinsic mechanisms, extrinsic appearance and scientific attributes. Furthermore, this paper analyzes the mathematical connotation and representation methods of geographical boundaries, discusses the characteristics of and differences between traditional and modern methods for geographical boundary delineation. Finally, we present a framework for a “geographical boundary model” with an integration of qualitative, quantitative, and positioning methods. Focusing on geographical boundary (a basic theoretical problem in geography), this study engaged in concept definition and method analysis, with the findings enriching the theory and methodology of geographical information science.

There are debates regarding whether a wet and warm climate or a dry and cold climate dominated Holocene fire activity in northern China on the millennial timescale, and when human activities overtook climate change as the dominant control on fire occurrence in the region. Here we present a high-resolution fire history for the past ~15,500 years from a sediment core in Dali Lake, located in the foothills of the Greater Hinggan Mountains, one of the areas of highest fire risk in China. The results demonstrate that fire activity was rare during the last deglaciation (~15,500-11,700 yr BP), gradually increased at the beginning of the Holocene, and reached its highest level during ~9000-5000 yr BP, after which there was a decreasing trend. However, after ~2000 yr BP this decreasing trend ended, and the most prominent feature is a peak in fire activity during the Medieval Warm Period (MWP). Overall, fire activity corresponded well to changes in the East Asian summer monsoon (EASM) precipitation on the millennial timescale during ~15,500-2000 yr BP, but this relationship changed after ~2000 yr BP. We propose that fire activity in northern China on the millennial timescale during ~15,500-2000 yr BP was dominated by the biofuels reserve under the control of the EASM precipitation. In contrast, with the intensification of human activities after ~2000 yr BP, human activity caused a ~62%-73% increase in fire activity, which altered the fire-climate relationship that had previously prevailed in northern China. Our results indicate that a wet-warm climate (increased EASM intensity), rather than a dry-cold climate, was the dominant control on fire activity in northern China during 15,500-2000 yr BP on the millennial timescale, but that human activities played an important role in fire occurrence after ~2000 yr BP.

The lower reaches of the Minjiang River and its adjacent areas were among the most active prehistoric archaeological areas in Fujian Province. The accumulation types of Neolithic archaeological strata are roughly divided into dune sites and dune/shell mound sites. The sites can also be roughly divided into estuarine, coastal, and sea-island sites based on their geomorphic features. The cultural development of these prehistoric sites is of great significance for understanding the migration and spread of Austronesian civilization. Based on luminescence dating of typical Neolithic sites on Haitan Island, their quartz-OSL (optically stimulated luminecesence) burial ages were determined. Synthesizing previously published results, the temporospatial distribution characteristics of the sea-island sites on Haitan Island are discussed, and the relationship between Neolithic human activities and regional geomorphic processes is analyzed. The results show that: (1) the spatial and temporal distribution of the Haitan Island Neolithic sites are closely related to small-scale geomorphic features and are controlled by mesoscale geomorphic processes. The sites were mainly distributed in the foothills of two high hills along an NNE-SSW trend. With an increase in altitude, the features were distributed as “single site (I) - superimposed site - single site (II)” and appear successively. Single type sites (I) mainly appeared at low sea level, whereas single type sites (II) mainly appeared at high sea level. Superimposed sites were not subject to sea level changes. The relative elevation of the superimposed sites in the study area indicates the optimal residential area for human activities in the region. The single site with an elevation lower than the optimal residential area was mainly restricted by the lowest residential area, whereas the single site at a higher elevation than the optimal residential area was mainly affected by livelihood patterns. (2) High sea level caused by the “backwater effect” in low latitude areas in the southern hemisphere, and coastal aeolian sand activity influenced by sea level fluctuations in the middle Holocene correspond well with human activities recorded in the cultural stratigraphy of sea-island type sites. The altitude of coastal aeolian sand accumulation can be used as an indirect index to estimate the age of coastal dunes.

