Interactions between Vegetation and Climatic Factors in Typical Arid and Humid Regions of China Based on NDVI

According to the distribution of arid and humid regions in China,the typical arid region (Erjina),the typical semi-arid/semi-humid region (Guanzhong basin/Loess Plateau) and the typical humid region (Poyang Lake basin) were selected as the study areas.Based on NDVI data from 1982 to 2000 and meteorological observing data of three study areas from 1981 to 2000,the interactions between vegetation NDVI and climatic factors (temperature and precipitation) in typical arid and humid regions were discussed in this study.The results showed that in the responses of vegetation to climatic factors,vegetation in the typical arid region (Erjina) was more sensitive to precipitation,while vegetation in the typical semi-arid/semi-humid region (Guanzhong basin/Loess Plateau) was more sensitive to both temperature and precipitation,and vegetation in the typical humid region (Poyang Lake basin) was more sensitive to temperature.As for effects of vegetation on climatic factors,there was a remarkable negative correlation between vegetation NDVI in the past winter and temperature in the present summer,and also a significant positive correlation between vegetation NDVI in the past winter and precipitation in the present summer.However,in the typical semi-arid/semi-humid region (Guanzhong basin/Loess Plateau),there was a significant positive correlation between vegetation NDVI in the present spring and temperature in the present summer.

Dynamic of Chinas cultivated land and landcover changes of its typical regions based on remote sensing data

Using the multi-temporal Landsat data and survey data of national resources, the authors studied the dynamics of cultivated land and landcover changes of typical ecological regions in China. The results of investigation showed that the whole distribution of the cultivated land shifted to Northeast and Northwest China, and as a result, the ecological quality of cultivated land dropped down. The seacoast and cultivated land in the area of Yellow River Mouth expanded by an increasing rate of 0.73 kma-1, with a depositing rate of 2.1 kma-1. The desertification area of the dynamic of Horqin Sandy Land increased from 60.02% of the total land area in1970s to 64.82% in1980s but decreased to 54.90% in early 1990s. As to the change of North Tibet lakes, the water area of the Namu Lake decreased by 38.58 km2 from year 1970 to 1988, with a decreasing rate of 2.14 km2a-1.

Trade-off and Synergy of Rural Functions Under County Depopulation in the Typical Black Soil Region of Northeast China

As the population continues to shrink in the black soil region of Northeast China since 2000,it is critical to master the impact of population shrinkage on rural functions to realize rural revitalization and sustainable development.In this study,we focused on the impacts of depopulation on the evolution and interrelationship of rural subfunctions.Based on the rural function indexes system,the TOPSIS(Technique for Order Preference by Similarity to an Ideal Solution)method,spatial analysis method,and mathematical statistics analysis method were used to summarize the spatial and temporal characteristics of rural function development,as well as the effect of population shrinkage in the typical black soil region of Northeast China.The results showed that depopulation varied in the extent and duration between the forested region and plain areas,which both impacted the trajectories of rural subfunctions evolution.For the economic development function and ecological conservation function,the effect of continuous slight depopulation was beneficial,while the effect of rapid depopulation was adverse,which was exactly opposite to the agricultural production function.All forms of population shrinkage were conducive to the development of the social security function.With the deepening population shrinkage,depopulation mainly promoted the collaborative development between subfunctions in this study,except the relationship between agricultural production and social security function.But effects of depopulation on the interrelationship of rural subfunctions varied between the forested region and plain areas in some cases.The results provided evidence for the cognition that population shrinkage had complicated effects on rural subfunctions.

Regions and Their Typical Paradigms for Soil and Water Conservation in China

China is experiencing conflicts between its large population and scarce arable land,and between a demand for high productivity and the severe soil erosion of arable land.Since 1949,China has committed to soil and water conservation(SWC),for which eight regions and 41 subregions have been developed to improve the environment and increase land productivity.To obtain information from the regional planning and strategies for SWC and to explore whether SWC practices simultaneously contribute to soil conservation,ecosystem functioning,and the livelihoods of local farmers,and to summarize the successful experiences of various SWC paradigms with distinct characteristics and mechanisms of soil erosion,this paper systematically presents seven SWC regions(excluding the Tibetan Plateau region)and 14 typical SWC paradigms,focusing on erosion mechanisms and the key challenges or issues in the seven regions as well as on the core problems,main objectives,key technologies,and the performance of the 14 typical paradigms.In summary,the 14 typical SWC paradigms successfully prevent and control local soil erosion,and have largely enhanced,or at least do not harm,the livelihoods of local farmers.However,there remain many challenges and issues on SWC and socioeconomic development that need to be addressed in the seven SWC regions.China,thus,still has a long way to go in successfully gaining the win-win objective of SWC and human aspects of development.

