Global/world city network research is gradually focusing on the phenomenon of science and technology globalization. The existing studies have been analyzed it based on the paper co-authorship or patent cooperation data, there is a paucity of analysis of the world city system from the perspective of talent flows. Based on the education and career mobility data of the world's top 500 AI scientists, this paper analyzed the spatial patterns, structural characteristics and influencing factors of the global elite education and career mobility network using spatial analysis and network analysis methods. The results are as follows. Firstly, the global mobility of AI elites is highly concentrated in the ''global triangle'' of North America, Europe and Asia. The scope of the global AI elite mobility at the education stage is broader than that at the career stage, which is related to the differences in the locational characteristics of education and market resources. Secondly, both the global AI elite education mobility network and the global AI elite career mobility network have a hierarchical structure. However, the disassortativity of the former is more significant than the latter. The top cities in both networks are mostly from the ''global north'', with a significant ''North-South gap''. The ''North-South gap'' in the global AI elite career mobility network is greater than that in the global AI elite education mobility network. Many US cities such as San Francisco, Boston and New York appear in the top 30 cities of both networks, while only Beijing and Hong Kong in China appear in the list of both networks. Third, the global intercity AI elite education mobility network community feature is characteristic with globalization and regionalization, and most communities are monocentric. The global intercity career mobility network community feature is characteristic with globalization, and most communities are polycentric. Finally, Spearman correlation analysis results show that national border is significantly and positively correlated with the global AI elite education and career mobility, regional international organization are only significantly and positively correlated with the global AI elite career mobility, and geographical proximity is not significantly correlated with both the global AI elite education and career mobility, which suggests that the mobility of top talent is almost not limited by geographical distance. The paper calls for future research on the global urban system from the perspective of talent mobility.
In order to reveal the impact of administrative hierarchy and land marketization level on the utilization benefits of urban construction land in China, based on the study of the temporal changes and differences of land marketization level and land utilization benefits in 276 cities and cities with different administrative levels from 2003 to 2019, this article empirically tested the effects of administrative hierarchy, land marketization level and their interaction on land utilization benefits by using least square virtual variable model, and uses a threshold effect model to further validate the threshold effect of land marketization level. The results show that: 1) The land marketization level and land utilization benefits in sample cities are on the rise. The land marketization level of first-level administrative cities is on the rise significantly, while the land utilization benefits is on the rise significantly in second and third-level administrative cities. 2) The land marketization level of first-level administrative cities are generally lower than that of second and third-level administrative cities, but the land utilization benefits are always higher than that of other cities. 3) There is a significant positive relationship between the cities' administrative level and the utilization benefits, economic and social benefits of land. And there is a significant U relationship between land marketization level and the utilization benefits and economic benefits of land. The interaction term between administrative level and land marketization level does not have a synergistic effect on land utilization benefits, but has a significant positive relationship with the economic and social benefits of land. 4) If the intensity of land investment is taken as a threshold variable, land marketization level has a significant double threshold for the land utilization benefits. The conclusion enriches the research on the effect mechanism of China's administrative hierarchy system and land marketization level on urban construction land utilization benefits, and can provide a basis for the urban construction land development in cities with different administrative levels and for coordinated regional development.
This article constructs an analytical framework for the relationship between border tourism and national security from an interactive perspective, using the Daluo Town area in Yunnan Province as a case study. The primary data are collected through interviews and observation. This article analyzes the dynamic evolution and the logic behind the evolution of the relationship between border tourism and national security. The following results were obtained. First, the evolution of the relationship between border tourism and national security is caused by the interaction between spatial cross-border and security threats, multiple stakeholders and security capabilities, and sensitive activities and security judgments. This process takes the right transfer and the interest divergence as the main path, and the social amplification as the secondary path. Second, the relationship between border tourism and national security, along with the evolution of the main ideas from economic development, absolute security to relative security, forms the risk accumulation mode, complete opposite mode and coordinated development mode, corresponding to rapid climbing stage, overall stagnation stage and re-development stage of the border tourism in Daluo Town. Third, the spatial cross-border of border tourism will form the source of security threat through power transfer. The multiple stakeholders of border tourism will weaken the security governance ability through interest differences. The social amplification of border tourism will disturb the security judgments by enlarging the power transfer and aggravating the interest differences. Therefore, the development of border tourism and national security governance need to start from three aspects: assessment of power transfer, balance of interest difference and suppression of social amplification. This study provides a practical guiding significance for dealing with the relationship between tourism development and national security in border areas.
