Fan economy is a rapidly emerging business in the Internet era. However, the existing literature lacks research on fan economy from a geographical perspective. Based on the theory of network space, and taking TikTok livestreaming commerce host as an example, combined with the influencing factors of e-commerce and urban amenity theory, this study constructed an index system of influencing factors affecting the spatial distribution of Chinese livestreaming commerce host. Using location quotient, global Moran's I, and cold-hot spot spatial analysis methods, we analyzed the spatial agglomeration characteristics of Chinese livestreaming commerce host, and the geographic factors that affect livestreaming commerce host distribution through spatial regression. The results indicate that: 1) China's fan economy shows a significant spatial agglomeration, and it is highly concentrated in the eastern coastal areas, with Guangzhou and Hangzhou as the most prominent. 2) The digital economy represented by livestreaming is reshaping China's original city tier systems. Cities with entertainment media, e-commerce, and characteristic tourism (such as Changsha, Jinhua, and Lijiang), are very attractive to livestreaming commerce hosts, even more than some first-tier cities (such as Beijing and Shanghai). 3) Through spatial regression analysis, it is found that the environment for e-commerce startups and cultural tourism have a strong explanatory power for the spatial distribution of livestreaming commerce hosts. The convenience of living and the natural environment also have an important impact, and the impact of human capital is small. At the same time, the number of patents has a significant crowding out effect on livestreaming commerce hosts, and livestreaming commerce has a strong grassroots nature. This research provides detailed empirical cases for in-depth understanding of the spatial process of fan economy and its influence mechanism and provides a reference for local governments to promote the development of digital economy and formulate talent introduction policies.

The Alps, a typical mountain in the Eurasia Continent with mountain elevation effect (MEE), plays an important role in determining the geo-ecological pattern of Europe. The cause of the MEE is that the uplifted plateau or mountain absorbs more solar radiation. Most of the previous studies used the difference of temperature at the same altitude or base height inside and outside the mountain to quantify the MEE. However, the above methods may have some errors. This study chose the Alps as the study area and analyzed the spatial distributions of the solar radiation, temperature, and forest line in the Alps based on the collected meteorological observation data, forest line data, and digital elevation data, as well as the solar radiation data calculated by the hemispheric horizon algorithm. For the purpose of exploring the implication of MEE for the forest line, this study used solar radiation as the representation of MEE to build a forest line distribution model. The results show that: 1) The Alps has great MEE, and solar radiations of the inner mountain are much higher than that on the edge of the mountain. It is also the main reason that the temperature and the height of forest line in the inner mountain are far higher than that in the mountain edge areas. The solar radiation in the warmest month, the coldest month, and the whole year is 10-20, 20-40 and 200-400 kWh/m² higher than that on the edge of the mountain, respectively. 2) Solar radiation can better quantify the MEE, and forest line distribution model established with solar radiations as the substitute factor of MEE has higher simulation accuracy. The accuracy of the forest line distribution model in this study (R² = 0.736) is higher than that of the model based on temperature and precipitation (R² = 0.522), and the contribution rate of solar radiation to forest line distribution is the highest (34.75% in January and 27.82% in July), which exceeds the contribution rates of temperature and precipitation (26.24% and 11.17%, respectively).

