Over the past 40 years of reform and opening up, the urban planning, construction and management in China has undergone qualitative changes, but the urban problems caused by rapid urbanization are still increasingly prominent. The concept of urban physical examination arises at the historic moment and is gradually implemented from the national strategy to the concrete practice of urban high-quality development. On the basis of sorting out and analyzing the background and function of urban physical examination. This article starts from the core connotation of high-quality urban development in China, which is eco-livable, distinctive, diverse and inclusive, innovative, healthy and comfortable, safe and resilient, convenient transportation, clean and orderly. We design the index logical framework of urban physical examination from the above eight aspects and sorts out the relationship among various indicators of urban physical examination. Urban physical examination must be a ‘global physical examination’ rather than a ‘department physical examination’, so the urban physical examination has the dual function of ‘examination of general planning’ and ‘physical examination of a city’. The article points out that we should adopt the trinity of physical examination, third party physical examination and social satisfaction survey, and apply the closed-loop mode of ‘evaluation-feedback-governance’. It also analyzes the similarities and differences of urban physical examination in different scales, proposes the methods of urban physical examination in China. This article aims to provide theoretical guidance for urban physical examination in China and provide a research framework and scientific support for future urban physical examination research topics
Tourist flows is one of the current issues in the field of tourism geography that should be urgently addressed. There is a sharp contrast between the rapid growth of China’s outbound tourism flow and the steady growth of inbound tourism flow. It is of great theoretical value and practical significance to understand the mutural tourist flows from and to China. Based on the multiple distances perspectives, this research draws upon the international trade field distance theory framework which includes economical distance, geographical distance, cultural distance and institution distance (CAGE), and the research method is Qualititive Comparative Analysis (QCA) method, which is very useful in exploring the path and mechanism of China’s high and low inbound and outbound tourism flows. In so doing, the structural characteristics, differences, evolution rules and influencing mechanisms of China’s inbound and outbound tourism at different levels can be analysed. The research results are as follows: 1) the influence of distance, as an influential factor is relatively certain. 2) Particularly, it influences China outbound tourism in a similar way that it affects the inbound tourism development. 3) When comparing China’s high international tourism flow and China’s low international tourism flow, distance has different effects on them. Among them, economic distance is the core condition of high international tourism flow. Geographical distance, cultural distance and institutional distance are the core conditions of low international tourism flow.
The conflicting relationship between tourist attractions and surrounding communities has become the common focus between scholars. It can be found by combing through relevant domestic and foreign literatures that many scholars tend to use the concepts of “tourist enclave” “tourist bubble” and “tourism island” to depict these conflicting relationships, among which the description of “tourism island” is more suitable for summarizing the isolated phenomena in China’s tourism development because it refers to two connotations of isolated space and unbalanced power between tourist attractions and surrounding communities.Therefore, this paper chooses “tourism island” as the core concept and constructs evolution model including process, characteristics and mechanism. According to the evolution model, tourism islanding effect goes through four stages of initialization, growth, isolation and intensification or fusion, reflecting the transformation of tourism islanding effect from differential state to blocking state, then to oppositional state, which essentially implies the driving mechanism of polarization effect, spread effect, and circular cumulative causation. In order to confirm the applicability of the theoretical model of tourism islanding effect, this paper takes Puzhehei tourist attraction as a case to analyze its space form and game relationship. Results show that Puzhehei had experienced four stages when considering its external relations, space form and border state, which highly corresponding to the four evolutionary stages of tourism islanding effect. The unique Karst tourism resources and the historical opportunities generated by the series of films and television dramas are the reasons for the polarization effect of the Puzhehei.Physical boundaries dominated by isolation barriers and transportation routes and functional boundaries dominated by economic gaps and cultural differences are the reasons why the spread effect is blocked. Under the contrast of polarization and spread effect, the tourism islanding effect is formed, which further attracts the accumulation of factors and solidifies the boundary, so that the polarization and spread effect continue to work. It is worth noting that similar conflicts occur from time to time at home and abroad. Therefore, the exploration into the evolution model of tourism islanding effect can provide regulation ideas for reducing differences, removing obstacles, and eliminating antagonism between tourist attractions and surrounding communities.
