The economic resilience of the Yellow River Basin in response to external shocks is the key to achieving the national strategy of ecological protection and high-quality development of the Yellow River Basin. We takes 91 cities in the Yellow River Basin as the research object and constructs an economic resilience index. The article analyzes the spatio-temporal characteristics of the economic resilience of the Yellow River Basin in the face of the 2008 international financial crisis, and explores its determinants. The results show that: 1) The resistance of the Yellow River Basin to the international financial crisis shows a significant decline over time, the economic resilience of the Yellow River Basin shows significant spatial agglomeration characteristics, and the economic resilience level of the south central part of the Yellow River Basin is relatively high; 2) There is a significant positive spatial autocorrelation in the economic resilience of the Yellow River Basin, which shows that cities with high (low) level of economic resilience are clustered in space, and the spatial autocorrelation index shows an upward trend; 3) Related variety, specialization, government control and the proportion of tertiary industry significantly promote the improvement of economic resilience in the Yellow River Basin, while the current economic development model is not conducive to the improvement of economic resilience; 4) The economic resilience of the Yellow River Basin has a significant spatial spillover effect, and the development of cities with high economic resilience level will promote the economic resilience of surrounding cities.
Ecological protection and high-quality development of the Yellow River Basin have been included in the major national strategy in 2019, which is a major strategic deployment to promote the construction of ecological civilization in China. Urban agglomeration is an important carrier of ecological protection and high-quality development in the Yellow River Basin. However, industrial development not only promotes the economic and social prosperity of urban agglomeration, but also leads to the increase of pollutant emissions. Environmental regulation efficiency plays an important role in promoting the construction of ecological civilization and high-quality development in the Yellow River Basin. Lanzhou-Xining urban agglomeration is an important industrial core area and environmental key area in the Yellow River Basin. Taking Lanzhou-Xining urban agglomeration as the research area, it is reasonable and representative to study the spatial characteristics and convergence of environmental regulation efficiency. Based on the county panel data of Lanzhou-Xining urban agglomeration in the Yellow River Basin from 2010 to 2018, spatial analysis technology and spatial convergence model are used to analyze the pattern of environmental regulation efficiency and its spatial convergence. The results show that: 1) Environmental regulation efficiency has the spatial pattern of “high in the center and low in the edges”, and the environmental regulation efficiency shows the transformation from “large gap and low intensity” to “small gap and high intensity”. 2) Environmental regulation efficiency has spatial dependence. Hot spot-cold spot of environmental regulation efficiency and the high-low level of economic development have spatial overlap. 3) Environmental regulation efficiency has a significant spatial convergence. When the socio-economic factors and spatial factors are considered, the convergence trend of environmental regulation efficiency is enhanced, and the spatial differences of environmental regulation efficiency among counties in urban agglomeration area are gradually narrowing over time. 4) Economic level, government intervention, industrialization rate and population density have positive effects to the convergence trend of environmental regulation efficiency, while energy consumption intensity has negative effects to the convergence trend of environmental regulation efficiency.
In order to reveal the spatial evolution and differential characteristics of the “production-living-ecological” function and quantitatively identify its influencing factors in 57 counties of Gansu Province in the Yellow River Basin, this paper comprehensively evaluates the “production-living-ecological” functionality of these counties during the period of 2006 to 2018 by the construction of an evaluation index system, the entropy weight method, the analytic hierarchy process (AHP) method, and geographic detectors. The results show that the functional index of “production-living-ecological” function in these counties shows an overall increasing trend, but the spatial difference is significant. The spatial pattern is higher along the mainstream of the Yellow River, i.e., “Maqu-Jingyuan” axis, and lower on both sides. The global Moran’s I index has proved that the “production-living-ecological” function in the research area shows an obvious spatial positive correlation, in which the characteristics of ecological function clustering are the most significant. In addition, the “production-living-ecological” function of the county’s changes over time, presenting a “group” type distribution of the obvious positive correlation clustering while a sporadic-like distribution of the low negative correlation clustering. It is found that in the study area, the urban-rural integration level of these counties is the main factor that affects the spatial differentiation of “production-living-ecological” function, and the interaction of different influencing factors enhances the spatial differentiation of “production-living-ecological” function.
