共查询到18条相似文献，搜索用时 109 毫秒
1.
2.
3.
综合考虑侧边界水通量、海表面风应力、热通量、蒸发和降水等,建立了一个采用垂向S坐标的西北太平洋海洋模式,模拟和分析西北太平洋环流和海温。S坐标具有使海洋上层趋于同一水深的物理平面和同时底层拟合海底变化的优点。与日本2008年西北太平洋实测温度断面资料比较,模式计算的海温在分布势态和量值上较为一致,模式能较好地验证海洋温度分布情况。与σ坐标相比,S坐标能更好地验证海温的变化。模式较好地模拟出了西北太平洋气候态环流和海温变化。由于在σ坐标系下水深的水平变化体现在σ层上,海洋表层的分辨率比S坐标系下低,以及初始海温的水平分布含有水深水平变化的信息,S坐标海洋模式能更好地模拟环流和海温的变化。 相似文献
4.
用已成功地模拟了大尺度环流和黑潮的三维、斜压以及具自由海水表面的数值模式,模拟了冬季南海流场、温度场和海面高度场。所用网格为0．25°×0．25°,垂直方向分为6层;除巴土海峡和台湾海峡外,其它边界假设为封闭;巴士海峡和台湾海峡的边界值用已模拟的大尺度环流值。模拟结果基本上反映了南海冬季环流的特征。从模拟结果可知,黑潮从巴士海峡南部进入南海后,其大部分又从对21°以北返回大洋。巴士海峡西侧的气旋型环流似乎具有相对的独立性;当然,涡旋东侧在巴士海峡的N向流可能与黑潮水混合,而且从这支流中分离出－小支流继续向北,汇入到“南海暖流”中。黑潮水虽然大部分返回太平洋,但是巴士海峡西侧的气旋型环流是由巴士海峡处的黑潮诱发的,南海海底地形对南海环流的形态（特别是对“南海暖流”的形成）有很大的影响。 相似文献
5.
冬季南海北部中尺度涡旋的数值研究 总被引：13，自引：1，他引：12
南海环流的一个主要特征是上层海洋环流具有多涡结构,海洋中尺度涡旋的演变(时间上的生消和空间上的迁移)是南海环流季节调整的可能方式。文中依据卫星遥感海面高度资料和实际海洋观测所揭示的南海北部存在中尺度涡旋体系的基本事实,采用一个改进了涡分辨(eddy-resolving)普林斯顿海洋模式(POM),对冬季处于强盛的东北季风强迫以及黑潮在巴士海峡入侵的共同作用下的南海北部环流的中尺度涡旋体系进行了数值研究,初步再现了冬季南海北部中尺度涡的生命史。计算结果表明,在实际的气候冬季风应力驱动下,具有的实际侧边界地形的南海北部呈现有强烈的中尺度涡旋。文中探讨了中尺度涡的垂直结构、温盐场的配置以及大尺度水平辐合辐散、海洋垂直运动与之相关的时空结构。由此可以得知,在冬季南海北部中尺度涡旋生命史的不同阶段,上述动力学因子的重要性是相对的。不同的敏感性试验表明,斜压调整是形成冬季南海中尺度涡旋体系的决定性因子;边界的入流和风应力驱动是影响中尺度涡旋运动的主要因素。 相似文献
6.
