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全球百年海表面温度年际和年代际变化特征分析 总被引：1，自引：0，他引：1
利用100 a(1903—2002年)HadiSST的逐月资料,将全球海表面温度异常(SSTA)作为整体进行经验正交函数分解(EOF分解),提取了控制各大洋SSTA的主导模态和各大洋之间的联合模态,分析了相应的空间分布和时间序列。研究结果表明:SSTA变化最剧烈的海区是赤道中东太平洋、西北大西洋湾流海区和北太平洋黑潮延伸体海区。热带太平洋厄尔尼诺和南方涛动是主导模态并具有2~7 a周期的年际变化;SSTA变化第二主模态和第三主模态都是以大约70 a为周期的年代际变化为主的跨大洋联合模态。第二主模态的空间分布主要表现为中纬度北太平洋和北大西洋反位相、热带太平洋与大西洋反位相的太平洋-大西洋双偶极子型分布。SSTA变化的第三模态主要呈现南北半球海洋反位相的特征,为北太平洋-北大西洋-南大洋联合模态。第四模态基本上是反映各个不同海域特有的局地海洋-大气相互作用模态,该模态的时间序列具有1~4 a周期的年际变化和约9 a周期的年代际变化。 相似文献
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用美国马里兰大学提供的海洋同化(SODA)月平均资料,深入揭示了ENSO模的海洋三维结构及其年际和年代际变率。研究结果指出,ENSO海洋模随深度呈明显规律变化。在热带太平洋,它由热带中东太平洋表层显著海温异常分布型随深度增加逐渐过渡为热带西太平洋次表层显著反号海温异常分布型;在赤道太平洋以赤道西太平洋暖池次表层海温显著异常与赤道中东太平洋表层海温反号显著异常为主要特征。El Nino期间,热带中东太平洋表层为强海温正距平中心,西太平洋暖池次表层为强海温负距平中心,在年际尺度上,160°E以西的西北太平洋副热带海域还存在一个与西太平洋海温异常变化反号、与热带东太平洋同号的区域;La Nina期间正好相反。ENSO循环主要由ENSO年际变率所决定,年际ENSO模具有东部型ENSO事件的海温异常分布特征,其循环是东部型冷暖事件之间的转换,在200m以浅,它具ENSO模相同的三维结构和3-5年的显著年际变化周期;年代际类ENSO模具有中部型ENSO事件的海温异常分布特征,年代际ENSO循环是中部型冷暖事件之间的转换,其影响主要限制在200m以浅的海洋上层,具有ENSO模相似的三维结构和9-23年的显著周期。 相似文献
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太平洋是海表温度年际变化和年代际变化发生的主要区域,但对太平洋海洋热含量变化的研究相对较少。为此, 本文分析了1980—2020年太平洋上层(0~300 m)热含量的时空变化特征。基于IAP数据,本文首先利用集合经验模态分解法(EEMD)提取不同时间尺度的海洋热含量信号,并利用正交经验分解法(EOF)对不同时间尺度的海洋热含量进行时空特征分析,得到了太平洋0~300 m海洋热含量的年际变化、年代际变化以及长期变暖的时空特征。结果表明,除了年际变化之外,热带西北太平洋上层热含量还存在明显的年代际变化和长期变暖趋势。在东太平洋和高纬度西太平洋,热含量的年代际变化特征并不突出。热带西北太平洋热含量的年代际变化在1980—1988年和1999—2013年较高,而在1989—1998年和2014—2020年期间较低。此外,针对热带西北太平洋热含量的经向、纬向和垂向特征分析,发现这种年代际变化主要发生在5°N—20°N,120°E—180°E,次表层50~200 m范围内。热带西北太平洋热含量的年代际变化对全球海表温度的年代际变化有着重要作用。 相似文献
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20世纪60年代， Namias(1969)就发现北太平洋海平面气压(SLP)存在10a以上长周期的变化，这种变化与北美冬季气温异常密切相关。70年代以后，又有人(White et al.，1972； Trenberth，1990； Trenberth et al.，1994)对上述变化作了进一步的验证，并指出1976年以后北太平洋的SLP异常偏低，即阿留申低压异常偏强。以阿留申低压为主要活动中心的大气年代际振荡被称为北太平洋涛动(NPDO)，它与北大西洋涛动(NAO)一起构成年代际气候变动最重要的观测依据，北太平洋年代际振荡的机制也引起了人们的广泛兴趣。作为大气运动的缓变下垫面强迫之一的海表面温度(SST)，它的异常变化对年际气候的显著影响已被公认(Wallace et al.，1981，1998)，由此推断，其对年代际时间尺度气候变化的影响可能也不可忽视。众所周知，SST年际变化最显著区位于赤道中东太平洋(如Nino 3区)，而与北太平洋年代际振荡显著相关的SST变化(时间变化和空间分布)又如何呢?作者就这一问题，分析了北太平洋大气环流年代际振荡的时、空变化特征，并揭示了与之相关的SST变化的时间变化和空间分布。 相似文献
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使用美国夏威夷大学发展的中等复杂程度海洋模式(IOM)在给定表面强迫条件下模拟了热带大西洋上层海洋年际和年代际变率的时空结构.利用NCEP的41a(1958～1998年)逐月平均表面资料作为强迫场,积分海洋模式41a作为控制试验,并利用模式分别做动量(风应力)通量和热量通量无异常变化的平行试验,与控制试验作比较.对3组试验模拟上层海洋变率状况的比较,并按年际和年代际时间尺度分别分析,揭示表面风应力和热通量异常对海表面温度和温跃层深度变化的影响,并比较了其影响的相对重要性.结果表明模式成功地模拟出了热带大西洋上层海洋的变率.模式模拟的海表面温度年际变化主要表现为弱ENSO型,年代际变化表现为南、北大西洋变化相反的偶极子型.在年际时间尺度上,热力强迫和动力强迫对海表温度变化都有贡献,其中赤道外海表面温度异常(SSTA)变化主要由热通量异常引起,而近赤道SSTA的变化主要由动量异常强迫引起.在年代际时间尺度上,热通量强迫的作用远比动量强迫重要.模式不仅能够模拟SST在年际和年代际时间尺度上的变率,还能够模拟温跃层深度在年际和年代际时间尺度上的变率.年际和年代际时间尺度上,温跃层深度的变率主要由动量异常决定,热通量异常强迫的贡献很小. 相似文献
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台湾海峡生态系统对海洋环境年际变动的响应分析 总被引：13，自引：2，他引：13
通过比较1985~2001年的海表温度与其间收集的现场营养盐、浮游植物和浮游动物丰度及群落结构变动信号,以及1971~1998年的中上层鱼类渔获量变动信息,发现了台湾海峡生态系统对物理环境年际变动产生的响应迹象.1997 年夏季台湾海峡处于偏冷状态,南部近岸上升流强度减弱;1997年冬季正值一个较强的暖事件发展到顶峰,北上入侵暖水强度增强、浙闽沿岸冷水强度减弱.导致这两个时期营养盐分布特征改变,发生了一系列从浮游植物到浮游动物,从生物量到群落结构的异常响应,暖水性中上层鱼类渔获量则似乎呈现出El Niño年偏高的趋势.根据有限的辅助证据推测,El Niño很可能不是控制台湾海峡海洋环境年际变动的强信号,而台湾海峡的气候海洋生态长期低频变动可能更多地受到东亚季风中国边缘海系统的控制. 相似文献
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采用经验模态分解法对太平洋沿岸验潮站的月平均海平面资料进行处理,结合T/P高度计资料、Church(2004)重构SSH资料、Ishii(2005)月均海温资料,研究太平洋海平面年际、年代际变化以及资料长度内海平面变化趋势。太平洋沿岸海平面总体呈上升趋势,平均上升速率为1.4 mm/a,趋势项分布有明显的区域性和纬度特征。ENSO对太平洋地区海平面年际变化有显著影响,海平面年际变化与Nino3指数在西(东)太平洋为负(正)相关,海平面年际变化与Nino3指数的相关性在热带太平洋最大,并随着纬度升高相关性减弱,且不同地区年际变化有滞后ENSO时间不等的最大相关。海平面年际变化与PDO指数在西(东)太平洋为负(正)相关,海平面与PDO的相关性分布有区域性和随时间演变特征。年代际变化对目前使用卫星高度计资料分析海平面长期趋势项的预测有直接影响,可能完全掩盖海平面长期变化趋势。 相似文献
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基于日本气象厅长时间序列的温、盐度再分析资料,利用动力计算方法分析了北太平洋西边界的北赤道流及其下游黑潮和棉兰老流流量的年际和年代际变化,并探讨了北赤道流变化的可能原因。结果表明,北赤道流和黑潮具有比较一致的年际和年代际变化,均在1976年前后发生了一次气候跃变,之后有长期偏强的趋势,而棉兰老流的年际和年代际变化则有所不同。特别是,北赤道流1976年之后增加的流量似乎大多进入黑潮,而流入棉兰老流的流量则减少。进一步的分析还表明,西传的Rossby波和棉兰老冷涡的变动可能对北赤道流的年际变化有重要影响。 相似文献
