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1.
Numerical experiment aimed at modeling the hydrophysical fields in the sea of Marmara with regard for Bosporus and Dardanelles 总被引：1，自引：0，他引：1
We performed a long-term prognostic experiment aimed at the investigation of the process of formation of the hydrodynamic
structure of the Sea-of-Marmara waters with regard for the influence of Bosporus and Dardanelles. It is shown that the mutual
adaptation of hydrophysical fields and their adjustment to the physical and geographical conditions of the sea proceed as
a result of the action of rapid (tens of days) and slow (several tens of years) mechanisms of adaptation. An S-like jet current
directed from Bosporus to Dardanelles was formed. Two stable anticyclonic formations are well visible in the central part
of the sea. In deeper layer, an abyssal jet current was formed as a result of penetration of heavy Mediterranean waters. The
established specific features of the circulation of waters in the Sea of Marmara are confirmed by the data of observations.
We conclude that the principal features of the dynamics of waters in the Sea of Marmara are formed under the influence of
two straits.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 28–41, May–June, 2007. 相似文献
2.
Model of palaeoenvironmental evolution of the Black Sea region during the last glacial maximum—Holocene 总被引：1，自引：0，他引：1
I. Genov 《Oceanology》2009,49(4):540-557
A model for the palaeoenvironmental evolution of the Black Sea and its adjacent basins during the past 20.000 years, in which
variations in sedimentation, erosion, and hydrologic processes as a result of climatic change are taken into consideration,
is developed. The data used include those from five cruises in the Black Sea with the participation of the author, seismo-acoustic
data in the possession of the Institute of Oceanology in Varna, and data from the published literature. The most important
result is that the water level of the Black Sea is controlled largely by that of the Marmara Sea via the Bosporus sill. The
water circulation in the south part of the Bosporus channel as natural regulative mechanism of the Black Sea level during
11800–9000 yr C14 BP is produced. A succession of climatic and water conditions for the Black Sea by pollen analysis is presented. The linear
ridges on the Black Sea shelf as result of the lower Holocene regression are proved by means of a stratigraphic interpretation
of the seismo-acoustic profiles. The levels of the Black Sea, Marmara Sea, and Mediterranean at regarded intervals of time
are presented. An attempt at explanation of maximum number of facts from the study region with this model is made. 相似文献
3.
E.V. Stanev J. Staneva J.L. Bullister J.W. Murray 《Deep Sea Research Part I: Oceanographic Research Papers》2004,51(12):2137-2169
Data from field observations and numerical model simulations are used to understand and quantify the pathways by which passive tracers penetrate into the Black Sea intermediate and deep layers. Chlorofluorocarbon (CFC) concentrations measured during the1988 R.V. Knorr cruise show strong decrease with increasing density in the Black Sea and illustrate the very slow rate of ventilation of deep water in this basin. We develop a 3D numerical model based on the Modular Ocean Model (MOM), and calibrate it in a way to produce consistent simulations of observed temperature, salinity and CFCs. One important feature is the implementation of a special parameterization for convection, which is an alternative of the convective adjustment in MOM and handles the penetration of the Bosporus plume into the halocline. The model forcing includes interannually variable wind, heat and water fluxes constructed from Comprehensive Ocean–Atmosphere Data Set and ECMWF atmospheric analysis data and river runoff data. The analysis of observations and simulated data are focused on correlations between thermohaline and tracer fields, dynamic control of ventilation, and the relative contributions of sources at the sea surface and outflow from the Bosporus Strait in the formation of intermediate and deep waters. A simple theory is developed which incorporates the outflow from the strait along with the vertical circulation (vertical turbulent mixing and Ekman upwelling) and reveals their mutual adjustment. The analyses of simulated and observed CFCs demonstrate that most of the CFC penetrating the deep layers has its source at the sea surface within the Black Sea rather than from the Marmara Sea via the Bosporus undercurrent. Under present-day conditions, the surface CFC signals have reached only the upper halocline. Intrusions below 600 m are not simulated. The major pathways of penetration of CFCs are associated with cold-water mass formation sites, Bosporus effluent, as well as with the diapycnal mixing in the area of Rim Current. Future CFC sampling strategies coherent with the unique conditions in the Black Sea are discussed. 相似文献
4.
