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1.
Employing harmonic analysis of tidal data in the Taiwan Strait, the cross-strait tidal characteristics are completely illustrated. Based on the two dimensional mild-slope equation which can be reduced to the shallow-water wave equation, a finite element model (Tsay et al., 1989) is applied to investigate the characteristics of tides in the Taiwan Strait. The co-range and equi-phase charts of major tidal constituents, such as M2, S2, N2, and K1, are reproduced. Anomalous amplification of semidiurnal tides in the Taiwan Strait is verified. With rotation effects neglected and by applying a non-reflective condition on the open boundaries, the numerical results of phase-lag and co-range distributions show very good agreement with observed data for semidiurnal tides in the Taiwan Strait. Due to crude representation of the topography at two ends along the China coast, computed tidal distributions deviate from the observations. However, both computed amplitudes and phase-lags compare very well with observed data along the central half of the China coast. 相似文献
2.
北部湾潮波数值研究 总被引：9，自引：1，他引：9
利用普林斯顿海洋模式(POM08)建立了北部湾及其临近海区潮汐潮流数值模式,模拟了K1,O1,M2和S2这4个主要分潮,分析了模拟的潮汐和潮流分布特征,从潮波能量的角度讨论了琼州海峡对北部湾潮波系统的影响,并给出北部湾潮能的耗散情况。研究表明,北部湾是典型的全日潮海区,K1和O1分潮在南部湾口形成半个旋转潮波系统,无潮点位于越南顺安附近岸边。琼州海峡中的欧拉潮汐余流为西向流,潮余流造成的水通量约为0.034×106m3/s;余流出海峡西口后,先折向北,然后转向南流出湾外。研究海区中两个强潮流区分别位于琼州海峡和海南岛的西侧,同时这也是两个潮能的高耗散区。北部湾的潮能自南部湾口由外海传入,通过西口涌入琼州海峡,到达海峡东口时日潮波的能量已基本耗散殆尽,在海峡内耗散的4个分潮的潮能约为3.33 GW,相当于北部湾潮能耗散量的35%左右。数值试验表明,琼州海峡作为潮能耗散的重要海区,其存在对于北部湾潮波系统的形成具有较大影响。计算了底边界潮能耗散,结果表明在北部湾和琼州海峡,底边界耗散的潮能分别占该海区总耗散的83%和80%。 相似文献
3.
A combination of a three-dimensional hydrodynamic model and in-situ measurements provides the structures of barotropic tides,
tidal circulation and their relationship with turbulent mixing in the Java Sea, which allow us to understand the impact of
the tides on material distribution. The model retains high horizontal and vertical resolutions and is forced by the boundary
conditions taken from a global model. The measurements are composed of the sea level at coastal stations and currents at moorings
embedded in Seawatch buoys, in addition to hydrographic data. The simulated tidal elevations are in good agreement with the
data for the K1 and M2 constituents. The K1 tide clearly shows the lowest mode resonance in the Java Sea with intensification around the nodal point in the central region.
The M2 tide is secondary and propagates westward from the eastern open boundary, along with a counterclockwise amphidromic point
in the western part. The K1 tide produces a major component of tidal energy, which flows westward and dissipates through the node region near the Karimata
Strait. Meanwhile, the M2 tide dissipates in the entire Java Sea. However, the residual currents are mainly induced by the M2 tide, which flows westward following the M2 tidal wave propagation. The tidal mixing is mainly caused by K1 tide which peaks at the central region and is consistent with the uniform temperature and salinity along the vertical dimension.
This mixing is expected to play an important role in the vertical exchange of nutrients and control of biological productivity. 相似文献
4.
Semi‐diurnal tides in Cook Strait 总被引：2，自引：2，他引：0
R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(2):87-97
The phases and amplitudes of the M2 and S2 constituents of tidal elevation in Coiok Strait may be adequately described as an open mouth reflection of tidal waves advancing from the east and west coasts of New Zealand and reflecting near the latitudes of Titahi Bay and Cape Campbell (a distance of approximately 60 km). Other reflection conditions give amplitude and phase distributions different from those observed. Best fits to the observed phases and amplitudes for the M2 tide elevation arise from non‐rotational one‐dimensional solutions which allow for the bathymetry. If rotation is introduced in the form of Kelvin Wave solutions, the result is a two‐dimensional phase‐distribution pattern qualitatively similar to that observed, with the change in phase more rapid and the tidal amplitude smaller on the eastern than on the western side of Cook Strait. The solution for the S2 tide also fits closest to the observed tidal elevations for the non‐rotational one dimensional solution, but the introduction of rotation leads to a two‐dimensional phase‐distribution pattern qualitatively similar to that observed. The ratio of the amplitude of the wave (£) advancing from the northwest into Cook Strait to that (A) advancing from the southeast is substantially greater for the S2 (B/A = 11) than for the M2 (B/A = 2) tidal constituent and leads to the region of most rapid phase change for S2 being shifted further to the south than that for M2. 相似文献
5.