Natural ecosystem is increasingly disturbed by the human system. It is of great significance to clarify the influence mechanism of landscape fragmentation on soil conservation services for soil conservation and land use policies formulation in the Yellow River Basin. However, previous studies lacked the studies about the impacts of landscape fragmentation on soil conservation services that considering the spatial dependence at multi-scale comprehensively, which, to a certain extent, limited the effective formulation and implementation of soil conservation and land use policy-making in the Yellow River Basin. This study attempted to measure the spatiotemporal pattern of soil conservation services and landscape fragmentation based on the current situation of land use remote sensing monitoring data in 2000, 2005, 2010, and 2015 using the landscape pattern metrics and equivalent factor method in the Yellow River Basin, respectively. The hot spots analysis tool, ordinary least squares, and the spatial regression models were used to explore the spatio-temporal evolution characteristics of soil conservation services in the Yellow River Basin from 2000 to 2015 at multi-scales and the influence mechanism of landscape fragmentation on soil conservation services. Results are as follows. 1) The low-valued soil conservation services areas in the Yellow River Basin were mainly distributed along Qinghai-Gansu-Ningxia-Shaanxi-Inner Mongolia and the lower reaches of the Yellow River basin in Henan and Shandong. In addition, provincial capitals and surrounding areas were also low-valued soil conservation services areas. Soil conservation services had significant scale dependence. 2) The hot spots of soil conservation services change in the Yellow River Basin were mainly distributed in the Loess Plateau region, and the cold spots were mainly distributed in the surrounding areas of the Loess Plateau during the study period. The spatial patterns of cold and hot spots of soil conservation services change at multi-scale exhibited obvious spatial differences. 3) Regression results showed that the socioeconomic factors had a significant negative association with soil conservation services. In natural background factors, altitude and the proportion of forestland area were significantly positively associated with soil conservation services. Landscape fragmentation metrics had significant influence on soil conservation services, but varied greatly. In the future, soil conservation and land use policy-making in different regions of the Yellow River Basin should not only consider the natural background and socioeconomic drivers, but consider the fragmentation of multi-scale landscape pattern and spatial spillover effect. Cross-regional joint governance is of great practical significance for the formulation of land use policies and ecosystem conservation.
Cultural corridor emphasizes the spatial and temporal scope of cultural diffusion and the overall development of realistic region. It is very important to define the spatial scope of corridor reasonably, which is the basic work of the related research and conservation strategy of linear cultural heritage. Based on the theory of landscape information chain, according to the process of identifying cultural genes, determining cultural points and simulating corridor space, combined with resistance model and principle, the CCSPM model is constructed by using ArcGIS tools from four aspects: the importance of cultural points to corridor culture transmission, the regional influence of cultural points, the spatial relationship of cultural points and the constraints of natural environment on cultural transmission, and the spatial scope of cross-border cultural corridor in Southwest Yunnan is defined by this method. The results show that: 1) The influence range of cultural elements in cross-border cultural corridor in southwest Yunnan is concentrated along the traffic line, but the spatial difference is large; 2) The overall spatial pattern and distribution trend of cross-border cultural corridors in Southwest Yunnan are roughly consistent with the historical process, and the model can effectively represent the spatial scope of cultural corridor. This method provides a new research idea for the spatial study of cultural corridor, and then provides spatial information support for analyzing the direction and degree of cultural connection in the corridor and the overall protection and development of cultural heritage.
