Archive

  • 2023 Volume 43 Issue 5
    Published: 30 May 2023
      

  • Select all
    |
  • Chen Fei, Li Yonghe, Zhang Shuai, Ma Xiaoqing, Yu Yiting
    Download PDF ( ) HTML ( )   Knowledge map   Save

    The disorderly sprawl of land hinders the effectiveness of urban operations. Achieving compact development through optimized territorial spatial planning tools has become a crucial issue for high-quality urban development. This is particularly true for large cities where there is a significant disparity in land expansion rates between the suburbs and the central urban areas. Thus, this study emphasizes the importance of targeted zoning optimization suggestions to achieve efficient space utilization. Based on the connotation of spatially compact development, a comprehensive index model is constructed to analyze the evolution characteristics of spatial compactness in Shanghai during 2005-2020 and compare it with domestic and foreign cities. In addition, a polynomial functional relationship regression model is used to explore the correlation between the sub-indices of urban form structure and spatial compactness, as well as the factors contributing to any differentiation observed. Finally, a Geographically and Temporally Weighted Regression model is used to analyze the effect of urban morphological structure on spatial compactness from the perspective of different city districts. Research Findings: 1) Shanghai is at a high level of compact development compared to similar cities. The pattern of spatial compactness is circular. It shows a high center and a low periphery, with the central region generally tending to be stable and the peripheral region growing faster. However, there are significant differences in the spatial pattern of compactness sub-indicators due to the influence of policies and planning. Compared with domestic and foreign cities, Shanghai presents the characteristics of highly compact development. 2) Urban density has an inverted "U"-shaped relationship with spatial compactness, and correlation is the strongest. In contrast, the mix degree of urban function and land-use form have a nearly linear relationship with spatial compactness, respectively. 3) Overall, it is evident that land-use form can inhibit spatially compact development, though both urban density and the mix degree contribute to it. At the zoning scale, the impacts of form, function, and density on spatial compactness vary dramatically. In the peripheral urban areas, the impacts of the three types of factors on spatial compactness align with the overall findings. However, in the central urban areas, urban density tends to have a negative effect on improving spatial compactness, while land-use form has a notable positive impact. 4) An adjustment to the spatial and morphological structures associated with territorial spatial planning may facilitate compact development within core and periphery areas. Specifically, the central urban areas should prioritize reducing urban density and optimizing land use structure, while the peripheral urban areas should focus on improving urban attractiveness and reducing land use fragmentation.

  • Feng Zhangxian, Li Jiaxin, Wang Shijun, Yang Zhipeng, Ji Gufeng
    Download PDF ( ) HTML ( )   Knowledge map   Save

    Based on the population change rates of municipal districts of cities in Northeast China from 2010 to 2018, this study first identified shrinking cities in Northeast China, and redefined urban vitality to construct its multi-indicator evaluation system, then characterized the spatial-temporal and evolutionary patterns of urban vitality of shrinking cities, and finally analyzed the influencing factors of these cities. The results showed that: 1) Based on the population data, there were 16 shrinking cities and 7 growing cities in Northeast China, which exhibited the spatial characteristics of "the coexistence of shrinkage and growth" and "the significant concentration of shrinkage". 2) The urban vitality of cities in Northeast China has improved as time went by, showing a spatial pattern of "core-edge" and a provincial spatial difference of "lower in the north and higher in the south". 3) The urban vitality of shrinking cities was generally lower than that of growing cities. From the perspective of different subsystems of urban vitality, the economic vitality of shrinking cities was generally low, but the performance of environmental vitality, cultural vitality and social vitality of certain shrinking cities was better than that of growing cities. 4) The evolutionary trends of urban vitality coordination degree of shrinking cities were not so characteristic. The original vitality foundations and background conditions of a city may have important influences on the change of urban vitality, and maintaining a high-level and coordinated urban development structure can play an important role in promoting urban vitality. 5) The main influencing factors of urban vitality were the degree of urban functionality mix, the proportion of tertiary industry in GDP and the treatment rate of urban domestic sewage. For shrinking cities, optimizing the environment quality of the built-up areas and ecological environment, improving the diversified accommodation degree of urban space, and speeding up the industrial transformation and upgrading are the keys to improve urban vitality. Two important contributions of this study are that it provides valuable insights into enhancing urban vitality and achieving high-quality development in shrinking cities, and it also offers guidance for effectively implementing the Northeast Revitalization Strategy and overcoming the challenges of regional decline in Northeastern China.