Automated image classification and visual interpretation of Landsat imagery were used to extract the glacier boundary in the Nujiang-Salween River Basin (NSRB) around the years 1975, 2000, and 2020. The spatiotemporal characteristics of glacier area changes in the NSRB were determined and the reasons for the spatial heterogeneity in glacier area changes were discussed, based on comparative analyses of temperature and precipitation data from meteorological stations around the NSRB. The results indicate that 1) the total glacier area in the NSRB decreased by 477.78 km² (28.17%) at a rate of -0.62%/a in 1975-2020. Most shrinkage occurred at low and mid altitudes, with the most severe occurring at 5290-5540 m, accounting for 40% of the total shrinkage. Considering other river basins in China, the relative glacier area change rate in the NSRB was similar to that for typical inland river basins in northwest China but lower than that for other transboundary river basins in the southeastern Tibetan Plateau. 2) These areal changes in the NSRB presented obvious regional differences. The glaciers in the Hengduan Mountains retreated significantly, followed by those in the Nyainqentanglha Mountains, with relatively low shrinkage observed in the Tanggula Mountains. The number of cold and hot spots indicating areal changes increased after 2000, along with their spatial heterogeneity. 3) The glacier shrinkage rate over different time intervals was positively correlated with temperature. Thus, spatial heterogeneity of climate change effects could elucidate differences in the glacier area change rate in different regions of the NSRB. The temperature rise was determined as the primary reason for the significant glacial retreat over the past 45 years. As the significant warming trend continues, the glacier area in the NSRB is likely to shrink further.

This paper examines the rise of informal economies in China, a hidden driving force overlooked in studies on China’s urbanization. Estimating the size of informal economies using the multiple indicators multiple causes model, the paper employs mathematical models to examine the driving effect of informal economies on urbanization and to reveal the paths by which such effect works. The results were as follows. (1) In 2018, the size of the informal economy in China accounted for 23.5% of GDP with an output value of 21.16 trillion yuan. (2) The informal economy had a driving effect on China’s urbanization, and every 1-percentage- point increase in its share of the GDP led to an increase of 0.291 percentage points in the urbanization rate. (3) The informal economy’s effect on urbanization showed regional differences, decreasing in size from the eastern to the central to the western regions. (4) The informal economy drives urbanization through four paths - by promoting foreign direct investment (FDI), fixed asset investment (FAI), social consumption (SC), and secondary sector employment (SSE). Their effect sizes are ranked in descending order as follows: FDI > FAI > SC > SSE. This paper contributes to theories on urbanization dynamics and process in China by highlighting the role of the informal economy as a hidden economic power lurking in the city.

Global urbanization has led to drastic land use change, interfering the ecosystem services (ES) supply-demand balance, in turn threatening the well-being of humans. However, existing studies mainly stranded at the historical and current analysis, and the effects of urban spatial expansion on the relationship between ES supply and demand in the future are less clear, in particular at an urban agglomeration scale. This study was constructed with a framework of assessing the effects of urban spatial expansion on ES supply-demand mismatching under different future scenarios in the Guanzhong Plain Urban Agglomeration (GPUA) by using the Future Land Use Simulation (FLUS) model and expert-based Land-Use and Land-Cover Change (LUCC) matrix. The results showed that: (1) Urban expansion is significant in the natural development (ND) scenario, mainly manifesting the great transfer of dry land to construction land. (2) The gap between total ES supply and demand is narrowed from 2000 to 2030 and the mismatch between ES supply and demand is mainly reflected in the spatial distribution pattern in the GPUA. The ES budgets were in high surplus in Northern Qinling Mountains and northeast mountain areas, while they were in severe deficit in urban center areas. The budgets deficit under the ND scenario in 2030 is the most severe. (3) The gradient differences of ES budgets of the GPUA between urban centers and suburbs increase from 2000 to 2030 under two scenarios. The deficit region expands largest under ND scenario. The findings revealed that ES declining and supply-demand mismatching were triggered by the drastic land-use change driven by rapid urban expansion. The expansion has brought about an increasing material demand and growing industries, threatening the sustainability of ecosystems. Scenarios setting could contribute to coordinating the relationship between future urban development and ecological protection, and the policy strategies proposed in the study could inform ecological management and urban planning in the regions facing the similar urbanization situation.