Improving urban land green use efficiency (ULGUE) is of great significance to achieve new progress in constructing ecological civilization, implementing the goal of peak carbon emissions and the prospect of carbon neutrality, and promoting high-quality economic development. This article first measures the ULGUE in 285 cities in China from 2009 to 2018 by using the undesired super-efficiency SBM model, then, based on the study of driving factors of ULGUE, including high efficiency of economic development, intensive urban development, ecological environment friendly, transparency of government behavior and social development equity, spatial and temporal geographical weighted regression and K-means clustering methods are used to identify and partition the spatial heterogeneity of these influencing factors to provide targeted suggestions on how to improve ULGUE. The research results show that: 1) From 2009 to 2018, ULGUE in 285 cities showed a fluctuating increase, and there are both significant agglomeration characteristics and significant inter-provincial and intra-provincial differences. On the region level, it presents a pattern of western > eastern > central China. On the scale level, it increases with the decline of the scale of the city. 2) ULGUE is interactively driven by many factors, with each influential factor having its apparent spatial heterogeneity, and these factors all show spatial banding or flake distribution pattern. Among these factors, the level of economic development, advanced industrial structure, ecological resource endowment, and environmental regulation have a positive impact on ULGUE; land marketization and land finance mainly play a negative effect; the positive and negative effect of population agglomeration, urban spatial agglomeration, the level of infrastructure, the level of scientific and educational input are all significant. 3) According to the spatial heterogeneity characteristics of ULGUE driving factors, it can be divided into five areas. They are southeast region, which is dominated by advanced industrial structure, environmental regulation, and scientific and technological investment levels; North China dominated by ecological resource endowments; southwest region dominated by economic development level and urban spatial agglomeration; northwest region dominated by land marketization; and northeast regions dominated by population agglomeration, land finance, and infrastructure levels. In the future, differentiated measures should be taken to improve the ULUE according to the city’s strategy and local conditions.
Megacities attract population clusters with high-quality and abundant medical public resources, however, with the rapid increase of population, they are not only facing the pressure of supplying medical service resources, but also the structural problems caused by the unbalanced and unequal spatial allocation of medical service resources. In order to plan the medical services rationally, accurately quantifying the spatial patterns of medical facilities will be helpful to the stable and sustainable development of the medical resource.
Taking Shanghai as an example, this paper uses the Optimized Two-step Floating Catchment Area (O-2SFCA) method to measure the spatial accessibility of medical facilities at the township (street) level. Moreover, we introduce the Gini coefficients and utilize spatial autocorrelation analysis to characterize the spatial differentiation of the accessibility of medical facilities in Shanghai. Finally, we discuss the main factors affecting the spatial differentiation of medical service resources in Shanghai.
The accessibility of medical service facilities in Shanghai gradually decreases from the central area to the suburbs. The high accessibility areas are concentrated within the outer ring road, while the low accessibility areas are concentrated in the distant suburbs. In general, medical resources are distributed centripetally in Shanghai. The allocation of medical service resources in the central city is relatively balanced, with lower variation in accessibility, while the accessibility of medical services in the suburbs varies widely. The spatial pattern of medical services accessibility in Shanghai is significantly influenced by the demographic and economic situation, and the centripetal distribution of high-quality medical resources meets the needs of the high-density population and the large elderly population in the central city. The medical financial payment of the Shanghai Municipal Government has limited effects on the spatial accessibility of medical service facilities at street-scale. Finally, we put forward relevant suggestions for optimizing the spatial allocation of medical public facilities in Shanghai and improving the capacity of urban medical public services.
The construction of ventilation corridors is considered to be an effective measure which can promote urban air quality, alleviate heat island effect and improve urban living environment. Urban ventilation corridor is a kind of energy-saving and ecological method which makes the most efficient use of the natural weather conditions to improve the urban environment. It can make the clean air from the outskirts of the city into the interior of the city through the ventilation path because of the characteristics of air flowing. Meanwhile, it can make the exhaust-gas and waste-heat to be dilutedly discharged with the wind. Thus, the purpose of purifying urban air and improving urban environment can be achieved. Basing on the data such as surface type with high-resolution, the urban building and the urban ventilated corridor planning in Beijing, the coupled of urban canopy model with the mesoscale meteorological model WRF (Weather Research and Forecasting) is used in this paper. In addition, the sensitivity simulation tests with high-resolution of 200 m was conducted in January and July of 2019 respectively. And the WRF model is verified by applying of the observational data from automatic meteorological station network. Some results can be obtained through the simulation tests. After the urban ventilation corridors have been constructed, the difference of meteorological elements will be not limited to the corridor area, but the whole area studied. The surface wind speed will increase significantly, the intensity of urban heat island will weaken, and the range of the urban heat island will shift caused by the advection effect of wind. After the corridor has been finished, the average monthly temperature in Beijing will decrease by 0.14-0.17℃, the average wind speed and the relative humidity will increase by 0.32-0.36 m/s and 2.02%-3.37% respectively. Through the analysis of the numerical simulation test results, the following conclusions can be drawn. The ventilation corridor is effective in improving the thermal environment and increasing the climate comfort in the city-intensive areas. And the greater the wind velocity is, the more obvious the mitigation effect of the ventilation corridor is. The diurnal variation distribution of the meteorological field shows that the influence of ventilation corridors on meteorological field is greater in the daytime than in the night. Further analysis indicates that the influence of ventilation corridors on local meteorological elements is mainly due to the advection effect caused by the increase of wind speed and the improvement of the quantity of the turbulence flux on underlying surface.