  • Yang Ningning, Luo Xiaolong, Tian Dong, Lu Jiancheng
    Download PDF ( ) HTML ( )   Knowledge map   Save

    The traditional core-periphery theory mainly focuses on how the edge develops to the core. However, the core can also develop inversely to the edge in practice. This research takes Bengbu as an example to study systematically the process and internal mechanism from provincial core city to the marginal city under the theory of core-periphery theory basing on the research aspect of "polarization" and "diffusion". The result shows that: 1) The external characteristics of the rise of the "core" of Bengbu is manifested in the transportation hub location where the Jinpu Railway and the Huaihe River water transport meet, and the internal characteristics are manifested in the economic status of the core city of industrial development in Anhui Province and the innovation resource agglomeration advantages of the core city of the Hewubeng National Independent Innovation Demonstration Zone. At the same time, the above three dimensions are also the power force for the rise of the "core" of Bengbu, following the theoretical path of the formation of the "core" under the framework of the traditional core-periphery theory. 2) The external characteristics of Bengbu's "marginalization" are mainly manifested in the marginal location of strategic virtual areas such as the regional integration of the Yangtze River Delta, the Hefei metropolitan area, and the Anhui River urban belt, as well as the superposition effect of the decline of the status of railway transportation hubs and the spatial scarcity of land and water transportation hubs. And the internal characteristics are mainly manifested in the insufficient momentum of economic development in the industrial dimension, as well as the resulting outflow of resources and factors, and the lack of innovation power. 3) The marginalization of ''core'' and the motivation of ''marginalization'' locking is originated from the inclination of policies and the spontaneous imbalance of the market economy. Among them, policy force plays a leading role, through the subjective initiative choice of core cities, and changes the path of resource agglomeration and diffusion under the traditional core-periphery theory framework, coupled with the interest-driven nature of market mechanisms, the "core" and "marginalization" status of Bengbu and Hefei have been reconstructed. At the same time, the marginalized Bengbu is facing the dilemma of urban contraction at the same time, and the cycle of the two forms a negative feedback to weaken the diffusion effect of Hefei's "core". 4) The localized theory explanation of the creative "core" regressive succession is that policy forces become the leading mechanism of core-marginalization structure formation, polarization and reconstruction, often based on specific development orientation to strengthen the polarization effect of the target "core", reverse the flow of economic resources under the spontaneous action of the market, and guide the "core" to exert diffusion effect in a timely manner; however, the market mechanism plays a decisive role in the specific implementation results of the diffusion effect. In view of the interest-driven nature of market players, the development gap between the "marginalization" and the "core" is the key, and the excessive development gap will lead to the displacement of the diffusion effect and weaken the radiation driving effect of the "core".

  • Sun Pingjun, Peng Yali, Cao Naigang, Quan Jinsong
    Download PDF ( ) HTML ( )   Knowledge map   Save

    The paper selects the Yanbian Korean Nationality Autonomous Prefecture in Jilin province as the sample unit. It theoretically explores and empirically verifies the development characteristics, formation mechanisms and response patterns of shrinking cities and towns under the context of ethnic autonomous regions. The results show that: 1) 62.5% of the cities and towns in the Yanbian Korean Nationality Autonomous Prefecture are diagnosed as shrinking areas. However, the whole is not a shrinking city. The five identified shrinking cities show obvious "common issues" in the aspect of industrial development, population structure, economic concept and land use. 2) The form of shrinking cities and towns are the result of the "drive" of spatial differentiation within the middle circle functionally related areas, the "extrusion" of individual development transformation of shrinking regions in the inner circle + the "pull" of external regional spatial connection in the outer circle. 3) This paper presumes the planning response path for the shrinking cities and towns in Yanbian Korean Nationality Autonomous Prefecture as "strengthening the integrated development with the functional areas in the middle circle, and improving the well-being index of the residents", and formulates specific countermeasures and proposals accordingly.