Based on the DPSIR model, a tourism ecological safety evaluation index system is constructed, and the dynamic evaluation of tourism ecological safety in 31 provinces (municipalities and districts) of China (excluding Hong Kong, Macao and Taiwan) is carried out using the fuzzy object element model, and the spatial autocorrelation is applied to analyze the evolutionary characteristics of the spatial pattern. At the same time, the obstacle factors of tourism ecological safety were diagnosed with the help of the obstacle degree model. The results show that: 1) Tourism ecological safety shows a “W”-shaped evolutionary trend, generally in a good trend of fluctuation weakening and steady improvement. From 2013 to 2016, each province showed a spatial distribution pattern of “high in the east and low in the west”, with an overall gradient distribution pattern from coastal to inland. However, over time, the pattern of “high in the north, low in the south; high in the middle, low on both sides” has changed, with the overall Euclidean proximity of tourism ecological safety in each province increasing and the gap between regions narrowing. 2) From a global perspective, the spatial distribution of tourism ecological safety in China from 2013 to 2017 is characterized by significant spatial clustering, but the spatial correlation of tourism ecological safety in each province has weakened and the degree of clustering has gradually decreased. In terms of local correlations, the spatial distribution of tourism ecological safety in China’s 31 provinces (municipalities and districts) is characterized by spatial agglomeration and inter-provincial spatial dependence. Most of the provinces show a strong local autocorrelation in tourism ecological safety, with a relatively stable overall pattern. A small number of provinces show negative correlation and significant spatial heterogeneity. 3) There are significant differences in tourism ecological safety obstacle factors among provinces, with more obstacle factors having an obstacle degree higher than 10%. The main obstacle factors are tourism economic density, tourist density, smoke and dust emission, domestic waste disposal rate and sewage disposal rate. The tourism ecosystem is a complex and integrated system composed of natural, social and economic elements. Therefore, when vigorously developing tourism, the degree of economic development and the ability to enhance tourism ecological safety need to be fully considered; attention should also be paid to the coordination between tourism policies and environmental protection policies.
By comparing topology structure of various copper-containing product trade network, this article comprehensively describes the global flow of copper resources and copper trade relations among countries or regions, which is conducive to enhancing the understanding of different countries and regions’ comparative advantages in the global value chain and promoting the sustainable use of resources. We build 5 types of global copper-containing product trade networks using bilateral trade data of copper ore, blister, refined copper, copper semis and copper scrap in the year of 2017. The data are collected from UNCOMTRADE and ITC Trade map database. Since the data are too huge to analyse, we first identify the backbone network using Top
In the process of urbanization, the increasingly rich place narrative practice of individuals helps to understand the root relationship between individuals and places. At present, China is undergoing an unprecedented process of urbanization and industrialization in terms of scale and range, with new strides constantly made in the modernization drive. The demolition of massive buildings and the migration of the population caused collective unconscious nostalgic. China’s rise in new folk songs cultures after the early of the 20th century are an attractive cultural phenomenon. Nostalgic is a recurrent theme of new folk songs and new folk songs provide fertile soil for nostalgic. The lyrics and comments on new folk songs themed nostalgic were selected to analyze the phenomenon of nostalgia. This article investigates the dimension characteristic and production mechanism of nostalgic by applying NVivo10 software techniques and natural language processing methods. The lyrics of new folk songs themed nostalgic construct nostalgia at four dimensions, namely spatial dimension, temporal dimension, memory dimension, and emotional dimension. Lyricist of new folk songs recalled the landscape in concrete space and time to express their feelings. A spatial dimension in nostalgia presents home, place, and region of different scales. A home-centered image is the most extensive practice. The time dimension contains days, months and years, showing the representation of nostalgia. Nostalgic is not only oriented to the past but also the future. Nostalgic memories can be pleasant, albeit bittersweet. It can also be divided into two parts: Emotions from the memory and emotions from reality. And the memory dimension presents a scene, character, and event. Nostalgia is awakened by the combination of people, place, and media factors. Changes in the individual’s perception of time and space, as well as life experience and personality characteristics, affect the level of perception of nostalgia. The sensory elements that arouse memory about hometown and social factors such as urbanization, modernization, and environmental changes will stimulate nostalgia. The content of nostalgic is the characteristics of the place, the memory it bears, and the places’ culture. The study’s theoretical contributions, limitations and practical implications for sustainable development from the perspective of nostalgic are discussed.