Through extensive and detailed field investigation inside and outside the Zoige Basin in eastern Tibet Plateau, a typical sedimentary profile containing the stratigraphic sequence of paleolake facies and paleo-riverbed floodplain facies was found in the front of the second terrace of the Yellow River in the Maqu section at the outlet of the Zoige Basin. Through grain size characteristic analysis and Optically Stimulated Luminescence(OSL) dating, we found that: 1) The pale-blue-grey paleolake sedimentary layer in the profile indicates that the lacustrine sediment formed in the deep-water anoxic environment, while the mottled pebble layer covered by the pale-yellow-orange lenticular sand layer was a typical fluvial floodplain sediment, which indicates the process of strong dynamic flow. The unconformable contact relationship between the two layers indicates that the profile is a typical sedimentary evidence for studying the Zoige Basin dissected by the Yellow River. 2) The OSL dating results of the top boundary of the pale-blue-gray paleolake sedimentary layer and the bottom boundary of the paleoshore-shallow lake sedimentary layer show that the Yellow River dissected the Zoige Basin at 37 ka BP, resulting in the leakage of lake water. At 35 ka BP, the lake water became shallow and disappeared, and then the Yellow River connected the water system of the Zoige Basin. 3) The strong neotectonic movement of the East Kunlun fault in late Pleistocene and the warm and humid climate of the Tibet Plateau in 37 ka resulted in the aggravation of the headward erosion of the paleo-Yellow River source in the rift valley grassland, and the Zoige Basin was dissected by the paleo-Yellow River from the west to the east in the Maqu bottleneck reach, resulting in the discharge of the paleolake water through the Yellow River, thus connecting the water system of the Zoige Basin and making it the source of the Yellow River. The study results have important scientific significance for an in-depth understanding of the evolution of river-lake water system and the formation of Yellow River water system in northeastern Tibet Plateau.

Territory is the key concept in political geography, and territorial trap is one of the most classical theories in political geography. This article systematically reviewed the literature on territorial traps, summarized the origin, development, and research progress of the territorial trap theory, and discussed its significance in Chinese political geographical studies. The theory of territorial trap proposed by Agnew is based on three geographical assumptions: the "trinity" of territory-state-sovereignty, the "dichotomy" of domestic-foreign, and the state as a social container. The territorial trap theory refutes the existing state-centric view of territory and emphasizes various effective forms of sovereignty besides the state's territory, such as extraterritorial sovereignty, graduated sovereignty, and social sovereignty. The extensive application of the territorial trap theory reflects its strong explanatory power in global governance, non-traditional security, cross-border migration control, cross-border resource protection, cross-border water politics, and so forth. This article argued that territorial issues should be understood from the complex interaction between territorial control and effective sovereignty and the perspectives from the center and periphery, and be examined by combining rationality and historical emotion. It has important implications for China to effectively resolve territorial issues, promote the realization of the Belt and Road Initiative, and establish the "community with a shared future for mankind".

Accessibility of park green space is an important indicator of the livability level of a city. In order to solve the problem of scale imbalance between population and park green space distribution data by traditional accessibility analysis, this study used mobile phone signaling data to obtain the spatial distribution of population, and adopted the Gaussian two-step floating catchment area method to calculate the accessibility of park green space at the scale of traffic analysis zone (TAZ) in Shenzhen City. It also conducted a cluster analysis based on the accessibility results, supply and demand, and traffic conditions. The main conclusions are as follows: 1) More refined population information can be obtained through mobile phone signaling data to improve the accuracy of demand assessment. For different types of parks, the Gaussian two-step floating catchment area method represents an improvement in calculating the accessibility of parks in the city. 2) The overall level of comprehensive accessibility of park green space in Shenzhen is relatively high, but there is an obvious decreasing trend from the city center to the periphery. The mismatch between the accessibility of community parks and the supply and demand of park green space is an important reason for the large difference of accessibility among different regions in Shenzhen. 3) According to the results ofK-means clustering analysis, the TAZ units of the city was divided into low supply low demand low accessibility zone, medium supply low demand medium accessibility zone, high supply high demand medium accessibility zone, and high supply low demand high accessibility zone. 4) The accessibility of park green space can be improved by optimizing park layout, road construction, and residential area planning and layout. By improving data source and model of the traditional accessibility calculation, this study enriches the cases of park green space accessibility evaluation, and the proposed accessibility analysis method based on mobile phone signaling can also provide a reference for the accessibility analysis of other geographic phenomenon.