Under the background of information, capital, labor, commodities and other factors with super mobility, the space-time compression effect has largely weakened the geographical distance barrier of knowledge flow. At the same time, the embeddedness in the knowledge production and learning process highlights the important role of non-geographical factors such as local socio-cultural, institutional and cognitive level in the cross-regional flow of knowledge. This paper uses the big data of authorized invention patents of knowledge-intensive industries in Chinese cities and constructs the mediation effect model to explore the invisible barriers and their mechanisms of knowledge flow across regions. The findings are as follows: 1) The cross-regional flow of knowledge in Chinese cities is increasingly significant, but the flow network is characterized by spatial imbalance, which conforms to the spatial differentiation of "Hu Line" on the whole. In addition, strong knowledge flows exist between adjacent cities and distant cities at the same time. This shows that local contexts such as social culture, institution and cognition have more and more significant impacts on knowledge flow, and knowledge flows across regions are characterized by the coexistence of proximity and distance in the era of the knowledge economy. 2) Under the premise of controlling traffic distance, local socio-cultural, institutions, and cognitive distance have a significant negative impact on knowledge flow across regions, becoming invisible barriers to regional collaborative innovation. 3) Socio-cultural and institutional barriers significantly block knowledge flow by influencing the intermediary path of the trust relationship between regions. Cognitive barriers significantly hinder knowledge flow across regions by influencing the intermediary path of regional learning and absorptive capacity. The research results provide references for regional innovation linkage and strategies for breaking down multiple invisible barriers and promoting regional high-quality integrated development. The academic contribution of this paper is that we introduce the trust-learning mechanism, deeply explain the mechanism of invisible barriers such as socio-cultural, institution and cognition that hinder the knowledge flow across regions, and deepen the understanding of the regional innovation school on knowledge dynamics in the process of economic development.
Under the context of Zhejiang shouldering the national mission of building a demonstration area for common prosperity, integration into the metropolitan area may be of great significance to the leapfrog development of underdeveloped areas. In the innovation-driven era, the driving force of regional spatial system development lies in a large number of innovations within the region. Based on IncoPat patent data, this paper collects patents and related data of the original 26 underdeveloped counties in Zhejiang Province from 2003 to 2019, and conducts social network, spatial pattern and econometric analysis through mapping and measurement software. Economic geographers' attention to innovation networks has changed from local to global, and then to "local-global" perspective. And previous studies have focused on innovation network research with developed regions as the core. However, there is a huge difference between underdeveloped regions and developed regions. It is meaningful to explore the construction rules of innovation networks in underdeveloped regions. Since the research area has few innovation links with foreign countries, we do not consider the global scale when discussing the scale of innovation networks in underdeveloped regions. Finally, we divide innovation links into four scales: local scale, metropolitan scale, provincial scale, and national scale. The following conclusions are drawn: 1) The innovation network construction of 26 counties in Zhejiang mountainous area is mainly based on the scale of metropolitan area. Underdeveloped regions have a weak innovation foundation and lack sufficient innovation knowledge at the local scale. And the innovation connection is limited by its own foundation and geographical distance at the national scale. Therefore, innovation linkages at both local and national scales are underdeveloped. 2) In terms of the structure of the innovation cooperation network, power system-related enterprises and universities occupy the central position of the network. Among them, colleges and universities have a wide range of cooperation, and maintain a high status of network center. However, the networking of power system-related enterprises is mainly internal networking. The State Grid Corporation of China has formed an important part of the patent cooperation field. However, private enterprises are relatively active in the patent transfer network. 3) The metropolitan area scale is the most significant and stable scale in promoting the 26 counties in the mountainous area of Zhejiang Province. The innovation network at the provincial and even national scales cannot significantly promote the independent innovation capability of the 26 mountainous counties in the mountainous area of Zhejiang. It can be seen that the innovation network construction strategy based on geographical proximity is more suitable for underdeveloped regions. There is a huge difference in the innovation basis between underdeveloped regions and developed regions. Therefore, the underdeveloped regions need to reconstruct the innovation network based on their own basis, rather than imitate the developed regions. 4) The innovation links in underdeveloped areas are mainly concentrated between universities and private enterprises. There is a great lack of high innovation level enterprises in innovation linkages, and the role of scientific research institutes and state-owned enterprises needs to be explored.