全球海洋环流模式中上层海洋对表面强迫的响应和调整Ⅱ.年代际变率 总被引：6，自引：1，他引：5
利用一个较高分辨率的全球海洋环流模式在COADS 1945～1993年逐月平均资料的强迫下对海温和环流场进行了模拟,分析了北太平洋海温和环流场的年代际变化特征,同时诊断了1976-77年代际跃变过程中海温场变化的机制.模式模拟出了北太平洋海温年代际异常的主要模态以及1976-77年跃变前后的演变特征,模拟的北太平洋中部、加州沿岸和KOE区的海温异常的强度和演变趋势均和观测比较一致;同时,模式重现了分别始于20世纪70和80年代的中纬度海温异常信号沿等密度面向低纬地区的两次潜沉过程.在表层,流场的异常主要表现为与风应力异常基本符合Ekman关系的一个异常海洋涡旋,而整个上层海洋平均的流场异常则表现为两个海洋涡旋的异常,其中副热带海洋涡旋的异常的强度要显著于副极地海洋涡旋的异常,而副极地海洋涡旋异常出现的时间比副热带海洋涡旋晚3a左右的时间.对1976-77年前后3个区域上层海温各贡献项的诊断结果表明,北太平洋中部变冷主要是水平平流和热通量异常贡献的结果;而加州沿岸变暖主要归因于热通量的贡献;在KOE区,垂直平流、热通量和水平平流三者都起了重要作用,其中水平平流异常对这一区域海温年代际跃变出现的时间起了至关重要的作用. 相似文献
7.
南海冬、夏季环流的三维数值模拟 总被引：6，自引：0，他引：6
本文利用一个斜压三维陆架海模式——HAMSOM模式对12月份和8月份的南海环流进行数值模拟,结果为:对上层流场,在12月份,在西沙群岛－中沙群岛海区间呈现一个气旋式环流,在越南中部东岸存在一支南向西边界流,在金兰湾的远海为一局地反气旋涡,在南海南部,主要表现为万安滩的气旋式大弯曲(气旋涡)及在北康暗沙北侧的反气旋涡;在8月份,在东沙群岛－中沙群岛－吕宋岛西侧海域间存在一大尺度的气旋涡,在南海西部主要表现为以西沙群岛南部的气旋涡与金兰湾－礼乐滩间的反气旋式大环流相对峙的局面,同时在万安滩东侧有－气旋涡.由于斜压效应、底形效应的作用,使冬、夏季的南海南部中层流场几乎与上层流场相反. 相似文献
8.
2000年8月南海中部与南部海洋温、盐与环流特征 总被引：13，自引：2，他引：11
根据2000年8—9月份南海中部与南部航次的温、盐资料,采用P—矢量诊断方法,结合ADCP测流资料和同期伪风应力资料以及TOPEX／Poseidon高度计资料,研究了2000年夏季风持续强迫之后南海大尺度环流与中尺度涡旋的空间结构。结果表明,南海夏季温度和盐度水平分布随深度有显著的变化：中层(250—400m左右)温、盐水平分布与其它各层的温度和盐度分布相比有很大的差异。用诊断方法计算得到的环流场与用TOPEX／Poseidon海面高度计资料计算得到的地转流场比较一致,即流场内部有多个中尺度的涡旋,主要有越南东南外海反气旋涡、中沙群岛东南反气旋涡以及南沙群岛东北角的气旋涡等,这说明南海中部与南部盛夏环流具有较强的地转分量和显著的多涡结构,并且这些中尺度涡在垂向上存在速度场的切变。 相似文献
9.
本文基于观测数据和模式产品,探讨了南海西边界流(South China Sea western boundary current, SCSwbc)区域海洋涡旋的统计特征、涡致热输运并重点探讨了两类冬季环流形态及其风场分布对它们的影响。结果表明研究区域的涡旋气候态上存在旋转速度很强,半径较大,振幅略高于平均值的涡旋统计特征,其中气旋式涡旋(cyclonic eddy, CE)的占比约为56.8%。并且涡旋的生成和消亡主要发生在冬/春季,而涡旋的振幅、半径和旋转速度在夏/秋季发展到顶峰。年际时间尺度上,年平均经向风应力与反气旋式涡旋(anticyclonic eddy,AE)的振幅、半径、旋转速度和消亡均有较好的相关性,但与CE特征的相关性并不好。“O”型冬季环流模态下,风场和南海西边界流显著减弱,冬季环流在越南沿岸发生向东分支。涡旋在“O”模态下吸收平均流能量迅速发展,在越南沿岸东部地区产生了强的涡致热输运(eddy-induced heat transport, EHT)。同时,涡旋内部旋转速度减小且反气旋式涡旋个数减少;“U”型冬季环流模态下,情况则相反。 相似文献
10.
