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排序方式: 共有1007条查询结果,搜索用时 15 毫秒
871.
为探讨地下水资源丰富而地表水资源短缺的喀斯特地区水资源安全评价问题,以典型喀斯特地区贵州省为例,构建了喀斯特地区水资源安全评价指标体系,将熵权法与模糊综合评价模型相结合,从空间和时间上对贵州省9个州(市)2005-2014年水资源安全进行定量评价,结果表明:贵阳、黔东南、铜仁地区水资源安全处于良好等级,遵义、黔南、毕节、黔西南处于一般等级,安顺、六盘水处于差等级;2005-2014年,贵州省水资源安全相对稳定,都处于一般等级,但水资源安全呈现上升的趋势,这是由于贵州省近年来高度重视生态环境保护的结果。随着生态环境与经济发展矛盾的加剧,贵州省要更多地注重水资源供水安全指标的管理,调整产业结构,使经济、社会效益逐渐成为生态效益的补充和实现形式。   相似文献   
872.
Earth observation satellites produce large amounts of images/data that not only must be processed and preserved in reliable geospatial platforms but also efficiently disseminated among partners/researchers for creating derivative products through collaborative workflows. Organizations can face up this challenge in a cost-effective manner by using cloud services. However, outages and violations of integrity/confidentiality associated to this technology could arise. This article presents FedIDS, a suite of cloud-based components for building dependable geospatial platforms. The Fed component enables organizations to build shared geospatial data infrastructure through federation of independent cloud resources to withstand outages, whereas IDS avoids violations of integrity/confidentiality of images/data in sharing information and collaboration workflows. A FedIDS prototype, deployed in Spain and Mexico, was evaluated through a study case based on a satellite imagery captured by a Mexican antenna and another based on a satellite imagery of a European observation mission. The acquisition, storage and sharing of images among users of the federation, the exchange of images between Mexican and Spanish sites and outage scenarios were evaluated. The evaluation revealed the feasibility, reliability and efficiency of FedIDS, in comparison with available solutions, in terms of performance, storage consume and integrity/confidentiality when sharing images/data in collaborative scenarios.  相似文献   
873.
为了实现矿业城市生态安全性评价,利用BJ2、GF1、ZY3等国产高分辨率卫星影像数据,采用遥感技术手段,基于GIS平台,构建景观安全评价体系。通过获取2017年度研究区内各土地资源类型分布现状数据,进行景观指数(破碎度、分离度、优势度、干扰度、脆弱度、生态风险度)计算,逐网格剖析后采用普通Kriging插值法(半变异函数)对研究区域的景观生态安全度进行定量分析与评价。结果表明:研究区内大部分地区景观生态安全处于中、中高和高水平,面积为538 951.58 hm2,占研究区面积的86.75%,呈现由矿产资源集中开采区向其外部、平原区向低山丘陵区安全等级逐渐升高,生态环境逐渐转好的趋势;低、中低安全区总面积为82 342.18 hm2,占研究区面积的13.25%,景观生态安全仍存在较大问题,需引起地方政府关注。  相似文献   
874.
Food security for a growing world population is high on the list of grand sustainability challenges, as is reducing the pace of biodiversity loss in landscapes of food production. Here we shed new insights on areas that harbor place specific social memories related to food security and stewardship of biodiversity. We call them bio-cultural refugia. Our goals are to illuminate how bio-cultural refugia store, revive and transmit memory of agricultural biodiversity and ecosystem services, and how such social memories are carried forward between people and across cohorts. We discuss the functions of such refugia for addressing the twin goals of food security and biodiversity conservation in landscapes of food production. The methodological approach is first of its kind in combining the discourses on food security, social memory and biodiversity management. We find that the rich biodiversity of many regionally distinct cultural landscapes has been maintained through a mosaic of management practices that have co-evolved in relation to local environmental fluctuations, and that such practices are carried forward by both biophysical and social features in bio-cultural refugia including; genotypes, artifacts, written accounts, as well as embodied rituals, art, oral traditions and self-organized systems of rules. Combined these structure a diverse portfolio of practices that result in genetic reservoirs—source areas—for the wide array of species, which in interplay produce vital ecosystem services, needed for future food security related to environmental uncertainties, volatile financial markets and large scale conflicts. In Europe, processes related to the large-scale industrialization of agriculture threaten such bio-cultural refugia. The paper highlights that the dual goals to reduce pressures from modern agriculture on biodiversity, while maintaining food security, entails more extensive collaboration with farmers oriented toward ecologically sound practices.  相似文献   
875.