Expanding the export of high-end technology products under the new normal is a new requirement put forward by the 19th National Congress for the development of high-quality foreign trade. How to build a “double cycle” development blueprint for high-end technology products with Chinese characteristics? The key is to grasp the existing trade pattern of China’s high-end technology products. In this context, by constructing a “multi-input-multi-output” export efficiency measurement model, this article explores the spatial pattern change and driving factors of China’s export efficiency of high-end technology products to 49 major trading partners from 2001 to 2019. The results show that: The overall export efficiency of China’s high-end technology products is increasing, and the gap between countries is gradually narrowing. The spatial pattern of China’s export efficiency of high-end technology products clearly has spatial agglomeration characteristics. “High-high” agglomeration countries are clustered along the “Belt and Road” and spread westward, while the distribution range of “low-low” agglomeration countries is shrinking year by year. The impact of bilateral trade relations on the export efficiency of China’s high-end technology products has spatial spillover effects. China’s export efficiency of high-end technology products to competing countries is 0.017% lower than its export efficiency to countries with complementary trade. China’s export efficiency of high-end technology products to neighboring countries in competing trade countries is 0.088% higher than its export efficiency to neighboring countries in complementary trade countries. Differences in regulatory systems have a direct role in promoting export efficiency, while the difference in economic freedom has a deterrent (negative spillover) effect on export efficiency as a whole. Based on this, this article suggests that China should take the countries along the “Belt and Road” as the main line and the regions in the northern Europe and the southwestern South America as the sub lines to further consolidate the market share and trade route of the export of high-end technology products. In addition, when formulating the export strategy of high-end technology products, China should give priority to countries with high regulatory systems. Simultaneously, it should be vigilant against the restrictions of developed economies on the export trade of China’s high-end technology products.
Scientific evaluation of the level of high-quality development of the marine economy is the key link to accurately grasping the high-quality development of the marine economy in the context of the New Era. Based on the multi-indicator evaluation models such as panel, threshold, and Bayesian, the article considers the study of the timeliness of indicators and the internal logical connection. It takes the premise-path-the purpose of high-quality development of the marine economy as the analytical framework to evaluate the level and regional differences of high-quality development of marine economy in 11 coastal provinces and cities in China from 2007 to 2017, to analyze its influencing factors and optimize the path selection, etc. The results show that: 1) Through index measurement and comprehensive analysis, the high-quality development of the marine economy in 11 coastal provinces, municipalities and autonomous varies greatly. From the premise of high-quality development, the provinces and cities are stable in development. The basic level is in three distinct echelons; from the path of high-quality development, there are great differences among provinces and cities, Shanghai having the strongest and most stable capacity, Tianjin and Guangdong having stronger and more stable capacity, Guangxi and Hainan having poor and less stable capacity, others having poor but relatively stable capable. From the perspective of high-quality development purposes, the development of provinces and cities is more unstable, achieving minor differences in results. There is no obvious echelon formation, but Guangdong and Zhejiang have a significant trend of improvement. 2) The innovation-driven marine economy has a ‘V’ shape impact on achieving high-quality development of the marine economy. At present, the innovation drive has the most significant impact on the high-quality development of China's marine economy and has greater potential. 3) The optimization of marine economic development structure has a ‘U’ shape impact on the realization of high-quality development of the marine economy. Currently, the structural advantage dividend is not yet obvious, and it is needed to promote structural optimization to cross the next threshold. 4) The improvement of marine economy development efficiency has a positive and significant impact on realizing the purpose of high-quality development of marine economy, and its development foundation is good and has the greatest potential. 5) The optimization of the marine economic market environment presents a positive influence trend of increasing first and then decreasing for the purpose of achieving high-quality development of the marine economy. The market environment dividend is not obvious at present, so it is necessary to push the optimization of market environment to the third threshold.