  • Li Yongzhen, Dong Xiaofeng, Byambakhuu Gantumur, Battsengel Vandansambuu, Tong Siqin, Bao Yuhai, Bao Meili, Wu Falin
    Download PDF ( ) HTML ( )   Knowledge map   Save

    Nighttime light data provides the strong data and technical support for monitoring urbanization and regional development, but its specific applicability needs to be further explored. Based on GIS and RS technology, this paper obtains Mongolian nighttime light data from 1992 to 2018 by correcting DMSP/OLS and NPP/VIIRS data, aiming to analyze the applicability of nighttime light data to less developed countries. The research results show that: 1) The agglomeration effect of nighttime lights in the capital city cluster of Mongolia is obvious, presenting a spatial pattern of "concentration in the north central regions, and rapid growth along the railway line"; The total value of nighttime light showed a significant growth trend after 2010, which indicates that the power supply has achieved rapid and stable growth; 2) When the spatial scale is larger, the more applicable the nighttime light data is, and the higher the accuracy of reflecting social and economic activities. At the same provincial scale, only when the urbanization rate is greater than 30% and the population cannot be lost in large quantities, the nighttime light data has a positive correlation with the number of people, otherwise it is negatively correlated or irrelevant; 3) NPP/VIIRS has detected more settlements than DMSP/OLS, and stable power supply is key to whether settlements were detected;

  • Li Xiaojian
    Download PDF ( ) HTML ( )   Knowledge map   Save

    By examining the relevant monographs and other literature in the field, we analyze the research characteristics and theoretical intersections of four major schools of Economic Geography in the international academics: Geographical Political Economy (GPE), Institutional Economic Geography (IEG), Evolutionary Economic Geography (EEG), and Relational Economic Geography (REG), being proposed and embraced by Economic Geographers. We conclude that there are many similarities among those schools in a common context. GPE and IEG intersect in the study of institutions; PEG and EEG both emphasize the study of "process" or "evolution"; and GPE and REG share commonalities in the relationship between people and organizations. REG and EEG share a common focus on path dependence; EEG emphasizes the relationship between institutions and economic evolution, while REG focuses on the relationship between institutions and economic interaction, and they cross with IEG. The core features of each school are: GPE focuses on the geographic process of political economy (production relations), IEG examines specific institutions at each place that shape or constrain economic behavior and economic outcomes, EEG focuses on the spatial evolution of economic actors such as firms and industrial clusters, and REG focuses on the interrelated role of various factors that shape the economic landscape. These schools of thought make up for some of the shortcomings of the normative analysis of Economic Geography, while forming a deficiency in the study of universal laws. Theoretical construction of Chinese Economic Geography should pay attention to the balance between the specificity of economic phenomena and the generality of theories while encouraging academic views to contend.

