共查询到19条相似文献，搜索用时 171 毫秒
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海洋锋是特性明显不同的两种或几种水体之间的水平分布高梯度带。海洋锋对海战场环境存在重要影响。文中基于高性能计算机平台,采用海洋动力模式和先进的数据同化技术制作的海洋数值再分析产品(China Ocean Reanalysis,CORA),研究了东中国海温度锋和盐度锋分别在表层和50 m层深度上的季节变化特征。通过分析发现温度锋在冬季主要分布在东海及台湾海峡,在夏季主要分布在渤海及黄海;春秋两季的变化介于冬夏两季之间;东海黑潮区四季皆存在温度锋。盐度锋主要存在于黄河和长江等径流入海区附近。温度锋和盐度锋的季节变化主要受气象条件、河流入海和近岸升降流季节变化的共同影响。 相似文献
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利用WOA13(1955-2012年)月平均数据提取东海黑潮主轴温度锋信息,并结合海表面温度、PN断面温度结构的季节变化特征,研究东海黑潮主轴温度在垂直方向和水平方向的季节变化,探讨黑潮主轴温度锋季节变化特征,为开展黑潮相关研究提供基础。结果表明WOA13数据对东海黑潮主轴温度锋信息的提取具有较好的效果;在PN断面上,冬、春季节的流核结构最为明显;在130~170 m深度上,东海黑潮主轴温度锋具有明显的季节变化特征,并且可以明显看到黑潮大弯曲的存在;温度锋在150 m上下的深度对黑潮路径的表征较为合理。 相似文献
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基于WOA东北亚海1/10°温盐统计数据产品、海洋水文图集和历史海洋调查相关研究成果,系统研究了东北亚海温度盐度结构主要特征;春季和夏季,黄海东西沿岸存在温度低值中心;描述和定义了黑潮右侧次表层伸向西南方向的"黑潮逆流冷舌";研究了东北亚海主要流系和部分海洋中尺度现象(海洋涡旋、海洋锋、上升流、长江冲淡水等)引起的温度盐度结构特征。日本海40°N附近海洋温度锋一年四季都比较强,中国东海海面温度锋在冬季和春季比较强。台湾东北冷涡和日本以南超级暖涡附近是温度极值中心。该研究成果为东北亚海海洋水文环境保障提供技术支撑。 相似文献
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《海洋技术学报》2014,(5)
由黑潮形成的海洋锋斜压性强,对海洋中的声传播带来极大影响,从而对各种依赖声学性质的海洋探测设备的使用造成极大影响,确定黑潮斜压性锋的位置和强度对海洋渔业和军事应用具有重要的意义。通过对海表温度梯度数据和地转流数据的分析,将海表温度梯度与地转流进行融合,从而检测黑潮流边缘的大温度梯度海洋锋。通过对实际数据的试验,说明了融合算法的原理、算法步骤和黑潮斜压性锋检测结果。试验数据表明,文中提出的融合算法能够很好地检测黑潮斜压性锋位置,同时提取其强度,与采用海面温度或地转流数据单一数据源检测相比,文中所述的方法检测位置准确,虚警率低,与文献报道的黑潮位置更为吻合。 相似文献
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海洋锋面是指不同性质的水团之间的交界面，由于水团之间的混合作用，一般是指不同水团之间的混合区。水团之间的混合是通过锋面进行的，浅海海洋锋区还往往出现上升流。观测表明，两种不同性质的水团或水体的交界面处，生物初级生产力较高，常是鱼群聚集的区域，渔获量较高。因此，海洋锋的研究有很高的理论和实践意义。在我国近海，大陆径流入海所形成的海洋锋，是黄海、东海陆架海区的重要锋面类别之一，本文利用“三峡工程对长江河口区生态与环境的影响和对策”专题调查资料(1985年8月-1986年10月)和国家海洋局断面调查资料(1975-1981年)，对长江冲淡水锋面的分布和变动特征作一初步分析。
长江口地处黄海和东海的交接处，南有台湾暖流及其延续体北上，并能越过长江口到达32°N以北海区(赵保仁，1982；苏育嵩，1986)，北有黄海沿岸流和苏北沿岸流南下，东邻面积宽广的黄海、东海混合水区(苏育嵩等，1983)。
洪水期丰沛的长江径流入海之后，在122°10''E以东海区显著层化，然后在长江冲淡水和外海高盐水之间形成明显的锋面。长江口区的温度平面分布比较均匀，而盐度的差异很大。本文所讨论的锋面，是指因盐度水平分布显著差异而形成的盐度锋。
在长江口附近海区，外海高盐水分属不同的流系，它们的盐度值和水平流速值各不相同，因此，与长江冲淡水之间形成的锋面强度和宽度也各不相同。一般地说，暖流系统盐度比较高，流速较大，因而与长江冲淡水之间形成的锋面较强，锋区宽度也较狭窄；相反，黄海沿岸流系的盐度较低，水平流速较小，从而与冲谈水之间形成的锋面相对较弱，且锋区宽度较大。
依照定义，锋区应是水文要素水平梯度最大的区域。据日本学者(Kanau et al.，1983)的观测，长江口区的锋区宽度只有1-5km左右。有的区域锋区宽度可能不足1km。与三峡工程有关的海上环境调查，在123°E以西海域，观测站距为10-15n mile; 国家海洋局断面观测站距一般为30''经距。基于这些资料确定出的锋区宽度就较大，强度则显著变弱。因此，为了弄清长江口海洋锋的水文结构和变化特征，需要针对海洋锋这种小尺度现象布设高密度观测站，或者用巡航式CTD进行专门调查。然而实际工作中仍然需要根据常规的海洋调查资料来确定锋面的大体位置，了解其水文结构和变化规律。 相似文献
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本文利用近十年来获得的ＮＯＡＡ卫星红外影像，较为系统地分析了东海海洋锋（黑潮锋、对马暖流锋和浙江沿岸锋）的波动谱特征以及形态的演变。同时还利用浮标测流结果分析了锋面波动中的流态。分析结果表明：东海黑潮锋通常存在４～５个折叠波形，其波长平均约２００ｋｍ，波动随黑潮流向东北方向传播，速度约１６ｃｍ／ｓ。浙江沿岸锋的波动多呈锯齿形，其波长较短，波数多。在浙江沿岸锋波动发展过程中，其波长从开始的２０～４０ｋｍ发展成３０～６０ｋｍ，它们约以１８ｃｍ／ｓ的速度向东北方向传播。东海海洋锋波动演变形态复杂，其中黑潮锋的波动可能演变成锋面涡旋、暖丝和暖环。 相似文献
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基于阈值区间的海洋锋面提取模型 总被引：1，自引：0，他引：1