The impact of urbanization on eco-environment has become an area of crucial concern in environmental conservation owing to the radical changes in habitat structure and pollution produced by urban and suburban development in China. This article reveals temporal and spatial change of urbanization and eco-environmental quality from 2003 to 2016 in the Yangtze River Delta, and analyzes how urbanization influences eco-environment. Based on the city level data mainly from China City Statistical Yearbook, the indexes of 19 items belonging to 6 categories including urban population, industrial wastewater discharge are extracted. Urbanization system and eco-environment quality system are constructed. The scores of urbanization and eco-environment quality are given based on entropy method. By comparing urbanization and eco-environment quality scores in 2003, 2009 and 2016, the spatial-temporal evolution characteristics of urbanization level and eco-environment quality in the Yangtze River Delta can be summarized. Through Linear Spatial Panel Model and Spatial Doberman Model, the direction, degree and path of urbanization affecting the eco-environment quality are discussed and identified in view of improved STIRPAT model. 1) It is concluded that the urbanization and eco-environment quality in the Yangtze River Delta has both been improved, and the regional difference of urbanization is greater than that of eco-environment quality. A high-value clustering area of urbanization with Shanghai, Nanjing and Hangzhou as the core is formed. The overall improvement of eco-environment quality in the Yangtze River Delta is obvious, while the regional difference of eco-environment quality is small. 2) Urbanization improves the quality of eco-environment. Specifically, urbanization of a city in the Yangtze River Delta has different impacts on the eco-environment quality of local and adjacent cities. For the local, urbanization plays a positive role in influencing the physical environment and people’s mind by changes in population, economy, land use and society. Population urbanization characterized by population agglomeration and structural optimization has brought concentrated consumption and emission, enhancing the efficiency of resource use and pollution control. Economic urbanization characterized by industrial agglomeration and economic development, has promoted industrial centralization and provided financial support for the response. Land urbanization characterized by land expansion and traffic optimization, has made cities more efficient. Spatial expansion reduces the internal pressure of the city. Social urbanization characterized by social progress, has changed individual actions by enhancing environmental protection awareness. For the adjacent, there is a “Siphon Effect” in urbanization. Pollution will be transferred to the adjacent because of the industrial transformation and environmental regulation, which will negatively affect the eco-environment quality.
The study takes the Xihu District of Hangzhou as an example, and uses the Amap POI data to identify 459 community centers through DBSCAN clustering, and describe its spatial characteristics from 3 parts: spatial layout, organizational form, and spatial association. Then explore the factors of the number and energy level of the center by logistic regression. the main conclusions are: 1) The spatial distribution of community centers has agglomeration characteristic and a spatial structure with ‘multi-pieces and one group’. Community centers has circle-like distribution pattern and road affinity. 2) There is a “strong-weak” network structure in the distribution of community centers. On a smaller scale, clusters are formed by the strong and weak centers complement each other, and a more complete network structure is formed at the community level. 3) The public services inside the community center have a guiding role, which can promote the formation of the community center, and the facilities inside the center have similar agglomeration characteristics. 4) The total number of permanent residents is the main influence factor. Road division, household registration ratio, average elevation, and type of community organization are significant for the formation of the center. Population density and the number of companies have important influence on the number and energy levels of community centers.