  • Deng Di, Zhang Xiaoming
    Download PDF ( ) HTML ( )   Knowledge map   Save

    Under the influence of postmodernism, the middle class are trying to extricate themselves through the choice of mobility from the dilemma of modernity. Lifestyle migration is an exploration and practice of modern people's yearning for ''a better life''. Now, there are many debates on the definition of lifestyle migration, hence this study takes Dali's lifestyle migrants as the case object, and uses the methods of in-depth interview, participatory observation, subject coding, and hermeneutic analysis to explore the connotation of ''lifestyle''. It is found that lifestyle is a multi-level and multi-dimensional conceptual system. For the reason of ''changing their lifestyle'', people migrate from cities to Dali with transforming the life objectives, reconstructing the activity orders, and changing the interpersonal ways. First, new migrants free themselves from the shackles of universal values and build a more self-centered life goal system. Second, migrants build a more flexible order to manage their daily activities. Third, new migrants construct new relationship boundary with a principle of ''non-interference''. In addition, the lifestyle change of new migrants in Dali is not an isolated individual practice, but also promotes the Dali lifestyle migrants' group develop to a distinctive value system, affairs system, and community system. This study provides an analytical framework from motivation to practice, from individual to group. The ''lifestyle'' in this study is seen as a ''fluidity'' phenomenon type that is always open, inclusive, and dynamic. On the one hand, this study aims to clarify the ''lifestyle'' in the context of migration. On the other hand, it helps local governments to better understand the demands and behavior of lifestyle immigrants, good for creating a better policy environment, further stimulate the production vitality and promote the tourism development.

  • Wen Xinyu, Fan Xingang, Yang Meiling, Zhu Zhiling, Mi Wenbao, Duo Junjie
    Download PDF ( ) HTML ( )   Knowledge map   Save

    Measuring the comprehensive characteristics and regionalization of regional public emergency risk is an important task to improve the predictability and operability of China's emergency management at present and in the future. Based on regional disaster system theory and risk concept, Integrate risk factors such as possibility, hazard and vulnerability, According to the process of risk identification, risk analysis, risk assessment, trying to build the PHV integration model (Possibility, harmfulness, vulnerability integrated model) for integrated regional risk assessment. Meanwhile, guided by the evaluation indicators, build the multi-source data interface of "news + space + Statistics". At the kilometer grid scale, the risk possibility, harm, vulnerability and comprehensive risk level of multiple disasters are calculated. And Inner Mongolia Alxa League as a case test. The results show that: 1) Probability model to disaster events do comprehensive weights of disasters, the risk loss in harmfulness index estimation, prone to identifying risks and included in the probability index calculation, to overcome the past research weight set unreasonable, quantitative approach to a single disaster influence degree and especially risk assessment results for the level value of the "bottleneck". 2) The case results show that the model and multi-source data method can realize multi-disaster comprehensive risk assessment in the absence of large-scale regional disaster data, which has certain application and promotion value.

  • Zhu Yuanyuan, Luo Yuan, Wang Youcong, Chen Siyun
    Download PDF ( ) HTML ( )   Knowledge map   Save

    The rapid exchange of factors between urban and rural areas has created a new spatio-temporal phenomenon that significantly affects the development of modern rural culture. The concept of this high-speed interaction and flow of people, goods, capital, and other elements has become an important factor to consider when exploring the evolution and mechanisms of public cultural spaces in suburban villages. This has led to the emergence of new spatial-temporal patterns that have significant implications for rural culture development. In light of this, the aim of this study is to re-examine and interpret the new era value of Chinese rural culture under the interaction of multiple elements. Specifically, it focuses on the diverse forms and carrier functions of public cultural spaces in a village that is situated in the context of urban-rural integration. Chaizhuang Village in Wuyang County, Henan Province, provides an excellent case study for our analysis due to its unique characteristics. To achieve our research goals, we used remote sensing images and survey interviews to analyze the development process and driving mechanisms of public cultural space in Chaizhuang Village. The research results indicate that: 1) The public cultural space in Chaizhuang Village has experienced 2 evolution processes. The first is the structural evolution process from villagers' self-organization to government leading and then to multiple subjects' participation. The second is the evolution process of the pattern from supply not meeting demand in the traditional period to supply adapting to demand in the transition period, and then supply-demand integration in the new era. 2) The preference and proportion of public cultural activity spaces in Chaizhuang Village, as well as the allocation of villagers' public cultural activity time, have undergone significant changes under the influence of urban-rural factors. 3) We find that the evolution of rural public cultural space is a result of the joint action of internal demand forces such as villagers' cultural needs and government construction, external supply forces such as policy promotion and market demand, as well as potential resistance forces such as changes in the villagers' living structure. Considering these findings, our study contributes to the expansion of the research objects and contents of rural cultural geography. At the same time, it also highlights the important role of geography in serving national strategic needs for rural revitalization by exploring the evolution and mechanisms of rural public cultural space from a macro perspective of China's urban-rural integration development.