1998年夏季南海环流的三维结构 总被引：1，自引：2，他引：1
利用1998年6月12日至7月6日南海的调查资料,采用三维海流诊断模式,计算了夏季南海三维海流,结合卫星海表面高度距平资料,得到结果如下:(1)南海北部,在吕宋岛以西海域和东沙群岛附近海域,分别存在一个反气旋式涡和东沙群岛西南的气旋式涡.(2)南海中部,越南以东海域出现由暖涡W3和冷涡C3组成的一个准偶极子.在冷涡C3和暖涡W3以北分别存在一个暖涡W2和冷涡C2.(3)在越南近岸存在较强的、北向的西边界射流,此北向射流在14°N附近离岸转为东,并流入两涡W3和C3之间.(4)南海南部,在巴拉望岛的西南海域,100m以浅水层存在反气旋式涡,而在其较深水层,此处变为气旋式涡.(5)南海环流的动力机制有两个:最重要的动力因子为斜压场与地形相互作用项,其次为风应力与地形相互作用项.(6)讨论了夏季南海环流垂向速度w分布,例如在30m层,Ekman抽吸对垂向速度w分布起着重要作用.(7)与2000年夏季南海环流的比较,1998年夏季计算海域涡旋W3,C3,C2等的位置变化并不大. 相似文献
11.
渤海环流与输运季节变化的数值模拟 总被引：8，自引：0，他引：8
渤海的风和温度层结有明显的季节变化 ,因而其环流与输运亦有明显的季节信号。以季节平均的海面气象条件和开边界的潮波系统驱动三维斜压水动力模型———HAMSOM ,模拟了渤海冬、夏季的总环流。渤海环流冬强夏弱 ,表层风漂流常被下层逆风流所补偿。深度平均环流 ,即水柱内的输运 ,流型有显著的季节变化 :冬季在渤海中部沿逆时针方向旋转 ,辽东湾顶有一个顺时针流涡 ,阻碍了湾顶水与外海水的交换 ;夏季则为一个大的贴岸的顺时针流环 ,内嵌许多局地涡旋。这些与渤黄东海海洋水文图集中给出的多年观测的环流基本相同 ,同时也被水文要素分布及耐盐浮游动物的出现所佐证。风的季节变化决定了渤海大部分海区、特别是海峡附近环流的季节变化 ,但辽东湾东岸众多的岬角涡旋却不随季节变化 ,因为它们是由潮波系统与岬角岸型变化的非线性相互作用产生的。 相似文献
12.
A numerical model of baroclinic circulation based on the use of a double sigma coordinate system is presented and its application
to the simulation of flows and temperature and salinity fields in the Dnieper-Bug Estuary is described. The model reproduces
the salinity and temperature fields surveyed in 1998. The results of simulations reveal the existence of a global influence
of the relatively narrow and deep ship channel (through which Black-Sea waters can penetrate deep into the estuary) on the
transport processes.
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 66–77, November–December, 2008. 相似文献
13.
An assessment of the fine-scale eddies in a high-resolution model of the shelf seas west of Great Britain 总被引：1，自引：0，他引：1
High-resolution (1.8 km) simulations of the shelf seas west of Great Britain with the Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS) demonstrate the formation of an intense field of baroclinic eddies in open stratified waters such as the Celtic Sea. These eddies are most likely to be the result of an inverse energy cascade resulting from tidal flow over rough topography, as demonstrated by a series of idealised model experiments. They are shown to possess many of the properties of eddies identified in idealised laboratory and numerical simulations. Namely, they are predominantly anticyclonic and they merge to increase their size up to a limit set by the internal Rossby radius. An investigation of satellite sea surface temperature observations provides indirect evidence that these model eddies are too energetic, long-lived and frequent. The inclusion of a horizontal diffusion term with a shear dependent diffusivity is shown to significantly reduce the eddy kinetic energy and improve the simulation, without significantly affecting the results in other regions. An optimal parameter value is suggested for this resolution, but the need to put the treatment of horizontal turbulence in such models on a sounder theoretical or empirical footing is identified. 相似文献
14.