Accelerating economic growth in formerly destitute areas and narrowing the economic gap with other regions are essential tasks for poverty alleviation in China after 2020. In this study, the spatio-temporal characteristics of economic growth in 14 formerly destitute areas of China were identified. Moreover, the spatial heterogeneity of various influencing factors was analyzed using a geographically weighted regression model. The results were as follows: (1) The economic level of the formerly destitute areas was low, but their economies grew rapidly after 2011, with annual per capita GDP growth of 10.54% until 2018, higher than the national average of 9.14%. Western and southern counties grew faster economically than central and northern counties. (2) The impact of various factors on the economic growth of counties exhibited clear spatial heterogeneity. The influences of secondary industry growth and level of financial development on economic growth were mainly positive, whereas the effects of initial economic level and market location were mainly negative. (3) Six economic growth driving modes were identified for the 14 contiguous destitute areas, among which the secondary industry-driven mode was the most common. The study can serve as a scientific reference for differentiating regional policies.

It is of great theoretical and practical importance to carry out research on the spatio-temporal evolution of urban air pollution and its driving forces, which helps to facilitate a deeper understanding of the mutual feedback mechanisms between the urban environment and socio-economic systems. Comprehension of these mechanisms will contribute to the design and implementation of efficient environmental policies that ultimately will improve the quality of urbanization development. This paper illustrates the spatio-temporal evolutionary characteristics of six urban ambient air pollutant concentrations, namely, CO, NO₂, O₃, PM₁₀, PM_2.5, SO₂, in 286 sample cities above the prefecture level in China from 2014 to 2019. The interactions between the pollutant concentrations are analyzed based on panel regression models. A random forest model is then employed to explore the correlations between the concentrations of these six pollutants and 13 natural and socio-economic impact factors to isolate the most crucial ones. The results reveal three aspects. First, within the research period, the average annual concentration of O₃ increased while that of other pollutants decreased year by year. Second, there were significant interactions between concentrations of the six pollutants, leading to obvious compound air pollution in urban areas. Third, the impact of natural and socio-economic factors on urban air quality varied greatly among different air pollutants, with air temperature, vegetation coverage, urbanization level and traffic factors ranking high and the different response thresholds to the dominant influencing factors. In light of the limited ability of humans to control the natural environment and meteorological conditions, it is recommended that urban air quality be further improved by optimizing urban density, controlling anthropogenic emission sources, and implementing strict air pollution prevention and control measures.

The geospatial distribution pattern in traditional Chinese settlements (TCSs) reflects the traditional harmony between humans and nature, which has been learned over centuries. However, TCSs have experienced serious disturbances by urbanization and migration. It is crucial to explore the local wisdom of geospatial patterns and dominant factors for TCSs at the national scale in China. This study sought to determine the geospatial wisdom of traditional settlements to enrich our future settlement development with the aim of establishing Chinese settlement values for modern living. Herein, a dataset of 4000 TCSs were analyzed and clustered for environmental factors that affect their geospatial patterns by machine learning algorithms. We concluded that (1) five geospatial patterns of TCSs were clustered on a national scale, and the threshold of environmental factors of TCS groups was detected. (2) Environmental conditions and settlement concepts interacted and determined the similarities and differences among TCS groups. (3) The key boundary for TCSs and the dominant factors for each zone were determined, and topographical conditions and hydrologic resources played significant roles in all five TCS zones. This study provides a better understanding of the adaptability of the environment in relation to the TCSs and aids in planning TCS conservation and rural revitalization.

Satellite technologies provide valuable areal precipitation datasets in alpine mountains. However, coarse resolution still limits the use of satellite precipitation datasets in hydrological and meteorological research. We evaluated different time scales and precipitation magnitudes of Tropical Rainfall Measurement Mission 3B43 V7 (TRMM) and Global Precipitation Measurement (GPM) products for alpine regions using ground precipitation datasets from January 2015 to June 2019 obtained from 25 national meteorological stations and 11 sets of T-200B weighing precipitation gauges in the Qilian Mountains. The results indicated that GPM outperformed TRMM at all temporal scales at an elevation <3500 m with a higher probability of detection (POD), false alarm ratio (FAR), and frequency bias index (FBI) and performed best at 3000 m; TRMM performed better than GPM at an elevation >3500 m, with the best performance at 4000 m. GPM and TRMM had the best estimation accuracy in areas with monthly precipitation of 30 mm and 40 mm, respectively. Both TRMM and GPM products underestimated mid to large daily precipitation and overestimated light daily precipitation averaging <2 mm/d. This research not only emphasizes the superiority of GPM/TRMM in different regions but also indicates the limitations of precipitation algorithms.

