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1.
国际全球变化研究发展态势文献计量评价   总被引:1,自引:0,他引:1  
全球变化研究是国际上地球系统综合研究的重大跨学科研究领域.随着全球环境问题的日益突出,国际上先后组织发起了全球环境变化研究的四大科学计划WCRP、IGBP、IHDP、DIVERSITAS及其组成的地球系统科学联盟ESSP,开展对全球变化和地球系统科学的研究.当前,全球变化问题不仅是科学界关注和研究的问题,也是政治界、经济界都关注的重大问题.科技文献能够反映科学前沿的发展动态.对SCIE和SSCI数据库收录的全球变化研究文献进行统计,从文献计量学的角度,分析国际全球变化研究领域的发展态势,了解中国全球变化研究的国际影响力.可以看出:国际上全球变化研究的论文数量一直呈增长趋势,以地球科学多学科、生态学、环境科学、自然地理学、植物学等学科领域为主.中国自2000年以来在该领域的发文数量增长较快,特别是中国科学院的发文量已进入国际前列,但中国在该研究领域尚缺少高影响力的论文.  相似文献   

2.
国际地震研究发展态势文献计量分析   总被引:5,自引:0,他引:5  
张树良  安培浚 《地球学报》2012,33(3):371-378
以ISI Web of Science论文数据库为数据源,采用美国汤姆森科技信息集团开发的专业数据分析工具TDA(Thomson Data Analyzer)对1900年至2010年(数据入库时间至2010年)国际地震研究发展特点及其现状予以分析。结果显示:国际地震研究持续增长,特别是近20年,增速显著;美国在该领域居于引领优势;政府科研机构、国立科研机构和公共研究机构是该领域研究的主导力量;国际地震研究主要集中于地震机理及成因、地震监测、地震影响及效应等方向;中国虽然已经步入地震研究的主要国家行列,但影响十分有限。  相似文献   

3.
国际及中国地球科学发展态势文献计量分析   总被引:7,自引:0,他引:7  
以SCI、ESI(基本科学指标数据库)、GEOREF等数据库为统计分析源,对1993—2003年国际及中国地球科学的发展现状和发展态势从文献计量学的角度进行统计分析,分析了国际地球科学论文产出的主要领域、国家、机构、科学家和期刊,对中国地球科学论文产出的主要领域进行比较分析,并通过论文产出、被引频次、篇均被引频次和国际1%顶尖论文数量对比反映中国的科学影响力。结果表明,国际环境科学和生态学研究论文增长很快,占地球科学相关主题领域论文的比例也比较大,但中国生态学研究论文无论从占国内22个学科论文产出的比例,还是从占全球该领域的比例来说都有较大差距;中国地质科学领域研究重点在地球化学、金属矿产和能源的经济地质学,但在环境地质学领域研究相对较少,而国际上环境地质学研究论文的发展已经大大高于传统的地质学论文。  相似文献   

4.
冻土是冰冻圈的重要组成部分,其对全球变暖敏感且对工程稳定性影响显著,近年来全球科学家更多地关注这一研究领域。作为世界冻土大区的中国,对冻土学科的发展和动态尤其重视。本文基于文献计量的方法,对近五年(2012-2016)冻土学领域发表的SCI(E)/CPCI收录论文进行统计分析,得到该领域在全球的研究力量分布。同时,分别从冻土工程、冻土力学、冻土环境、冻土物理这四个方向加以区分,得到其不同机构与科学家论文发表情况。从论文产出的角度,宏观地反映了冻土科学在这五年中的发展脉络与国际影响力。这一工作可为全面了解近期该领域的研究发展动态提供数据参考。  相似文献   