Estimation of horizontal salt transfer from the central part of the Black Sea to the continental slope is carried out based on numerical modeling. A box hydrodynamic model of the Black Sea based on the POM model is used. Horizontal transport caused by seasonal variability of vertical velocity in the central part of the Black Sea and horizontal turbulent diffusion is considered. In this work we demonstrate that, in the 0- to 30-m layer on average for the year, there is an outflow of salty water under the impact of both factors. In the surface layer, the transport caused by seasonal variability contributes significantly (30%). In the 80- to 150-m layer on average over the year, the waters from the continental slope arrive into the central part of the basin; they are characterized by higher salinity due to the inflow of the Marmara Sea waters across the Bosporus Strait. 相似文献
5.
Water masses in the subsurface and the intermediate layer are actively formed due to strong winter convection in the Japan
Sea. It is probable that some fraction of pollution is carried into the layer below the sea surface together with these water
masses, so it is important to estimate the formation rate and turnover time of water masses to study the fate of pollutants.
The present study estimates the annual formation rate and the turnover time of water masses using a three-dimensional ocean
circulation model and a particle chasing method. The total annual formation rate of water masses below the sea surface amounted
to about 3.53 ± 0.55 Sv in the Japan Sea. Regarding representative intermediate water masses, the annual formation rate of
the Upper portion of the Japan Sea Proper Water (UJSPW) and the Japan Sea Intermediate Water (JSIW) were estimated to be about
0.38 ± 0.11 and 1.43 ± 0.16 Sv, respectively, although there was little evidence of the formation of deeper water masses below
a depth of about 1500 m in a numerical experiment. An estimate of turnover time shows that the UJSPW and the JSIW circulate
in the intermediate layer of the Japan Sea with timescales of about 22.1 and 2.2 years, respectively. 相似文献
6.
《Marine Geology》1999,153(1-4):275-302
Detailed interpretation of single-channel air-gun and deep-tow boomer profiles demonstrates that the Marmara Sea, Turkey, experienced small-amplitude (∼70 m) fluctuations in sea level during the later Quaternary, limited in magnitude by the sill depth of the Strait of Dardanelles. Moderate subsidence along the southern shelf and Quaternary glacio-eustatic sea-level variations created several stacked deltaic successions, separated by major shelf-crossing unconformities, which developed during the transitions from global glacial to interglacial periods. Near the Strait of Dardanelles, a series of sand-prone deposits are identified beneath an uppermost (Holocene) transparent mud drape. The sandy deposits thicken into mounds with the morphology and cross-sectional geometries of barrier islands, sand waves, and current-generated marine bars. All cross-stratification indicates unidirectional flow towards the Dardanelles prior to the deposition of the transparent drape which began ∼7000 years BP, in strong support of the notion that the Marmara Sea flowed westwards into the Aegean Sea through the Dardanelles at times of deglaciation in northern Europe. The global sea-level curve shows that, at ∼11,000 and ∼9500 years BP, sea level rose to the sill depths of the Straits of Dardanelles and Bosphorus, respectively. The effect from ∼11,000 to ∼9500 years BP was seawater incursion into the Marmara Sea, drowning and formation of algal-serpulid bioherms atop lowstand barrier islands, and transgression of shelves and lowstand deltas. At ∼9500 years BP, glacial meltwater temporarily stored in the Black Sea lake, developed into a vigorous southward flow toward the Aegean Sea, forming west-directed sandy bedforms in the western Marmara Sea and initiating deposition of sapropel S1 in the Aegean Sea. This strong outflow persisted until ∼7000 years BP, after which a mud drape began to accumulate in the Marmara Sea and euryhaline Mediterranean mollusks successfully migrated into a progressively more saline Black Sea where sapropel deposition began. Most eastern Mediterranean sapropels from S1 to S11 appear to correlate with periods of rising sea level and breaching, or near-breaching, of the Bosphorus sill. These events are believed to coincide with times of vigorous outflow of low-salinity (?fresh) surface waters transiting the Black Sea–Marmara Sea corridor, and ultimately derived from melting of northern European ice sheets. 相似文献
7.
