网络空间地理学的理论基础与技术路径

网络空间作为人类活动新的空间形态,是人和信息的共同载体,网络空间安全是国家安全的重要基础。对网络空间的科学刻画,是网络事件分析、网络空间治理、网络安全保障的重要基石,也是信息化时代地理学研究拓展的新领域。在全球网络空间激烈竞争的背景下,亟需加强地理学与网络空间安全等学科的交叉融合,在传统地理学的基础上进行理论创新和方法创新,创建网络空间地理学。网络空间地理学是地理学研究内容从现实空间向虚拟空间的延伸,理论基础是从传统地理学的人地关系理论演变为人地网关系理论;研究内容包括构建网络空间、现实空间的映射关系,在网络空间重新定义传统地理学关于距离、区域等基本概念,构建网络空间可视化表达的语言、模型、方法体系,绘制网络空间地图,探究网络空间结构和行为的演变规律等;技术路径包括网络空间要素数据采集与融合、网络空间可视化表达、网络空间态势与行为智能认知等,其中智能认知涵盖了网络空间态势现状评估、网络热点事件传播与溯源分析、网络事件态势模拟与风险预测等。网络空间地理学的创建将为网络空间的科学认知、地理学与网络空间安全等学科建设以及国家网络安全防控和全球网络空间命运共同体的构建提供新视角。     

The resource-ecological basis of the forest complex in East Siberia

The resource-ecological potential of forests is represented by the reserves of growing stock and total phytomass. Non-exhaustion forest exploitation can be based on a balance of deafforestation and appropriate regeneration of timber and other forest resources, and efficient protection against fires and other negative impacts for a stable development of the forest complex and for sustained resource and ecological functions of forests.     

The scale of forest transition: Amazonia and the Atlantic forests of Brazil

This article adapts a general equilibrium model that provides a spatial solution for land use, labor allocation, and product markets in a two good economy. The adaptation, based on von Thünen, considers the multi-regional case, and solves for two regions, one industrial and the other, a newly opened agricultural frontier. The conceptual framework is considered with reference to Brazil, where forest recovery in the Atlantic Rainforest occurs simultaneously with forest losses in Amazonia. Simulation results of the theoretical model are given, demonstrating the impacts of comparative advantage in regional agriculture on the spatial system. The main theoretical interest of the article, aside from providing a formal spatial statement, is to define a distinction between aggregate forest transition (A-FT), when the area of all forests in a multi-regional system increases with the advent of trade relations, and regional forest transition (R-FT), when forest recovery is spatially constrained, and depends on forest losses elsewhere. Thus, the article addresses the role of scale in defining forest transition, and does so by representing spatial dynamics with a formal model. It also suggests that forest transition privileges one biome at the expense of others, and that a concept of landscape turnaround is more germane from a wildlands conservation perspective. The article closes with a discussion of Brazil, and how its forests in Amazonia and along the Atlantic will fare in the coming years.     

Elementary forms for land surface segmentation: The theoretical basis of terrain analysis and geomorphological mapping

Land surface morphology is fundamental to geomorphological mapping and many GIS applications. Review and comparison of various approaches to segmentation of the land surface reveals common features, and permits development of a broad theoretical basis for segmentation and for characterization of segments and their boundaries. Within the context of defining landform units that maximise internal homogeneity and external differences, this paper introduces the concept of elementary forms (segments, units) defined by constant values of fundamental morphometric properties and limited by discontinuities of the properties. The basic system of form-defining properties represents altitude and its derivatives, constant values of which provide elementary forms with various types of homogeneity. Every geometric type of elementary form can be characterized by a defining function, which is a specific case of the general polynomial fitted function. Various types of boundary discontinuity and their connections and transformations into other types of morphological unit boundaries are analysed.The wealth of types of elementary forms and their boundaries is potentially unbounded and thus is sufficient to cover the real variety of landforms. Elementary forms in the basic set proposed here have clear potential for genetic and dynamic interpretation. A brief worked example documents the possibility of analytical computation of various models of ideal elementary forms for particular segments of landform. Ideal elementary forms can be considered as attractors, to which the affinity of surface segments can be measured by multivariate statistical methods. The use of the concept of elementary forms in landscape segmentation is promising and it could be adapted for elementary segmentation of various other spatial fields.     