Submarine cable network is one of the most important connectivity infrastructures in the digital era. In the past 20 years, the submarine cable network of Chinese mainland has formed a complex connectivity structure. This paper focuses on exploring the structure and evolution of the submarine cable network of Chinese mainland. The results show that the evolution can be divided into four stages: an initial stage (1993-1998), a developmental stage (1999-2002), a stagnation stage (2003-2015) and an accelerated stage (2016-2018). The connectivity structure can be analyzed at micro, meso and macro scales. Statistically, the connectivity increased significantly overall, but showed significant differences in space. For the microscale, the landing cities were characterized by “extensive but low, exclusive and high”; for the mesoscale, the connectivity of countries or regions was characterized by “distance attenuation” as a whole, but, in part, by a “regional identity”; for the macroscale, intercontinental connectivity differences have been declining. The hierarchy has been upgraded from a “3 system” to a “2 + 3 system”. Finally, this paper discusses the interaction between submarine cable network construction and international relations, and puts forward policy suggestions for China’s submarine cable construction.

National parks are useful entities for looking at coordinated efforts to improve the Tibetan Plateau’s function as an ecological safety barrier and the region’s green development. Research on the characteristics of the function structures of the Tibetan Plateau’s national parks is vital to promoting their systematic and coordinated development. This paper combines the pressure-state-response model, the rank-size rule and a coupling and coordination model to identify and evaluate the functions of national parks on the Tibetan Plateau and to analyze the categories, hierarchy and structures behind those functions. The results indicate the following: (1) The Tibetan Plateau National Park Cluster needs to maintain internal and external relations. Internally it needs to rationally allocate resources between ecological protection, recreation and community development, and externally it needs to promote its role as an ecological security barrier and promote regional green development by rationally ranking and organizing the individual national parks, so as to handle their co-evolution of functions at multiple scales. (2) Ecological protection, recreation and community development are the most prominent functions of the Tibetan Plateau National Park Cluster, but there is scope to develop their scientific research and education functions. The Zipf index shows that their multi-functional level conforms with the rank-size rule, indicating balanced development. Individual national parks need to strengthen their optimal functions according to their characteristic localization. (3) The degree of coupling between the functions of the Tibetan Plateau National Park Cluster is 0.7809, and the degree of coordination is 0.6227, which indicates a very strong coupling and moderate coordination. The coupling strength and degree of coordination between the multiple functions vary greatly among the individual national parks, which reflects their different function structures. There are four function structure types: fully coordinated, optimally developed, moderately developed and moderately underdeveloped. This study contributes to research on evaluating the functions of national park clusters and analyzing their structures, and it serves as a reference on optimizing and sustainably developing the Tibetan Plateau National Park Cluster.

The trade-offs and synergies of forest ecosystem service are important research topics for several disciplines. The multi-scale analysis of service trade-offs and synergies assists in the implementation of more effective forest resource management. Based on multi-source data including forest distribution, topography, NDVI, meteorology and soil conditions, key forest ecosystem services, including total forest volume, carbon storage, water yield, soil retention and habitat quality were mapped and evaluated for the Funiu Mountain Region through integrated deployment of the CASA model, the InVEST3.2 model and the ArcGIS10.2 software. The characteristics of trade-offs and synergies among different ecosystem services were then mapped and considered across multiple spatial scales (i.e., by region, north and south slopes, vertical belt) using the spatial overlay analysis method. The main results are as follows: (1) Mean forest volume is 49.26 m³/ha, carbon density is 156.94 t/ha, water yield depth is 494.46 mm, the unit amount of soil retention is 955.4 t/ha, and the habitat quality index is 0.79. (2) The area of forests with good synergy is 28.79%, and the area of forests with poor synergy is 10.15%, while about 61.06% of forests show severe trade-offs and weak trade-offs. The overall benefits of forest ecosystem services in the study area are still low. In the future, bad synergy and severe trade-off areas should be the focus of forest resource management and efficiency regulation. (3) Synergy between ecosystem services is better for forest on south slope than that on north slope. Deciduous broad-leaved forest belt at moderate elevations on south slope in the mountains (SIII) has the highest synergies, while that at low elevations on north slope (NI) exhibits the lowest synergy levels.