In recent years, the spatiotemporal distribution and its hazards to republic health of air pollution in China have shown new characteristics. Using hourly air quality monitoring data for five years (2015-2019) in 332 Chinese cities, this study analyzed the spatiotemporal distribution characteristics of air quality and urban population exposure risks by different methods. The results suggest that: 1) Air quality in Chinese urban areas has improved in recent years. Ambient Air Quality Index (AQI) decreased in 303 cities (91.3%). The concentrations of PM_2.5, PM₁₀, SO₂, and CO declined while the concentrations of NO₂ and O₃ increased. 2) The hotspots of PM_2.5, PM₁₀, SO₂, and CO concentration change rates were distributed in Xinjiang and Yunnan-South China. The hotspots of NO₂ concentration change rate were in the Xinjiang area and the Hetao Plain. The hotspots of O₃ concentration change rate were from the North China Plain to the middle and lower reaches of the Yangtze River. The trends of air quality change in the Northwest and South China were relatively slow. 3) Nine cities were exposed to PM_2.5, PM₁₀, SO₂, NO₂, O₃, and CO pollution, which were located in Shanxi, Hebei, and Shandong provinces; 12 cities had no exposure risks to these six pollutants, which were distributed in Xinjiang, Yunnan, Guizhou, Sichuan, Guangdong, Fujian, and Heilongjiang provinces. These conclusions are of important reference value for collaborative treatment of cross-regional air pollution and formulating spatially diffenrentiated population flow management policies in China.

The locational association of industrial layout is an important element in the study of the spatial structure of regional industries and their spatial relationship. In this study, we constructed a database of semiconductor enterprises in the Pearl River Delta (PRD) region and examined the spatial pattern of the semiconductor industry and its locational association characteristics in the region by using kernel density analysis and synergistic locational analysis. The results show that: 1) Guangzhou, Shenzhen, and Dongguan formed important spatial clusters of the semiconductor industry in the PRD region, and the semiconductor design segment is a common choice for entering the semiconductor industry chain in the PRD region. 2) Although Guangzhou has formed specialized clusters in design, materials, and discrete device manufacturing, only its discrete device manufacturing segment has formed a locational synergy with the design and packaging segments; while Shenzhen has formed a synergistic relationship with the design equipment. 3) Guangzhou's specialization in discrete device manufacturing is a transitional state in the construction of the semiconductor industry chain, while Shenzhen's advantage in the construction of the whole industry chain is based on the high concentration of digital technology enterprises in the city and the establishment of common knowledge, technology, and human resources bases through the semiconductor design segment and other segments.

The Huhuanyong Line is a real portrayal of the spatial pattern of population, economic, and social development in China. It perfectly describes key characteristics of energy production and consumption. Quantitatively simulating the spatial pattern of energy consumption on the two sides of the line can provide a reference to achieve regional coordinated development. This study employed data from the China Energy Statistical Yearbook (2005-2014). We first constructed the System Dynamics Model Based on the Huhuanyong Line Energy Consumption Simulation Model (HLECSM-SD) using the \mathrm{GM} \left( \mathrm{1,1} \right) model and System Dynamics (SD) model. Then, we simulated the pattern of various energy consumptions on the two sides of the line from 2020 to 2025. Finally, this study analyzed energy consumption of China under three scenarios. The results indicate that: 1) The HLECSM-SD model fits the data well. 2) Energy consumption presents the spatial pattern of more in the east and less in the west in China. 3) The change trend of energy consumption growth rate is consistent across the two regions. The east side has a lower growth rate than the west side. 4) On the east side of the line, coal consumption has the characteristics of more in the north and less in the south. This is consistent with the spatial distribution of China's coal resources. The consumptions of petroleum, natural gas, and electricity all have the characteristics of more in the east and less in the central region. This is determined by many factors, such as resource endowment, economic development, population scale, and industrial structure of each province. 5) The influencing factors have different degrees of impact on energy consumption under different scenarios. Our findings can provide some reference for the macro decision making in the energy field.