A new theoretical treatment of compaction and the advective-diffusive processes in sediments: a reviewed basis for radiometric dating models

Classical treatment of mass conservation of solids in growing sediments states an advection-diffusion equation for the bulk sediment density. Thus, the diffusion coefficient has to account for elemental processes of exchange of solid particles by pore water or reciprocally. Nevertheless, in a gravity field, these exchanges are forced and cannot be treated as diffusion but as mass flow. A compaction potential energy is defined so that its spatial gradients force a mass flow involving a conductivity function. This leads to a more consistent definition of mass sedimentation rates and to a writing of the continuity equation for density involving only an advection term. Typical bulk density profiles show an asymptotic increase with depth. With the present formulation, this can be obtained as a steady-state solution under constant sedimentation rate and constant conductivity, while the classical formulation fails to do it. Alternatively, it can be found that under these conditions, the compaction potential is a linear function of the bulk density. The mass flow due to compaction and the compaction potential are found for several sediment cores from literature data. From this basis, the advection-diffusion equation for a particle-associated tracer is rewritten. In particular, when the mass flow term due to compaction is considered, the resulting sub-grid scale processes lead to a different formulation of the diffusive fluxes: they are proportional to the gradients of specific concentration in solids instead of the concentration per unit bulk volume. This new formulation is most suitable to find out analytical solutions for radiometric dating models involving mixing and compaction. Numerical solutions are found for the new and the classical treatment for some particular cases to illustrate differences.     

美丽中国建设的理论基础与评估方案探索

美丽中国建设是关系中华民族永续发展的根本大计,也是落实到2030年联合国可持续发展议程的中国实践。党和国家针对“五位一体”的总体布局对建设美丽中国做出了战略部署,国家主席习近平在全国生态环境保护大会上进一步提出了美丽中国建设的“时间表”和“路线图”。但目前对美丽中国建设的理论基础、评估指标体系、评估标准及建设成效等问题并不清晰。本文从广义和狭义视角提出了美丽中国建设的基本内涵,将人地和谐共生论、五维一体美丽论作为美丽中国建设的核心理论基础,进一步构建了包括生态环境、绿色发展、社会和谐、体制完善、文化传承等5个维度的美丽中国建设评估指标体系,运用联合国人类发展指数（HDI）测评方法,对2016年中国341个地级市（州）的美丽中国建设成效进行了科学评估。结果显示,美丽中国建设的综合美丽指数（中科美丽指数）平均值为0.28,总体处于偏低水平,生态环境美丽指数、绿色发展美丽指数、社会和谐美丽指数、体制完善美丽指数和文化传承美丽指数分别为0.6、0.22、0.29、0.22和0.07,分项指数值均较低,且地域发展差异较大,说明美丽中国建设进程总体缓慢且不平衡。为了高质量、高标准地贯彻落实美丽中国建设的“时间表”和“路线图”,建议构建并发布通用的美丽中国建设进程评估体系,对美丽中国建设进程开展动态监测与阶段性综合评估,编制并发布美丽中国建设评估技术标准,做好美丽中国建设综合区划,分区域因地制宜地开展美丽中国样板区建设试点,并把美丽中国建设成效纳入各级政府考核指标。     

Earthquake prediction: a new physical basis

Summary. Subcritical crack growth in the laboratory occurs slowly but progressively in solids subjected to low stresses at low strain rates. The cracks tend to grow parallel to the maximum compressive stress so that, when this stress is aligned over a large enough region, the cracks will also be aligned and possess effective seismic anisotropy. It is suggested that such subcritical crack growth produces extensive-dilatancy anisotropy (EDA) throughout earth-quake preparation zones. This process is a possible driving mechanism for earthquake precursors observed at substantial distances from impending focal zones, and provides, in the shear-wave splitting which has been observed in several seismic regions, a possible technique for monitoring the build-up of stress before earthquakes.     

蓝色经济通道的概念、理论基础及中国维护蓝色经济通道安全的路径

不同于海上交通线和海上战略通道,蓝色经济通道具有安全、政治、经济、地理、文化等多层面的含义,致力于可持续利用海洋资源,实现全人类的可持续发展,重点关注小岛屿发展中国家和沿岸最不发达国家,是一条海上大通道、海上合作平台,而不是具体的交通线、咽喉要道、海峡或海上交通线附近的战略岛屿。蓝色经济通道的海上大通道、海上合作平台内涵决定了其拥有理论基底。复合相互依赖理论、全球海洋治理理论、地理环境理论是其理论基底。安全维度是蓝色经济通道的最基本内涵。维护海上安全是发展蓝色经济的重要保障。     

森林的保护和可持续经营

2001年9月4～6日在北京,由全国政协人口资源环境委员会、全国政协外事委员会、中国国家环境保护总局、中国国家林业局共同组办了“21世纪论坛——绿色与环保′2001”专题论坛会议。来自世界各国或组织的知名专家学者参加了会议,一起探讨了人类共同关心的生态建设与环境保护领域的重大现实性问题。这里我们选刊了几位国际组织代表的讲稿,了解一下他们是如何评价和建议中国的环境保护与林业建设事业的,以从另一个角度对我国的林业与环境政策制定有所启迪。     