  • Niu Qiang, Sheng Jiafei, Liu Xiaoyang, Yan Xuexin
    Download PDF ( ) HTML ( )   Knowledge map   Save

    With the development of country's economy, people's demand for a higher quality of life has become stronger and stronger, and commercial and public service facilities have become an important factor affecting intra-urban migration. Taking Wuhan Urban Development Zone as an example, this paper firstly uses mobile phone signaling time series data to mine intra-urban migration behavior, and then combines POI (point of interest) data of service facilities, comprehensively uses multiple linear regression and geographically weighted regression methods to analyze commercial facilities (catering, daily life, shopping facilities) and public service facilities (medical and educational facilities) on intra-urban migration. The results show that the influence of different service facilities on the intra-urban migration is different, and the influence of service facilities in the central urban area and the suburbs shows obvious spatial differentiation characteristics: 1) Among the commercial service facilities, catering facilities have the greatest impact on intra-urban migration, followed by daily life facilities, and finally shopping facilities. In terms of space, the influence of commercial service facilities in suburban areas on intra-urban migration is stronger than that in central urban areas, and the influence of each new city is also different; 2) Among public service facilities, medical facilities compared with educational facilities, the impact on intra-urban migration is stronger, and the impact of public service facilities in central urban areas on intra-urban migration is higher than that in suburban areas. The research results can provide a reference for the differentiated configuration of service facilities, the enhancement of regional attractiveness and the optimization of urban spatial structure.

  • Yu Linghui, Yuan Feng, Wu Di, Wu Jiawei
    Download PDF ( ) HTML ( )   Knowledge map   Save

    Analyzing the reinvestment process of multinational enterprises (MNEs) in China—one of the countries that receive the largest foreign capital inflows-helps to unpack the strategies and behaviors of MNEs' foreign capital localization in host countries. Based on the initial investment entry paths and reinvestment network expansions of the Fortune 500 companies in China, this paper constructs an analytical framework including country-of-origin factors, host country factors, and firm-level factors based on a dual-embedded and dynamic evolutionary perspective, and uses a negative binomial regression model to explore the multi-scale, multi-dimensional and multi-mechanism processes of subsidiary (re)investment in China. The study shows that there are differences in the investment paths of MNEs from different countries in China. Specifically, MNEs from North America and Western Europe, which have greater economic and cultural distance from China, prefer to enter the Chinese market from springboard cities, while MNEs from Japan and Korea prefer to set up branches in China directly. The reinvestment of MNEs' subsidiaries in China shows double embeddedness: On the one hand, the institutional distance between the country-of-origin and China has a restraining effect on the reinvestment decision of MNEs' subsidiaries in China, but the effects of economic, cultural and geographical distance become insignificant; On the other hand, the reinvestment behavior of MNEs is also influenced by the location of the city where they first invested in China and the network relationship between Chinese cities. In addition, the reinvestment process of subsidiaries in China is characterized by path dependence and dynamic evolution, and the accumulation of knowledge in terms of the investment city and experience in the investment industry helps to expand the spatial choice of reinvestment.