Mesoscale eddies, which are mainly caused by baroclinic effects in the ocean, are common oceanic phenomena in the Northwest Pacific Ocean and play very important roles in ocean circulation, ocean dynamics and material energy transport. The temperature structure of mesoscale eddies will lead to variations in oceanic baroclinity, which can be reflected in the sea level anomaly (SLA). Deep learning can automatically extract different features of data at multiple levels without human intervention, and find the hidden relations of data. Therefore, combining satellite SLA data with deep learning is a good way to invert the temperature structure inside eddies. This paper proposes a deep learning algorithm, eddy convolution neural network (ECN), which can train the relationship between mesoscale eddy temperature anomalies and sea level anomalies (SLAs), relying on the powerful feature extraction and learning abilities of convolutional neural networks. After obtaining the temperature structure model through ECN, according to climatic temperature data, the temperature structure of mesoscale eddies in the Northwest Pacific is retrieved with a spatial resolution of 0.25° at depths of 0–1 000 m. The overall accuracy of the ECN temperature structure is verified using Argo profiles at the locations of cyclonic and anticyclonic eddies during 2015–2016. Taking 10% error as the acceptable threshold of accuracy, 89.64% and 87.25% of the cyclonic and anticyclonic eddy temperature structures obtained by ECN met the threshold, respectively. 相似文献
15.
Recent changes in the North Atlantic circulation simulated with eddy-permitting and eddy-resolving ocean models 总被引：1，自引：0，他引：1
Robert Marsh Beverly A. de Cuevas Andrew C. Coward Julien Jacquin Joel J.-M. Hirschi Yevgeny Aksenov A.J. George Nurser Simon A. Josey 《Ocean Modelling》2009,28(4):226-239
Three eddy-permitting (1/4°) versions and one eddy-resolving (1/12°) version of the OCCAM ocean model are used to simulate the World Ocean circulation since 1985. The first eddy-permitting simulation has been used extensively in previous studies, and provides a point of reference. A second, improved, eddy-permitting simulation is forced in the same manner as the eddy-resolving simulation, with a dataset based on a blend of NCEP re-analysis and satellite data. The third eddy-permitting simulation is forced with a different dataset, based on the ERA-40 re-analysis data. Inter-comparison of these simulations in the North Atlantic clarifies the relative importance of resolution and choice of forcing dataset, for simulating the mean state and recent variability of the basin-scale circulation in that region. Differences between the first and second eddy-permitting simulations additionally reveal an erroneous influence of sea ice on surface salinity, dense water formation, and the meridional overturning circulation. Simulations are further evaluated in terms of long-term mean ocean heat transport at selected latitudes (for which hydrographic estimates are available) and sea surface temperature errors (relative to observations). By these criteria, closest agreement with observations is obtained for the eddy-resolving simulation. In this simulation, there is also a weak decadal variation in mid-latitudes, with heat transport strongest, by around 0.2 PW, in the mid-1990s. In two of the eddy-permitting simulations, by contrast, heat transport weakens through the study period, by up to 0.4 PW in mid-latitudes. The most notable changes of heat transport in all simulations are linked to a weakening of the subpolar gyre, rather than changes in the meridional overturning circulation. It is concluded that recent changes in the structure of mid-latitude heat transport in the North Atlantic are more accurately represented if eddies are explicitly resolved. 相似文献
16.
