基于CiteSpace的国内外海洋空间规划研究发展态势分析          下载免费PDF全文

王珏  郭振  张志卫  孙永根 《海洋开发与管理》2022,39(1):12-22

海洋空间规划是一个对海洋资源可持续开发利用的规划和管理过程。文章采用可视化工具CiteSpace,基于WOS核心合集和CNKI数据库,系统梳理分析2000—2020年海洋空间规划领域的国内外研究主题及其突现词演变路径。结果表明:当前国内外海洋空间规划相关研究数量总体呈上升趋势,美国、澳大利亚和英国3国占比超过50%,各机构间合作度较高、跨国交流活跃;国际方面,栖息地、海洋保护区域、渔业发展、生物多样性是热点研究方向,国内则更加关注陆海统筹和可持续发展;近20年来,国际研究趋势变化为"空间规划体系的构建-空间规划尺度的拓展及跨界研究-经验总结与环境保护",国内规划时期则从"空间规划政策综合管理-具体功能区划分-可持续发展"不断发展;在此基础上提出未来深入探索的重点领域以及建议。  相似文献   

Terrestrial surface-area increment: the effects of topography,DEM resolution,and algorithm     

Ling-Xiao Ying  Shi-Long Piao  Yu Liu  George P. Malanson 《自然地理学》2014,35(4):297-312

The area increment of land surface compared with its projected area is an effect of topographic relief and is also a source of environmental variations. To examine the effects of topography and data resolution on surface area calculation, we calculated incremental area coefficients (IACs), based on two different algorithms, for a DEM of China at a series of spatial resolutions. Sampling the DEM with a regional network of 50?km?×?50?km cell size, we explored the relationships among the two IACs and topographic features. Both IACs studied were exponential functions of resolution. At 30-m resolution, the IACs were 4.31 and 4.89% over China, respectively. The largest increment for a 50?km?×?50?km cell was >45%. Between the IACs there was a linear relationship that varied with DEM resolution. Hierarchical variation partitioning revealed that the factors included contributed in a very similar percentage composition to the two IACs, mean slope (37.5 or 38.7%) and standard deviation of slope (22.3 or 19.6%) at local scale dominated the area increment, followed by regional elevation range. Data resolution contributed about 10%, while the deviation of slope exposure only had minimal (1.4 or 1.7%) impact on surface-area increment. For a specific type of geomorphology, a threshold resolution of DEM can be determined, below which the surface-area increment (i.e., IAC) is negligible. Our results provided the first comprehensive estimate of the contributions of the topographic features, DEM resolution, and algorithms for the surface-area increment, and indicated the scale-related properties and potential environmental consequences of topographic heterogeneity in various estimates of natural resources and ecosystem functions when area needs to be taken into account.  相似文献   

Geographies of folded life: How immunity reframes biosecurity     

《Geoforum》2014

Biosecurity, in broad terms, aims to reduce the impact and incidence of threats to life through regulatory means. For reasons we raise in this paper, such regulation can often lead to the specification of disease free processes within the food and farming industry, with biosecurity success measured in terms of the degree of compliance with and allegiance to modern farming practice. We counter this progressive narrative in three ways. First we draw on UK-based qualitative fieldwork with vets, farmers and pigs to demonstrate how biosecure farming and disease freedom are translated and qualified, in practice, to pathogen free, pathogen management and ultimately to configuring health through immunity management. Second, these translations demonstrate how building health is dependent on spatial and microbiological diversity rather than uniformity. Crucially, health involves patch-work and situated knowledge practices that are under threat within an industry increasingly marked by control and homogeneity. Third, in conceptual terms, we argue that while pig farming is organised through both biosecurity and a biopolitical regulation of life, immunity opens up political space for exploring an alternative politics of life, one where farmers and others are not so much made responsible for disease prevention, but make valued contributions to understandings of animal health and food security.  相似文献   

Sedimentary stylolite networks and connectivity in limestone: Large-scale field observations and implications for structure evolution     