A model （Bayesian oceanic front detection, BOFD） of sea surface temperature （SST） front detection in satel- lite-derived SST images based on a threshold interval is presented, to be used in different applications such as climatic and environmental studies or fisheries. The model first computes the SST gradient by using a Sobel algorithm template. On the basis of the gradient value, the threshold interval is determined by a gradi- ent cumulative histogram. According to this threshold interval, front candidates can be acquired and prior probability and likelihood can be calculated. Whether or not the candidates are front points can be deter- mined by using the Bayesian decision theory. The model is evaluated on the Advanced Very High-Resolution Radiometer images of part of the Kuroshio front region. Results are compared with those obtained by using several SST front detection methods proposed in the literature. This comparison shows that the BOFD not only suppresses noise and small-scale fronts, but also retains continuous fronts. 相似文献
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吕宋海峡西部深海盆内孤立波潜标观测研究 总被引：2，自引：0，他引：2
Using a net surface heat flux （Qnet） product obtained from the objectively analyzed air-sea fluxes （OAFlux） project and the international satellite cloud climatology project （ISCCP）, and temperature from the simple ocean data assimilation （SODA）, the seasonal variations of the air-sea heat fluxes in the northwestern Pa cific marginal seas （NPMS） and their roles in sea surface temperature （SST） seasonality are studied. The seasonal variations of Qnet, which is generally determined by the seasonal cycle of latent heat flux （LH）, are in response to the advection-induced changes of SST over the Kuroshio and its extension. Two dynamic regimes are identified in the NPMS： one is the area along the Kuroshio and its extension, and the other is the area outside the Kuroshio. The oceanic thermal advection dominates the variations of SST and hence the sea-air humidity plays a primary role and explains the maximum heat losing along the Kuroshio. The heat transported by the Kuroshio leads to a longer period of heat losing over the Kuroshio and its Extension. Positive anomaly of heat content corresponds with the maximum heat loss along the Kuroshio. The oceanic advection controls the variations of heat content and hence the surface heat flux. This study will help us understand the mechanism controlling variations of the coupled ocean-atmosphere system in the NPMS. In the Kuroshio region, the ocean current controls the ocean temperature along the main stream of the Ku roshio, and at the same time, forces the air-sea fluxes. 相似文献
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为了探究海表温度和海面高度之间的瞬时相关性,介绍了一种卫星测高数据的拉格朗日分析指数--有限尺度李雅普诺夫指数(Finite Size Lyapunov Exponent,FSLE),以黑潮延伸体区域的涡旋和南大西洋的亚南极锋为例,通过对观测、模式结果和融合产品结果的分析,探讨了该指数与海表温度梯度(Sea Surface Temperature Gradient,SSTG)之间的相关性。比较FSLE图像和SSTG图像发现,FSLE与SSTG均呈丝状结构,对海洋表层水体结构描述具有一致性,尤其在温度梯度大和地转流强的区域更为一致。二者的一致性要远好于其他常用方式,比如全流速、OW参数涡旋识别方法和Winding-Angle涡旋识别方法。不同区域FSLE与SSTG之间的相关性表现不同,黑潮延伸体区域相关系数存在显著的季节变化,而南大西洋亚南极锋区域季节内变化突出。 相似文献