Resilience is the cornerstone of high-quality development. County is the most basic administrative unit in China, exploring the dynamic evolution law of its spatial resilience is of great significance to the high-quality development of regional space. This paper takes 63 counties in the Harbin-Changchun Urban Agglomeration as the research object, and analyzes the dynamic changes of their spatial resilience and response mechanism from 2000 to 2020 based on the dimension of spatial "exposure-resistance-adaptation", using spatial autocorrelation, VAR model and other research methods, in order to further improve the theoretical system of China's spatial resilience research and provide reference for other urban agglomeration counties in China. At the same time, this paper provides new ideas for the regional system to adapt to complex disturbances by accurately quantifying and diagnosing the dynamic changes of county spatial resilience in the Harbin-Changchun Urban Agglomeration. The results show that: 1) From 2000 to 2020, the resilience index of the Harbin-Changchun Urban Agglomeration has increased, but the overall county spatial resilience is not strong and is always dominated by lower resilience, and the geographical distribution of spatial resilience in 63 counties is concentrated. 2) The Harbin-Changchun Urban Agglomeration spatially presents a 'basin-like' pattern with a high surrounding and a low center, in which the low-resilience zone is distributed in the central part of the Harbin-Changchun Urban Agglomeration in the shape of a group, and the middle-resilience zone and the high-resilience zone are located on the east and west sides of the Harbin-Changchun Urban Agglomeration in the shape of a 'cluster'. 3) The spatial variability of different levels of resilient areas in the county spatial resilience of the Harbin-Changchun Urban Agglomeration is significant, and the spatial clustering characteristics between resilient areas of the same level are significant, but the trend of clustering is weakening. 4) The spatial resilience of counties in the Harbin-Changchun Urban Agglomeration was initially affected by its own development. With the evolution of time, the three factors of economic foundation, social demand and environmental control have had different degrees of impact on spatial resilience. The response of the spatial resilience of counties in the Harbin-Changchun Urban Agglomeration to economic foundation is the most active, forming a significant dynamic response relationship with the spatial resilience. The response of the spatial resilience of counties in the Harbin-Changchun Urban Agglomeration to social demand and environmental control has a time lag and less fluctuation, which is a driving force for the improvement of the spatial resilience of counties.
Passenger and freight transport are essential components of urban and regional mobility and play different roles in forming urban and inter-regional linkage systems. This study constructs a spatial interaction network of passenger and freight flows based on GPS trajectory data of passenger and freight vehicles of Hunan Province, China. The statistical characteristics, the competitiveness of nodes, and passenger and freight network community structures are compared using social network analysis methods. The differences in passenger and freight flow patterns among counties in the study area are explored. The results are as follows: 1) The connectivity of the passenger network nodes is similar to those in the freight network. Each node has passenger or freight connections with about 40 surrounding districts or counties on average, but the flow between the nodes of the passenger network is larger than that in the freight network, and its average weighted degree is 2.5 times that of the freight network. 2) The passenger network forms an east-west corridor linking Changsha, Yiyang, Changde, Zhangjiajie, and Xiangxi Tujia and Miao Autonomous Prefecture, while the freight network establishes a north-south corridor centered on Changsha, extending from Yueyang in the north to Chenzhou in the south. 3) Both passenger and freight networks have a clear internal grouping structure, revealing significantly different spatial grouping patterns of passenger and freight networks.
The outbreak of COVID-19 epidemic at the end of 2019 had a huge impact on China's economic development. Affected by economic globalization, industrial development will continue to face the impact of global supply chain obstruction and falling external demand. The downward pressure on the economy is huge, and achieving post-epidemic economic recovery has become an urgent and practical problem that needs to be solved. Based on micro-enterprise data, this study explores the industry characteristics and spatial differentiation of industrial resilience in Jiangsu Province under the impact of COVID-19, and using binomial logistic regression analyzes the influencing factors of industrial resilience from the perspectives of industrial structure and regional environment. There are four main findings. First, the industrial resilience of different industries showed that technology-intensive was greater than capital-intensive than labor-intensive. Second, the spatial distribution of technology-intensive, capital-intensive, and overall industrial resilience all present a pattern in which Southern Jiangsu was higher than Middle and Northern Jiangsu. Third, there was a significant positive spatial autocorrelation in the distribution of labor-intensive, technology-intensive and overall industrial resilience. The high-high agglomeration area of industrial resilience was mainly distributed in Southern Jiangsu, while the low-low agglomeration area was concentrated in Northern Jiangsu. Fourth, among the influencing factors of industrial resilience, specialization had a negative impact on the resilience labor-intensive industries, unrelated diversity could promote the resilience of labor-intensive industries. Related diversity and the density of related industries all had significant impacts on the industrial resilience, and the dependence on foreign trade had an inhibitory effect on industrial resilience. Finally, specific countermeasures and suggestions are proposed to improve industrial economic resilience of Jiangsu Province from the aspects of sectors differences, regional differences, industrial structure and foreign trade dependence, hoping to provide reference for high-quality economic development after the COVID-19.
