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1.
Cornelia Saukel Rüdiger Stein Christoph Vogt Vladimir P. Shevchenko 《Geo-Marine Letters》2010,30(6):605-616
In this study, the grain-size and clay-mineral compositions of 73 surface sediment samples collected in a variety of environmental
settings in the White Sea are presented to characterize recent sedimentation processes, reconstruct transport pathways, and
identify potential source areas of the terrigenous components. Areas >100 m deep are invariably characterized by silty clay,
whereas areas <100 m deep exhibit more heterogeneous grain-size compositions plausibly explained by coastal erosion and (re-)distribution
mechanisms, particularly tidal currents. The dominance of sand in the estuarine areas of the Onega and Dvina rivers as well
as toward the Gorlo Strait connecting the White Sea with the Barents Sea is attributed to increased current speeds. Illite
and smectite are the dominant clay minerals in recent sediments of the southwestern and eastern White Sea sectors, respectively.
Their distribution patterns largely depend on the geology of the source areas, and mirror surface circulation patterns, especially
in Dvina Bay. Smectite is a key clay mineral in White Sea surface sediments, as it reveals the dominating influence of the
Northern Dvina’s runoff on sedimentation and water circulation throughout the basin. In comparison to other Eurasian shelf
seas, the White Sea is characterized by a greater diversity of clay-mineral assemblages, which range from illite- to smectite-dominated
sectors containing variable amounts of chlorite and kaolinite. 相似文献
2.
Takashige Sugimoto 《Journal of Oceanography》1975,31(1):1-14
The effects of the coastal boundary geometries on the tidal currents and the tidal mixing are studied mainly on the basis of hydraulic model experiments. Mizushima-Nada Sea, which is located in the central part of Seto Inland Sea, and the whole Seto Inland Sea were chosen as the prototypes.Currents and eddies geometrically induced in the tidal currents and in the ocean currents have significant effects on the water exchange, from small scales to meso scales, in the bays and near-shore regions of the ocean.As to small scale phenomena near irregular coastal boundaries such as river mouths, headlands and harbors, tidal currents produce organized eddy currents of the width scale. They are important to the temporary flushing and the local redistribution of the river water or the waste water.As to phenomena of larger scales, the tidal currents produce rather steady residual circulations in each part of the Inland Sea, due to the non-linear effects of the oscillating component. They are controlled by the geometry of the sea as separated by a narrow strait. These horizontal circulations of about 20 km in scale become the main mechanism of the water exchange in the Inland Sea. The one-dimensional dispersion coefficient due to these circulations is proportional to the product of the diameter and the current velocity of the circulations. The proportional constant takes the value of 0.40.5. 相似文献
3.
古长江河口湾充填潮流作用机制的初步探讨 总被引：10，自引：0，他引：10
长江三角洲的发育是以古长江河日湾的充填来实现的.研究潮汐、潮流在古长江河口湾充填中所起的作用,可深入了解长江三角洲的形成发育过程.建立了渤海、黄海、东海的二维潮流数学模型,数值模拟了冰后期最大海侵,即现今长江三角洲地区为巨大河口湾时的M2潮汐、潮流.在此基础上,计算了古长江河口湾及其周围海域8种粒径泥沙的潮平均悬移与推移输沙率,并根据输沙率散度的正负,划分了海底冲刷区与淤积区.根据计算结果得出,冰后期最大海侵时,存在大致以古长江河口湾湾口中点为腹点、波腹线向海凸起的独特驻潮波波腹区.在其控制下,外海潮流大致以古长江河口湾湾口中点为顶点作辐聚、辐散运动.在古潮流场作用下,经历每一个潮周期后,古长江河口湾周围海域的泥沙均向河口湾内净输运,并在河口湾内淤积.古长江河口湾的充填是在长江带来大量泥沙,外海的潮汐、潮流又有利于泥沙向河口湾内净输运,且在河口湾内沉积的情况下实现的.外海的潮汐、潮流为古长江河口湾的充填、长江三角洲的发育提供了必要而又有利的水动力环境. 相似文献
4.