Since the beginning of the 21st century, the conflict between the degradation of ecosystem services (ES) and the increase of human needs has become increasingly intensified. How to improve the interrelationship between ecosystem services and human well-being (HWB) towards a coordinated and balanced state naturally becomes a core theme of sustainable development. Based on the reviews of ES-HWB interrelationship through three phrases, the existing research mainly started from the influences of ES on and responses to HWB, and further focused on the practices of their interrelationship through some key fields including supply-demand relationship and spatial flows, trade-offs/synergies, valuation of cultural ecosystem services, payments for ecosystem services, and optimized regulation and sustainable management. However, the interrelationship research is still led by "influence chain" of the ES cascade while distinct deficiencies exist in terms of theoretical framing, technical methods of direct interrelationship measurement, and support applied for sustainable management. Moreover, the ES-HWB interrelationship tends to become more nonlinear, which urges for certain theoretical innovation from synthetic integration paradigm of the coupled human and natural system framework. This article, therefore, proposed a new path for the ES-HWB interrelationship research—from cascade to coupling, with which the interactive coercing effect and its intrinsic dynamic change mechanism are clear to distinguish in a systematic way. On this basis, an exploratory theoretical research framework of ES-HWB coupling was built with a main thread of "interactive coercing effect measurement-coupling relationship deconstruction-coupled pattern and process evolution-coordinated management and application", so were the technical coupling approaches. In such regards, the ES-HWB coupling research is bound to develop as a pivotal issue enriching the coupled human and natural system studies. First, there is a need to untangle ES-HWB interrelationship as a foundation. Then, further in-depth research should be enriched to achieve the orderly and coordinated development oriented by ecological civilization, including the decoupling of coupled interactions, transmission mechanism and dynamic integration, human needs-oriented differentiated evolution, and sustainable optimization based on the ES-HWB coordination.

The spatial heterogeneity of urban built environments is a primary challenge in the research of urban pluvial floods in terms of the model representativeness, computational efficiency, and data requirements. The development of new technologies, including artificial intelligence, big data, and remote sensing, provides opportunities for the research of urban pluvial floods, such as efficient approaches and high-resolution data. This study conducted a comprehensive review of the research progress on urban pluvial floods from four perspectives—flood characteristics, mechanisms, data, and research methods, and finally came to four conclusions: 1) Urban pluvial floods have typical features such as short duration, scattered and evolving spatial distribution, chain effect, and sharp increase of losses at the critical scenario. 2) Micro-topography plays an important role in the spatial distribution of urban pluvial floods, and the topographic control index shows the potential of identifying frequently flooded areas. 3) The highly variable rainfall processes are the bottleneck in the near-real-time flood simulation, and the radar rainfall data provide a solution. Internet-based big data provide a new way to extract flood inundation data with high spatial coverage, but still face the problems of quality control and fusion with multi-sources data. 4) Machine learning could be coupled with hydrodynamic models to improve the efficiency of near-real-time flood simulation.

Located on the southeast edge of the Qinghai-Tibet Plateau, the Nyainqêntanglha Mountains are an important area of mountain paleoglaciers. Affected by the monsoon, the glacier change characteristics in each region are obviously different. Based on Landsat TM/ETM+/OLI data, ASRTMGDEM and meteorological data, using the method of threshold ratio, visual interpretation, VOLTA model and combined with field investigations, this study analyzed the advance and retreat conditions, area changes, ice reserves changes, and glacier changes deal with climate change of modern glaciers in the middle Nyainqêntanglha Mountains from 1990 to 2020. The results show that: 1) During the period 1990-2020, the elevation of the five studied glaciers (G094383E30581N, G094574E30563, G094637E30633N, G094770E30626N and G094928E30607N) gradually increased. The glacier area and ice reserves decreased by 30.38 km² and 64 km³ respectively. 2) The ice reserve of each glacier decreased by 0.14-1.92 km³, with an overall change rate of 0.40%·a^-1. By 2020, the reserves of the above glaciers will account for 0.70, 0.99, 0.98, 0.91 and 0.82 in 1990 respectively, which shows that the larger the scale of the glacier, the smaller the change is in a short time. 3) Through the analysis of meteorological data, during 1990-2020, the average temperature change rate of the study area was 0.51 ℃, which shows that the overall glacier change was dominated by the temperature rise. It is predicted that the glacier change in the future will be controlled by the temperature and show a trend of accelerated retreat. 4) The regional comparative study showed that the glacier area change in the Nyainqêntanglha Mountains is generally in a state of retreat, but the characteristics of glacier change in different regions are obviously different. The research on glacier ice reserves in the region is relatively weak, and the simulation results of different research methods for the same glacier ice reserves have large errors, with the relative error range of 34.45%-115.49%.