The super-efficient SBM model considering undesired output was introduced to measure the green innovation efficiency of equipment manufacturing in 46 prefecture-level cities along the Beijing-Shanghai high-speed railway, and the spatial association network pattern was depicted based on the revised gravitational model, and node cities and their radiation characteristics were analyzed by combining Converse fault points, maximum gravitational lines and field strength models. The results show that, the green innovation efficiency of the equipment manufacturing industry along the Beijing-Shanghai high-speed railway was generally an "S" growth trend, which could be divided into growth period and stable period, and the spatial distribution pattern was gradual and robust. The spatial connection network was generally distributed in a pattern of "dense at both ends and sparse in the middle". The number of network relationships and network density were fluctuating, with a significant network small-world nature. Beijing, Shanghai, Nanjing, Suzhou and Tianjin played the role of "navigator" and "broker" in the network, and Suzhou played an obvious role as a "bridge". The radiation range of Beijing, Shanghai and other node cities was expanding, and the radiation intensity was continuously strengthening. Therefore, it was the key to improve the overall level of the green collaborative innovation network of equipment manufacturing industry along the Beijing-Shanghai high-speed railway to reasonably guide the radiation effect of the advantageous leading areas.
Based on the panel data of TCM (Traditional Chinese Medicine) resources of China (not including the data of Hong Kong, Macao and Taiwan) from 2011 to 2020 and the POI data of TCM tourist attractions, this paper applied GIS spatial analysis and statistical methods to analyzing the spatial distribution and type characteristics of TCM resources in China from three dimensions of TCM, TCM and tourism, and proposed the tourism development model of TCM resources in China. The results showed that: 1) The market scale of TCM resources was large, reaching one-third of the total scale of China's pharmaceutical market, and showed a steady growth trend. Its spatial distribution has obvious regional characteristics, showing that Chengdu-Chongqing region and the Central Plains region lead the development on the whole, and the cold temperate zone in Northeast China, tropical zone in South China and temperate zone in Northwest China are relatively backward. Yunnan, Sichuan, Hubei, Gansu and Henan are the main gathering areas of authentic medicinal materials. 2) The spatial differentiation of TCM resources was obvious, with more TCM resources distributed in Guangdong, Shandong, Henan, Jiangsu, Sichuan, Shanxi, Hebei and other provinces and regions, but less in Tianjin, Hainan, Ningxia, Qinghai, Tibet and other provinces and regions, and the differences between provinces (regions) gradually expanded. However, from the perspective of spatial agglomeration characteristics, the number of TCM resources in most regions was on the rise; 3) The distribution of TCM tourist attractions in China is spatial agglomeration, with large concentration and small dispersion, mainly concentrated in the Beijing-Tianjin-Hebei, the Yangtze River Delta, the Pearl River Delta, Chengdu-Chongqing and the middle and lower reaches of the Yellow River. Among them, the Beijing-Tianjin-Hebei is the high-density core area, the Yangtze River Delta, the middle and lower reaches of the Yellow River, the Chengdu-Chongqing and the Pearl River Delta are the sub-density core areas. 4) According to the matching relationship of "medicine-medicine-tourism", 31 provinces and regions can be classified into 3 categories: optimal matching area, sub-optimal matching area and unbalanced matching area, accounting for about 1/3 of the total. Based on the mechanism analysis of "push-pull" theory, the logical relationship between TCM, TCM and tourism matching was clarified. Accordingly, three major tourism development modes of TCM resource optimization, key development and special development were put forward to clarifing the advantages and paths of TCM resource tourism development in each region. To sum up, the research on the spatial distribution of TCM resources and its matching relationship with tourism development is of great significance for ensuring the development of TCM tourism industry and promoting the coordinated development of regions. Further analysis and consideration are needed for the regionalization, regional product development and market potential of TCM tourism in China.