With the implementation of the rural revitalization strategy in the new era, China has entered the stage of rapid transformation of rural development, and the population migration tend to have a new differentiation and development trend. To have a scientific cognition about the relationship between the population migration and rural transformation development is of great significance for implementing the rural revitalization strategy and adjusting the urban and rural population development pattern. Based on the content and perspective of the population migration research, this paper systematically expounds the relationship between the population migration and rural transformation development from the perspective of rural labor migration and return, and the counter-urbanization. Finally, based on the needs of rural revitalization strategy in the new era, the research areas and directions of the future focus between the population migration and rural transformation development are discussed.
Based on the literature data of abandoned land in WOS and CNKI databases, this article used CiteSpace software to sort out the research subjects, authors, contents, hotspots and progress of abandoned land at home and abroad, and then analyzed the causes, mechanisms and impacts of abandoned land. To understand the research process and research status of abandoned land at home and abroad, and summarize the specific measures and methods to curb land abandonment, expecting to provide guidance for the study of abandoned land in China. The results showed that: 1) Scholars at home and abroad paid different attention to farmland abandonment. Foreign scholars mostly studied the formation mechanism of farmland abandonment, while domestic scholars focused on revealing the phenomenon of farmland abandonment. Abandonment of agricultural land is a research hotspot abroad, while abandonment policy, model simulation and application of remote sensing technology are domestic research hotspots. 2) The development process of abandoned land research is different at home and abroad, and each stage presents different research characteristics. 3) There is a consensus among Chinese and foreign scholars on the causes, mechanisms, impacts and measures of abandoned land. It is suggested that Chinese scholars use geospatial big data, streaming data and remote sensing image data to conduct research on spatio-temporal simulation, trend deduction and risk assessment of abandoned land. Furthermore, the driving and evolution laws of abandonment under different resource endowments and socio-economic backgrounds were explored and the evolutionary process was summarized. Scientific and systematic research methods on nature, society and economy have been put forward to enrich the research contents and achievements. Small-scale case studies at the village level can provide support for theoretical deepening and method innovation, and further provide theoretical support and case reference for ecological restoration and management of abandoned land in small-scale regions.
The Industrial transformation of growing resource cities is related to national energy security, national economy and people’s livelihood, and regional green development. Especially under the carbon peaking and carbon neutrality goal, it is urgent to coordinate the promotion of industrial transformation and upgrading, energy structure optimization and continuous industrial development. Using the methods of industrial economics and geography, taking the county of Yulin City, Shaanxi Province as an example, the paper evaluates the temporal and spatial evolution characteristics of industria transformation capability, and puts forward the specific optimization path. The results show that: 1) The industrial transformation capacity of Yulin showed significant spatial differentiation, which was higher in the north and lower in the south from 2008 to 2018. The utilization efficiency of elements input and the degree of technology utilization were the keys to improving the industrial transformation capability. 2) In the direction of county level industrial transformation, leading industries should be reasonably selected based on industrial transformation capabilities and regional resource advantages. There were energy and chemical industry, equipment manufacturing industry, emerging industry and logistics industry in the six counties northern of Yulin, while the six counties southern were agriculture and sideline products processing industry, tourism industry, salt and chemical industry. 3) The industrial transformation of resource-based cities was more suitable for the compound path of coordinated development of multiple industries under the guidance of the concept of green development.