  • Yan Jiahui, Zhang Yuejie
    Download PDF ( ) HTML ( )   Knowledge map   Save

    The three-stage super-efficiency SBM-DEA model was used to include the carbon emission in the efficiency measurement framework. Then the carbon emission efficiency of the four major favorable regions for beef cattle in China from 2007 to 2019 was measured, and the spatial and temporal evolution characteristics were discussed. Later, the exploratory spatial data analysis method was applied to discuss the spatial distribution pattern of each major production area. The results showed that: 1) External factors and random interference would have a significant impact on the calculation results of carbon emission efficiency in the major production areas of beef cattle, and the three-stage super efficiency SBM-DEA model could make the calculation results more consistent with the actual situation. 2) The carbon emission efficiency of beef cattle production areas in China is not high and the spatial distribution is not balanced, showing a spatial distribution pattern of ''Central Plains > Northeast > Northwest > Southwest''. 3) The low scale and low utilization rate of production factors were the main reasons for the low GML index of carbon emission efficiency in Chinese beef cattle production areas, and the deficiency in breeding technique support also caused the loss of carbon emission efficiency. 4) There was a positive spatial correlation in the carbon emission efficiency of the major beef cattle producing areas, and there was an aggregation effect in the spatial distribution, showing a ''U'' trend. During the study period, the H-H agglomeration area transferred from the central plains to Liaoning and Xinjiang, and then gradually gathered in the southwest main production area. As the H-L agglomeration area, Guizhou has not yet driven the low-efficiency areas around the southwest production area to form a regional growth pole.

  • Wang Yixuan, Tian Fang, Ni Jian, Cao Xianyong
    Download PDF ( ) HTML ( )   Knowledge map   Save

    Biomization is the traditional method for pollen-based biome reconstruction by assigning pollen taxa to plant functional types (PFTs) and then to biomes. However, the artificial setting of weight and threshold for pollen taxa during calculation could bias the objectivity and reliability of the reconstruction. In this study, we employed the modern pollen dataset (2324 sampling sites) from China together with their modern biomes to construct a neural network model for pollen-based biome reconstruction. By comparing the observed modern biome with the model-fitted biome for all modern sites, neural network model was confirmed to behave high reliability in biome reconstruction, supported by the higher accuracy (86.6%) than the traditional Biomization approach (68.8%) using the same pollen dataset. The neural network model was applied to the late Quaternary fossil pollen dataset from China to reconstruct the temporal-spatial patterns of terrestrial biome in China since the Last Glacial Maximum (LGM) at 500-year interval. The reconstruction results present that the forest was restricted in southern China during the LGM with cold and dry climate. Since the Last Deglaciation, forest expanded northward and westward, and its spatial distribution reached the maximum in the warm and humid Mid-Holocene. The change process of biome was consistent with the general patterns of global climate changes. However, during the late Holocene with enhanced human activities, biome changes for some special regions could be caused by human activities.

  • Wang Yong, Zi Feng, Lu Shanlong, Li Mingyang, Zhou Jinfeng, Yang Xiaohong, Wang Wenzhong, Niu Ruiji
    Download PDF ( ) HTML ( )   Knowledge map   Save

    Comprehensively using multi-source remote sensing satellite data, the interannual trends in the area of water bodies in the Tarim River Basin and its various water systems from 1989 to 2019 and the impact of surface water changes of each water system on groundwater in a typical area (Lop Nur) under the influence of climate change and ecological water diversion were analyzed. The results of the study show that: 1) The surface water area of the Tarim River Basin has been increasing in a significant trend the surface water area of the Tarim River Basin has been increasing significantly in the last three decades; 2) Precipitation is the main climatic factor causing changes in surface water area in the basin, while ecological water transfer affects the spatial distribution pattern of surface water in the basin; 3) The changes in the growth of surface water in each water system in the basin have a significant effect on the recovery of groundwater reserves in the Lop Nor area. The research results of this paper are of great significance for understanding the long-term changes of the surface-groundwater system in the Tarim River Basin and formulating a scientific and reasonable water resources development and utilization strategy.