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This study investigated the seasonal variation in the atmospheric response to oceanic mesoscale eddies in the North Pacific Subtropical Countercurrent (STCC) and its mechanism, based on satellite altimetric and reanalysis datasets. Although mesoscale eddy in the study area is more active in summer, the sea surface temperature (SST) anomaly associated with mesoscale eddies is more intense and dipolar in winter, which is largely due to the larger background SST gradient. Similarly, the impact of the oceanic eddy on sea surface wind speed and heat flux is strongest in winter, whereas its effect on precipitation rate is more significant in summer. The study revealed that the SST gradient in STCC could impact the atmosphere layer by up to 800 hPa (900 hPa) in boreal winter (summer) through the dominant vertical mixing mechanism. Moreover, the intensity of the SST gradient causes such seasonal variation in mesoscale air-sea coupling in the study region. In brief, a stronger (weaker) background SST gradient field in wintertime (summertime) leads to a larger (smaller) eddy-induced SST anomaly, thus differently impacting atmosphere instability and transitional kinetic energy flux over oceanic eddies, leading to seasonal variation in mesoscale air-sea coupling intensity. 相似文献
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Using a combination of Quick Scatterometer (QuikSCAT), Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E),
and Lagrangian drifter measurements, we demonstrate that wind data alone are not sufficient to derive ocean surface stress
(momentum flux) over mid-latitude ocean fronts, specifically the Kuroshio Extension. There was no continuous and large-scale
stress measurement over ocean until the launch of the scatterometers. Stress had been derived from winds through a drag coefficient,
and our concept of stress distribution may be largely influenced by our knowledge of wind distribution. QuikSCAT reveals that
the variability of stress could be very different from wind. The spatial coherence between the magnitude of stress and sea
surface temperature (SST), between the divergence of surface stress and the downwind SST gradient, and between the vorticity
of stress and crosswind SST gradient, are the inherent characteristics of stress (turbulence production by buoyancy) that
would exist even under a uniform wind field. The coherence between stress vorticity and SST gradient is masked by the rotation
of ocean currents over the Kuroshio meanders. Surface stress rotates in the opposite direction to surface currents because
stress is the vector difference between wind and current. The results are in agreement with a previous study of the Agulhas
Extension and confirm the unique stress measuring capability of the scatterometer. 相似文献
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Tim J. Smyth Peter I. Miller Steve B. Groom Samantha J. Lavender 《Progress in Oceanography》2001,51(2-4)