An Analysis of China's Trade Balances with Other Countries and Regions

This article utilizes a large amount of statistical data to analyze the global distribution of foreign trade in China since 1990,as well as the factors involved and the changes in trends.The research results indicate that China has gained a favourable balance against developed countries and a disadvantageous balance against developing countries;China enjoys a trade surplus with North American and European countries while suffering deficits with those in the Asia.pacific region,as well as with resource-abundant Australia,Africa and South America. With regard to trends,the structure of China’s foreign trade will not undergo fundamental changes in the short term,but in the long run will be transformed in line with restructuring of the growth pattern.

Groundwater quality and land use change in a typical karst agricultural region:a case study of Xiaojiang watershed,Yunnan

Taking the typical karst agricultural region, Xiaojiang watershed in Luxi of Yurman Province as a research unit, utilizing the groundwater quality data in 1982 and 2004, the aerial photos in 1982 and TM images in 2004, supported by the GIS, we probe into the law and the reason of its space-time change of the groundwater quality over the past 22 years in the paper. The results show： （1） There were obvious temporal and spatial changes of groundwater quality during the past 22 years. （2） Concentrations of NH4^＋, SO4^2- , NO3, NO2^-, Cl^- and the pH value, total hardness, total alkalinity increased significantly, in which NH4^2-, NO3, and NO2^- of groundwater exceeded the drinking water standards as a result of non-point pollution caused by the expansion of cultivated land and mass use of the fertilizer and pesticide. （3） Oppositely, Ca^2＋ and HCO3^- showed an obvious decline trend due to forest reduction and degradation and stony desertification. Meantime, there was a dynamic relation between the groundwater quality change and the land use change.

Integrated Prevention and Control System for Soil Erosion in Typical Black Soil Region of Northeast China

The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to direct threats to national food security and regional sustainable development. Therefore, it is necessary to summarize integrated prevention and control experience of small watersheds in black soil region of Northeast China. Tongshuang small watershed, a typical watershed in rolling hills of typical black soil areas in Northeast China, is selected as the study area. Based on nearly 50 years' experience in prevention and control of soil and water loss, the structures and overall benefits of an integrated prevention and control system for soil and water loss are investigated. Then, the 'three defense lines' tri-dimensional protection system with reasonable allocation of different types of soil and water control measures from the hill top to gully is systematically analyzed. The first line on the top hill can weaken and block uphill runoff and sediment, hold water resources and improve soil property. The second line on the hill can truncate slope length, slow down the runoff velocity and reduce erosion energy. The third line in the gully is mainly composed of waterfall engineering, which can inhibit soil erosion and restore land resources. The 'three defense lines' system is feasible for soil and water loss control of small watersheds in the typical black soil region of Northeast China. Through the application of the in Tongshuang small watershed, There are effective improvements in ecological conditions in Tongshuang small watershed after the application of 'three defense lines' soil and water control system. Moreover, the integrated treatment paradigm for soil and water loss in typical black soil region is compared with that in loess region. The results of this study could offer references and experiences for other small watersheds in typical black soil region of Northeast China.

Dynamic influence of Holocene characteristics on vadose water in typical region of central North China Plain

In the typical region of central North China Plain, vadose sediments are Holocene sediment strata. With samples from field drillings, the study analyzes the sedimentary characteristics of vadose zone. The study takes the content of silty sand as the basis for sedimentary environment analysis, and the content of clay and sand as the sensitive indicator for sedimentary characteristics. Combining palynology analysis, the study divides vadose zone from top to bottom into diluvia oxbow lacustrine sediments, lacustrine sediments, lacustrine and swamp sediments, weak palaeohydrodynamic lacustrine sediments and alluvial sediments. Based on the sedimentary characteristics of Holocene strata, it analyzes the changes across depth of vadose zone water potential and matrix potential, obtaining the influence of vadose zone sedimentary characteristics on the migration of water in typical region of central North China Plain.