In recent years, more and more Chinese people tend to travel to and live in rural areas, which deserves much more attention. In essence, this phenomenon can be understood as a new type of tourism mobility, the idea of which is consistent with “the new mobilities paradigm” within the social sciences. Specifically, rural stay has shared similar embedded contexts with various tourism activities in the West from mid-1980s, elaborated by Lane and Kastenholz (2015), as well as the second home tourism since the 1990s, reported by Müller (2007). At the tourism and migration continuum, the phenomenon approximates more to the tourism end. Moreover, the terminology of ‘rural stay’, used by some of global rural tourism literature, is also applied in this paper, the idea of which is similar to the new phenomenon arising in rural China. Base on these considerations, this research defined the basic meaning of rural stay in China, and analyzed and discussed its certain features through meta data and main evidences from extant relevant empirical papers. Results show that: 1) Rural stay behavior is essentially driven by core values delivered by rurality, the motivations of which can be expressed into a 3-dimensional model that is consist of relaxation and escape-oriented vs. destination appeal-oriented, new experiences and learning-oriented vs. family and socialization-oriented, and for self-oriented vs. rural life-oriented. 2) Given that individual travel career and physical abilities have moderating effect, four patterns of rural stay behavior can be identified, three of which are dominated by staying in rural areas while the other is mainly for mass tourism activities with rural stay as a indispensable supplement. It is the motivation that distinguish each pattern from others. With reference to the direction of major migration flows of individuals in different age groups to second homes in Sweden 1991-2001, reported by Müller and Marjavaara (2012), a hypothesis for the development model of a rural stay destination is proposed for future efforts. More specifically, two common development models of rural stay destination were hypothesized, either of which may provide possibilities of consumption-led rural revitalization for many traditional villages or rural areas with a single economic structure and modest tourism resources.
The construction of livable community for the elderly is of great significance to adapt to the change of pension mode and improve the quality of life of the elderly. Based on domestic and foreign scholars’ research, in view of China’s realities and according to the connotation of livable community for the elderly, the article develops an indicator system of human settlements on livable community for the elderly. Based on multi-source data, 149 urban communities in Liaoning Province are selected for research, in order to reveal and evaluate the basic situation of the construction of the human settlements on livable community for the elderly, and provide ideas for the change of the population structure of the community, and provide suitable supporting environment for the home-based elderly care. The results show that: First, on the whole, the quality of livable environment for the elderly in the community is poor, 58% of the communities are below the middle level. Second, from the perspective of spatial distribution characteristics, the distribution exhibit the characteristics of ‘Central South bulge, northwest North Depression’. Dalian and Shenyang formed a ‘dual core’ and lead the development of livable environment quality for the elderly of Liaoning Province. Third, the subsystem study shows that the quality of the facility system is the worst. The participating cities present different advantage and disadvantage regarding different subsystem. Among the five sub-systems, those indicators with the lowest scoring: the number of community day care institutions, the number of community pension service centers (stations), the construction index of barrier free facilities, the number of universities for the elderly, the number of elderly associations, the number of comfortable days, air quality and the registered centenarian population. The last, from the comparison of public indicators and special indicators, the evaluation value of public indicators is significantly higher than the special indicators, and there is intergenerational inequality in the construction of community human settlements. It is imperative to strengthen the construction of livable environment for the elderly.
This article aims to systematically demonstrate the evolution and development of scale theory and its features in different periods. The perspective of scale theory is then used to elaborate the formation of city-regional governance in China. A conceptual framework is proposed in this article. Four major conclusions are presented as follows. First, the geographical scale of China’s city-region consists of two modalities, namely, metropolitan area and urban agglomeration. The governing scale of China’s city-region is essentially constituted by administrative powers, all of which made up a top-down power matrix. The restructuring of governing scale oriented geographical scale of city-region is the nature of rescaling of China’s city-regional governance. This restructuring process is central to understand the rationale of China’s city regional governance. Second, the macro socioeconomic development in China has manifested as the dynamic adjustment process between decentralization and recentralization. The rise of city-regional governance in China is the outcome of state spatial selectivity oriented city-regions to overcome the crises brought by the conventional city-based accumulation regime. Third, the governance of urban agglomeration is featured by the soft rescaling. Correspondingly, the governance of metropolitan area is characterized by rigid rescaling. This rigid rescaling has embodied as the reconfiguration of various jurisdictions oriented a new administrative relation. Last but not the least, there are complicated games between multiple actors at the city-region scale. To sum up, China’s city-regional governance reflects the changing political economy of regional development in post-reform era.