The representation of baroclinic instability in numerical models depends strongly upon the model physics and significant differences may be found depending on the vertical discretization of the governing dynamical equations. This dependency is explored in the context of the restratification of an idealized convective basin with no external forcing. A comparison is made between an isopycnic model including a mixed layer (the Miami Isopycnic Coordinate Ocean Model, MICOM), its adiabatic version (MICOM-ADIAB) in which the mixed layer physics are removed and the convective layer is described by a deep adiabatic layer outcropping at the surface instead of a thick dense mixed layer, and a z-coordinate model (OPA model).In the absence of a buoyancy source at the surface, the mixed layer geometry in MICOM prevents almost any retreat of this layer. As a result, lateral heat exchanges in the upper layers are limited while mass transfers across the outer boundary of the deep convective mixed layer result in an unrealistic outward spreading of this layer. Such a widespread deep mixed layer maintains a low level of baroclinic instability, and therefore limits lateral heat exchanges in the upper layers over most of the model domain. The behavior of the adiabatic isopycnic model and z-coordinate model is by far more satisfactory although contrasted features can be observed between the two simulations. In MICOM-ADIAB, the more baroclinic dynamics introduce a stronger contrast between the surface and the dense waters in the eddy kinetic energy and heat flux distributions. Better preservation of the density contrasts around the dense water patch maintains more persistent baroclinic instability, essentially associated with the process of dense water spreading. The OPA simulation shows a faster growth of the eddy kinetic energy in the early stages of the restratification which is attributed to more efficient baroclinic instability and leads to the most rapid buoyancy restoring in the convective area among the three simulations. Dense water spreading and warm surface capping occur on fairly similar time scales in MICOM-ADIAB although the former is more persistent that the latter. In this model, heat is mainly transported by anticyclonic eddies in the dense layer while both cyclonic and anticyclonic eddies are involved in the upper layers. In OPA, heat is mainly brought into the convective zone through the export of cold water trapped in cyclonic eddies with a strong barotropic structure. Probably the most interesting difference between the z-coordinate and the adiabatic isopycnic model is found in the temperature distribution ultimately produced by the restratification process. OPA generates a spurious volume of intermediate water which is not seen in MICOM-ADIAB where the volume of the dense water is preserved. 相似文献
17.
《Ocean Modelling》2002,4(2):121-135
Numerical studies of surface ocean fronts forced by inhomogeneous buoyancy loss show nonhydrostatic convective plumes coexisting with baroclinic eddies. The character of the vertical overturning depends sensitively on the treatment of the vertical momentum equation in the model. It is less well known how the frontal evolution over scales of O(10 km) is affected by these dynamics. Here, we compare highly resolved numerical experiments using nonhydrostatic and hydrostatic models and the convective-adjustment parametrization. The impact of nonhydrostatic processes on average cross-frontal transfer is weak compared to the effect of the O(1 km) scale baroclinic motions. For water-mass distribution and formation rate nonhydrostatic dynamics have similar influence to the baroclinic eddies although adequate resolution of the gradients in forcing fluxes is more important. The overall implication is that including nonhydrostatic surface frontal dynamics in ocean general circulation models will have only a minor effect on scales of O(1 km) and greater. 相似文献
18.
为了揭示沿岸海区冬季垂直环流及其温盐结构的分布特征和变化规律，利用三维斜压流体动力学模型，对具有岸界坡度变化、河流入海、海湾、岛屿和海槽的理想海区冬季的垂直环流及其温盐结构进行了数值模拟。其环流的数值结果表明，冬季沿岸海区的垂直环流普遍呈逆时针流动。在近表层为向岸流，沿岸为下降流，近表层以下为离岸流；近表层以下的离岸流在外海有明显的上升趋势；沿岸下降流自表层至底层逐渐由强变弱；就整个海区而言，随着自南往北海区水深的逐渐变浅和岸界地形坡度的由大变小，其沿岸下降流则由强变弱。 相似文献