5.
国际生态系统研究发展态势文献计量分析   总被引:4,自引:0,他引:4  
生态系统研究是地球系统科学的重要组成部分,近年来,各国和各相关研究机构对生态系统的研究力度不断加大.利用Thomson Data Analyzer、NetDraw和Aureka等文献计量工具,结合Pathfinder算法对SCIE和SSCI数据库中国际生态系统研究相关文献进行了分析.在对主要国家和机构的发文进行统计分析后发现:美国、德国和英国等国的生态系统研究论文的综合影响力较高,其中美国是国际生态系统研究合作的中心;加州大学伯克利分校、美国国家海洋与大气管理局和法国农业科学研究院等机构的论文影响力较大;美国农业部、德国马普学会、华盛顿大学和瑞典隆德大学是国际生态系统研究的中心;中国生态系统研究论文在总量上优势明显,但整体论文质量不高;国际生态系统研究的主要研究热点集中在珊瑚礁生态系统研究、气候变化研究和生态系统管理等方面.  相似文献   

6.
近5年国际地球科学领域发展态势文献计量分析   总被引:2,自引:0,他引:2  
史静  朱薇薇  王鑫  肖仙桃  刘振锋  王欢  柴新夏 《地质学报》2017,91(12):2881-2888
本文基于Web of Science平台,以SCI-E数据库2012~2016年地球科学领域各年度居前10%的高被引论文为统计分析源,从国际地球科学研究论文的总体概况、研究的主要国家和机构、研究热点等方面对近年来地球科学发展态势进行文献计量分析,旨在为相关管理部门了解地球科学研究发展态势提供参考。  相似文献   

7.
美国全球变化研究1992年度计划介绍   总被引:1,自引:0,他引:1  
一、概况 美国联邦科学、工程和技术协调委员会(FCCSET)地球与环境科学委员会(CEES)就美国总统1992财政年度关于美国全球变化研究计划(USGCRP)预算给国会起草了一份题为“我们变化着的行星”的报告。  相似文献   

8.
以文献计量看中亚成矿域研究发展态势   总被引:2,自引:0,他引:2  
凭借巨量矿产资源供给能力和资源通道的特殊功能,中亚成矿域构成了我国资源安全体系的不可缺失的重要组成部分和举足轻重的一翼.科技文献能够反映科学研究的发展动态,利用Thomson DataAnlyzer(TDA)和UCINET对SCIE文献数据库中收录的1990—2010年间的中亚成矿域研究论文进行数据挖掘和分析.结果表明...  相似文献   

9.
中国全球变化研究的战略思考   总被引:5,自引:0,他引:5  
林海 《地学前缘》1997,4(1):9-15
文章简要叙述了全球变化研究的重要性,特点和中国在全球变化中的地位,回顾和评述了近十多年来我国所开展的有关全球变化的研究进展。据统计,在1985年至1995上期间,我国全球变化研究项目已达350项左右,由国家级项目,部委级项目和一般项目组成。通过这些项目的研究,中国科学院已在国际上圈-生物圈计划的一些核心计划,如全球古环境变化,全球变化和陆地生态系统,全在气化学,全球海洋通量研究以及世界气候研究计划  相似文献   

10.
近5年中国地球科学领域发展态势文献计量分析   总被引:1,自引:0,他引:1  
朱薇薇  王鑫  史静  王欢  王婧皎  李娜 《地质学报》2018,92(12):2582-2588
本文采用文献计量学方法,以CSCD数据库收录的2013~2017年地球科学领域文献为数据源,从发文量趋势、学科分布、期刊分布、核心机构及作者、研究热点、基金支持情况几个方面统计分析了近5年来国内地球科学领域的发展态势,为今后进一步把握地球科学领域发展趋势提供参考。  相似文献   