Our study constructed 80 indices of climate and underlying surface in 340 middle and small river basins of China, as well as explored the sensitivity of hydrological model simulation efficiency to environmental factors, and also discussed the interactions between the process of runoff yield and concentration and environmental factors. We found that: 1) Significant correlations were observed between the same type of climate and the underlying surface factors, while the correlation coefficient of different types of environmental factors was relatively low. In the K-means analysis, the Hopkins Statistic was first used to analyze the agglomeration of all watersheds, and the result showed that the Hopkins statistic was 0.83, indicating that the data is highly aggregated. The middle and small rivers in China could be roughly divided into south region, north region and northwest region; 2) Variance of the principal component analysis for the classified environmental factors increased, the classification effect of climate, vegetation and land use, soil, and terrain for river basins is better, whilst the classification effect of geomorphology, geology, human activities, and watershed morphology was not ideal; 3) GR4J model exhibited good applicability in Chinese rivers, aridity index, clay content and leaf area index showed the greatest impacts on the efficiency of the hydrological model; other environmental factors such as precipitation, elevation and basin area also affected the simulation efficiency of the model; 4) Precipitation, other woodland and leaf area index had the highest correlation with production store capacity (PSC); evapotranspiration, air temperature and sand standard deviation showed the greatest impact on intercatchment exchange coefficient; the proportion of low-cover grassland, the proportion of primitive soil and the proportion of hilly area exhibited the greatest correlation with routing store capacity (RSC), and the environmental factors with the highest correlation with unit hydrograph time constant (UTH) were the wetness index, percentage of tableland and the proportion of arid and deserts soil. Our results indicated that it was feasible to estimate the parameters of the hydrological model from the perspective of climate and underlying surface. Furthermore, the results in this study could provide a basis and reference for the transplantation of hydrological parameters from gauging basin to ungauged basin.
Under the background of land space planning reform, the land space of county is divided into three types: Urban space, agricultural space and ecological space. Among them, the planning of rural residential area system is the key to the agricultural space reconstruction. The implementation of Rural Revitalization Strategy requires the construction of rural community system according to the law of rural population migration. The characteristics of rural settlement spatial pattern and the optimized reconstruction mode are the foundation of rural community reconstruction. Based on the land GIS data and the statistical data of villages and towns, the cluster analysis and fractal method are used to explore the form types and spatial system characteristics of rural settlements in the Jianghan Plain. The research shows that the Jianghan Plain has formed ‘two category and four types’ of rural settlement space forms due to the difference of its internal natural environment matrix: One is the balanced mosaic settlement form in the low-hilly and mound areas, which can be divided into two subtypes: high-density & low-hilly point form and medium-density & mound crumb form, this rural settlement present a ‘star point’ spatial structure. Another is shaft-dependent settlement form in the river and ditch network areas, which can be divided into two subtypes: low-density & lake-arc form and medium-low density & river-ditch linear form, this rural settlement presents a ‘point-axis’ spatial structure. The characteristics of ‘two category and four types’ rural settlement form and spatial system in the Jianghan Plain are typical in the middle reaches of the Yangtze River Plain. It can provide theoretical basis and practical guidance for the spatial reconstruction of such rural settlements and the optimization of rural residential area system.