Floating seaweeds and associated fauna in Kandalaksha, Onega, and Dvina bays and in the Gorlo of the White Sea were studied. The bulk of the drifting objects were composed of various algae of the Fucus, Chorda, and Chordaria genera. In these drifting communities, 82 different animal and plant species were encountered. The drifting objects were most abundant in Kandalaksha and Onega bays. The minimal abundances were detected in the Gorlo and in Dvina Bay. The total abundance and biomass of the drifting seaweeds and animals were estimated as 25.5 million individuals and 24.2 thousand tons, respectively. The role of the phenomenon considered in the distribution of the animals and seaweeds and in the balance of matter and energy in the White Sea is discussed. 相似文献
5.
The Bohai Strait is the only passage-way of the semienclosed Bohai Sea into the outer ocean. The various dynamical processes have great effects on both sides of the strait, especially on the Bohai Sea. Tidal current dominates in the strait, and among the tida! components the M, component tide is prevailing.The seawater in the strait is homogeneous vertically almost the whole year because of strong tidal mixing. The M, component tide was simulated numerically using two dimensional barotropical model, and the Eulerian tide-induced residual currents were also deduced. The results showed that the tidal currents were dominated by the coastal line and topography. There exist many eddies in the tide-induced residual current fields, particularly near the northern coast.On the basis of the simulation of the tidal currents, the movements of the water particles in the strait were tracked by means of Lagrangian techniques. Consequently the Lagrangian residual currents were obtained. Somewhat similar to the Eulerian 相似文献
6.
A. V. Zimin I. E. Kozlov O. A. Atadzhanova B. Chapron 《Izvestiya Atmospheric and Oceanic Physics》2016,52(9):951-960
Widespread short-period internal wave (SPIW) activity in the White Sea has been revealed for the first time based on long-term (2009–2013) monitoring performed using satellite and in situ observations, and the statistical characteristics of these waves have been obtained. Two main regions where short-period waves constantly exist have been identified: the shelf area near the frontal zone at the boundary between the Basin and the Gorlo Strait and the shallow shelf area where the depths are about 30–50 m near Solovetskie Islands. Intense internal waves (IIWs), which are substantially nonlinear and are related to specific phases of a barotropic tide, are regularly observed near frontal zones. The wave height can reach half the sea depth and the wave periods vary from 7 to 18 min. 相似文献
7.
南黄海西侧的江苏海岸近岸区域,素以地形复杂、潮流强劲、悬沙输运剧烈著称,但是较长期的同步潮位和潮流观测数据仍然缺乏,尤其是在近岸(20 km)浅水(20 m)区域。2014年1月在大丰港附近开展了连续潮位和潮流观测,获得的数据揭示了一系列特征。此地潮汐潮流为正规半日潮,浅水分潮显著。平均潮差为3.05 m,最显著的两个分潮为M2和S2分潮,振幅分别为1.45 m和0.52 m。潮流最显著的半日分潮M2分潮和最显著的浅水分潮M4分潮在沿岸方向上振幅分别为0.84m/s和0.12m/s,在跨岸方向上振幅分别为0.24 m/s和0.01 m/s,沿岸方向占绝对优势。潮波的沿岸传播介于前进波和驻波之间,驻波的特征稍强。M2分潮潮流椭圆最大流(长轴)方向为南偏东7.4°。存在冬季沿岸向北的余流,垂向平均值的大小为2.2 cm/s。以上潮汐潮流特征为该区域海洋物质输运研究提供了基础资料。 相似文献
8.
Internal tide is one of the major oceanic phenomena. Determination of internal tide is important for theoretical study and for ocean engineering research. As an inverse problem, extraction of internal tidal currenls from sea currents is diffi-cult. In this paper, a method is developed to extract internal tidal currents from a portion of the sea current profile based on the fact that the directions of internal tidal currents above and below the thermocline are inverse. Sea current data col-lected from the South China Sea is processed with this method. The internal tidal currents and the depth of the thermocline are successfully extracted. The depth of the thermocline determined is in good agreement with that measured in 1959. 相似文献
9.
The mean multiannual temperature regime of the surface water layer in the near-shore regions of the White Sea is analyzed from the data obtained at the VNIIGMI-MTsD (Obninsk). A function describing the seasonal temperature trend in the surface layer was found by the method previously used for an analysis of the Onega and Ladoga lakes. The method is based on the nonlinear approximation of the field observations by a function composed of a combination of exponents with coefficients to be calculated. Explicit seasonal dependences of the mean temperature of the surface water layer in the White Sea were obtained for nine near-shore stations. The root-mean-square deviations of the measured values of the water temperature were estimated. 相似文献
10.