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This paper reviews the main studies dealing with epiphytes of both leaves and rhizomes of Posidonia oceanica, the main seagrass found in the Mediterranean Sea. A total of 660 epiphyte species has been recorded, including 430 on leaves and 437 on rhizomes. Of these, 205 are Rhodophyta, 59 Ochrophyta, 43 Chlorophyta, 78 Porifera, 82 Cnidaria, 19 Annelida, 155 Bryozoa and 19 Tunicata. The epiphyte assemblages demonstrate a gradient of dissimilarity from west to east, with the eastern area being the most unlike the others. The differences can be attributed mostly to rare species that differ amongst the Mediterranean regions. Many of the dominant taxa have been found in all meadows studied. Data concerning species composition, abundance, and patterns of spatial and temporal variability are summarized, and biotic and abiotic factors controlling the structure of assemblages are discussed. Responses of epiphyte assemblages to anthropogenic stressors, such as nutrient enrichment and biological invasions, are discussed in relation to the use of epiphytes as ecological indicators. 相似文献
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Cyclic sequences occur worldwide in nearly every stratigraphic sequence; they are particularly well-developed in fluvial and
deltaic sediments that have been influenced by high-frequency eustatic sea-level fluctuations. The large data base for this
study (including 471 deep foundation borings, thousands of line kilometers of high-resolution seismic, and sedimentological
and dating analyses) represents the most complete information on high-resolution chronostratigraphy and lithostratigraphy
that is available on any modern continental shelf/upper slope. These data are used to document sedimentological characteristics
and high-resolution seismic responses during three complete sea-level cycles over the entire continental shelf/upper slope
of offshore Louisiana.
Examination of high-resolution seismic records indicates that well-defined, high-amplitude, laterally continuous reflectors
correlate with rising and high stand condensed sedimentary sequences and that the deposits laid down during falling and low-stand
periods (expanded sections) are characterized by a wide range of acoustic responses. Discontinuous reflectors with high-amplitude
variability, continuous parallel reflectors, and chaotic and amorphous zones are common acoustic responses. The association
between a particular lithofacies and a specific acoustic response on 3.5-kHz records was found to be very poor. 相似文献
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Understanding fishermen's perspectives and responses relating to climate variability is important for sustainable fisheries management. To this end, a survey of captains of commercial passenger fishing vessels (CPFVs) was conducted in San Diego. The survey demonstrates that fishermen have observed and adapted to changes in the environment and fish populations associated with climate variability. However, only 12.9% of respondents agreed that global climate change is a possibility. In order to explain fishermen's divergent beliefs on climate change, a semiparametric discrete choice model is used to identify the potential determinants. The empirical results highlight the importance of the following factors: fishermen's experience, observations of the phenomena that are associated with climate variability, and an interaction of fishermen's experience and their observations. 相似文献
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太平洋年代际海洋变率研究进展 总被引：10，自引：1，他引：10