Out-of-school hours care place (OSHCP) is a new type of educational auxiliary facility, mainly provides meals and rest places for primary and secondary school students, has gradually become the third activity space for students outside their homes and schools, and worth further examination from a spatial perspective. Based on the data of OSHCPs and related points of interest (POIs) in Yanta District of Xi'an City, we used spatial analysis, statistical analysis, and field investigation methods to explore the basic functions and location choice and its influencing factors of OSHCPs. The results indicate that: 1) The service demands of OSHCPs are from families with childcare needs in the lower grades of compulsory education for childcare assistance and children's "transfer" and "deposit", and the service types include student care, catering, help with homework, and so on. 2) The distribution of OSHCPs generally showed a trend of extending along the east-west direction, which is consistent with the urban morphology and the development status of residential committees, mainly in the traditional neighborhoods, high-rise housing estates, and work unit housing areas, concentrated in the low floors (1-5 floors). 3) Regional population, educational environment, investment costs, and spatial location influence the layout and location of OSHCPs, with the number and distribution of primary and secondary schools, the number and distribution of residential neighborhoods, and the distance from the central city having significant impacts. Finally, we summarized the influencing factors of location choice from three scales including urban area, residential committee, and care place in combination with the needs of the population, and provide an outlook on future research directions in conjunction with the "double reduction" education policy.

Geopolitical setting research is the focus and hot spot of political geography in China. Significant progress has been made in the areas of conceptual framing, connotation, analytical framework, spatial differentiation, system simulation, and so on. However, the study of geopolitical setting in geopolitical-strategic intersection areas has not been fully developed. This study constructed an evaluation model of geopolitical setting in geopolitical-strategic intersection area based on the space and power of geopolitical strategy, by combining the theories of geopolitical setting and geopolitical potential in political geography, and realism, liberalism, and constructivism in international relations, and by giving consideration to the philosophy of inter-subjectivity. This study also took Ukraine as an empirical study to verify the reliability of the model. The results show that: 1) On the whole, Ukraine's geopolitical setting tends to be improving, but it fluctuates violently, and will be intermittently turbulent in the future. 2) Under the influence of historical and cultural origin, military material power, strategic investment willingness, economic interdependence, geographic and spatial distance, and other factors, Russia has maintained a large geopolitical potential advantage in Ukraine. 3) Germany's geopolitical potential in Ukraine fluctuates greatly from year to year, and is on the rise in recent years due to the influence of geoeconomic factors. The geopolitical potential of France and the United States in Ukraine has been lower than Russia and Germany. In the future, the geopolitical potential of France will increase slightly, while that of the United States will decrease. The geopolitical setting evaluation model of geopolitical-strategic intersection area proposed in this study has been verified by historical data, and the assessment results have a high fitting degree with the evolution of domestic political situation in Ukraine. The model has reasonable reliability, and can provide reference for the geopolitical setting evaluation in other geopolitical-strategic intersection areas.