Takashige Sugimoto 《Journal of Oceanography》1976,32(6):297-304
I feel greatly honored to have recieved the Okada Prize of the Oceanographical Society of Japan this time. I would like to express many thanks to my teachers, and to members of our society, for their kindness provided to me up to the present.Here I have presented some of my studies which are mostly still under way. First I have presented my idea about the study on the near-shore oceanographic processes. Secondly, I have discussed about the significance and the similitude of the hydraulic model experiment, including the model experiment on the tidal mixing. Thirdly, my study on the near-shore oceanographic processes mainly by use of the hydraulic model experiment have been told. They are the effect of boundary geometries on the tidal currents and tidal mixing, the formation processes of the tidal residual circulations, the role of the air-sea boundary processes on the water-mass formation in semi-closed bays and the effect of boundary geometries on the intrusion of salt-wedge. 相似文献
11.
L. V. Ilyash I. G. Radchenko V. P. Shevchenko A. P. Lisitzin V. T. Paka V. I. Burenkov A. N. Novigatskiy A. L. Chul’tsova A. N. Pantyulin 《Oceanology》2011,51(6):993-1003
The species composition and biomass of the phytoplankton, as well as the hydrophysical and hydrochemical characteristics of
the water masses, were estimated for different areas of the White Sea at 24 stations for the period of August 26 to September
3, 2007. The micronutrient concentrations were lower compared to the average long-term values for the summer period. The total
biomass of phytoplankton (B
t
) varied from 87 to 1914 mg C/m2. For most of the studied sites, B
t
was low; dinoflagellates were the most abundant species. Diatoms dominated in the areas of elevated hydrodynamic activity,
i.e., in the Gorlo (vertical mixing of the water layers), in intrusions of the Gorlo water masses into the basin of the White
Sea, and in the peripheral areas of the Dvina outflow current. The B
t
was also the highest in the listed areas. 相似文献
12.
Internal tide is one of the major oceanic phenomena. Determination of internal tide is important for theoretical studyand for ocean engineering research. As an inverse problem, extraction of internal tidal currents from sea currents is diffi-cult. In this paper, a method is developed to extract internal tidal currents from a portion of the sea current profile basedon the fact that the directions of internal tidal currents above and below the thermocline are inverse. Sea current data col-lected from the South China Sea is processed with this method. The internal tidal currents and the depth of the thermo-cline are successfully extracted. The depth of the thermocline determined is in good agreement with that measured in 1959. 相似文献
13.
A. V. Zimin 《Oceanology》2013,53(3):259-268
Experimental data obtained in the summer of 2011 in three White Sea continental shelf areas with different stratification are analyzed. The measurements were conducted using a unified procedure that combines frequent oceanographic stations (scanning) and deployment of moorings. It is shown that the tide-induced variability of the thermohaline fields and internal waves is of different types. A shelf area is detected where intense short-period internal waves are observed during every tidal cycle and their contribution to water mixing is significant. 相似文献
14.
15.
《Marine Geology》2005,216(4):239-247
The Ayeyarwady continental shelf is a complex sedimentary system characterized by large sediment influx (> 360 million ton/yr), a wide shelf (> 170 km), a strong tidal regime (7 m maximum tidal range), and incised by the Martaban Canyon. Grain size distribution on the Ayeyarwady shelf reveals three distinct areas in terms of sediment texture (i) a near-shore mud belt in the Gulf of Martaban and adjacent inner shelf (ii) outer shelf relict sands and (iii) mixed sediments with varying proportions of relict sand and modern mud in the Martaban Canyon. The bulk of the terrigenous sediment discharged by the Ayeyarwady River is displaced eastwards by a combination of tidal currents and clockwise flowing SW monsoon current and deposited in the Gulf of Martaban resulting in shoaling of its water depths. Part of the sediment discharge reaches the deep Andaman Sea via the Martaban Canyon and the rest is transported westward into the Bay of Bengal by the counter-clockwise flowing NE monsoon currents. 相似文献
16.