随着“气候变率与可预报性研究”（CLIVAR计划）的实施，年代际气候变率研究已经成为国际气候研究的一个新热点，由于海洋特别是海洋次表层具有巨大的热损性，海洋环流在年代际气候变率中所起的作用已得到越来越多的重视。但迄今为止，海洋以什么方式参与到年代际气候变化中，海洋次表层在年际和年代际时间尺度上起到什么作用这些与海洋环流有关的问题仍未得到解决，而这些问题的解决将有助于建立一种完备的年代际气候变化机制的理论，文章通过对近10a来国内外在该领域内研究进展的回顾，提出了一个关于太平洋年际变化（如ENSO循环）和年代际变化（如PDO循环）相互作用的猜想，为今后在国内开展相关研究提供了一些设想。 相似文献
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《Marine Policy》2015
Some of the most important development goals for the countries and territories of the Western and Central Pacific Ocean (WCPO) involve the sustainable management of their fisheries in light of environmental, economic and social uncertainties. The responses of fish populations to variability in the marine environment have implications for decision making processes associated with resource management. There is still considerable uncertainty in estimating the responses of tuna populations to short-to-medium-term variability and longer-term change in the oceanic environment. A workshop was organised to examine how advances in oceanography, fisheries science and fisheries economics could be applied to the tuna fisheries of the WCPO and in doing so identify research priorities to improve understanding relevant to progressing management. Research priorities identified included: (i) improved parameterisation of end to end ecosystem model components, processes and feedbacks through expanded biological observations and incorporation of higher resolution climate models; (ii) development of seasonal and inter-annual forecasting tools enabling management responses to short-term variability in tuna distributions and abundances; (iii) improved understanding of the population dynamics of and the energy transfer efficiencies between food web components; (iv) assessment of the optimal value of access rights and overall fishery value under multiple scenarios of tuna distribution and abundance and influences on decision making by fisheries managers and fleets and (v) development of management strategy evaluation frameworks for utilisation in the implementing and testing of fishery management procedures and to help prioritise research directions and investment. Issues discussed and research priorities identified during the workshop have synergies with other internationally managed fisheries and therefore are applicable to many other fisheries. 相似文献
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The California Current System (CCS) is forced by the distribution of atmospheric pressure and associated winds in relation to the west coast of North America. In this paper, we begin with a simplified case of winds and a linear coast, then consider variability characteristic of the CCS, and conclude by considering future change. The CCS extends from the North Pacific Current (～50°N) to off Baja California, Mexico (～15–25°N) with a major discontinuity at Point Conception (34.5°N). Variation in atmospheric pressure affects winds and thus upwelling. Coastal, wind-driven upwelling results in nutrification and biological production and a southward coastal jet. Offshore, curl-driven upwelling results in a spatially large, productive habitat. The California Current flows equatorward and derives from the North Pacific Current and the coastal jet. Dominant modes of spatial and temporal variability in physical processes and biological responses are discussed. High surface production results in deep and bottom waters depleted in oxygen and enriched in carbon dioxide. Fishing has depleted demersal stocks more than pelagic stocks, and marine mammals, including whales, are recovering. Krill, squid, and micronekton are poorly known and merit study. Future climate change will differ from past change and thus prediction of the CCS requires an understanding of its dynamics. Of particular concern are changes in winds, stratification, and ocean chemistry. 相似文献
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On the basis of the experimental investigations conducted from an oceanographic tower, the variability of the structure of