11.
记述了新生代深海冷水碳酸盐泥丘近期的9个重要研究事件;总结了冷水泥丘具有全球海洋(大陆斜坡为主)分布、形态各异、冷水枝状珊瑚构筑泥丘的特点;介绍了冷水泥丘形成的(地质流体渗流和微生物作用)内因及(海底牵引底流作用)外因两种主要观点.对2005年IODP 307航次实施的北大西洋Porcupine Seabight冷水泥丘大洋钻探工作初步成果进行了编译,公布了中国科学家在碳氧同位素方面的初步实验结果.实验结果显示上新世中期以来的2 Ma里冷水碳酸盐泥丘启动和发育过程中存在2次碳氧同位素偏移事件(Ⅰ和Ⅱ),碳氧同位素偏移事件Ⅰ与泥丘的启动相呼应,暗示北大西洋古海洋气候发生巨大变化,可能与北极冰盖极盛有关.  相似文献   

12.
Cold-water coral carbonate mounds, owing their presence mainly to the framework building coral Lophelia pertusa and the activity of associated organisms, are common along the European margin with their spatial distribution allowing them to be divided into a number of mound provinces. Variation in mound attributes are explored via a series of case studies on mound provinces that have been the most intensely investigated: Belgica, Hovland, Pelagia, Logachev and Norwegian Mounds. Morphological variation between mound provinces is discussed under the premise that mound morphology is an expression of the environmental conditions under which mounds are initiated and grow. Cold-water coral carbonate mounds can be divided into those exhibiting “inherited” morphologies (where mound morphology reflects the morphology of the colonised features) and “developed” morphology (where the mounds assume their own gross morphology mainly reflecting dominant hydrodynamic controls). Finer-scale, surface morphological features mainly reflecting biological growth forms are also discussed.  相似文献   

13.
北极海冰与全球气候变化   总被引:7,自引:2,他引:7  
李培基 《冰川冻土》1996,18(1):72-80
最近有关北极海冰在全球气候系统中作用的研究发现,北冰洋边缘海域大洋深水的形成与海冰发育有关,海冰冻融过程对盐度层结具有重要影响,海冰变化可引起盐度突变层的灾变和热盐环流的突然停止,热盐环流的变化与北大西洋海冰10年际变化相联系,北大西洋气候的不稳定性与热盐环流变化密切相关。北极海冰-海洋-大气间耦合作用,使北极海冰构成了北大西洋和全球气候反馈循环中的重要环节。  相似文献   

14.
The ubiquity of carbonate platforms throughout the Cretaceous Period is recognized as a product of high eustatic sea-level and a distinct climatic optimum induced by rapid sea-floor spreading and elevated levels of atmospheric carbon-dioxide. Notably, a series of global oceanic anoxic events (OAEs) punctuate this time-interval and mark periods of significantly reduced free oxygen in the world's oceans. The best records of these events are often from one-dimensional shelf or basin sections where only abrupt shifts between oxygenated carbonates and anoxic shales are recorded. The Comanche Platform of central Texas provides a unique opportunity to study these events within a well-constrained stratigraphic framework in which their up-dip and down-dip sedimentologic effects can be observed and the recovery of the platform to equilibrium states can be timed and understood. Stable isotope data from whole cores in middle Hauterivian through lower Campanian mixed carbonate-siliciclastic strata are used to construct a 52-myr carbon isotope reference profile for the northern Gulf of Mexico. Correlation of this composite curve to numerous global reference profiles permits identification of several anoxic events and allows their impact on platform architecture and facies distribution to be documented. Oceanic anoxic events 1a, 1b, 1d, and 2 occurred immediately before, after, or during shale deposition in the Pine Island Member, Bexar Member, Del Rio Formation, and Eagle Ford Group, respectively. Oceanic anoxic event 3 corresponds to deposition of the Austin Chalk Group. Platform drowning on three occasions more closely coincided with globally recognized anoxic sub-events such as the Fallot, Albian-Cenomanian, and Mid-Cenomanian events. This illustrates that the specific anoxic event most affecting a given carbonate platform varied globally as a function of regional oceanographic circumstances.Using chemo- and sequence-stratigraphic observations, a four-stage model is proposed to describe the changing facies patterns, fauna, sedimentation accumulation rates, platform architectures, and relative sea-level trends of transgressive-regressive composite sequences that developed in response to global carbon-cycle perturbations. The four phases of platform evolution include the equilibrium, crisis, anoxic, and recovery stages. The equilibrium stage is characterized by progradational shelf geometries and coral-rudist phototrophic faunal assemblages. Similar phototrophic fauna typify the crisis stage; however, incipient biocalcification crises of this phase led to retrogradational shelf morphologies, transgressive facies patterns, and increased clay mineral proportions. Anoxic stages of the Comanche Platform were coincident with back-ground deposition of organic-rich shale on drowned shelves and heterotrophic fauna dominated by oysters or coccolithophorids. Eustatic peaks of this stage were of moderate amplitude (∼30 m), yet relative sea-level rises were greatly enhanced by reduced sedimentation rates. In the recovery stage, heterotrophic carbonate factories re-established at the shoreline as progradational ramp systems and sediment accumulation rates slowly increased as dysoxia diminished. Full recovery to equilibrium conditions may or may not have followed. Geochemical and stratigraphic trends present in the four stages are consistent with increased volcanism along mid-ocean ridges and in large-igneous provinces as primary drivers of Cretaceous OAEs and the resulting transgressive-regressive composite sequences.  相似文献   