Takaki Hatayama 《Journal of Oceanography》2004,60(3):569-585
Numerical experiments with two-dimensional nonhydrostatic model have been performed to investigate tidally generated internal
waves at the Dewakang sill at the southern Makassar Strait where two large-amplitude “bumps” of relatively shallow water exist.
We investigate the effect of these features on vertical mixing, with emphasis on the transformation of the Indonesian throughflow
(ITF) water properties. The result shows that large-amplitude internal waves are generated at both bumps by the predominant
M2 tidal flow, even though the condition of the critical Froude number and the critical slope are not satisfied. The internal
waves induce such vigorous vertical mixing in the sill region that the vertical diffusivity attains a maximum value of 6 ×
10−3 m2s−1 and the salinity maximum and minimum core layers characterizing the ITF thermocline water are considerably weakened. Close
examination reveals that bottom-intensified currents produced mainly by the joint effect of barotropic M2 flow and internal tides generated in the concave region surrounding both bumps can excite unsteady lee waves (Nakamura et al., 2000) on the inside slopes of the bumps, which tend to be trapped at the generation region and grow into large-amplitude
waves. Such generation of unsteady lee waves does not occur in case of one bump alone. Trapping and amplification of the waves
in the sill region induce large vertical displacements (∼60 m) of water parcels during one tidal period, leading to strong
vertical mixing there. Since the K1 tidal currents are relatively weak, large-amplitude internal waves causing intense vertical mixing are not generated.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Abstract We evaluate a set of current measurements done in a section of the Strait of Juan de Fuca. The flow is of estuarine character, the upper layer flow usually being directed seaward. The RMS value of steady current exceeds its mean value appreciably in the upper layer; it also exceeds the mean near the bottom. The near‐surface currents do change their direction on occasions and can run landward for over five consecutive days, especially in the southern part of the channel. The lower layer flow (landward) and the upper layer flow (seaward) varied in magnitude from 90 to 160 thousand m3/sec, and their fluctuations were in phase; their difference, the net flow, is of the order of 5% to 10% of these flows and could not be calculated with any confidence. Tidal motion is barotropic in the section, with some deformation in the vertical caused by bottom friction and internal stresses. The M2 tide in the system Juan de Fuca‐Georgia Strait can be represented by a standing Kelvin wave influenced by friction. The K1 tide can also be represented by a standing Kelvin wave if some leakage is allowed in the northern end of Georgia Strait. Topographic effects mask the Coriolis influence on the intensity of tidal currents. 相似文献
7.
Tomoharu Senjyu Hidekazu Yasuda Shigehiko Sugihara Masato Kamizono 《Journal of Oceanography》2001,57(1):15-27
A hydrographic survey and a 25-hour stationary observation were carried out in the western part of Suo-Nada in the summer of 1998 to elucidate the formation mechanism of the oxygen-deficient water mass. A steep thermocline and halocline separated the upper layer water from the bottom water over the observational area except for near the Kanmon Strait. The bottom water, in comparison with the upper layer water, indicated lower temperature, higher salinity, lower dissolved oxygen, higher turbidity, and higher chlorophyll a. Turbidity in the upper layer water changed with semi-diurnal period while the bottom water turbidity showed a quarter-diurnal variation, though the M2 tidal current prevailed in both waters. From the turbidity distribution and the current variation, it is revealed that the turbidity in the upper layer water is controlled by the advection due to the M2 tidal current. On the other hand, the quarter-diurnal variation in the bottom water turbidity is caused by the resuspension of bottom sediments due to the M2 tidal current. The steep thermocline and halocline were maintained throughout the observation period in spite of the rather strong tidal currents. This implies an active intrusion of the low temperature and high salinity water from the east to the bottom of Suo-Nada. Based on the observational results, a hypothesis on the oxygen-deficient water mass formation was proposed; the periodical turbidity variation in the bottom water quickly modifies the oxygen-rich water in the east to the oxygen-deficient bottom water in Suo-Nada in a course of circulation. 相似文献
8.