  • Xiang Juncheng, Yang Hao
    Download PDF ( ) HTML ( )   Knowledge map   Save

    Quantitative reconstruction of the time-space disaster sequence on the provincial scale in historical era helped to keep better understand the environmental mechanism of the disaster. Based on the historical document data, the geographical regularity of flood and drought disasters in Qing Dynasty of Guizhou Region has been discussed by adopting the mathematical statistics and the spatial analysis. The results show that: 1) There were 1416 times of flood and drought disasters in the Qing Dynasty of this region. The slight, moderate and severe disasters accounted for 24.712%, 46.75% and 28.53%. 2) In all years of the Qing Dynasty, there were three extreme dry period in the 1650s, the 1910s and the 1990s. The prevalence of flood and drought disaster seemed more frequently in summer, the disasters of season span were more frequently from spring to winner. 3) On the prefecture scale, The frequency of floods and droughts in Zuiyi was the highest, in Songtao was the lowest. The flood disaster was much widely distributed than the drought disaster at the scale. The frequency of flood disaster had a positive relation with the frequency of drought disaster. 4) According to the average of Palmer Drought Severity index, the relative humidity was measured. The dry areas were distributed in spots in the province-wide, while, progressively narrow. The humid areas were progressively extend. 5) The temporal and spatial pattern was restricted by multiple factors such as climate, population pattern and social environment. Dry-cold climate was the catalyst of flood and drought disasters, and natural disaster was the inducing force. Flood and drought disasters are concentrated in dam with high population density and along land and water transportation. The disaster-affected degree had been exacerbated by unreasonable agriculture policy, unbalanced planting structure and useless relief system.

  • Han Yixin, Zha Xiaochun, Huang Chunchang, Zhou Yali, Pang Jiangli, Zhang Yuzhu, Wang Na, Bai Xin
    Download PDF ( ) HTML ( )   Knowledge map   Save

    Base on the field investigation in the Zoige Basin, the typical first terrace sedimentary sequence of the Yellow River outlet at the western of the basin was selected as the research object. Through the analysis of sediment grain size, end-member and OSL dating, the study result showed that the bed facies sand and gravel and the floodplain sand layer at the bottom of the terrace constitute a binary structure sedimentary layer, in which a layer of shallow depression bog mud deposits accumulated during 5.0—4.2 ka B.P. was lenticularly sandwiched, these results suggest that the first terrace of the Yellow River in this reach began to form from 5.0 ka B.P. The river floodplain sand layer was covered with aeolian sand layer, and the paleoflood slackwater deposit layer was sandwiched in the aeolian sand layer, indicating that the Yellow River experienced several catastrophic flood events during 4.2—4.0 ka B.P. during the period of 4.0—2.8 ka B.P., the climate was humid, the bog mud deposits was formed on the shallow depression of the terrace surface. Then the sandstorm carried the coarse silt to the terrace and formed aeolian loess layer. The upper part of aeolian loess layer was transformed by biological weathering, and developed into modern subalpine meadow soil layer with granular structure. The results revealed the development process of the first terrace in the outlet section of Zoige Basin, which was of great significance for understanding the environmental changes and surface processes in the source area of the Yellow River since the middle Holocene.

  • Li Fan, Zhou Yi, Chen Rong, Liu Chang, Li Ying
    Download PDF ( ) HTML ( )   Knowledge map   Save

    In this article, the concept of plateau slope is systematically sorted out and defined. Based on 5 m resolution DEM and 0.6 m resolution Quickbird images, Taking the tableland slope as the main body, this study constructs the index system of topographic statistical characteristics, spatial distribution characteristics and erosion development characteristics, deeply analyzes the topographic characteristics of the Loess Tableland, and quantifies the erosion development degree of small watersheds and their internal sub watersheds at all levels. The results show that: 1) The area of plateau slope accounts for about 10%-35% in the seven watersheds, and the topographic statistical characteristics show that the erosion degree and roughness gradually intensify from the tableland to the valley; 2) The spatial distribution characteristics show that the tableland slope is the most complex topographic unit in the gully slope system, and the adjacency of tableland to tableland slope is weaker than that of gully to tableland slope; 3) Erosion index is an important indicator of erosion development in small watersheds in the tableland area, which reveals the law of erosion differentiation within the watershed: The degree of erosion intensifies with the increase of sub watershed level, and the more serious the degree of erosion of the watershed, the more serious the degree of erosion of the internal sub watershed. The correlation of each erosion index increases with the increase of sub watershed level. At the confidence level of 0.01, the minimum correlation between erosion indexes increases from 0.33 to 0.80.