temperature profiles has been analysed. The paper provides a classification of the basis types of temperature profiles and
determines their frequencies and duration in the annual cycle. Dynamics of the transition from one type of a temperature profile
to another has been found to have synoptic scales. The variability of parameters during an occurrence of some typical profile
have been assessed; it has been deduced that variations in profile shape are linked with fine structure effects of internal
waves.
Translated by Vladimir A. Puchkin. 相似文献
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A reanalysis of atmospheric circulation in the Black Sea region is performed with a high spatial resolution of 25 × 25 km for the period from 1958 to 2001. Climatic wind speed fields are estimated, as are their spatial structure and seasonal variability. Mesoscale regions of cyclonic and anticyclonic speed vorticity, which are connected with edge effects and orography, are distinguished. To single out the monsoon mechanism in the annual votricity cycle, numerical experiments on the sensitivity that the regional atmospheric circulation has to the sea-surface temperature perturbations have been carried out. Large-scale regional peculiarities of the surface wind field are considered for different seasons. The vorticity of the surface wind speed and strength is assessed. Large annual average values of the vorticity are obtained which are comparable with the range of seasonal variability; they evidence the defining role that wind plays in the generation and seasonal variability, as well as the average cyclonic water circulation in the Black Sea. 相似文献
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Thomas Gorgues C. Menkes L. Slemons O. Aumont Y. Dandonneau M.-H. Radenac S. Alvain C. Moulin 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(4):567-576
A biogeochemical model of the tropical Pacific has been used to assess the impact of interannual variability in a western Pacific iron source on the iron-limited ecosystem of the central and eastern Pacific during the 1997–1998 El Niño. A reference simulation and two simulations with an iron source in the western Pacific have been performed. The two “source” simulations differed only in the temporal variability of the iron source. In the variable source simulation, the iron concentration in the source region was proportional to the velocity of the New Guinea Coastal Undercurrent (NGCUC). In the constant source simulation, the same time-averaged concentration of iron was imposed with no temporal variability. The variable source was designed to mimic variations of iron flux from the northeast slope of New Guinea to the NGCUC due to modulation of sedimentary iron resuspension as previously hypothesized. Through the comparison of these simulations, it appeared that: (i) an iron source in the NGCUC, regardless of its source variability, increases biomass in the eastern equatorial Pacific because of the greater eastward iron flux by the Equatorial Undercurrent and (ii) a variable NGCUC iron source does not change the temporal variability of eastern Pacific chlorophyll, and in particular the timing and intensity of the June 1998 bloom. To explain eastern Pacific biological variability, local rather than remote processes are needed, such as wind-driven upwelling, the local depth of the thermocline, tropical instability waves and biological processes such as high grazing pressure. Therefore, while the western Pacific sources of dissolved iron are important in our model to sustain annually integrated equatorial Pacific production, they are unlikely to strongly constrain the timing of blooms in the central and eastern Pacific such as during the 1998 La Niña. 相似文献