Elena Hubareva Leonid Svetlichny Ahmet Kideys Melek Isinibilir 《Estuarine, Coastal and Shelf Science》2008
In October 2005 spatial distribution of live and dead Acartia clausi and Acartia tonsa was studied in the Black and Marmara Seas and near the Marmara Sea inlet of the Bosphorus, in order to understand their fate upon transportation between two seas. The morphometric characteristics in both species from all studied areas, and the decreased abundance of A. clausi and A. tonsa from the Black Sea towards the Marmara Sea indicate that the Marmara Sea Acartia populations are formed by recruitment from the Black Sea. We observed mass mortality of A. clausi in the Marmara Sea near the Prince Islands. The majority of carcasses (66% of total A. clausi numbers in the Marmara Sea) were found in the salinity gradient layer. 相似文献
8.
《Oceanologica Acta》2003,26(3):243-253
Observations from hydrographic surveys are used to describe the density current flowing through the Dardanelles strait into the Marmara Sea. Aegean water plunges below the surface and flows into the Marmara Sea. This flow joins into the Marmara Sea as a negatively buoyant plume and sinks through the deeper parts. Seasonal variation in the incoming water density results in the observing mainly two different forms of the density current in this area. These two forms are boundary currents and intrusion. Boundary currents were observed as a dense bottom current during the winter when the inflowing water density attains to annual maxima and as an overflow during the autumn when the inflowing water density drops to annual minimum. Intrusion form of the density current was observed during the summer. 相似文献
9.
10.
基于该系列文章前文研究中构建的海气耦合气候模式和所揭示的北大西洋热盐环流年代际振荡机制,针对海气要素对该振荡机制的影响问题进行了重点的探讨。为细致准确的研究北大西洋海洋要素同北大西洋热盐环流年代际振荡的关系,有针对性的定义了副极地海区表层密度指数和北大西洋暖流强度指数并对模式结果进行了全面分析。分析结果表明副极地海区表层密度变化领先大西洋径向翻转环流(MOC)变化7 a,北大西洋暖流的变化领先 MOC变化4 a,格陵兰－苏格兰海脊溢流水强度(包括丹麦海峡溢流水和法鲁海峡溢流水,是北大西洋深层水的重要来源)的变化领先 MOC的变化3 a;北大西洋大气要素变化对北大西洋热盐环流年代际振荡有非常重要的调制作用,当副极地流环和北大西洋暖流(NAC)达到最强的2 a之前,高纬度地区大气为气旋式环流异常,中纬度地区大气为反气旋式环流异常,海表热通量在大西洋副极地海区是负异常,这都有利于副极地流环和NAC的加强,更多高盐度的北大西洋水进入格陵兰-冰岛-挪威海(GIN)海域,由此可以导致GIN海域表层密度上升,使水体的层结稳定性减弱,有利于深层对流的发生,同时大气变化通过风应力旋度和海表热通量也直接影响GIN海域深层水的生成,进而导致格陵兰－苏格兰海脊溢流水的强度增加。 相似文献
11.