The fisheries data supplied to the Food and Agriculture Organization of the United Nations (FAO) by national agencies have served as the primary tool for many global and regional studies. However, it is recognised that these data are incomplete and often underestimate actual catches, particularly for small-scale fisheries. This study reconstructed total marine fisheries catches from 1950 to 2005 for Mozambique and the United Republic of Tanzania, by applying an established catch reconstruction approach utilising all available quantitative and qualitative data, combined with assumption-based estimations and interpolations. Since the 1950s, Mozambique has reported primarily industrial catches and has substantially under-reported the country's small-scale fishing sector due to lack of resources and civil war. In Tanzania, Zanzibar's recorded fisheries statistics prior to 2000 are absent from Tanzania's marine fisheries catches reported to FAO, and total mainland catches are at least one-third larger than officially reported. Based on our reconstruction, since 2000, Mozambique caught between 150 000 and 172 000 t y?1, while the United Republic of Tanzania caught at least 95 000 t y?1. For the period 1950–2005, reconstructed total marine catches were 6.2 and 1.7 times greater than data supplied to FAO by Mozambique and Tanzania respectively. The reliance on incomplete and substantially under-reported national data puts authorities under serious risk of over-licensing fishing access and mismanaging marine ecosystems and national food security.  相似文献   
876.
1998~2007年中国农业用水分析   总被引:10,自引:0,他引:10       下载免费PDF全文
李保国  黄峰 《水科学进展》2010,21(4):575-583
中国农业用水在未来将面临巨大的挑战。根据国际农业用水研究和政策领域近10年出现的范式变迁的核心内容,建立了基于"绿水"、"蓝水"的中国农业用水的新综合分析框架。并利用广义农业水资源量和广义农业水土资源匹配的概念和评估方法,分析了全国1998~2007年10年间4种主要粮食作物(水稻、小麦、玉米和大豆)的农业用水、耗水以及水分生产力变化趋势和现状。结果表明:中国广义农业水资源量中57%来源于耕地有效降水的"绿水",43%来源于耕地灌溉"蓝水"。主要粮食作物水分生产力水平已经接近或达到世界较高水平。未来继续提升水分生产力的任务将会更加艰巨。因此,为保证中国粮食安全,建议国家设立"粮食安全水资源红线"。同时,根据广义农业水资源量的分析计算,主要粮食作物用水安全红线应该划定在大约7800亿m3左右。  相似文献   
877.
石油期货市场机制及对中国石油安全的影响   总被引:7,自引:7,他引:0  
林建  王安建  于汶加  邹愉 《地球学报》2010,31(5):693-698
本文通过系统分析2003-2008年石油期货市场过度炒作的影响和动因, 结合不同历史时期国际石油期货市场机制的演变, 指出目前的石油期货市场已由以往的价格发现、平抑油价和规避风险的场所, 转变为发达国家和国际大型金融机构借以谋利和制约发展中国家经济社会发展的工具; 提出目前的石油市场机制使中国的石油安全乃至经济安全面临严峻的挑战, 中国应一方面提高国内企业和金融机构参与国际金融市场交易的能力, 积极参与国际石油期货市场交易, 以规避价格波动的风险; 另一方面加快步伐打造中国的石油期货市场, 获得国际石油定价权。  相似文献   
878.
本文阐述了在工程勘察设计行业高速发展的形势下档案管理工作中面临的问题,如档案的归属、档案数量的增加、现代企业制度的建立、档案信息化建设、工程档案编研等,并针对这些问题提出了自己的见解。  相似文献   
879.
刘伟 《山东地质》2010,(11):72-73,76
为贯彻落实科学发展观对测绘工作的要求,应以科学发展观统领国土资源测绘工作全局,充分利用测绘成果以及现代测绘技术,为推进科学发展提供保障服务。  相似文献   
880.
冷战结束以来,北约在安全思想上经历了从原有通过强化军事机器到通过加强协调、消除危机、增进社会稳定等非暴力手段为重点来实现国防安全的转变。从地域空间上讲,通过建立受北约控制的、具有一定空间层次结构的欧亚大西洋安全区等方式完成北约“东扩”乃至全球化。为了消除北约“东扩”给我国地缘政治环境带来的影响,我们应该加快祖国统一步伐、极大地增强综合国力,在发展与周边国家睦邻友好关系、建立合作机制的基础上,发展与世界各国的关系,建立有利于我国国防安全的地缘政治环境。  相似文献   
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