ECONOMIC COOPERATION BETWEEN CHINA AND PAN-PACIFIC COUNTRIES:IMPLICATIONS FOR ECONOMIC AND REGIONAL DEVELOPMENT OF CHINA

The primary aim of this paper is to elucidae economic and spatial impacts of the Sino-Pan-Pacific economic relationships on China. Specffically, it explores the following questions: what is the historical Process of economic cooperation between the two economies? What is the Position of inter-trade between China and Pan-Pacific countries in China's total international trade? What is the position of Pan-pacific countrys' direct investment in China? And what is the potential subsequent meaning of favorable location choice of sevral major investment countries in China?

Effect of climatic change on surface environments in the typical region of Horqin Sandy Land

The town of Agura,a typical region in Horqin Sandy Land,was selected as the study area in this paper.Using 12 remote sensing images and climatic data from the past 20 years,the effects of climate change on surface environments were analyzed.The impact indices of climatic factors,along with their corresponding ranks,were used to characterize the responses of different types of surface environments to climate change.Results show that in the past 20 years,the surface environments of the study area have been deteriorating.Furthermore,there is a positive relationship between the changes in surface environments and those in climatic factors.Various climatic factors influence surface environments in different ways and at different levels.The most sensitive factor is relative humidity,followed by precipitation and evaporation.Overall,moisture is the key factor that affects the changes in surface environments of arid and semi-arid areas.

The Regional Conference of the IGU on Asian Pacific Countries Successfully Held in China

TheThe Regional Conference on Asian Pacific Countries of the IGU was held from August 13 to 19,1990 at Beijing,on the premises of Peking University.It was the first of such event of the Union to take place in China.The Conference was attended by 1017 geographers from 40 countries of six continents(Asia 788,Europe 125,North America 74,Oceania 15,Latin America 7,Africa 3),with the larger delegations from:U.S.A.(45),South Korea(44),Japan(31),France(18),Italy(17),FRG(16),Canada(16),U.S.S.R.(13),Australia(10),Spain(9),U.K.(8)and India(8).China composed the majority,and Taipei sent a sizable delegation of 15,the rest of the participating countries sent 1-4 delegates each.The organizing committee of the Conference included the executive committee members of the Geographical Society of China and members of China Committee for the IGU.Profs.Huang Bingwei and Wu Chuanjun were responsible for all the activities organized during the Conference.

Human Rights Organizations in Transition Countries

The paper examines the challenges faced by the human rights organizations in the Arab region. It will focus on those challenges resulting from the radical changes that happened since 2011. It will also look into the prospective role of the human rights organizations in the future phases of the political transition.

Changes of spring wind erosion based on wind erosion climate factor in the black soil region of Northeast China

The dry and windy climate and low ground cover in spring in the black soil region of Northeast China make the soil strongly affected by wind erosion,which seriously threatens the food security and ecological security of this region.In this paper,based on the daily observation data of 124 meteorological stations in study area from 1961 to 2020,seasonal and monthly wind erosion climate factor(C)in spring(March to May)were calculated by using the method proposed by the Food and Agriculture Organization of the United Nations(FAO),the wind erosion characterization in spring were systematically analyzed based on C by various statistical analysis methods.The results showed that in the past 60 years,spring wind erosion climate factor(CSp)and monthly C of the whole region and each province(region)all showed highly significant decreasing trend,but they began to show rebounded trend in the middle or late 2000s.CSp of the study area showed a significant upward trend since 2008 with an increase of 4.59(10a)^(-1).The main contributors to this upward trend are the changes of C in March and in April.For the four provinces(regions),CSp in Heilongjiang,Jilin,Liaoning and eastern Inner Mongolia all showed rebounded since 2008,2011,2008 and 2009,respectively.The rebounded trend of CSp in eastern Inner Mongolia was the most obvious with a tendency rate of 11.27(10a)^(-1),and its mutation occurred after 1984.The rebound trend of CSp in Heilongjiang Province takes the second place,with a trend rate of 4.72(10a)^(-1),but there’s no obvious time mutation characteristics.The spatial characteristics of CSpand monthly C are similar,showing decreasing characteristics centered on the typical black soil belt of Northeast China.Compared with 1961-1990,in the period from 1991 to 2020,the proportion of high value areas(CSp>35,monthly C>10)has decreased to varying degrees,while the proportion of low value areas(CSp≤10,monthly C≤4)has increased.The trends of seasonal and monthly C in 82.2%~87.7%of the stations show significant decreases at 95%confidence level.CSp is closely related to wind speed at 2m height,temperature difference,minimum temperature and precipitation in the same period,of which the correlation between CSp and wind speed is the strongest,indicating that the main control factor for CSp in the study area is wind speed,but the impact of the change of temperature and precipitation on CSp cannot be ignored.