Patterns of upper layer circulation variability in the South China Sea from satellite altimetry using the self-organizing map 总被引：2，自引：2，他引：0
Patterns of the South China Sea (SCS) circulation variability are extracted from merged satellite altimetry data from October 1992 through August 2004 by using the self-organizing map (SOM). The annual cycle, seasonal and inter-annual variations of the SCS surface circulation are identified through the evolution of the characteristic circulation patterns. The annual cycle of the SCS gener- al circulation patterns is described as a change between two opposite basin-scale SW-NE oriented gyres embedded with eddies: low sea surface height anomaly (SSHA) (cyclonic) in winter and high SSHA (anticyclonic) in summer half year. The transition starts from July--August (January--February) with a high (low) SSHA tongue east of Vietnam around 12°～14° N, which de- velopa into a big anticyclonic (cyclonic) gyre while moving eastward to the deep basin. During the transitions, a dipole structure, cyclonic (anticyclonic) in the north and anticyclonic (cyclonic) in the south, may be formed southeast off Vietnam with a strong zonal jet around 10°～12° N. The seasonal variation is modulated by the interannual variations. Besides the strong 1997/1998 e- vent in response to the peak Pacific El Nino in 1997, the overall SCS sea level is found to have a significant rise during 1999～ 2001, however, in summer 2004 the overall SCS sea level is lower and the basin-wide anticyclonic gyre becomes weaker than the other years. 相似文献
12.
I&#x;khan Güler Yal&#x;n Yüksel Ahmet Cevdet Yal&#x;ner Esin evik Christian Ingerslev 《Ocean Engineering》2006,33(13):1718-1748
The straits connect two large water bodies show highly strong and stratified currents related to meteorological, morphological and hydrodynamic conditions. In some cases, spatial and temporal changes of the stratified currents and their thickness, direction and magnitude are so complex. This complexity directly affects the circulation pattern in the region, water exchange between both ends of the straits and migration of fish species. In order to understand general characteristics of this kind of straits and identifying the complexity of the hydrodynamics of the region and evaluate the secondary currents and recirculation need long term, intensive, field work and measurement studies. As an example of this kind of hydrodynamically complex straits, Bosphorus strait is selected for a field study. The Bosphorus strait has a strongly stratified two-layer system and a unique case of the maximal exchange regime typical of strait flows, which is largely determined by conditions at the Black Sea. Although the Bosphorus strait has distinct two-layer stratification with an associated two-layer system exchange, no continuous current measurements have been made so far, previous measurements all having been random sampling.In this paper, a detailed measurement program has been applied to Bosphorus strait. In the measurement program, a short-term current profile measurement at selected locations at southern part of the strait has been conveyed. Additionally a long-term measurement of current profile has been performed at a selected critical location (in front of the Dolmabahçe Palace) where a recirculation flow exists in the strait. The scope of this paper is to present the techniques and the results of analysis of measurement data. In the measurements the current profile (magnitude and direction) has been determined at every 1 m depth intervals from the surface to the sea bottom at 3 min duration at every hour. Measurements provide that lower-layer flows in northward direction from the Sea of Marmara towards the Black Sea, whereas the upper-layer flow comes from the Black Sea and flows towards the Sea of Marmara in the opposite direction of lower layer. The Bosphorus strait exhibits distinctive features associated with variations in its width and depth. The meandering features of Bosphorus also cause recirculation flows. These results of measurements are presented, discussed and compared with previous studies. 相似文献
13.
The seasonal variation of water circulation in the Seto Inland Sea is investigated using a high resolution, three-dimensional
numerical ocean model. The model results are assessed by comparison with long-term mean surface current and hydrographic data.
The simulated model results are consistent with observations, showing a distinct summer and winter circulation patterns. In
summer the sea water is highly stratified in basin regions, while it is well mixed near the straits due to strong tidal mixing
there. During this period, a cold dome is formed in several basins, setting up stable cyclonic eddies. The cyclonic circulation
associated with the cold dome develops from May and disappears in autumn when the surface cooling starts. The experiment without
freshwater input shows that a basin-scale estuarine circulation coexists with cyclonic eddy in summer. The former becomes
dominant in autumn circulation after the cold dome disappears. In winter the water is vertically well mixed, and the winter
winds play a significant role in the circulation. The northwesterly winds induce upwind (downwind) currents over the deep
(shallow) water, forming a “double-gyre pattern” in the Suo-Nada, two cyclonic eddies in Hiuchi-Nada, and anticyclonic circulation
in Harima-Nada in vertically averaged current fields. 相似文献
14.