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
9.
A unique, five-year long data set of ferry-mounted ADCP measurements in the Marsdiep inlet, the Netherlands, obtained between 1998 and 2003, is presented. A least-squares harmonic analysis was applied to the water transport, (depth-averaged) currents, and water level to study the contribution of the tides. With 144 tidal constituents, maximally 98% of the variance in the water transport and streamwise currents is explained by the tides, whereas for the stream-normal currents this is maximally 50%. The most important constituent is the semi-diurnal M2 constituent, which is modulated by the second-largest S2 constituent (about 27% of M2). Compound and overtides, such as 2MS2, 2MN2, M4, and M6, are important in the inlet. Due to interaction of M2 with its quarter-diurnal overtide M4, the tidal asymmetry in the southern two thirds of the inlet is flood dominant. The amplitudes of all non-astronomic constituents are largest during spring tides, strongly distorting the water level and velocity curves. The M2 water transport is 40° ahead in phase compared to the M2 water level, reflecting the progressive character of the tidal wave in the inlet. The currents are strongly rectilinear and they are sheared vertically and horizontally, with the highest currents at the surface above the deepest part of the inlet. During spring tides, near-surface currents can be as large as 1.8 m s− 1. Due to the relative importance of inertia compared to friction, the M2 currents near the centre (surface) lag maximal 20° (3°) in phase with the currents near the sides (bottom). The tidal-mean currents are directed into the basin in the shallower channel to the south and out of the basin in the deeper channel to the north. 相似文献
10.
The tidal volume transport in the Seto Inland Sea is calculated. The cross-section where the volume transport of the M2 tide is zero, is located around the western part of Bisan Strait. The tidal energy dissipation of the M2 tide by friction is 6.30×1016 ergs s–1 in the Seto Inland Sea. The quality factorQ for the M2 tide is 20.2. The total energy dissipation of the M2, S2, K1 and O1 tides is 7.99×1016 ergs s–1. 相似文献
11.
中国陆架潮流沉积体系和模式 总被引：27，自引：1，他引：26
在1991年中法合作渤海潮流沉积研究的基础上,查阅了国内外有关研究成果,分析了中国陆架的水深地形、沉积地貌与潮流动力的关系,认为潮流对中国陆架的海底地貌和沉积的形成发育起了主导作用。当潮流流速大于3节时,潮流的侵蚀作用是主要的,往复潮流多形成冲刷深槽,大大刷深了海峡或水道。当潮流流速1－3节时,潮流的沉积作用是主要的,多形成浅滩,即潮流沙脊和潮流沙席。以M2分潮椭率绝对值0．4为界,大于0．久者意味着潮流旋转性强,多形成潮流沙席;小于0．4者意味着潮流往复性强,多形成潮流沙脊。提出了我国邻近陆架发育了5个现代潮流沉积地貌体系：（1）黄海东部潮流沉积体系,它由西朝鲜湾潮流沙脊和其南部的沙席两者组成;（2）渤海东部潮流沉积体系,它由老铁山水道冲刷槽,辽东浅滩沙脊和渤中浅滩沙席三者组成;（3）长江口外潮流沉积体系,它由江苏滨外潮流沙脊和长江口浅滩潮流沙席组成;（4）台湾滨外潮流沉积体系,它由台湾海峡冲刷槽、台湾浅滩沙脊、澎湖水道冲刷槽和台中浅滩沙席四者组成;（5）琼州海峡潮流沉积体系,它由琼州海峡冲刷槽、东浅滩沙脊和西浅滩沙脊三者组成。此外,在东海陆架上还有冰后期海侵早期形成的残留潮流沉积体系。全新世陆架浅海潮流沉积模式可分海峡一浅 相似文献
12.
胶州湾水交换及湾口潮余流特征的数值研究 总被引：5，自引：3，他引：5
利用基于普林斯顿海洋模式建立的胶州湾及临近海域潮汐潮流数值模型,结合胶州湾口走航式声学多普勒海流剖面仪(ADCP)测流资料,研究了胶州湾口的潮(余)流特征,并在潮流模型的基础上耦合建立了水质模块,模拟了胶州湾的水交换过程。考虑M2,S2,K1,O1,M4和MS4六个主要分潮,胶州湾口潮流场的模拟与ADCP观测数据吻合较好。外湾口水道上的潮流非常强,大潮期间观测到201 cm/s的峰值流速。团岛岬角的两侧分别存在一个流向相反的余流涡旋,两涡旋在团岛附近辐合,形成了57 cm/s的离岸强余流。整个胶州湾平均水体存留时间为71 d,平均半交换时间为25 d。胶州湾水体交换能力在空间分布上有很大差异:湾口海域最强,向湾顶逐渐减弱。湾内存在两个弱交换区,分别位于湾的西-西南部和东北端,水体存留时间多超过80 d,湾西局部水域最长达120 d,而半交换时间也大多超过40 d。潮流场的结构、强度,以及与湾口距离的远近是造成湾内水交换能力空间差异的主要原因。 相似文献
13.
