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北极拥有其独特的地理位置和战略价值，同时也是全球变暖最关键的敏感区，世界各国针对北极地区制定了一系列政策计划，并开展了多年的北极海洋科学研究。基于Web of Science数据库收录的1998~2017年SCIE文章，采用文献计量与引文分析的方法与工具，分析了13784篇北极海洋科学研究的整体态势与热点前沿，结果表明：①全球北极海洋科学研究呈现出加快增长趋势，近5年的发文已经翻了一番，年均发文在689篇以上； ②环北极八国是该领域研究的主要力量，美国遥遥领先其他国家，挪威、丹麦研究基底深厚但近年发展稍缓，英国、德国是主要的非北极研究国，瑞典、法国的论文质量均衡，中国、波兰、格陵兰和荷兰则是该领域的后起之秀； ③俄罗斯科学院在本领域发文最多但文章质量良莠不齐，德国极地与海洋研究所、丹麦&格陵兰地质调查机构与挪威海洋研究所的第一作者与通讯作者研究占比高，哥本哈根大学、德国极地与海洋研究所、华盛顿大学在该领域科研影响力较大； ④全球海洋科学研究主要涉及地质学、海洋学、环境生态学、自然地理学、地球化学与地球物理学以及气象学与大气科学等领域，研究热点包括北极气候变化与极端天气、冰川消融与海平面上升、北极生态系统特征结构、北极海洋酸化与污染防治等方面。随着“一带一路”、“冰上丝绸之路”和《中国的北极政策》白皮书的发布，建议我国针对本国情况制定综合性北极科研计划，并注重科研机构间跨部门、跨领域的研究合作，加强与环北极国家和“一带一路”国家的合作，加大科研投入并开展国际规模的科学考察活动。 相似文献
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全球变暖"停滞"研究综述 总被引：3，自引：0，他引：3
全球变暖"停滞"现象自提出以来，备受关注，是近来全球气候变化领域的热点问题。全球变暖停滞主要表现为全球平均表面温度在1998-2012年增温速率明显偏低。除此之外，大气环流和海洋环流也发生了显著改变。在归因分析方面，很多科学家认为太平洋年代际振荡发挥了重要作用，另外的可能因素还有大西洋经向翻转环流和南极底层水的改变等。然而，由于观测资料在时间一致性和空间覆盖区域等方面存在偏差，从而为全球变暖停滞增添了诸多不确定性。但气候系统内部变率发生改变，导致深层海洋吸收热量增多是众多科学家的共识。尝试解答变暖停滞研究中的不确定性问题，观测资料的丰富和完善是必要条件。 相似文献
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基于变分理论算法实现了METOP-A卫星AVHRR传感器探测数据的海洋表面温度变分反演，进行了连续1个月的海表温度反演试验，并分别从全球、分纬度带和天气系统活跃区域3个方面，将变分反演结果（VAR SST）与利用统计回归方法反演相同卫星得到的海表温度产品（GBL SST）、其他海温融合产品（OISST）及实际浮标观测数据等进行一系列评估。从全球评估指标看出，以OISST为参照，VAR SST要优于GBL SST；以浮标观测为参照，VAR SST略逊于GBL SST，而且VAR SST还改进了GBL SST随时间波动大的缺点；从分纬度带对比看出，在与OISST对比时，VAR SST在低纬度地区和北半球中纬度地区的质量要优于GBL SST，海温反演精度较高。研究还表明，由于变分方法考虑了大气状态的变化，能够更加有效订正卫星遥感过程中大气的削弱作用，从而反演出精度更高的海表温度，尤其在天气系统较为复杂的区域效果明显。 相似文献
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21世纪以来全球变暖进入停滞时期,研究表明,大量热量进入海洋深层是导致全球平均表面温度暂缓上升的主要原因。本文估计和研究了2002.4-2014.12间由热膨胀导致的海平面变化趋势,以此来探测海洋热含量的变化情况。研究使用GRACE重力卫星CSR RL05数据计算了全球海洋的水质量变化,并结合海平面异常数据,计算了由热量变化导致的海平面变化（Net SLA）。将Net SLA与Ishii温度数据计算的海洋热含量进行相关性分析后表明,Net SLA与海洋热含量存在高度相关性,相关系数最大值达0.95。考虑到海洋观测只能表现海洋上层2000m的热含量变化,而除去水质量变化的海平面变化则反映了整层海洋的热含量变化,是估计海洋增暖趋势快慢的有利工具。经计算得出,2002至2014年间南太平洋和南印度洋存在加速增暖趋势,而近年来南半球环状模的增强是导致其增暖的主要原因。 相似文献