Science and technology innovation platform constitute a crucial aspect of the regional innovation system. A well-designed platform system positively impacts the improvement of regional innovation capacity and efficiency. Consequently, there is a pressing need to examine the distribution patterns and formation mechanisms of innovation platforms. Based on the data of the Ministry of Science and Technology from 1984 to 2020, this paper reviews the development context of national innovation platforms in the Yangtze River Delta (YRD). On this basis, we analyzed the spatial-temporal evolution characteristics of innovation platforms in the years 2000, 2010, and 2020, focusing on three categories, namely, research and development (R&D) platform, industrial technology platform, and service innovation platform. Additionally, we also explored the influencing factors that impact the spatial distribution of innovation platforms by using the econometric model. The main conclusions are as follows: 1) In terms of the time series evolution, the cultivation of innovation platforms in the YRD began in the 1980s and has since evolved over time. Initially, the focus has been on research and development platforms. As policies for innovation have evolved, there has been a significant growth in innovation platforms that center on technological enterprise transformation and mass innovation. The system of innovation platforms is becoming increasingly diversified and open. 2) In terms of the spatial evolution, the geographical distribution of sci-tech innovation platforms across cities is spatially uneven. Jiangsu Province has the greatest number of platforms and the least city variation, whereas Anhui Province has the fewest number of platforms and the greatest city variance. The spatial pattern of innovation platforms has shifted from single-center and axis agglomeration to multi-center and regional agglomeration, presenting a trend of diffusion from the center towards the periphery. 3) The distribution patterns of different types of innovation platforms exhibit significant heterogeneity. Specifically, the R&D platforms show a spatial pattern as "point-pole" configuration, while the industrial technology innovation platforms are concentrated in an area shape like ">" with Shanghai, Nanjing and Hangzhou as endpoints. The service innovation platforms present a "Z" type spatial pattern with a relatively low degree of agglomeration. 4) The overall spatial distribution of innovation platforms results from the interplay of economic and political factors, which show both similarities and differences between different types of innovation platforms. Regional higher education institutions, human capital and financial investments in science and education have a significant positive impact on the distribution of various innovation platforms. On the basis of these findings, we propose recommendations for optimizing the spatial distribution of innovation platforms in the Yangtze River Delta.
Ensuring national food security is an important part of implementing the national strategy of northeast revitalization, and the coordination between black soil protection and regional development is an important practical problem to be solved in the development of Northeast China. This article comprehensively evaluates the regional development and black soil protection of the county units in 2020 by constructing the index system, using the coupled coordination degree model to measure the coupling and coordination between black soil protection and regional development, and put forward the targeted measures of black soil protection and regional high-quality development of different types. The study found that: 1) A large number of county-level units with low level of regional development in black soil area have formed obvious regional development subsidence areas in the central part of northeast China, indicating that the utilization of black soil has not become the main driving force for the development of central Northeast China. 2) The coupling degree between black soil protection and regional development in Northeast China is strong, which indicates a high degree of interaction between regional development and black soil protection, and the relationship between the two needs to be valued; 2/3 county units' black soil protection and regional development are in the dysregulation stage in the coupling and coordination process, indicating that coordinating the relationship between black soil protection and regional development by different types is very urgent. 3) Based on the comprehensive level of black soil protection and regional development and the coupling coordination, the northeast black soil area can be divided into seven types: Weak regional development-weak black soil protection; Weak regional development-good black soil protection; Weak regional development-strong black soil protection; good regional development-weak black soil protection; Good regional development-good black soil protection; Good regional development-strong black soil protection; Strong regional development-good black soil protection, according to each type's area characteristics, can promote black soil protection and regional development by classification.