Vegetation plays an important role in the dry deposition of particles with significant spatial variability, but the magnitude remains unclear at the global scale. With the aid of satellite products, this study estimated the vegetation-related dry deposition of fine particulate matter (PM_2.5). Methodologically, dry deposition was first calculated using an empirical algorithm. Then, deposition on the leaf surface was estimated to evaluate the influence of vegetation. Our results showed that the mean deposition velocity (V_d) of global PM_2.5 was 0.91×10^?3 µg·m^?2·s^?1, with high velocities observed in sparsely vegetated regions because of the high friction velocity. Under the combined effect of the PM_2.5 mass concentration and deposition velocity, the global mean dry deposition reached 0.47 g·m^?2·yr^?1. Global vegetation absorbed 0.26 g·m^?2·yr^?1 from PM_2.5 pollution sources, contributing 54.98% of the total dry deposition. Spatially, vegetation-related dry deposition was high in the Amazon, Central Africa and East China due to dense vegetation coverage or serious pollution. Temporally, the increasing trends were mainly in Central Africa and India because of worsening air pollution. The results of this study helped to clarify the impact of vegetation on air pollution, which supported related land management and planning for air quality improvement.

Patent transfer has been regarded as an important channel for the nations and regions to acquire external technology, and also a direct research object to depict the relationship between supply and demand of technology flow. Therefore, based on traceable patent transfer data, this article has established a dual-pipeline theoretical framework of transnational-domestic technology transfer from the interaction of the global and local (glocal) perspective, and combines social networks, GIS spatial analysis as well as spatial econometric model to discover the spatial evolution of China’s transnational technology channels and its determinant factors. It is found that: (1) The spatial heterogeneity of the overall network is significant while gradually weakened over time. (2) The eastward shift of the core cities involved in transnational technology channels is accelerating, from the hubs in North America (New York Bay Area, Silicon Valley, Caribbean offshore financial center, etc.) and West Europe (London offshore financial center etc.) to East Asia (Tokyo and Seoul) and Southeast Asia (Singapore), which illustrates China has decreased reliance on the technology from the USA and West Europe. (3) The four major innovation clusters: Beijing-Tianjin-Hebei region (Beijing as the hub), Yangtze River Delta (Shanghai as the hub), The Greater Bay Area (Shenzhen and Hong Kong as the hubs) and north Taiwan (Taipei and Hsinchu as the hubs), are regarded as global technology innovation hubs and China’s distribution centers in transnational technology flow. Among those, Chinese Hong Kong’s betweenness role of technology is strengthened due to linkage of transnational corporations and their branches, and low tax coverage of offshore finance, thus becoming the top city for technology transfer. Meanwhile, Chinese Taiwan’s core position is diminishing. (4) The breadth, intensity, and closeness of domestic technology transfer are conducive to the expansion of transnational technology import channels. Additionally, local economic level has positive effect on transnational technology transfer channels while technology strength and external economic linkage have multifaceted influences.

With the rise of smart phones, mobile applications have been widely used in daily life. However, the relationship between individuals’ mobile application usage and cities’ economic development has yet to be investigated. To study this question, this work utilizes a dataset containing users’ history of mobile application usage records (MAURs) and investigates how MAURs are related to Chinese cities’ economic development. Our analysis shows the cities’ GDP and number of MAURs are highly correlated, and at the individual level, people in wealthier cities (higher GDP per capita) tend to have more active mobile application usage (MAURs per capita). The results also demonstrate the relevance between cities’ GDP and MAURs varies significantly among different demographic groups, with male users’ relevance consistently higher than female users’ and working-age people’s relevance higher than other age groups. A boosted tree regression model is then applied to predict cities’ GDP with MAURs and proves to achieve high goodness-of-fit (over 0.8 R-square) and good prediction accuracy, especially for the economically developed and populous regions in China. To the best of our knowledge, this is the first time that the relationship between MAURs and cities’ economic development is revealed, which contributes to novel knowledge discovery for regionalization and urban development.