《Journal of Structural Geology》2014

Stylolites are rough surfaces, formed by localized rock dissolution, and prevalent in carbonates and other sedimentary rocks. Their impact on porosity and permeability, and capacity to accommodate compactive strain, are well documented. This paper presents a meso-scale field study on sedimentary stylolites in carbonates, characterizing large-scale distributions of stylolites, including measurements conducted on longer than kilometer-long stylolites. Our field study suggests that on large scales connections between stylolites become important. Since connectivity, and also lack of connectivity, are expected to play a significant role in strain accommodation and hydraulic rock properties, we suggest that large-scale analysis may require a new characterization scheme for “stylolite populations”, based on their connectivity. We therefore divide sedimentary stylolite populations into three end-member types, which are correlated with the three possibilities for percolation of such systems: isolated stylolites (with zero percolation/connectivity), long-parallel stylolites (with 2-dimensional percolation/connectivity), and interconnected stylolite networks (with 3-dimensional percolation/connectivity). New statistical parameters and measures are devised and used to quantitatively characterize the different population types. Schematic mechanistic models are then offered to explain the evolution of the three end-member connectivity-classes. In addition we discuss the effect on fluid flow of the different population types.  相似文献   

Linking pesticides and human health: A geographic information system (GIS) and Landsat remote sensing method to estimate agricultural pesticide exposure     

《Applied geography (Sevenoaks, England)》2015

Accurate pesticide exposure estimation is integral to epidemiologic studies elucidating the role of pesticides in human health. Humans can be exposed to pesticides via residential proximity to agricultural pesticide applications (drift). We present an improved geographic information system (GIS) and remote sensing method, the Landsat method, to estimate agricultural pesticide exposure through matching pesticide applications to crops classified from temporally concurrent Landsat satellite remote sensing images in California. The image classification method utilizes Normalized Difference Vegetation Index (NDVI) values in a combined maximum likelihood classification and per-field (using segments) approach. Pesticide exposure is estimated according to pesticide-treated crop fields intersecting 500 m buffers around geocoded locations (e.g., residences) in a GIS. Study results demonstrate that the Landsat method can improve GIS-based pesticide exposure estimation by matching more pesticide applications to crops (especially temporary crops) classified using temporally concurrent Landsat images compared to the standard method that relies on infrequently updated land use survey (LUS) crop data. The Landsat method can be used in epidemiologic studies to reconstruct past individual-level exposure to specific pesticides according to where individuals are located.  相似文献   

SVOM数据档案库软件原型系统的设计与实现   总被引：1，自引：0，他引：1  

王玉涵  黄茂海  刘飞飞 《天文研究与技术》2015,(3)

作为中法天文卫星(Space multi-band Variable Object Monitor,SVOM)中方科学中心的重要组成部分,中法天文卫星数据档案库承担了中方科学数据产品本地存储和管理的任务,提供统一的数据产品管理平台,实现中法天文卫星科学数据产品的归档、检索、检出、维护与管理等功能。作为中法天文卫星科学中心预研的一部分,对中法天文卫星数据档案库原型系统进行了需求分析、系统设计,实现能够运行的原型系统,以演示中法天文卫星数据档案库的基本功能和工作流程,验证设计方案的可行性。档案库原型系统具有开放性和低耦合的特点,能够适应中法天文卫星中方数据产品结构的不断变化,在项目早期即可投入试用并不断完善,满足中法天文卫星的任务需求。  相似文献   

Imaging Borrelly     

L.A Soderblom  D.C Boice  R.H Brown  R.L Kirk  R.M Nelson  B.R Sandel  N Thomas 《Icarus》2004,167(1):4-15

The nucleus, coma, and dust jets of short-period Comet 19P/Borrelly were imaged from the Deep Space 1 spacecraft during its close flyby in September 2001. A prominent jet dominated the near-nucleus coma and emanated roughly normal to the long axis of nucleus from a broad central cavity. We show it to have remained fixed in position for more than 34 hr, much longer than the 26-hr rotation period. This confirms earlier suggestions that it is co-aligned with the rotation axis. From a combination of fitting the nucleus light curve from approach images and the nucleus' orientation from stereo images at encounter, we conclude that the sense of rotation is right-handed around the main jet vector. The inferred rotation pole is approximately perpendicular to the long axis of the nucleus, consistent with a simple rotational state. Lacking an existing IAU comet-specific convention but applying a convention provisionally adopted for asteroids, we label this the north pole. This places the sub-solar latitude at ∼60° N at the time of the perihelion with the north pole in constant sunlight and thus receiving maximum average insolation.  相似文献   