15.
Global climate change has been one of the most concerned environmental problems in the world since the 1980s. Since stable carbon composition (13C) in plant tissues can record abundant information on climate changes, it has been widely used as an important climate proxy in global change studies and becomes a powerful tool for obtaining paleoclimate information, understanding paleoenvironment reconstruction and modern climate change, and predicting future climate trends. However, a lot of potential uncertainties have always involved in the reconstruction of paleoclimate and paleoenvironment by carbon isotope of the past period sediment or fossils. Among them, the most dominant uncertainty is due to our poor understanding of the relations between carbon isotope ratios of plants and climatic factors and the climatic and environmental significance indicated by modern plant 13C. This may limit the application of plant 13C in the study of climatic and environmental changes. Based on the Summary of plant 13C fractionation and carbon isotope distribution of different photosynthetic plants, the effects of environmental factors, e.g., temperature, precipitation, atmospheric CO2 concentration, and altitude on terrestrial plant 13C and their relationships were reviewed in this paper, and the response mechanism of plant 13C to climate changes were also analyzed. Furthermore, the current existing problems and the future prospects in carbon isotope study were discussed. It is pointed out that strengthening some studies such as the response of C4 plants 13C to climate environmental parameters, the transformation relation of different scale plant 13C, intersection and permeation of related disciplines, and various proxies and scientific method, will undoubtedly make us have a more accurate understanding of the climate history and eventually broaden the development of the field during the process of global change study by plant carbon isotope techniques.  相似文献   

16.
气候变化对水文水资源影响评价的不确定性分析   总被引:8,自引:1,他引:8  
在评价气候变化对水文水资源影响的各个环节中都存在不确定性。以蓝塘和花园两流域为例,应用MonteCarlO和非参数方法研究区域水文评价模型参数和径流的不确定性估计。结果表明:径流对降水的变化要比对气温升高敏感;径流系数较小的流域,其变化幅度反而大。若考虑信度水平为5%的不确定度和最不利的气候情景组合,蓝塘和花园两流域的洪峰流量将分别增大45.21%和49.27%,这将对防洪工程造成重大和不利的影响。  相似文献   