基于机器学习的“一带一路”投资国别风险预测研究

“一带一路”倡议提出十年间,中国对沿线国家的投资规模持续扩大。然而,企业在抓住机遇,进行“一带一路”沿线国家投资的同时,也需要重点关注“一带一路”投资国别风险。本文从政治、经济、社会和对华关系4个维度构建“一带一路”投资国别风险预测指标体系;运用灰色关联分析计算样本国家的综合风险评价值;基于2012~2022年间“一带一路”沿线国家的数据,利用机器学习构建GA-BP神经网络、支持向量回归和随机森林3种预测模型;通过对比预测精度,确定最佳预测模型,利用2021年的指标数据,对2022年的投资国别风险进行预测。研究结果表明:(1)在“一带一路”投资国别风险的研究背景下,支持向量回归模型预测效果最优,证明机器学习模型能够有效应用于风险管理领域;(2)“一带一路”投资国别风险存在明显的地区差异,中东欧地区和东南亚地区投资国别风险普遍较低,而南亚地区投资国别风险普遍较高,但都存在特例。本文研究结果可为“走出去”企业在“一带一路”沿线国家的投资决策提供参考。

中国农产品出口贸易隐含碳排放测算及异质性分析——来自“一带一路”沿线国家(地区)的证据

采用环境拓展投入产出法测算了2007—2021年中国对“一带一路”沿线国家(地区)农产品出口贸易的隐含碳排放,进而运用LMDI模型探究贸易规模因素、出口结构因素和农业技术因素对隐含碳排放变动的贡献值与贡献率,从农产品部门和贸易区域两个层面对隐含碳排放变动的驱动因素进行异质性分析。研究发现:第一,2007—2021年中国对“一带一路”沿线国家(地区)的出口贸易隐含碳排放整体呈上升趋势,农产品出口贸易隐含碳排放年均增长率超过农产品出口贸易额年均增长率2.75%,隐含碳排放效率下降。第二,农产品出口贸易隐含碳排放存在明显的部门差异,因不合理的出口结构,农业、食品制造业和食品加工业等中高度碳排放密集型部门对隐含碳排放总量变动的贡献值占比较大,而林业、畜牧业等低度碳排放密集型部门的这一占比较小。第三,农产品出口贸易隐含碳排放存在明显的区域差异,对东南亚国家(地区)出口农产品产生的隐含碳排放占总碳排放的60%以上,贸易规模因素和农业技术因素是造成区域差异的主导因素。上述发现揭示了中国农产品出口贸易隐含碳排放变动的原因,为优化农产品出口结构、调整农产品出口贸易策略及碳排放双控制度的实施提供了新的思路与经验证据。

我国区域典型城市国际化水平的定量分析及对策思考

采用层次分析法,从经济开放、科技创新、国际影响和城市宜居四个层面构建准则层,选取18个指标评价14个区域典型城市的国际化水平,结果表明:(1)区域典型城市的国际化水平总体评分及经济开放指标评价呈现东部最优、西部次优,而中部最靠后;(2)科技创新上,东部科技创新实力强劲,中部城市的武汉处于第二位次城市组别,西部城市成都处于第一层次城市群里;(3)国际影响上,第一层次东部占据前三城市,中部4个城市均居于第三层次,西部城市成都处于第一层次里第四位次;(4)城市宜居上,东中西部典型城市分值差别不大。