As both the number and percentage of the elderly population continue to rise, population aging has become a new trend in China. How to improve the quality of life of the elderly has become an urgent issue in both academic and practical circles. As frequently visited places by the elderly in their daily lives, urban parks play important roles in the background of population aging. Leisure involvement and place attachment of the elderly directly affect the leisure experience and emotional status of the elderly. Research on leisure involvement and place attachment of the elderly in urban parks is of great importance for improving the quality of life of the elderly and the quality of parks. Previous research has investigated the relationship between place attachment and involvement, suggesting that involvement is an antecedent variable of place attachment. While most of the studies on involvement and place attachment have focused on tourism destinations, relatively few studies have investigated involvement and place attachment in urban parks, especially among the elderly. Based on the existing literature, we conceptualized leisure involvement as a three-dimensional concept consisting of attraction, centrality, and self-expression; and conceptualized place attachment as a two-dimensional concept consisting of place dependence and place identity. Using data collected from seven urban parks in Guangzhou (N=423), we constructed a model of the relationship between leisure involvement and place attachment of the elderly. Confirmatory factor analysis and path analysis were conducted in AMOS to explore the relationship between leisure involvement and place attachment, and its mechanisms. Qualitative data were also collected to support the findings of the quantitative analysis. Results suggest a complicated relationship between place attachment and leisure involvement: the attraction dimension of leisure involvement has a significant positive impact on place dependence but no significant effect on place identity; The self-expression dimension has a significant positive impact on place identity, but no significant effect on place dependence; And the centrality dimension has significant positive impacts on both place dependence and place identity. These findings indicate that improving the attractiveness of urban parks may enhance functional attachment and improving the self-identity of the elderly may enhance emotional attachment. The centrality of urban parks in the elderly’s daily lives may improve both functional and emotional attachment. These findings resonate with the existing argument by supporting the positive correlation between leisure involvement and place attachment among the elderly in urban park settings in China. The qualitative analysis also finds that the location and accessibility of urban parks may also improve the elderly’s place attachment. Based on the above findings, we also discuss the mechanism of the impact of leisure involvement on place attachment among the elderly in urban parks. This study provides theoretical implications and practical suggestions for improving place attachment among the elderly in the context of population aging.
The representation of space, as a kind of conceptual abstract space or the discourse of space, influences the practice of space. At present, the spatial cognition and theoretical definition of ‘traditional village ’have had an important impact on the national policy, system, law making, and the concept of village operation and management. As a representation of space, it acts on residents’ life, scenic spot development, government management and other practical aspects, so it should be paid more attention. Based on the theory of social space and discourse power theory, using knowledge archaeology and textual discourse analysis methods, this paper studies the representation of traditional village space and the logic of its intervention practice. The study finds that: The survival crisis of villages caused by global modernization and China’ s urban and rural practice constitutes the conditions and basis for the formation of traditional village spatial discourse; cultural heritage, protection and development, rural tourism, etc. constitute the social representation of traditional village space in contemporary Chinese society; as a result of joint efforts of experts, scholars and governments, traditional villages contain modern social order and development logic, and regulate village practice; political and capital subjects dominate the spatial practice concept and system design of traditional villages and intervene in the practice process to realize the purpose of space governance and capital appreciation. Therefore, for practical dilemmas, the power attribute of the spatial discourse of ‘Chinese traditional villages’ makes it necessary to constantly rethink on and adjust their spatial cognition, practical concept and institutional system.
In the post COVID-19 epidemic era, cultural conflict could become a vital factor impeding Chinese inbound tourism demand recovery. Based on the data of international arrivals of 66 regions of origin of mainland China from 2002 to 2018 gathered from the Yearbook of Tourism Statistics issued by the UNWTO, the impact of cultural conflict on Chinese inbound tourism demand and its mechanism are explored by using the panel data estimation strategies. The results show that: 1) Cultural conflict has a significant negative effect on Chinese inbound tourism demand. 2) The impact of cultural conflict on Chinese inbound tourism demand is heterogeneous in different gender, region, age and purpose groups. 3) Cultural identity is a mechanism variable in the process of cultural conflict affecting Chinese inbound tourism demand. This study can promote the theoretical researches on inbound tourism demand determinants, and provide new theoretical basis and policy reference for Chinese inbound tourism demand recovery.