David Prandle 《Progress in Oceanography》1991,27(3-4)
Since 1984 the OSCR HF Radar system has been used in over 50 deployments to measure near-shore surface currents for both scientific and engineering applications. The enhanced scope, resolution and accuracy of these measurements have yielded new insights into the tidal, wind and density driven dynamics of the near-shore zone.Tidal current ellipses obtained from these radar measurements have been shown to be in good aggrement with values calculated by numerical models both for the predominant constituents and also for higher harmonics. Coherent patterns of wind-forced currents ahve been determined with strong evidence of a “slab-like” surface response. In one deployment, with offshore winds blowing over relatively deep water, this “slab” rotated clockwise at near-inertial frequency. Strong (up to 20cm s−1), persistent surface residual currents are commonly observed, these are almost certainly generated by (small) horizontal density gradients. These observed surface residuals provide ideal data for rigorous testing of 3-D numerical models.With a threatened rise in sea level, HF Radar is well-suited for observing the expected changes in the dynamics of near-shore regions. Continuing development of these radar systems offers exciting prospects of remote sensing of both surface waves and currents. Future applications may extend beyond the near-shore region to measurements along the shelf-edge, in oceanic gyres and for “beach-processes”. 相似文献
17.
Model estimates for the interaction of wind waves and tides in the Pechora Basin-White Sea subsystem
The “weak-interaction” approximation is used to investigate the role of wind waves in tidal dynamics. The resulting expression for the drag coefficient in the wave-affected tidal flow is incorporated into the QUODDY-4 three-dimensional finite-element hydrothermodynamic model, and the thus modified model is used to calculate the K 1 diurnal tide in the Pechora Basin-White Sea subsystem. It is shown that, depending on a combination of local and nonlocal factors, wind waves can cause opposite variations in the amplitudes and phases of tidal oscillations of the level. Local factors control variations in the tidal regime nearly in the entire water area of the subsystem under consideration, apart from the eastern part of the Pechora Basin, the outlet from the White Sea Throat, and Dvina Bay. In the aforementioned areas, the tidal regime changes are due either to the displacement of the nearest amphidromy or to other nonlocal factors resulting from the reorganization of the fields of tidal characteristics. It is also shown that the variations in tidal characteristics induced by wind waves vary within a fairly wide range and that allowance for the interaction of wind waves and tides improves the agreement between calculated and observed values of the amplitudes and phases of tidal oscillations of the level. 相似文献
18.
An improved method of two-dimensional kinematical structural analysis of tides (the “method of the orbits”) is presented.
This method allows us to determine the parameters of the primary tidal waves shaping the observed tidal structure. The construction
of the vertical orbits for the individual tidal harmonics is performed along the horizontal coordinate axes; one of them is
oriented along the so-called “reactive azimuth,” which coincides with the direction of the tidal current at the instant of
the zero tidal level. In this case, the orbit parameters include information on the amplitude-phase relations of the interfering
waves and allow us to determine the angle of the waves crossing. The suggested method enables us to quantitatively describe
the mechanism of the tidal formation with oblique interference both close to the shore and in the open sea. We tested the
new method in two local zones of the White Sea (Morzhovets Island and in the vicinity of the entrance to Kandalaksha Gulf)
where the presence of rotating semidiurnal tidal currents evidences the significant role of oblique interference of tidal
waves. In these zones, the developed method made it possible to perform a detailed quantitative analysis of the local tide
structure caused by the M2 tidal wave, which plays the dominant role in the White Sea. The result describes the structure of the propagation of the
primary tidal waves better than the field of “pure” energy fluxes that was used earlier. 相似文献
19.
We observed strong internal tidal waves in the Kara Gates Strait. Internal tides are superimposed over a system of mean currents from the Barents to the Kara Sea. Field studies of internal tides in the Kara Gates were performed in 1997, 2007, and 2015. In 2015, we analyzed data from towed CTD measurements, numerical model calculations, and satellite images in the region. An internal tidal wave with a period of 12.4 h is generated due to the interaction between the currents of the barotropic tide and the bottom relief on the slopes of a ridge that crosses the strait from Novaya Zemlya to the continent. The depths of the ridge crest are 30–40 m. A constant current of relatively warm water flows from the Barents to the Kara Sea. An internal wave propagates in both directions from the ridge. In the Barents Sea, internal waves are intensified by the current from the Barents to the Kara Sea. Internal bores followed by a packet of short-period internal waves are found in both directions from the strait. Satellite images show that short-period internal waves are generated after the internal bore. A hydraulic jump was found on the eastern side of the strait. Numerical modeling agrees with the experimental results. 相似文献