17.
The sedimentological and chronological analysis of the last deglacial reef sequences of Tahiti (French Polynesia), drilled during the Integrated Ocean Drilling Program Expedition 310, provide a high‐resolution data set allowing a well‐constrained forward modelling study. This study represents the first attempt to model in three dimensions the coral reef development of Tahiti during the last deglacial sea‐level rise (23 000 to 6000 cal yr bp ) using the software dionisos developed by IFP Energies nouvelles. It allows the testing of the reconstructed last deglacial sea‐level curve and the different environmental parameters (for example, wave energy and sediment fluxes) that could have influenced the reef development. These last deglacial reef sequences form two prominent ridges occurring seaward of the living barrier reef that consist of successive submerged reefs. These reefs have been prone to drowning because the window of maximum carbonate production rate is inhibited by high water turbidity (sediment supply from a nearby river), shallow depth of wave action and substrate availability. These factors, combined with rapid sea‐level rise, have driven the growth of retrograding reef pinnacles. Local factors (substratum nature, sediment supply and wave energy) were the main processes that induced the drowning of the inner ridge, whereas interplay of local and global factors (acceleration of the sea‐level rise) was responsible for the drowning of the outer ridge. This particular acceleration of sea‐level rise of 16 m between 14·6 ka and 14 ka bp corresponds to meltwater pulse 1A.  相似文献   

18.
High-resolution seismic profiles, swath bathymetry, side-scan sonar data and video imageries are analysed in this detailed study of five carbonate mounds from the Belgica mound province with special emphasis on the well-surveyed Thérèse Mound. The selected mounds are located in the deepest part of the Belgica mound province at water depths of 950 m. Seismic data illustrate that the underlying geology is characterised by drift sedimentation in a general northerly flowing current regime. Sigmoidal sediment bodies create local slope breaks on the most recent local erosional surface, which act as the mound base. No preferential mound substratum is observed, neither is there any indication for deep geological controls on coral bank development. Seismic evidence suggests that the start-up of the coral bank development was shortly after a major erosional event of Late Pliocene–Quaternary age. The coral bank geometry has been clearly affected by the local topography of this erosional base and the prevailing current regime. The summits of the coral banks are relatively flat and the flanks are steepest on their upper slopes. Deposition of the encased drift sequence has been influenced by the coral bank topography. Sediment waves are formed besides the coral banks and are the most pronounced bedforms. These seabed structures are probably induced by bottom current up to 1 m/s. Large sediment waves are colonised by living corals and might represent the initial phase of coral bank development. The biological facies distribution of the coral banks illustrate a living coral cap on the summit and upper slope and a decline of living coral populations toward the lower flanks. The data suggest that the development of the coral banks in this area is clearly an interaction between biological growth processes and drift deposition both influenced by the local topography and current regime.  相似文献   

19.
以内蒙古地区的锡林河流域为研究对象,采用考虑融雪的水量平衡模型(SWBM模型),在对锡林河流域水文模拟的基础上,评估了流域水资源对气候变化的响应。结果表明:SWBM模型锡林河流域月径流过程具有较好的模拟效果,率定期和检验期的模型效率系数均超过60%,相对误差也均小于8%,在未来全球气候变化背景下,流域水资源以减少趋势为主,2030年之后,减少幅度将可能超过10%。  相似文献   

20.
Deep-sea corals live in the dark cold-water environments, the food of which that provides them with energy and nutrition is a key ecological and biogeochemical problem. Currently, the most common understanding is that their food mainly comes from organic matter produced by and deposited from surface seawater. However, more and more studies have found that they can also obtain food supply through symbiosis with a variety of chemosynthetic autotrophs and heterotrophs. Carbon and nitrogen isotopes have been used to trace and reveal the food sources of deep-sea corals. They also have been successfully used to reconstruct the phytoplankton community structure and the changes of nitrate isotopes in surface seawater in the past, thus providing valuable biogeochemical data for paleoceanographic study. However, due to the widespread existence of symbiosis with chemosynthetic autotrophs, further studies are needed to assess the reliability of organic carbon and nitrogen isotopes of deep-sea corals to reflect changes in the surface seawater. The deep-sea gorgonian coral, like those gorgonian forests recently found in the South China Sea, is relatively new and insufficiently studied in the field of deep-sea corals. Thus, basic biochemical and paleoceanographic researches on the South China Sea deep-water gorgonians will provide profound and novel insights to understanding the cold-water coral system.  相似文献   

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