To explore the characteristics of spatial and temporal variation of drought in Sichuan and Chongqing during 1450 to 1949, employed the wavelet tools of Matlab (Version 8.3) and ArcGIS (Version 10.2) software to analyze the counter data of drought . The results showed that: 1) Drought occurred in 312 years during 1450-1949 A.D, while accounting for 62.4%, once every 1.6 years. The frequency of drought was relatively high in the early period (1450-1650), decreased in the middle period (1650-1870), and increased significantly in the later period (1870-1949), with a cycle of 200, 100, 65, 30 and 10 years. 2) Severer drought was the most common, followed by general drought, and extreme drought was the least, accounting for 50.1%, 44.2% and 5.7%, respectively in 212 statistical units. 3) Spatially, drought was mainly localized, with 80.38% in 1-20 counties, and 56.01% in less than 5 counties. The frequency of drought increased significantly from west to east with obviously agglomeration effect. The drought was relatively light in the western Sichuan Plateau and the southwest Sichuan Mountains region, and severer in the middle reaches of Tuojiang River, the middle and lower reaches of the Jialing River and the both sides of the Yangtze River. More than 85% of the drought was concentrated in Sichuan Basin. 4) Natural factors such as solar activity, geographical location, landform, climate change and soil properties are the main causes of disasters, while human conditions such as population distribution, human production activities and the detailed records are also influencing factors. This result can provide reference for the study of historical climate and the prediction of environmental change in Southwest China.
The Songshan Region is considered as the origin of Chinese civilization. The Holocene evolution of regional vegetation that is closely related to early human activities has also attracted much attention. Pollen analysis is an important method of such research. This article analyzed 19 sets of pollen data from 16 locations in the Songshan area, and sorted out the vegetation evolution history of the region since the Late Pleistocene. The results showed that before 10 ka B.P., there was very little trees in the area, which was a grassland vegetation landscape; 10-7 ka B.P., trees increased, hilly and platform areas were sparsely forested and grassland, and plain areas were more arbors, which were forest grassland; 7-5 ka B.P., arbor pollen content continues to increase, hilly areas are still sparsely wooded and grassland, platform areas already have the characteristics of forest and grassland landscape, and plain areas are vegetation landscapes of coniferous and broad-leaved mixed forest; 5-2.5 ka B.P., arbor pollen content gradually decreases , The area is transformed into a vegetation landscape of sparse forest and grassland. Early regional vegetation research has problems such as low pollen content in sedimentary samples, low stratum chronological resolution, fewer natural sedimentary profiles, and insufficient data in mountainous and hilly regions. Future research needs to effectively introduce information technology, and carry out high-resolution research on various types of landforms on the basis of continuous improvement of sporopollen extraction and identification methods. The research ideas also need to extend from the reconstruction of the climate evolution from the pollen data to the interaction between vegetation characteristics and human activities.
Lake surface water temperature (LSWT) is an important factor affecting the aquatic ecosystem. This study aimed to reveal the influence of regional climate change on the surface water temperature of Tonle Sap Lake. For this purpose, based on the datasets of the Tonle Sap Lake’s daytime surface water temperature (LSWTday), near-surface atmospheric temperature (AT), solar radiation (SR), surface pressure (SP), total precipitation (TP), relative humidity (RH), wind speed (WS), total cloud cover (TCC) and water level (WL) from 2001 to 2019, the temporal-spatial distribution and variation characteristics of LSWTday and climate factors were studied by trend analysis, stability analysis, persistence analysis and mutation analysis. Then, through correlation analysis, regression analysis and Z-score standardization method, the impact of climate factors on LSWTday was clarified. Results showed that: 1) At the time scale, the Tonle Sap Lake region climate was characterized by a significant increase in AT, WS and TCC, and a significant decrease in WL. The average warming rate of LSWTday was 0.372℃/10a, and showed a continuous warming trend. LSWTday had time consistency with the abrupt change point of climatic factors. At the spatial scale, the spatial distribution and change trend of LSWTday and climate factors had obvious spatial heterogeneity. Among them, except for the slight cooling trend in the western lake area, the LSWTday of other lake areas showed an obvious warming trend. Among climatic factors, the distribution of the rate of change of AT, SP, TP, TCC, and RH was roughly high values in the south and low values in the north, while the distribution of change rates of SR and WS was low in the south and high in the north. 2) In different time scales, the factors driving LSWTday change were different. On the average annual scale, LSWTday was mainly driven by AT, WS and WL. At the monthly mean scale, the change of AT was still the main driving factor of LSWTday. At the seasonal scale, the increase of TP, WL and TCC was the main reason for the cooling of LSWTday in spring and summer, RH was the main influencing factor for the fluctuation of LSWTday in autumn, and LSWTday was warming in winter along with the warming of AT.