Since the 1990s, a new branch discipline, health geography, has developed from Western medical geography. Under this new disciplinary framework, the focus of geographic research has gradually shifted from disease and medical services to health and well-being in a broad sense, and related studies have had a significant impact in the fields of geography and social sciences. These studies on healing share a common theoretical foundation—the concept of "therapeutic landscape" proposed by Gesler in 1992—and gradually developed a set of influential theories in the subsequent development, becoming a well-deserved important theoretical contribution to health geography. As a core theoretical framework of health geography, the study of therapeutic landscapes is rarely mentioned in geographic research in China. This article reviewed the theoretical development process and current research progress on the use of therapeutic landscapes since the 1990s. The therapeutic landscape concept draws on structuralist and humanistic theories of new cultural geography. Influenced by the relational turn of geography in the later period, it gradually developed into the most influential theoretical framework of health geography. Therapeutic landscape research from a relational perspective has been deeply influenced by theories such as non-representational theory, actor network theory, and the mobility turn, and has gradually developed branch theories such as therapeutic assemblage, enabling place, therapeutic mobility, and therapeutic "taskscapes". Finally, the article summarized some challenges in the current research on therapeutic landscapes, and put forward suggestions for the development of health geography under the framework of therapeutic landscapes in the future.

In order to solve the problem of unbalanced supply and demand of park green space in high density cities, this study used a Gaussian based two-step floating catchment area method to analyze the spatial accessibility of existing park green space in Huangpu District of Shanghai, under walking conditions. First, we extracted the point of interest (POI) data of residential areas from the Internet and aggregated them into a 100 m long hexagonal cellular network to calculate the number of people and population density, then through the Application Programming Interface (API) of Baidu Map we extracted the travel time between supply and demand points based on actual road conditions. Second, the paper took the park green space built by the end of 2018 in Huangpu District of Shanghai as an example, and considered the four aspects of residents' demand, accessibility classification, cold and hot spots, and blank areas. The results show that the accessibility level of park green space in Huangpu District is higher in the north and lower in the south, which is negatively correlated with the population density distribution. The dominant blind areas (9.16% of the total area) and the recessive blind areas (16.5% of the total area) should be eliminated. This study made a quantitative analysis on the supply and demand allocation, to provide guidance for the further optimization of green space layout and site selection. Finally, recommendations were made from three aspects of "increasing green space appropriately", "strengthening the quality of existing green space" and "community co-governance", in order to provide theoretical support for the Fourteenth Five-Year Plan of greening Huangpu District.

The glaciers of the Meili Snow Mountain are now rapidly retreating and thinning, owing to climate change. The main aim of this study was to monitor the dynamics of the Mingyong Glacier in the Meili Snow Mountain based on unmanned aerial vehicle (UAV) survey and UBase. The result of the digital surface model (DSM) in the Mingyong Glacier terminus shows that the surface morphology has a significant difference between the upper and lower sections. The lower section was covered by a large amount of debris, and a few crevasses developed along the direction of glacier flow. Little debris was found in the upper section, and a lot of transverse crevasses developed there. A mean ice thinning of 1.67 m was observed in the terminus of the Mingyong Glacier from November 2018 to November 2019, and surface lowering was heterogeneous. There were positive and negative alternations in surface lowering in the upper section, surface thinning was observed in the middle section, while a significant thickening was observed in the lower section. Compared with glacier changes in other areas in the High Asia Mountains, the Meili Snow Mountain was the region with the most significant glacier surface elevation change.