Satellite derived sea surface temperature (SST) and chlorophyll data are used to characterise the period of upwelling during a cruise on which two Lagrangian drift experiments were conducted off the Iberian Atlantic coast in August 1998. During the cruise there was a prolonged period of equator-ward winds which favour upwelling; three distinct maxima were observed in the meteorological data interspersed with periods of relaxation. The SST and chlorophyll imagery show upwelling to be active with distinct offshore filaments that are cooler and of higher chlorophyll concentration than the surrounding oceanic water; these filaments represent an important cross-shelf transport mechanism. A front detection methodology has been applied to satellite images and suggests that these filaments are distinct, long-lived features, characterised by enhanced primary production. 相似文献
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Smaller mesoscale eddies (SMEs) have an important effect on the transmission of ocean temperatures, salinity, energy, and marine biochemical processes. However, traditional altimeters, the dominant sensors used to identify and track eddies, have made it challenging to observe SMEs accurately due to resolution limitations. Eddies drive local upwelling or downwelling, leaving signatures on sea surface temperatures (SSTs) and chlorophyll concentrations (Chls). SST can be observed by spaceborne infrared sensors, and Chl can be measured by ocean color remote sensing. Therefore, multisatellite observations provide an opportunity to obtain information to characterize SMEs. In this paper, an eddy detection algorithm based on SST and Chl images is proposed, which identifies eddies by characterizing the spatial and temporal distribution of SST and Chl data. The algorithm is applied to characterize and analyze SMEs in the Kuroshio Extension. Statistical results on their distribution and seasonal variability are shown, and the formation processes are preliminarily discussed. SMEs generation may be contributed by horizontal strain instability, the interaction of topographic obstacles and currents, and wind stress curl. 相似文献
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海温是海洋环境影响因子之一,对于海洋生态环境、海水养殖业等尤为重要。本文以Argo数据提取的南海海洋温度场数据为例,结合GIS(GeographicInformationSystem)技术,研究南海海温点过程、面过程可视化表达的方法。利用GIS作为可视化框架提供南海海温场的可视化显示,包括放大、缩小和拖动等基本功能,绘制多种形式的数值图像并进行空间分析,包括海温数据曲线绘制、海温值查询、空间插值、等值线等。基于Argo数据可视化表达的结果,从南海海温年变化、随纬度的变化、垂向变化、季节分布特征四方面对南海的海温时空特征进行了分析,结果表明:(1)南海海表温度高温的持续时间比较长,升温过程比降温过程相对要短一些;(2)随着纬度的降低,温度整体升高,温度的年变化幅度越来越小。夏秋两季随着纬度的变化,温度变化不大,春冬两季的温度变化较大;(3)在0~30 m温度变化很小,在深度为30m处温度开始逐渐下降,到达500m以下,海温一年四季都比较接近;(4)冬季海温总体最低,夏季海温总体最高。冬季和秋季,在南海西南方向等值线呈现西北—东南向,等值线比较密集。海温的时空变化研究可以对海洋温跃层、海洋温度锋,海水不同层次的结构的研究提供一定参考。 相似文献
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Contrasting decrease and increase trends of sea surface temperature（SST） have been documented in the western Subarctic（WSA） and the rest of the Northwest Pacific（NWP） from 1958 to 2017, respectively. Consequently, more（less） total carbon dioxide（TCO2） due to ocean cooling（warming） is transported to the surface, which leads to increase（decrease） of oceanic surface partial pressure of carbon dioxide（pCO2）. With the combined influence of the rising atmospheric carbon dioxide（C... 相似文献