突出流行性还是稀缺性?——地理标志农产品地区典型性与广告诉求方式的匹配效应研究

地理标志农产品的本质特征在于产品与产地的关联性,但不同的地理标志农产品,消费者对其产品与产地关系的联想即地区典型性存有差异。针对地区典型性不同的地理标志农产品,如何采用配套的广告诉求方式以提升品牌传播的有效性?为此,本研究将地区典型性与广告诉求方式相匹配探究其对消费者态度的影响,以及这一影响发生的内在机制与边界条件。四个实验结果表明,当地理标志农产品的地区典型性高时,采用流行性诉求更能引发消费者对产品的积极态度,感知可靠性在其中起中介作用;当地理标志农产品的地区典型性低时,采用稀缺性诉求更能引发消费者对产品的积极态度,感知独特性在其中起中介作用。此外,产品属性在地区典型性与广告诉求方式对消费者产品态度的交互作用中起调节作用,高地区典型性与流行性诉求对消费者产品态度的交互作用在实用性属性下更显著,低地区典型性与稀缺性诉求对消费者产品态度的交互作用在享乐性属性下更显著。本研究为地理标志农产品消费行为研究提供了新的视角,同时对提升地理标志品牌价值及促进地理标志产业均衡发展具有实践意义。

关帝山3个典型森林群落优势种的氮素利用策略差异

【目的】研究关帝山林区华北落叶松林、白桦林和沙棘林3个典型森林群落优势种的新生枝叶氮含量、地上生物量和氮利用效率对5个土壤施氮梯度的差异化响应,阐明3个森林群落优势种不同的氮利用功能特性和氮利用策略,为氮沉降背景下的森林质量提升和精准经营提供理论依据。【方法】采用野外5梯度土壤氮(0、9、18、27和36 g·m^(−2) a^(−1))添加试验的方法,比较3个森林群落优势种和群落总体的新生枝叶氮含量、地上新增生物量和氮利用效率对土壤不同施氮量的响应;采用线性模型拟合地上新增生物量随新生枝叶氮含量、氮利用效率和土壤氮素供应水平的变化过程;通过构建结构方程模型,分析土壤氮添加影响地上新增生物量的作用路径。【结果】3个群落优势种的新生枝叶氮含量总体表现为华北落叶松<白桦<沙棘,新生叶氮含量显著高于新生枝,两者的差异表现为白桦>华北落叶松>沙棘,生长盛期的枝叶氮含量都高于末期,生长期之间的差异也表现为白桦>华北落叶松>沙棘;新生枝和新生叶在生长盛期和末期的氮含量都有随施氮量增加而增加的趋势,但3个优势种的变化表现出显著不同的趋势,饱和施氮量和饱和氮含量均表现为华北落叶松<白桦<沙棘;3个群落新生枝叶生物量都随施氮量的增大而升高,但递增率拟合结果表现为华北落叶松林>沙棘林>白桦林;群落氮利用效率都随施氮量增大而降低,以华北落叶松林的降幅最大,沙棘林最小,也随优势树种枝叶氮储量的升高而降低,以白桦林降幅最大,沙棘林最小;群落优势种和群落类型对群落新生枝叶氮储量和氮素利用效率直接作用显著,也受施氮量的影响,进而正向驱动群落新增生物量积累。【结论】华北落叶松林、白桦林和沙棘林3个森林群落新增生物量的差异主要取决于群落类型及其优势种的差异,直接受群落优势种的氮利用效率和新生枝叶氮含量的影响,并受土壤供氮水平的调节;三者的氮利用策略分异表现在氮需求、氮利用效率、环境氮敏感性、饱和氮供应水平4个方面;依次表现为“低需求-高效率-高敏感-低饱和”、“较低需求-低效率-较高敏感-较低饱和”和“固氮型-高需求-低效率-低敏感-高饱和”3个氮利用策略类型,可为不同氮沉降情境或林地氮含量水平下的林分优势树种选择、结构调控和林地精准管理提供依据。