Technological innovation and environmental protection are two major themes of urban development at present. However, it is still controversial question that whether technological innovation can reduce environmental pollution and improve the ecological environment. This article holds that this debate is meaningless without considering spatial scale and factors. Therefore, it is necessary to study the spatial differentiation and mechanism of the impact of urban technological innovation on environmental pollution. In this study, based on the data of 285 cities (excluding those in autonomous prefectures, Hong Kong, Macau and Taiwan) at prefecture level and above in China, the spatial autocorrelation model is used to analyze the spatial correlation between technological innovation and environmental pollution at global and local scales, geographically weighted regression model is used to analyze the regional differences of the impact of technological innovation on environmental pollution, and Geodetector is used to analyze its influence mechanism. The results show that: 1) Both technological innovation and environmental pollution have significant spatial agglomeration, they have positive spatial correlation on the global scale, while positive and negative correlation coexist on the local scale. And there are 4 agglomeration types: high innovation-high pollution, low innovation-low pollution, high innovation-low pollution, low innovation-high pollution. 2) Technological innovation of all cities in the study area has a negative impact on environmental pollution, and the impact degree presents a spatial differentiation pattern with increasing impact degree from east to west. The calculation results of the existing samples conditionally verify the EKC curve, that is, technological innovation can promote the healthy development of economy and environment, and technological innovation in the eastern region can accelerate the arrival of EKC inflection point. 3) Environmental pollution is the result of many factors. Economic development, industrial structure, human capital, foreign direct investment and environmental regulation can all strengthen the effect of technological innovation on improving environmental pollution. The impact of technological innovation on environmental pollution is more to optimize industrial structure through technological progress, thereby reducing environmental pollution.
The rising of POI (Point of Interest) data drives an innovation of urban research. In order to sort out the progress of urban research using POI data in China, summarize the directions of research, methods of data analysis and shortcomings, and provide references for the future application of POI data in China’s urban development, CiteSpace was used to analyze 625 related literatures in CNKI (China National Knowledge Infrastructure) database from 2010 to 2019. Result shows that a large number of literatures in urban research using POI data emerged since 2013, and boomed in 2017. According to the results of knowledge map analysis, the main applications of POI data in urban research are identification of urban functional areas, division of urban central areas and boundaries, identification of business agglomeration and recommendation of interested points. While the main methods for analyzing POI data are kernel density analysis, spatial correlation analysis and DBSCAN algorithm. Plenty researches show that POI data is a kind of effective data for urban research, and very helpful for researchers to better understand the spatial structures, distribution patterns and development rules of cities. In future, it can be combined with machine learning and the other algorithms to provide a decision-making method for a long-term development of urban expansion and internal functional structure adjustment. However, POI data can not replace the shape data in some scenarios, and the impact of public awareness should be seriously taken into account individually for different researches.
The study uses A-F method to measure multidimensional poverty, and makes a systematic analysis of its regional differentiation by hot spot analysis, geographic detector and principal component analysis. The results showed: 1) Rural multidimensional poverty rate is 14.73%. The main poverty causing dimensions of farmers were housing, education and development, with contribution rates of 32.25%, 23.94% and 15.98%, respectively. 2) Rural multidimensional poverty shows the concentrated contiguous nature and regional difference. The hot area is located in the southern mountain area, and the cold area is located in the Yanghuang irrigation area and tableland area in the north. 3) The surface slope, village location conditions, altitude and arable land per capita area are the leading factors affecting of MPI regional differentiation, and the q value of the determining force is respectively 0.51, 0.44, 0.41 and 0.34. 4) Under the mutual combination and action of various factors, the poverty-stricken area of countryside present a regional differentiation mechanism in which the natural environment restricts the development of farmers, geographical location affects the welfare of groups, and resource abundance restricts agricultural production. To alleviate the regional multidimensional poverty, need to strive to promote the development of urban and rural public service equalization and fusion.
Based on the perspective of water-saving, water stress was defined as the ratio of the planned consumption of water resources to available water resources. This article estimated the water resources stress index of 31 provinces from 2005 to 2017, the ESDA (Exploratory Spatial Data Analysis) model was applied to study the spatial changing characteristic and correlation pattern of water resources stress index, the results showed that: 1) During the study period, the water resources stress index had a rising tendency in general, in the Bohai bay area, water resources stress index was high. Bohai Rim, the lower reaches of the Yangtze River and the Yellow River had great water-saving potential; water resources stress was unevenly distributed in space. The difference of values from west to east were more than that of values from south to north. 2) The water resource stress index had obviously spatial agglomeration, and the agglomeration phenomenon showed a trend of strengthening. The spatial distribution of water resource stress index in high agglomeration areas and low agglomeration areas were relatively stable. 3) From 2005 to 2017, the main factors influencing the spatial distribution of water resource stress index across the country were water consumption per 10000 GDP and water consumption of ten thousand yuan industrial added value. The spatial differentiation in eastern China was mainly determined by the population, domestic water consumption, livestock quantity and water consumption of ten thousand yuan industrial added value. The less developed areas in the central and western regions were mainly determined by the water consumption per 10000 GDP and COD emissions.