High-quality industrial development (HID) is a requirement of the modern economy and regional development. This paper designed a four-dimensional HID evaluation framework according to the logic of “development foundation-development theme-development subject-development guarantee.” Specifically, momentum cultivation as the foundation, efficiency improvement as the theme, and quality promotion as the subject are the three pivots driving the industrial transformation from high-speed development to high-quality development. A stable economic environment and a harmonious social environment are the guarantees of HID. Choosing the π-shaped Curve Area of the Yellow River basin in China as the study area, this paper measured the spatiotemporal pattern of HID and its four dimensions using the entropy-weighted TOPSIS method based on relevant economic indicators. Besides, the obstacle recognition model was adopted to identify the obstacles to HID. Findings include: From 2005 to 2019, the HID in the Curve Area was characterized by spatial unevenness and relative stability. The industrial structure and industrial layout were more rational in provincial capitals and large cities than in other cities. The spatial organization of the industrial economy presented an incompact polycentric structure, and the industrial association was relatively weak in the curve’s upper reaches. Almost all cities have experienced an increase in single-factor productivity, and technological progress contributed most to the total factor productivity growth. During the study period, the development momentum stabilized at high levels in Inner Mongolia while at low levels in resource-based cities. The development environment in most cities has remained stable, and the social welfare has increased and distributed more equitably in the Area. The technological introduction and the rationalization of the industrial structure were the primary obstacle factors for the Area in realizing HID, and the upgrading of the industrial location index was critical to the upper reaches of the curve. This paper was expected to provide new ideas for studying industrial transformation and practical policy proposals for regional development in the Curve Area.

Over the past 20 years, China has experienced multiple economic transitions characterized by marketization, globalization, decentralization, and urbanization; as a result, urban land development intensity (ULDI) has become a significant issue for sustainable development. As China’s largest globalized urban area, the rapid socio-economic development of the Yangtze River Delta has created a huge demand for urban land. We apply a theoretical framework for a four-dimensional analysis tool to understand the dynamic evolution of the ULDI in the context of economic transition. It reveals that marketization, globalization, decentralization, and urbanization affect the ULDI in the economic transition of Yangtze River Delta. Marketization, especially the continuous improvement of land marketization, optimizes the spatial allocation of land resources and encourages urban land users to improve ULDI. Globalization promotes the rapid growth of economy and population through an increase in foreign direct investment. In the process of decentralization, local governments rely on developing a mode of land finance, resulting in a disordered urban space and low ULDI. Population growth and agglomeration during urbanization stimulates residents’ consumption capacity and promotes economic growth, thus creating a greater demand for urban land. However, a low level of development and utilization restricts the improvement of development intensity. Economic development can improve the level of land-intensive use by promoting the adjustment, optimization, and upgrade of urban industrial structures.

A transportation hub is the key link in the construction of the comprehensive three-dimensional transportation corridor of the Yangtze River Economic Belt, and is the basic factor responsible for the promotion of this belt. A high-speed railway hub has the “last kilometer of time-space compression” effect and is the key to building an efficient, convenient, modern, and comprehensive transportation system. This study constructed a model for measuring the connection-distribution performance of the high-speed railway hub, determined the connection-distribution performance of the urban high-speed railway hub in the Yangtze River Economic Belt, and analyzed its spatial differentiation characteristics, further revealed the influencing mechanism of the connection-distribution performance of the high-speed railway hub. The main results are as follows: (1) The connection-distribution performance of the high-speed railway hub in the Yangtze River Economic Belt presented an “olive-shaped pattern” grade structure with two small ends and a large middle section, that is, the number of high-speed railway stations with high performance and average performance was small, and the number of high-speed railway stations with good performance and medium performance was large. (2) The connection-distribution performance of the high-speed railway hub in the Yangtze River Economic Belt showed a regional differentiation pattern of “high in the east and low in the west” and “high in the north and low in the south”, and showed an urban agglomeration differentiation pattern of “high in the core areas but low in the marginal areas”; moreover, spatial differences were prominent in the distribution of nine evaluation indexes of the connection-distribution performance of the high-speed railway hub. (3) GDP, urbanization rate, city level, station passenger flow and frequency of shuttle bus were key driving factors affecting the connection-distribution performance of the high-speed railway hub. At the same time, there were significant differences in the key driving factors for the connection-distribution performance grades of high-quality, good, medium and average.