Surveying co-located space-geodetic instruments for ITRF computation   总被引：2，自引：2，他引：0  

P.?SartiEmail author  P.?Sillard  L.?Vittuari 《Journal of Geodesy》2004,78(3):210-222

A new and comprehensive method is presented that can be used for estimating eccentricity vectors between global positioning system (GPS) antennas, doppler orbitography and radiopositioning integrated by satellites (DORIS) antennas, azimuth-elevation (AZ-EL) very long baseline interferometry (VLBI) telescopes, and satellite laser ranging (SLR) and lunar laser ranging (LLR) telescopes. The problem of reference point (RP) definition for these space-geodetic instruments is addressed and computed using terrestrial triangulation and electronic distance measurement (EDM) trilateration. The practical ground operations, the surveying approach and the terrestrial data processing are briefly illustrated, and the post-processing procedure is discussed. It is a geometrically based analytical approach that allows computation of RPs along with a rigorous statistical treatment of measurements. The tight connection between the geometrical model and the surveying procedure is emphasized. The computation of the eccentricity vector and the associated variance–covariance matrix between an AZ-EL VLBI telescope (with or without intersecting axes) and a GPS choke ring antenna is concentrated upon, since these are fundamental for computing the International Terrestrial Reference Frame (ITRF). An extension to RP computation and eccentricity vectors involving DORIS, SLR and LLR techniques is also presented. Numerical examples of the quality that can be reached using the authors approach are given. Working data sets were acquired in the years 2001 and 2002 at the radioastronomical observatory of Medicina (Italy), and have been used to estimate two VLBI-GPS eccentricity vectors and the corresponding SINEX files.  相似文献   

Essential characteristics of natural dissolved organic matter affecting the sorption of hydrophobic organic contaminants   总被引：5，自引：0，他引：5  

Jarkko?AkkanenEmail author  Rolf?D.?Vogt  Jussi?V.?K.?Kukkonen 《Aquatic Sciences - Research Across Boundaries》2004,66(2):171-177

  相似文献   

Large-strain deformation and strain partitioning in polyphase rocks: Dislocation creep of olivine–magnesiowüstite aggregates     

Misha Bystricky  Florian Heidelbach  Steve Mackwell   《Tectonophysics》2006,427(1-4):115

Aggregates composed of olivine and magnesiowüstite have been deformed to large strains at high pressure and temperature to investigate stress and strain partitioning, phase segregation and possible localization of deformation in a polyphase material. Samples with 20 vol.% of natural olivine and 80 vol.% of (Mg_0.7Fe_0.3)O were synthesized and deformed in a gas-medium torsion apparatus at temperatures of 1127 °C and 1250 °C, a confining pressure of 300 MPa and constant angular displacement rates equivalent to constant shear strain rates of 1–3.3 × 10^− 4 s^− 1. The samples deformed homogeneously to total shear strains of up to γ  15. During constant strain rate measurements the flow stress remained approximately stable at 1250 °C while it progressively decreased after the initial yield stress at the lower temperature. Mechanical data, microstructures and textures indicate that both phases were deforming in the dislocation creep regime. The weaker component, magnesiowüstite, controlled the rheological behavior of the bulk material and accommodated most of the strain. Deformation and dynamic recrystallization lead to grain refinement and to textures that were not previously observed in pure magnesiowüstite and may have developed due to the presence of the second phase. At 1127 °C, olivine grains behaved as semi-rigid inclusions rotating in a viscous matrix. At 1250 °C, some olivine grains remained largely undeformed while deformation and recrystallization of other grains oriented for a-slip on (010) resulted in a weak foliation and a texture typical for pure dry olivine aggregates. Both a-slip and c-slip on (010) were activated in olivine even though the nominal stresses were up to 2 orders of magnitude lower than those needed to activate these slip systems in pure olivine at the same conditions.  相似文献