南极威德尔海区域海冰异常对初夏东亚大气环流和天气影响的数值研究 总被引：5，自引：2，他引：3
利用经过改变用于长期数值预报的CCM1(R15L7)模式以1975年1月16日00Z模式适应场为初始场积分5个月,研究南极威德尔海附近(60°W～30°E)海冰的面积异常对东亚初夏环流转换季节的影响.发现当南极海冰偏多时,在亚洲北部冷空气活动在初夏仍然很多,势力还很强,东亚南北两支急流分支仍很明显,各种环流特征更偏向于冬季型,不利于东亚初夏的环流季节转换.海冰异常偏少时则相反,亚洲北部的冷空气活动明显减弱,南方暖气流势力明显加强北移,东亚的两支急流也趋于合并北抬,环流形势更接近于夏季型,海冰的减少促进了东亚初夏的环流季节转换过程. 相似文献
15.
本文利用Argo表层盐度、OSCAR海流等数据,基于盐度收支方程的平流输送项来阐述海洋平流输送对热带印度洋表层盐度的调整作用;利用淡水输运量计算公式揭示6条关键断面海洋平流输送对表层盐度空间结构的调整机制。结果表明,海洋平流将赤道西印度洋和阿拉伯海的高盐水输送到低盐海域的赤道东印度洋和孟加拉湾、安达曼海;将赤道东印度洋和孟加拉湾、安达曼海的低盐水输送到高盐海域的赤道西印度洋、阿拉伯海以及赤道南印度洋海域,起到了调整印度洋盐度基本平衡的作用。断面淡水输运量的分析结果表明,导致苏门答腊岛西部海域的强降水中心与低盐中心不重合,澳大利亚西部海域的强蒸发中心与高盐中心不重合的主要原因是水平环流所致;夏季,来自赤道西印度洋和阿拉伯海的高盐水在西南季风环流的驱动下,入侵孟加拉湾,是导致孟加拉湾夏季表层盐度较高的主要原因。 相似文献
16.
Variability of Sea Surface Circulation in the Japan Sea 总被引：3，自引：0，他引：3
Composite sea surface dynamic heights (CSSDH) are calculated from both sea surface dynamic heights that are derived from altimetric data of ERS-2 and mean sea surface that is calculated by a numerical model. The CSSDH are consistent with sea surface temperature obtained by satellite and observed water temperature. Assuming the geostrophic balance, sea surface current velocities are calculated. It is found that temporal and spatial variations of sea surface circulation are considerably strong. In order to examine the characteristics of temporal and spatial variation of current pattern, EOF analysis is carried out with use of the CSSDH for 3.5 years. The spatial and temporal variations of mode 1 indicate the strength or weakness of sea surface circulation over the entire Japan Sea associated with seasonal variation of volume transport through the Tsushima Strait. The spatial and temporal variations of mode 2 mostly indicate the temporal variation of the second branch of the Tsushima Warm Current and the East Korean Warm Current. It is suggested that this variation is possibly associated with the seasonal variation of volume transport through the west channel of the Tsushima Strait. Variations of mode 3 indicate the interannual variability in the Yamato Basin. 相似文献
17.