The COVID-19 pandemic has caused a huge impact on the social and economic system of the whole world. Countries quickly halted work and production and adopted epidemic prevention policies, so world trade was once suspended. In this context, export resilience began to attract attention. Using Chinese Customs database, this paper analyzes the evolution of the geographical pattern of China's export and the changes in China's position in the world trade network during the COVID-19 pandemic, and explores China's regional and industrial export resilience. The main findings are as follows: 1) During the COVID-19 pandemic, China showed strong resilience while its export resistance is relatively weak, and it has industrial and regional heterogeneity. The difference mainly comes from factors such as factor endowment, industrial structure, global supply chain dependence, prevention policies, and trade barriers. 2) China's strong export resilience comes from the import demand of the destination country for epidemic prevention materials, the supply capacity brought by China's rapid control of the epidemic and its strong ability to switch production. 3) The pattern of China's export destination countries has not undergone major changes. It is found that the distribution of export value is positively correlated with the degree of activeness of epidemic prevention and control in the destination country; 4) After the epidemic, China's position in the world trade network has increased significantly, especially in the medical supplies, and the world trade has formed a network with China as a high-throughput central node. Finally, this paper also discusses the differences in regional economic resilience under the background of the COVID-19 pandemic and the financial crisis. It is believed that under the background of the COVID-19 pandemic, the urban export-oriented economy, the two-way impact of the supply side and the demand side, and policy factors have a more obvious impact on economic resilience.
Sexual crime is an unlawful behavior that seriously violates personal rights, human dignity, and social order. It has become a widespread social concern to prevent and control sexual crime. Based on the sexual crime records obtained from Haining Municipal Public Security Bureau, this research compares the spatial-temporal patterns of rape and indecency crimes between January 2014 and September 2021. The results show that: 1) Both rape and indecency crimes tended to occur in the nighttime period from 19:00 to 3:00 the next day. Rape crimes showed no apparent seasonal variations while indecent crimes showed a monthly pattern that peaked in July and August. 2) Both rape and indecent crimes were concentrated in commercial and residential areas. Rape crimes are more spatially clustered than indecent crimes. Rape crimes showed a spatial distribution pattern with a core surrounded by several hotspots, while indecency crimes were spatially distributed with a pattern of "two centers, one area, multiple hotspots". 3) Common factors significantly driving spatial variations of rape and indecency crimes included population density, male population, female population, the male population aged 14-25, presence of Internet cafes, hotels, chess and card rooms, KTVs, and foot massage parlors. 4) The interaction between population variables and urban functional place variables can explain the spatial distribution of both rape and indecency crimes better than either of them alone. The indecency crime can be better explained by the interactions than the rape crime, and there were more functional places that had a significant impact on the indecency crime than the rape crime. In summary, both rape and indecency crimes showed obvious spatial-temporal patterns and were influenced by both the spatial distribution of population variables and certain types of urban functional places. In places where there were more hotels, internet cafés, teahouses, chess and card rooms, bars, and KTVs, the numbers of rape and indecency crimes were also higher. These findings provide important support for the practical prevention of sexual crimes in Haining City.
This study collated the research results of forest canopy and litter sites in Southwest China from 2009 to 2018, combined with three models (canopy interception, litter interception and soil water storage model), evaluated the water conservation of forest ecosystems in Southwest China from three aspects: canopy interception, litter interception and soil water storage, and analyzed the spatial and temporal variability of water conservation. The results showed that: 1) The average annual water conservation of forest ecosystems in Southwest China (2009—2018) was (1101.54×108 ± 313.15) m3, of which canopy interception accounted for 24.57%, litter interception accounted for 1.61%, and soil water storage accounted for 73.82%. 2) The mixed forest ecosystem in Southwest China was dominant, contributing 44.04% of water conservation. The water conservation capacity of deciduous broad-leaved forest per unit area is the highest [(4228.57 ± 2325.71) t/hm2]. 3) As the altitude increases, the water conservation increases first and then decreases, reaching the maximum at 1000-1500 m. The results of this study can serve the future value assessment of forest ecosystem service functions in Southwest China.