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海洋环流是海洋系统物质能量收支、配置、平衡、维持和变化的关键通道与机制。从全球海洋视角，基于目前海洋环流多变率动力过程与趋势演变的认知，重点综述气候变化下海洋环流的海盆尺度三维联动特征机制、洋际交换与协同、世界大洋经向输运变化以及相关的海洋气候与环境生态效应，依据研究现状和需求，提出研究建议。结果表明：全球一致性变暖路径与进程调控下，受驱动因子的演变与胁迫，海洋环流变化对副热带中高纬地区年际、年代际气候与环境变迁具有突出作用影响，并可产生显著环境生态效应和严重致灾风险。建议加大专精特新观测仪器自主研发，通过国际合作加大中高纬海洋环流多尺度动力过程综合调查的参与度和主导性，增强多学科融合交叉研究力度，有效提升深层次海洋环流变异及动力、环境、生态灾害影响的气候变化综合风险预测预评估和防治能力，为海洋领域能源开发、生态系统保护、气候变化应对与灾害风险治理提供必要的动力学参考。 相似文献
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在加入温室气体和太阳常数后,FOAM较好地模拟出20世纪气候变化的主要特征,与IPCC AR4模式和观测的结果基本保持一致,主要特征如下:(1)全球平均地表气温升高约0.6~0.7℃,海表面温度升高约0.4~0.5℃;地表温度升高不均匀,冰面大于陆地,陆地大于海洋,北半球大于南半球;对流层变暖,平流层变冷。(2)中纬度西风增强,西风带和信风带都有往极地移动的趋势,在南半球更明显;南北半球增暖的不对称可能影响信风的变化。(3)海表面温度经向梯度增大,和中纬度西风增强有互为因果的关系。(4)中低纬度蒸发加强,大气中的水汽增加,水汽的温室效应增强。(5)海洋上层增暖,副热带地区更明显;高纬度海洋变淡,太平洋变淡,印度洋和大西洋中低纬度变咸;北大西洋热盐环流减弱。 相似文献
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红树林是以红树植物为主体的常绿灌木或乔木组成的潮滩湿地木本植物群落, 具有“四高”特性(高生产力、高归还率、高分解率和高抗逆性)的典型海洋生态系统; 目前, 全球约有红树林1700万公顷, 主要分布在南北半球25℃等温线内。红树林生态系统的净初级生产力高达2000gC·m-2·a-1, 具有高强度的物质循环、能量流动以及丰富的生物多样性, 对热带、亚热带海洋生态系统的维持与发展起到关键作用, 并在全球变化过程中扮演着十分重要的角色。近30年来, 全球气候变化已引起了国内外学者的极大关注。红树林生态系统位于热带、亚热带海岸潮间带, 是一个脆弱的、敏感的生态系统, 也是首先受全球气候变化影响的典型海洋生态系统之一。作为全球海岸带地区应对全球气候变化最为重要的生态屏障之一, 气候变化将严重影响着全球红树林的生存和分布方式。本文将从全球变暖、海平面上升、大气中CO2浓度的增加和极端天气4个主要方面, 揭示全球气候变化对红树林生态系统的影响与变化特征, 阐述红树林对全球变暖、海平面上升、大气中CO2浓度增加和极端天气响应与适应的生态学机制, 并简要概述了红树林在减缓全球气候变化危害中的重要作用。全球气候变化也将为红树林的研究、保护和发展带来机遇与挑战。 相似文献
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利用Hadley中心海冰和海表面温度资料集Had ISST和美国国家海洋大气管理局的扩展重建海温(ERSST)海表面温度(sea surface temperature,SST)观测数据,结合政府间气候变化专门委员会(Intergovernmental Panel on Climate Change,IPCC)中CMIP3(Coupled Model Intercomparison Project 3)的24个耦合模式的模拟结果,通过经验正交函数(EOF)分解等方法,对20世纪热带海洋在的SST年际变化进行了分析。结果表明,20世纪热带海洋年际变化的主要规律是ENSO信号,且有持续增强的趋势;热带海盆间存在显著的SST梯度,其长期变化与热带东太平洋显著相关。本文结论有利于理解在全球变暖背景下,海盆间的相互作用对赤道海域气候改变的影响。 相似文献
9.