Based on atmospheric data of NCEP/NCAR re-analysis, NOAA Sea Surface Temperature (SST) data, and the daily precipitation from 1961-2018 in Shaanxi Province, the climatic characteristics of the First Rainy Season's onset date of Shaanxi (FRSOD_SX) and influential systems areanalyzed with synthetic analysis and regression analysis.The results show that FRSOD_SX has significant interannual variability. The FRSOD_SX is later in the 1960s and earlier from the 1970s to the 1980s. While the FRSOD_SX is later in the 1990s and earlier after entering the 21st century.The rainy season is mainly concentrated in the early to mid-July. In the years with early FRSOD_SX, the East Asia subtropical westerly jet stream (SWJS) establish earlier in late June and are stronger compared with their climatological means in the upper troposphere. There is ‘a two troughs and one ridge’ circulation pattern above mid-high latitude. The subtropical high is stronger, westward and northward than normal. In the lower layer, there is cyclonic anomaly circulation from the bay of Bengal to the South China Sea, and anticyclonic anomaly circulation on the West Pacific Ocean. In the years with late FRSOD_SX, the circulation system is opposite to the years with early FRSOD_SX.SST anomalies (SSTA) in the preceding winter and spring are the important forcing factors that affect the FRSOD_SX. When the Indian Ocean SST in winter and tropical North Atlantic SST in spring are abnormally warm, the FRSOD_SX is earlier than normal.
Soil microbial biomass, as an important index of soil active nutrients, is sensitive to microbial activity, environmental factors and climate change. Thus frozen ground degradation may exhibit striking influences on it. However, up to now, the related research is lacking in the Qinghai-Tibet Plateau (QTP). For this, two ecological plots containing the stable permafrost (SP) and extremely unstable permafrost (EUP) were selected, and investigated the quantity and distribution of soil microbial biomass carbon (SMBC) and nitrogen (SMBN) at depth of 0-50 cm, and further analyzed how soil physicochemical factors affect them in the Shule River headwaters, the Qilian Mountains, northeastern of the QTP. Here, our study was conducted upon an existing way that different permafrost types could shift to the temporal series that displayed different stages of permafrost degradation, which has been defined as a spatial-temporal shifts method. Results showed that the range of SMBC was 0.015-0.620 g/kg and 0.019-0.411 g/kg, and that of SMBN was 0.644-12.770 mg/kg and 0.207-3.725 mg/kg, respectively in the SP and EUP. Soil microbial biomass of the SP at depth of 0-50 cm was significantly higher than that of the EUP, indicating that the permafrost degradation had a distinct inhibition on the accumulation of soil microbial biomass. Moreover, ratios of soil microbial biomass to soil nutrients in the SP were significantly higher than that in the EUP, suggesting that the permafrost degradation could also inhibit the mineralization of soil microorganisms. Soil microbial biomass and its ratio to soil nutrients had obviously profile distribution, which decreased with the profile depth increase. Furthermore, permafrost types mainly controlled correlations between SMBC, SMBN and soil physicochemical factors, belowground biomass. Both SMBC and SMBN were negatively correlated with soil temperature and positively correlated with belowground biomass. In addition, in the SP, SMBC and SMBN were positively correlated with the ratio of carbon to nitrogen and negatively correlated with redox potential; in the EUP, SMBC and SMBN are positively correlated with soil pH. In the profile, SMBC and SMBN were significantly correlated with soil temperature and pH. The stepwise regression analysis showed that factors driving microbial biomass carbon and nitrogen were different in different types of frozen ground and profile. In conclusion, the study of characteristics about soil microbial biomass carbon and nitrogen in this region provides scientific support for assessing soil quality, health and predicting global carbon and nitrogen cycles under frozen ground degradation.