冬季黄海暖流西偏机理数值探讨 总被引：1，自引：0，他引：1
利用海洋数值模式(MITgcm)模拟了冬季黄海流场并对冬季黄海暖流西偏的机理进行了探讨。冬季黄海流场模拟试验表明,黄海暖流由济州岛以西约32.5°N,125°E附近进入黄海,然后沿着黄海深槽西侧70 m等深线附近向北偏西运动;海面高度调整对黄海暖流路径具有重要影响,沿着黄海暖流路径的海面高度梯度比周围海区大,由海面高度梯度产生的地转流引起的北向体积输运占总的北向体积输运的78%。狭长海湾地形控制试验表明,单纯的黄海地形分布不足以引起黄海暖流西偏。黄海典型断面试验与渤海、黄海、东海地形控制试验说明,黄海暖流进入黄海的地理位置对流场分布有重要影响,黄海暖流进入黄海的位置恰好位于深槽西侧地形坡度较大区域,在位涡守恒的约束下黄海暖流受地形捕获沿70 m等深线附近向北偏西运动;试验还表明,黄海暖流进入黄海的位置与东海北部环流和地形分布有关,在冬季风的作用下东海北部环流的一部分沿着地形陡坡进入黄海形成黄海暖流。由此认为,黄海、东海环流在其特殊地形的约束下对冬季风的响应和调整,是引起黄海暖流西偏的主要原因。 相似文献
18.
A comparison of the contribution of zooplankton and nekton taxa to the near-surface acoustic structure of three Turkish seas 总被引：1，自引：0，他引：1
Erhan Mutlu 《Marine Ecology》2005,26(1):17-32
The bioacoustics of upper waters of the Black Sea, the Sea of Marmara, and the Mediterranean Sea were studied in October 1999 with an echosounder with 120 and 200 kHz dual‐beam transducers. Net tows were taken to ground‐truth the acoustic volume backscattering. A forward solution was applied to determine significant scatterers of the three seas with regard to detection limits of the frequencies and background noise measured in each sea. The noise was 4 dB higher in the Sea of Marmara than in the other two seas. 200 kHz data showed significant correlation between measured and calculated volume backscattering strength, and density (biomass and abundance) of the taxa. Large‐sized copepods and chaetognaths in the Black Sea, Aurelia, Beroe, chaetognaths and large‐sized and abundant appendicularians in the Sea of Marmara, and fish larvae in the Mediterranean Sea contributed most to the volume backscattering. 相似文献
19.
冬季南海上层环流动力机制的数值研究 总被引：13，自引：2，他引：13
通过利用一个分区性的正压-斜压衔接模式来探讨冬季南海的上层环流特征及其动力机制,结果表明:(1)在南海北部,流态主要受黑潮的影响,除了东沙群岛西南的大陆架海域以及吕宋岛北部西岸附近各为一反气旋涡外,整个南海北部为一气旋式大环流所控制.(2)在南海南部主要是风生环流,源自粤西沿岸的水体在东北季风的作用下顺南海西边界岸线向南流动,形成一支相当强的西边界流;同时,由于受北康暗沙以南的陆架坡底形效应和β效应的作用,使得在南海南部出现以一个反气旋涡在南沙海槽处产生、发展并向西传播乃至衰减的约50d的周期性过程 相似文献
20.
《Ocean Modelling》2004,6(1):83-100
A series of vertical mixing schemes implemented in a circumpolar coupled ice–ocean model of the BRIOS family is validated against observations of hydrography and sea ice coverage in the Weddell Sea. Assessed parameterizations include the Richardson number-dependent Pacanowski–Philander scheme, the Mellor–Yamada turbulent closure scheme, the K-profile parameterization, a bulk mixed layer model and the ocean penetrative plume scheme (OPPS). Combinations of the Pacanowski–Philander parameterization or the OPPS with a simple diagnostic model depending on the Monin–Obukhov length yield particularly good results. In contrast, experiments using a constant diffusivity and the traditional convective adjustment cannot reproduce the observations. An underestimation of wind-driven mixing in summer leads to an accumulation of salt in the winter water layer, inducing deep convection in the central Weddell Sea and a homogenization of the water column. Large upward heat fluxes in these simulations lead to the formation of unrealistic, large polynyas in the central Weddell Sea after only a few years of integration. Furthermore, spurious open-ocean convection affects the basin-scale circulation and leads to a significant overestimation of meridional overturning rates. We conclude that an adequate parameterization of both wind-induced mixing and buoyancy-driven convection is crucial for realistic simulations of processes in seasonally ice-covered seas. 相似文献