森林认证对森林经营和林产品贸易的影响

<正> 1.森林认证对森林经营的直接影响 (1)改善森林经营是所有的森林认证计划的目标和要求。森林经营认证的标准要求都不同程度地高于国家法律法规,或至少包括了更多的因素,如环境方面。而且几乎每个森林认证都有相应的森林经营条件,也就是说森林经营不仅要达到森林认证的要求,而     

Demographic transition in Sri Lanka: a spatial perspective

Demographic transition theory involves a lagging fertility transition induced by a leading mortality transition. This article focuses on the linkage between the mortality and fertility transitions in Sri Lanka; it discusses the measurement of areal fertility, demonstrates the use of a measure not commonly used in population geography, and shows areal association between past mortality and recent fertility. The Coale or Princeton fertility indices allow a reasonably good view of structural and behavioral aspects of fertility; the Coale indices examine the contribution of structure to total fertility and the contribution of marital fertility. Although recent fertility decline has been less rapid than the post-war mortality decline, Sri Lanka's crude birth rate in 1975 was the 5th lowest in Asia. Sri Lanka experienced very high crude death rates in 1930, and quite low rates in 1950 and in subsequent years. This demonstrates an association between historic mortality and recent fertility, and that association can be linked deductively to demographic transition theory. In 1930, malaria was endemic throughout the Dry Zone of Sri Lanka, and hyperendemic in several districts. The Spearman rank correlation coefficients reveal the strongest relationship between malaria and nuptiality; this lends evidence to the notion that structural influences on fertility--such as delayed marriage--are more important than influences on marital fertility--such as coital frequency. The evidence suggests that mortalily decline in Sri Lanka led to an increase in fertility in those areas where malaria had been concentrated. This suggests the possibility that measures constituting malaria control or eradication also stimulate increased fertility; therefore, anti-malarial programs must be integrated with family planning.     

The basis for earthquake prediction

Summary. Recent advances in understanding the behaviour of shear waves propagating in the crust make the routine prediction of earthquakes seem practicable. Accumulating evidence suggests that most of the Earth's crust is pervaded by distributions of fluid-filled cracks and microcracks that are aligned by the contemporary stress-field so that the cracked rockmass is effectively anisotropic to seismic waves. This causes shear-waves to split, and shear-wave splitting is observed whenever shear-waves propagating along suitable raypaths in the crust are recorded by three-component instruments. These distributions of cracks are known as extensive-dilatancy anisotropy or EDA. Many characteristics of the crack- and stress-geometry can be monitored by analyzing shear-waves propagating through the cracked rockmass. Observations of temporal variations of the behaviour of shear-wave splitting in seismic gaps confirm these hypotheses, and suggest that stress changes before earthquakes may be monitored by analyzing shear-waves. In particular, monitoring earthquake preparation zones with three-component shear-wave vertical-seismic-profiles could lead to techniques for the routine prediction of earthquakes.     

The landscape-geophysical basis of geoecology

The system-geophysical approach to solving a triad of debatable problems in landscape science and geoecology, namely: 1 — substantiating the structure of the formation mechanism for geographical landscape integrity; 2 — selecting quantitative indices for assessing the differentiation of landscapes in potential intensity of matter transport, and 3 — substantiating the notion of complex ecological indicator of the quality of functioning and development stability of landscapes. The law is formulated in relation to geographical landscape integrity as the universal manifestation of the triunity of the geophysical (radiation-gravity-hydrothermal), component and geochemical structures with the system-forming role of the geophysical system of landscapes.     

The remittance forest: Turning mobile labor into agrarian capital

How does labor migration affect Indonesian forests? In the mountains of Java, where political forests and plantations date back to colonial state land acquisitions in the nineteenth century, forests are being reconstituted and reconfigured by unusual subjects: the wives and daughters of contracted forest workers and other forest farmers. Working as maids and other domestic laborers in Hong Kong and other prosperous Asian cities, these landless women are sending home remittances to invest in rural resources and changing the understory of the political forest where their husbands and fathers are required to remain available for formal forest labor. Slowly, without really intending to, these women have regendered the forest, not completely ousting the men or the masculine associations with logging and resin collection, but making inroads into the control of the forest lands via the under‐used understory. This article tells how poor, landless women, marginalized as forest residents and as free household labor, reforestation farmers, and poor agricultural laborers, signed up to work as maids in Hong Kong and ended up remaking the forest.     