Exploring the construction and reconstruction of the global value chain led by Huawei mobile phones from the perspective of urban networks is of great significance. This study examined the construction and reconstruction of the global value chain dominated by Huawei mobile phones in the process of catching up in technology development. Taking the official effective date of the "Entity List" as the turning point, this study systematically examined the data of Huawei's mobile phone suppliers before and after the "supply disruption". With the application of the headquarters-branches model, social network analysis, and community detection methods, the spatial distribution, network structure, and community structure of research and development (R&D)-oriented, production-oriented, and original equipment manufacturer (OEM)-oriented urban networks are uncovered. The results show that: 1) The production organization mode of Huawei mobile phones has a typical feature of global R&D + domestic production/OEM. After the supply disruption, R&D suppliers withdraw obviously, and the substitution trend of core components was clear. 2) After the supply disruption, the influence and control power of Shenzhen, Shanghai, and Beijing in the urban networks increased significantly, especially in the R&D-oriented urban network. 3) The influence and control power of cities where U.S. high-value suppliers are located have dropped significantly. The influence and control power of cities where high-value suppliers from Japan and South Korea are located, mainly memory chips and camera chips, have increased significantly. 4) After the supply disruption, the network agglomeration effect of high-, medium-, and low-value production links increased to varying degrees, promoting a more regionalized Huawei value chain. 5) After the supply disruption, the biggest changes from before the disruption occurred in the R&D urban communities. The number and scale of production-oriented urban communities were moderate, and there were obvious hierarchical differences among communities. The number of OEM-oriented urban communities was the smallest, and the connections within the community were sparse. The combination strategy of globalized layout and domestic substitution is a feasible path for Huawei to solve the supply problem. It also provides some references for high-tech firms in developing countries to achieve catch-up.

The relationship between urban and rural areas in China has been an important relationship for economic and social development and a major concern of the party and the government. In order to explore the relationship between urban and rural areas and its governance logic, the CiteSpace software was used to analyze the research hotspots of rural-urban relationship since the reform and opening up in the 1970s and to interpret its change based on the historical background, and then reveal the contextual characteristics of rural-urban relationship and the internal logic of governance reform. The research shows that since the reform and opening up, rural-urban relationship has gone through four stages—from an improving urban-rural relationship, to rural-urban re-separation, rural-urban relationship adjustment, and integrated rural-urban development. The process reflects the governance logic of breaking the rural-urban division, favoring the urban field, balancing rural-urban development, and promoting rural-urban integration. Since the 19th National Congress of the Communist Party of China, the relationship between urban and rural areas has developed in the direction of rural-urban integration. Rural-urban co-governance is the internal demand and governance trend of integrated rural-urban development in the new era. Finally, the article discussed the prospect of integrated rural-urban development and rural-urban co-governance from the aspects of abolishing the rural-urban dual system and establishing new supporting systems and mechanisms, breaking disciplinary boundaries and integrating interdisciplinary knowledge and cross-application of practice, and organically combining the two strategies of new urbanization and rural revitalization.

In the context of global climate change, extreme weather events and the concomitant natural disasters are becoming a primary risk restricting the socioeconomic development in coastal areas that are often highly urbanized. This study sets out to explore the new characteristics of natural hazards and disasters in the coastal areas of China against the backdrop of a changing climate. Major conclusions are as follows. First, the occurrences of extreme weather and climatic events are considerably uncertain. The climate and disasters are different across various temporal and spatial scales, and the components of the disaster risk system become more complicated. Second, in view of the new challenges brought by climate change, we suggest paying close attention to three issues in the future, including the change of temporal and spatial scales that are used to depict the disasters, the synergism of multi-disasters, and the effects of climate change and urbanization. Based on these, a new framework of disaster risk system is established to reflect the qualities of disasters in complex spatiotemporal contexts. Lastly, to develop more effective coping strategies for the climate and natural hazards and disasters in coastal areas, it is necessary to promote diversification of the disaster prevention system and enhance its robustness, and to strengthen the self-recovery capability of the social, economic, and ecological environments. Meanwhile, information sharing in multi-disaster management and risk sharing and transfer policies are also important for accommodating the negative impacts of extreme events and disasters coming with climate change.