The characteristics of currents and tidal currents in the Andaman Sea(AS) are studied during the second half of2016 using observed data from a moored acoustic Doppler current profiler(ADCP) deployed at 8.6°N, 95.6°E.During the observation period, the mean flow is 5–10 cm/s and largely southward. The root mean square and kinetic energies of the low and high frequency flows, which are divided by a cutoff period of 5 d, are at the same level, indicating their identical importance to the total current. A power spectrum analysis shows that intraseasonal oscillations, a tidal-related semilunar month signal, a semidiurnal tidal signal and periods of 3–4 d are prominent. The barocliny of an eddy kinetic energy is stronger than the mean kinetic energy, both of which are the strongest on the bottom and the weakest at 70 m depth. Residual currents are largely southward(northward) during the summer(winter) monsoon season. Two striking peaks of the southward flow cause the 80 d period of meridional currents. The first peak is part of a large-scale circulation, which enters the AS through the northern channel and exits through the southern channel, and the second peak is part of a local vortex. The 40 d oscillation of the zonal current is forced by geostrophic variations attributed to local and equatorial remote forcing. The tidal current is dominated by semidiurnal constituents, and among these, M2 and N2 are the top two largest major axes. Moreover, astronomical tidal constituents MM and MSF are also significant. Diurnal constituents are weak and shallow water tides are ignorable. The aims are to introduce the new current data observed in the AS and to provide initial insights for the tidal and residual currents in the Andaman Sea. 相似文献
14.
During 1999–2000, 13 bottom mounted acoustic Doppler current profilers (ADCPs) and 12 wave/tide gauges were deployed along two lines across the Korea/Tsushima Strait, providing long-term measurements of currents and bottom pressure. Tidally analyzed velocity and pressure data from the moorings are used in conjunction with other moored ADCPs, coastal tide gauge measurements, and altimeter measurements in a linear barotropic data assimilation model. The model fits the vertically averaged data to the linear shallow water equations in a least-squares sense by only adjusting the incoming gravity waves along the boundaries. Model predictions are made for the O1, P1, K1, μ2, N2, M2, S2, and K2 tides. An extensive analysis of the accuracy of the M2 surface-height predictions suggests that for broad regions near the mooring lines and in the Jeju Strait the amplitude prediction errors are less than 0.5 cm. Elsewhere, the analysis suggests that errors range from 1 to 4 cm with the exception of small regions where the tides are not well determined by the dataset. The errors in the model predictions are primarily caused by bias error in the model’s physics, numerics, and/or parameterization as opposed to random errors in the observational data. In the model predictions, the highest ranges in sea level height occur for tidal constituents M2, S2, K1, O1, and N2, with the highest magnitudes of tidal velocities occurring for M2, K1, S2, and O1. The tides exhibit a complex structure in which diurnal constituents have higher currents relative to their sea level height ranges than semi-diurnal constituents. 相似文献
15.
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16.
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
17.
The fortnightly and monthly variability of the exchange through the Strait of Gibraltar has been studied from two simultaneous five-month long moored datasets, at Camarinal Sill and the East Section. The study focuses on the Msf and Mm tidal components and their role for the subinertial exchange. A significant monthly signal is observed in the upper layer transport. Also, a significant fortnightly signal is observed in the lower layer transport, which minimum (maximum flow toward the Atlantic) takes place approximately on spring tides. In consequence the net transport has both signals, with maximum taking place during neap tides and a small monthly inequality. Fortnightly and monthly variability in the interface depth is also observed at Camarinal Sill, the interface being deeper on neap and shallower on spring tides. At the East Section the interface depth signals are not significant.The subinertial variability of the transports is separated in two contributions. The first one is called quasistatic transport and arises from the subinertial fluctuations of currents. The second contribution, called tidally rectified transports, arise from the non-linear correlation of currents and interface depth at tidal frequencies. The tidally rectified transports are important at Camarinal but not at the East Section. An apparent contradiction between the fortnightly signals of the subinertial currents and subinertial transports is resolved when the fortnightly signal of the tidally rectified transports are considered. The fortnightly signal of the quasistatic and tidally rectified transports mutually cancel in the upper layer, but not in the lower layer where the rectified transports dominate. A simple model for the spring-tide mixing forcing accounts for the fortnightly variability of the lower layer quasistatic transports but underestimates it for the upper layer. Finally, the observed lower layer transport is compatible with the hydraulic control condition at Camarinal Sill except for certain periods during intense spring tides. 相似文献
18.