Nature and theoretical foundation of ecoregionalization:a case study in China

lintroductionPhysicalgeographers,ecologistSandotherresearchershavebeeninvolvedinanal}aingspahalchrenhationofvariousfactorsontheearthsurface,suchasbiome,close,andsoil,toexplainandunderstandthephysicogeographicalprocessesandtheirSPatialpatternssincetheestablislunentoftheacademicfieldsofgeogT'aphyandecology.Theynotedablythattheregional~onoffactorsonthe~~cewashelpfulnotonlytoimpellingthedevelopmentofgeographyandecology,butalsotobroadeningtheirapplicahons,andtheybeganclasssingfactorswithvallousmet…     

Forest transition and biogeographic meaning of the current laurel forest landscape in Canary Islands,Spain

This study provides a geographical synthesis of the current natural landscape dynamics of the Canarian laurel forest based on the results of a biogeographic study of its structure, composition, and dynamics. Historical socioeconomic changes and recent environmental conservation strategies have led to natural forest dynamics that make it necessary to change our current scientific conception of the Canarian laurel forest landscape. According to the forest transition theory, in the protected areas of Anaga and Teno Rural Parks (Tenerife) and Garajonay National Park (La Gomera), the forest reaction to the gradual abandonment of economic activity reveals how strongly human activity has shaped the features of the laurel forest, which traditionally has been considered to be relatively untouched by humankind. How natural disturbances have affected this forest over the past few years has also contributed to a better understanding of its dynamics. This study explains the key patterns of spontaneous dynamics in the Canarian laurel forest to enrich our understanding of this forest and its landscape, while highlighting the importance of human activity as the catalyst for its current vigorous dynamics.     

Dieback affects forest structure in a dry Afromontane forest in northern Ethiopia

Forests are highly susceptible to dieback under ongoing climate warming. In degraded forests, dead standing trees, or snags, have become such prominent features that they should be taken into account when setting management interventions. This study investigated (1) the extent and spatial pattern of standing dead stems of Juniperus procera and Olea europaea subsp. cuspidata along an elevational gradient, and (2) the effect of dieback on forest stand structure. We quantified abundance, size, and spatial pattern of tree dieback in 57 plots (50 m × 50 m) established at 100 m intervals along five transects. The snag density and basal area (mean ± SE) of the two species combined were 147 ± 23 stems ha⁻¹ and 5.35 ± 0.81 m² ha⁻¹, respectively. The percentages of snags were extremely high for both J. procera (57 ± 7%) and O. europaea subsp. cuspidata (60 ± 5%), but showed a decreasing trend with increasing elevation suggesting that restoration is even more urgent at the lower elevations. Snags of the two species accounted for 31 and 45% of total stand density and basal area, respectively. Living stems exhibited truncated inverse-J-shaped diameter and height class distributions, indicating serious regeneration problems of these foundation species in the study area. In addition to direct interventions to assist recruitment of climax tree species, sites with high dieback would probably benefit from snag reduction to prevent fire incidents in the remaining dry Afromontane forests in northern Ethiopia.     

中国森林生态系统能值与服务功能价值的关系

本研究利用1901-2009 年全球温度和降水数据以及全国1266 块森林样地主要森林类型数据作为基础数据,应用能值理论和生态系统服务功能理论,建立了中国森林能值与服务功能价值之间的函数关系,并且研究了1990 年和2009 年中国森林服务功能价值密度的变化。结果表明：应用函数关系模拟1994 年中国森林生态系统服务功能价值的结果与Costanza 评估结果在空间分布上具有较高的一致性。2009 年全国有林地栅格数目比1990 年增长14.02%,其平均森林生态系统服务功能价值密度增加了54.46 USD/hm²。北京、上海、江苏、天津、河北平均森林生态系统服务功能价值密度分别降低了86.87%、85.45%、81.99%、46.48%和23.07%。河南、湖南、吉林、江西、黑龙江和浙江平均森林生态系统服务功能价值密度分别下降了71.35%、58.65%、52.70%、34.56%、23.36%和22.03%。广西、西藏、甘肃、内蒙古、四川、云南、宁夏森林破坏也比较明显,这些省份的平均森林生态系统服务功能价值密度下降了2.89%~22.36%。根据全国第四次和第七次森林清查报告显示,近年来我国森林面积持续增加。但研究结果显示很多省份的森林生态系统服务功能价值密度仍然降低,这说明森林生态系统仍然没有完全恢复。中国森林生态系统服务功能普遍低于全球森林生态系统服务功能值的平均水平,说明我国森林生态环境并不理想,人类活动对生态系统产生巨大的负面影响。