This study selected 1897 county-level cities in China as the research unit to examine the spatial distribution pattern of carbon emissions and the effects of population, economy, and multi-dimensional urbanization levels on carbon emissions. The data sources are CHRED-online carbon emission public database and social and economic statistics of counties and county-level cities. Spatial autocorrelation and geographic detector methods were used in the empirical research. The results show that: 1) County-level cities of China are relatively highly different in carbon emissions, and the number of areas with high carbon emissions is relatively small, but the emission value is relatively large. The carbon emissions per unit of GDP are higher than the national average. 2) The spatial distribution of total carbon emissions mainly presents a pattern of high in the east and low in the west. The high-value areas of total carbon emissions are mainly concentrated in the east, the periphery of large cities in central China, and the central and northern regions of Inner Mongolia, showing a clustered distribution structure. Per capita carbon emissions and carbon intensity show a pattern of high in the north and low in the south, mainly concentrated in the central and northern parts of Inner Mongolia and the border areas of Xinjiang and Qinghai. 3) The spatial heterogeneity of the level of economic and land urbanization has a strong explanatory power for the difference in the total carbon emissions of county-level cities, and the impact of population urbanization on the total carbon emissions is not obvious. The interaction between economic urbanization and land urbanization has the most dramatic impact on carbon emissions, and shows a nonlinear enhancement effect. 4) With regard to regional differences, the level of urbanization has the most dramatic effect on the underdeveloped areas in the west. The eastern, central, and western regions also show different spatial characteristics in terms of the explanatory power of the same indicators and the key influencing factors.

Unmanned aerial vehicle (UAV) is increasingly widely used, but with the continuous progress of urban development, the safe operation of UAV in cities is increasingly more prominent. Therefore, environmental risk assessment of obstacles has become one of the key issues in the field of low-altitude UAV research. In this study, taking the Beijing-Tianjin New Town as an example, the low-altitude airspace was divided into micro, light, and small UAV flight zones according to the low-altitude UAV types and operating heights. Based on the shape and size of UAVs, their motion constraints, and obstacle constraints, this research proposed an algorithm for approximation point expansion. The algorithm generates an expanded boundary on the basis of the original boundary of the obstacles, and this expanded boundary serves as a transitional zone between high risk and low risk areas in the low-altitude flight environment. Based on the UAV image data of 0.5 m resolution in the Beijing-Tianjin New Town in 2019, this study extracted obstacle elements in different assessment areas, and generated low-altitude flight obstacle environmental risk maps for different UAV types and different heights based on the risk assessment. The study area was divided into high-risk zone, high-risk transitional zone, medium-risk zone, and low-risk zone according to the threat posed to UAVs. The results show that: 1) The risk transitional zone in the micro, light, and small UAV control areas in the study area accounted for 10.9%, 7.3% and 9.0%, respectively, and the sharp-angle convex vertex optimization of the approximate point expansion algorithm can save about 1% of the airspace resources. 2) The proposed method can calculate the potential collision risk area of the UAVs in the flight area based on the mutual influence of the UAVs and the obstacles, and realize the effective assessment of the environmental risk of the low-altitude obstacles and provide a scientific reference for the navigability of the UAVs of different types in the flight area.

Resilience is a basic characteristic of the rural system, which plays a crucial role in rural revitalization. By the end of 2020, China had completed the mission of poverty alleviation in the new era. However, rural development in some areas is of low quality and when facing external risks and challenges, these areas have the risk of returning to poverty. Therefore it is urgent to improve rural resilience. This study selected Yangyuan County of Hebei Province in the contiguous poverty-stricken area of Yanshan-Taihang Mountains as the research object. The "Pressure-State-Response" (PSR) model was constructed to comprehensively evaluate the rural economic resilience. The study found that: 1) The average value of rural economic resilience in Yangyuan County is 0.13 (total score is 1), which indicates that the quality of rural economic development is not high. 2) The areas located near the town and township seats and close to the main traffic lines display high economic resilience. In contrast, mountainous areas and areas far from the main traffic lines display low economic resilience. 3) Low per capita income of rural households, low per capita arable land, and insufficient investment in rural fixed assets are the main constraints to economic resilience. The article proposed four aspects to improve rural resilience: establishing multi-level development system of "individual farmers-rural collectives-urban centers", strengthening the development of infrastructure such as rural transportation and communication systems, promoting farmers' skill training, and strengthening the collective economy of the villages. Developing key towns-central villages-new rural communities effectively accelerates the development of ruralization, which drives rural development together with urbanization.