China has entered the middle-to-late stage of urbanization. The scale of urban- to-urban migrants, which more refers to the urban-to-urban floating population (UUFP) across China, has significantly increased. UUFP settlement intention is a crucial issue for urbanization development. This study examines the spatial pattern and factors influencing the settlement intention of the UUFP in China based on data obtained through its dynamic monitoring in 2017 and the binary logistic model. The results show that most members of the UUFP were married, older, better educated, and had a higher income than the average person with extensive migration experience. We correlated a high settlement intention with developed economies, coastal areas, good environmental conditions, and more amenities in cities such as Beijing, Tianjin, Shanghai, and Zhuhai. Amenities were more impactful on settlement intention than economic factors, from individual and regional perspectives. The UUFP more often sought equality of education for children and social integration in its choices of destinations. However, the distance was not a hindrance to intention to settle but played a substantial role in influencing it. We suggest optimizing the stock of the UUFP in large cities, improving public education services, and promoting remote urbanization. Likewise, industrial transfer and enhanced public resources may ease the pressure of large UUFP flows into large cities.

Since the Bonn 2011 conference, the “water-energy-food” (WEF) nexus has aroused global concern to promote sustainable development. The WEF nexus is a complex, dynamic, and open system containing interrelated and interdependent elements. However, the nexus studies have mainly focused on natural elements based on massive earth observation data. Human elements (e.g., society, economy, politics, culture) are described insufficiently, because traditional earth observation technologies cannot effectively perceive socioeconomic characteristics, especially human feelings, emotions, and experiences. Thus, it is difficult to simulate the complex WEF nexus. With the development of earth observation sensor technologies and human activity perception methods, geographical big data covering both human activities and natural elements offers a new opportunity for in-depth WEF nexus analysis. This study proposes a five-step framework by leveraging geographical big data mining to dig for the hidden value in the data of various natural and human elements. This framework can enable a thorough and comprehensive analysis of the WEF nexus. Some application examples of the framework, major challenges, and possible solutions are discussed. Geographical big data mining is a promising approach to enhance the analysis of the WEF nexus, strengthen the coordinated management of resources and sectors, and facilitate the progress toward sustainable development.

Wetlands are important natural resources for humans and play an irreplaceable ecological function in the terrestrial ecosystem. To curb the continued loss of wetlands globally, international organizations and many countries have taken a series of major conservation and restoration measures. This work reviews these wetland conservation and restoration measures, interprets China’s wetland conservation and restoration management policies, and proposes that future research on wetland resources in China should be conducted from the aspects of international frontiers and national strategic plans, socioeconomics, and smart services. The results show that the 27 International Wetlands Days from 1997 to 2023 provided new goals and tasks for the protection and management of wetlands. The important topics and outcomes of the 14 Conferences of the Contracting Parties to the Convention on Wetlands from 1980 to 2022 provided new directions and new challenges for wetland development. In the future, we should enhance wetland ecological functions, promote sustainable wetland development, and overcome the technical bottleneck of fragile wetland ecosystem restoration. From 1992 to 2022, China embarked on a new phase of wetland protection and restoration. The overall experience of wetland protection and restoration in China has been formed through national strategic deployment, legal policy establishment, and project planning and implementation. The needs to provide for and plan the long-term protection of wetlands at the national level, to innovate restoration and management techniques and application systems, and to effectively address the complex issues of wetland protection and restoration through collaborative division of labor among multiple departments were emphasized. Research on the future trends of wetlands should be directed towards the exploration and practice of the United Nations Sustainable Development Goals and several international conventions in support of sustainable wetland development. Wetland protection, restoration, and management services should be promoted for national strategic needs and local, high-quality social and economic development. In addition, research on cross-integration and academic innovation should be enhanced for disciplinary development, global supervision, comprehensive assessment, and smart decision making.