与太平洋和印度洋不同，全球变暖下热带大西洋变化的研究较少。本文使用地球系统模型CESM（Community Earth System Model），发现全球变暖后热带大西洋在秋季的升温类似大西洋尼诺（Atlantic Niño）的正位相，即大西洋西部增暖幅度小于东部；在夏季类似大西洋尼诺的负位相，即大西洋西部增暖幅度大于东部。利用覆盖（overriding）技术，分离了风应力、风速和CO2的直接热效应对海洋升温的作用，探讨了大西洋尼诺本身和全球变暖作用下类似大西洋尼诺正位相（下文简称“类大西洋尼诺升温”）的形成机制。结果表明，这两种情况下的形成机制基本相同，风应力的变化是导致大西洋东部暖异常的主要机制。但两者之间也存在区别：1）全球变暖下海表温度的季节变化振幅减小，而大西洋尼诺时变化不大；2）全球变暖下西风异常主要集中在大西洋东部，而大西洋尼诺时主要集中在大西洋中部；3）除风应力外，CO2的热效应对类尼诺升温的变化也有一定影响。 相似文献
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Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
13.
The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
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《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
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The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance. 相似文献
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Rahul Sharma 《Marine Georesources & Geotechnology》2000,18(3):237-250
Observations on seafloor features from subbottom profiling and seabed photography data show that the undisturbed and natural conditions before the benthic disturbance undergo a substantial change after operation of the disturber. The effects can be seen in the form of deep trenches and grooves, formed by the action of the sleds and the pumping of the sediment along its path, as well as sediment piles on either side of the track. Biological traces such as fecal coils, casts, tubes, burrows, and trails get obliterated in the areas of disturbance and resedimentation. The smooth, uniform nature of the seafloor observed in predisturbance phase shows microtopographic changes in and around the disturbed area as a result of sediment excavation and resettlement. Vertical mixing as well as lateral transport of sediment alter the geological, biological, physical, and chemical conditions on the seafloor, which need to be monitored over time to assess the process and the time taken for restoration of environmental conditions. 相似文献
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Vance P. Vicente 《Marine Ecology》1989,10(2):179-191
Abstract. Long-term changes in the distributional patterns of commercial sponges ( Spongia spp. and Hippospongia spp.) within the West Indian Region indicates that: 1) commercial sponges had a widespread distribution throughout the whole West Indian Region and were ubiquitous in very shallow water until about the first half of the present century; 2) they were fished commercially not only in the traditional northern Caribbean sites (Florida, Gulf of Mexico, Bahamas) but also in the Greater ( e. g. , Hispaniola, Jamaica) and Lesser Antilles; and 3) they became extinct throughout most of the Lesser Antilles ( e. g. , Puerto Rico, Vieques, St. Thomas) sometime during the first half of this century. Mortalities of spongiids within the Antilles were found to differ from other marine mortalities in that: 1) species disappeared from a large region; 2) species vanished from different habitats and depths; and 3) natural populations never recovered. Species richness patterns suggest that commercial sponge genera ( Spongia and Hippospongia ) evolved under slightly cooler elimatic conditions than those found at present, and that these extinctions occurred as a direct or indirect effect of positive thermal anomalies in sea surface and atmospheric temperatures between 1900–1950. The concept that species diversity is stable on a regional scale is questioned. 相似文献
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The behaviour of an axially pre-loaded cylindrical member of an offshore structure, hit by a supply ship, has been investigated. The effects of axial pre-loading on the dynamic properties of members, the extent of damage and propagation of dynamic instability in the tubular members have also been investigated. Numerical models have been validated using available experimental data from the literature although these are mostly static with no pre-loading. Axial pre-loading was found to change the dynamic characteristics of some cylindrical members quite dramatically while it had no significant effect on others. The study examined whether there was any change in the behaviour between local and global modes when the loading was dynamic rather than static. The effect of damping on the dynamic instability of axially pre-loaded tubes under lateral dynamic loads was also studied. It was observed that for some geometries the quasi-static response can be used to define the boundary between bounded and unbounded dynamic responses. The main contribution of this study, compared with previous investigations reported in the literature, is that both pre-loading and dynamic effects have been included. 相似文献