A vertically integrated 2D numerical model was developed for the simulation of major tidal constituents (M2, S2, N2, K1 and O1) in the Bay of Bengal. The bathymetry for the model domain was derived from an improved ETOPO5 dataset prepared in our earlier work. The simulated tidal elevations showed good agreement with the hourly tide gauge observations at Paradip, Visakhapatnam, and Chennai. The amplitudes and phases of M2, S2, K1, and O1 at the coastal stations, obtained from harmonic analysis of simulated tides, were found to agree well with those obtained from Admiralty Tide Tables with the RMS misfit 9.2, 5.6, 2.9 and 3.1 cm, respectively. In the Bay of Bengal, semi-diurnal tides (M2, S2, and N2) attain highest amplitudes (180, 80, 30 cm, respectively) in the Gulf of Martaban while amplitudes of diurnal tides (K1, O1) reaches maximum (20, 12 cm, respectively) in the Malacca Strait. The continental shelf in the head bay and along the southern coast of Myanmar is about 200 km wide and the amplitudes of semi-diurnal tides are doubled in these regions while the diurnal tides amplify only marginally, which is consistent with Clarke and Battisti theory. In the north eastern end of the head bay and the Gulf of Martaban, the geometrical configuration of the coastline, in addition to the wide continental shelf, could contribute to the amplification of both semi-diurnal and diurnal constituents. In the Malacca Strait, the amplitudes of both semi-diurnal and diurnal tides are found to increase gradually from the northern end to the 2.5°N and decreases towards southern boundary. The co-tidal and co-range charts of M2 and S2 tidal constituents also show the presence of two degenerate amphidromic points in the head bay. A virtual amphidromic point for M2 is identified in the Malacca Strait. 相似文献
19.
In order to re-evaluate the water volume exchange through Naruto Strait, we have performed a numerical experiment (nonlinear barotropic model including the actual depth of water and the details of shoreline) where trajectories of a number of labeled particles are calculated during a full cycle of the M2 tidal current. The ratio of water volume exchanged through Naruto Strait to that through Akashi Strait is found to be twice as large as the previously estimated value. The calculated water exchange rate is 104 % for Naruto Strait, 52 % for Akashi Strait and 28 % for Kitan Strait. In the case where the tide-induced residual current is excluded from the calculated velocity field (i.e. considering only the M2 current), the calculated exchange rate maintains the level of 68 % for Naruto Strait, 18 % for Akashi Strait and 11 % for Kitan Strait, respectively. The mechanism of tidal exchange through these three straits is discussed, and it is shown that a suitable exchange rate is obtained by starting the calculation of trajectories of labeled particles at the time of either a maximum ebb- or flood-current. 相似文献
20.
Three-dimensional structure of tidal current in the East China Sea and the Yellow Sea 总被引：9，自引：0，他引：9
A three-dimensional tidal current model is developed and applied to the East China Sea (ECS), the Yellow Sea and the Bohai
Sea. The model well reproduces the major four tides, namely M2, S2, K1 and O1 tides, and their currents. The horizontal distributions of the major four tidal currents are the same as those calculated
by the horizontal two-dimensional models. With its high resolutions in the horizontal (12.5 km) and the vertical (20 layers),
the model is used to investigate the vertical distributions of tidal current. Four vertical eddy viscosity models are used
in the numerical experiments. As the tidal current becomes strong, its vertical shear becomes large and its vertical profile
becomes sensitive to the vertical eddy viscosity. As a conclusion, the HU (a) model (Davieset al., 1997), which relates the vertical eddy viscosity to the water depth and depth mean velocity, gives the closest results to
the observed data. The reproduction of the amphidromic point of M2 tide in Liaodong Bay is discussed and it is concluded that it depends on the bottom friction stress. The model reproduces
a unique vertical profile of tidal current in the Yellow Sea, which is also found in the observed data. The reason for the
reproduction of such a unique profile in the model is investigated. 相似文献