In this study, the interplay between ecosystem services and human well-being in Seni district, which is a pastoral region of Nagqu city on the Qinghai-Tibet Plateau, is investigated. Employing the improved InVEST model, CASA model, coupling coordination model, and hierarchical clustering method, we analyze the spatiotemporal patterns of ecosystem services, the levels of resident well-being levels, and the interrelationships between these factors over the period from 2000 to 2018. Our findings reveal significant changes in six ecosystem services, with water production decreasing by 7.1% and carbon sequestration and soil conservation services increasing by approximately 6.3% and 14.6%, respectively. Both the habitat quality and landscape recreation services remained stable. Spatially, the towns in the eastern and southern areas exhibited higher water production and soil conservation services, while those in the central area exhibited greater carbon sequestration services. The coupling and coordination relationship between ecosystem services and human well-being improved significantly over the study period, evolving from low-level coupling to coordinated coupling. Hierarchical clustering was used to classify the 12 town-level units into five categories. Low subjective well-being townships had lower livestock breeding services, while high subjective well-being townships had higher supply, regulation, and support ecosystem services. Good transportation conditions were associated with higher subjective well-being in townships with low supply services. We recommend addressing the identified transportation disparities and enhancing key regulatory and livestock breeding services to promote regional sustainability and improve the quality of life for Seni district residents, thus catering to the diverse needs of both herdsmen and citizens.

Traditional music is an important component of cultural heritage. However, studies have scarcely explored the tourism development potential and the obstacle factors of traditional music. This study takes Xiangxi as the research site, constructs an evaluation index system, and utilizes survey and geographical methods. The major research results are as follows: First, the average potential of resource endowment, tourism industry development, and socio-economic conditions are 0.28, 0.36, and 0.24, respectively. The potential of resource endowment is higher in the west and lower in the east, that of tourism industry development is higher in the north and south and lower in the center, and that of socio-economic conditions is higher in the south and lower in the north. Second, the comprehensive potential is 0.29, which is higher in the northwest and southwest regions. Coordination in most administrative units is at a medium level, and most regions have obvious advantages in resource endowment. Third, the primary obstacle factor is socio-economic conditions (39.21%), followed by resource endowment (30.73%) and tourism industry development (30.06%). The administrative units can be classified into four groups: socio-economic condition obstacle, resource endowment and tourism industry development obstacles, resource endowment and socio-economic condition obstacles, and tourism industry development and socio-economic condition obstacles. The highest priority goals for Xiangxi involve economic development and the integration of modern technologies to stimulate passenger flow. For regions with limited traditional music items (eastern area of Xiangxi), tourism development should be restrained and other resources with stronger inherent advantages should be exploited. This study explored the quantification of traditional music tourism potential, representing a novel breakthrough in this field of research. The indicator system and research methods used in this study can provide guidance and methodological references for cultural heritage research. The suggestions proposed in this article contribute to the rational development and effective protection of cultural heritage resources and the healthy development of the tourism industry.

The transboundary influence of environmental change is a critical issue in the Lancang-Mekong region. As the largest river-connected lake in the lower Mekong, the ecological change and influence of Tonle Sap Lake have received widespread attention and discussion, especially after 2008, when the hydrological regime of the Lancang-Mekong River mainstream underwent distinct changes. However, the linkage and coupling mechanism between the lake riparian environment and mainstream water level change are still unclear. In this study, the interannual spatiotemporal changes in land cover in the Tonle Sap Lake riparian zone (TSLRZ) and their relationship with mainstream water levels were analysed. The results showed that the expansion of farmland was the most notable change in 1988-2020. After 2008, the land cover changes intensified, manifested as accelerated farmland expansion, intensified woodland fragmentation and significant water body shrinkage. Furthermore, the responses of the water body, degraded land, wasteland and grassland areas to the mainstream water levels weakened after 2008. Evidently, the land cover changes in the TSLRZ in the last 30 years were less related to the mainstream water level change than to local reclamation and logging. These results can offer a new scientific basis for the transboundary influence analysis of hydrological change.