In the simulation of glacier energy and mass balance, integrating and assimilating multi-source high-quality dataset is an important way to understand glacier change in a longer time dimension, which is of great significance to quickly and effectively deal with the drastic change of glacier and its impact under the background of climate warming. Based on the evaluated and corrected datasets of High Asia Refined analysis version 2 (HAR v2), the single-point COupled Snowpack and Ice surface energy and MAss balance model (COSIMA) was used to systematically analyze the mass and energy exchange process and its response to climate change in 2012 at the meteorological station (4550 m), which is located in the Laohugou Glacier No.12 ablation zone of Qilian Mountains. On this basis, the time series of mass and energy balance from 1991 to 2020 were reconstructed. The results showed that: 1) HAR v2 dataset had a good applicability in the study area. Simulation result of COSIMA driven by this dataset indicated that the annual cumulative mass balance in the glacier ablation zone in 2012 was –2333 mm w.e.. The net shortwave radiation was the primary sources of glacial melting (90.1%), and net longwave radiation was the main output of surface energy (58.6%). 2) The glacier mass balance in the ablation zone generally maintained a linear response to precipitation change, while it showed an obvious asymmetric and nonlinear response to temperature change. 3) In recent 30 years, the multi-year average proportion of net shortwave radiation and sensible heat flux which are chiefly responsible for glacial melting was 89.2% and 10.8%, respectively. For energy output, the multi-year average proportion of net longwave radiation, melting energy, latent heat flux and ground heat flux was 58.6%, 26.5%, 12.4% and 2.5%, respectively. The glacier ablation zone has been in a state of high mass loss which reached to –2392 mm w.e. annually. Under the influence of cloud cover and other meteorological factors (e.g., relative humidity, wind speed), the changing range of net shortwave radiation was much larger than that of other energy terms such as sensible heat flux, net longwave radiation and latent heat flux. This was the main reason for the formation of strong and weak ablation years. In addition, solid precipitation also played an important role in glacier mass balance.
Based meteorological data from 14 weather stations in Hexi Area during 1960—2019, the wind erosion climatic factor index was calculated using function given by the UN Food and Agriculture Organization and the basic features of wind erosion climatic erosivity were analyzed. The results showed that the wind erosion climatic factor indexes were in range of 8.7-132.9 and the average value was 36.6. The annual average C values obviously decreased at the rate of approximately 4.03/10a (α=0.001) in Hexi Area during 1960—2019. On the spatial, the C values increase from the southeast to the northwest. The C values can reach to 132.9 in the west and reduced to about 8.7 in the eastern part of Wuwei City. The C values has a significant seasonal variation. The largest value is in spring with the value of 14.8 and the second large value in winter with the value of 10. Summer shows very small value. Abrupt change was found in the long-term climate variation. The Mann-Kendall abrupt change test showed that the year of 1984 can be viewed as turning point of the abrupt change on an annual C value. While from the perspective of seasonal C values, the abrupt change points in spring and summer appeared slightly earlier than those in autumn and winter. The abrupt change of the average C values happened in 1983 and 1984 in spring and summer while that of autumn appeared in 1987. The abrupt change of winter happened in 1988. Wind speed was the decisive factor of the C values in Hexi Area.
Due to the accumulation of detrital materials, dry lake basins and rivers often became the main sand/dust emission source areas in arid and semi-arid regions. At present, the research on the sand/dust process of dry lakes is mostly concentrated in arid and semi-arid areas. Due to the climate and underlying surface characteristics of the Qinghai-Tibet Plateau (QTP), previous studies often ignore the sand/dust emission process. However, in recent years, affected by the trend of warming and humidification, the rainfall in the QTP has increased, and flood events have occurred frequently, resulting in an increase in surface erodible sediments. Under the influence of its high wind energy environment, it is easy to cause ssand/dust events. In order to put forward scientific sand/dust control countermeasures, it is necessary to clarify the spatio-temporal distribution process of sand/dust emission. Therefore, based on meteorological, remote sensing, global land data assimilation systems and other data, the IWEMS (integrated wind-erosion modelling system) and DEAD (dust entrainment and deposition) were used to simulate the sand/dust emission process in the Zhuonai Lake Watershed from 2000 to 2020. The results show: 1) The seasonal variation rate of sand/dust emission in Zhuonai Lake watershed is large. The high value of sand/dust emission generally occurs in winter and spring, and the low value is mostly in summer and autumn. The annual variation of sand/dust emission was large before the Zhuonai Lake broken, and after the break event, the sand/dust emission showed a significant upward trend, indicating that after the lake burst, the backwater lake bank provided a rich source of sand/dust emission. 2) From the perspective of spatial distribution, the sand/dust emission in the Zhuonai Lake has great spatial heterogeneity, and the sand/dust emission rate along the lake coast is significantly higher than that in other areas. After the lake burst, the high value area of sand/dust emission gradually moves from the north bank to the southeast bank. 3) After the lake burst, the influence mechanism of wind speed on sand/dust emission has changed greatly, and the sand/dust emission process is more likely to occur. The results provide a theoretical basis and data support for the prevention and control of wind and sand/dust disasters in the Zhuonai Lake Watershed.
