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1.
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
2.
泰国湾及邻近海域潮汐潮流的数值模拟 总被引：2，自引：0，他引：2
本文基于FVCOM(Finite-Volume Coastal Ocean Model)模式,模拟了泰国湾及其周边海域K1、O1、M2和S2四个主要分潮。采用47个验潮站实测调和常数与模拟结果进行比较,所得4个分潮的均方差分别为4.06cm、3.76cm、8.22cm和4.71cm,符合良好。根据计算结果分析了泰国湾及其周边海域的潮汐、潮流的分布特征和潮波的传播特征。数值试验表明,现有的数字水深资料(ETOPO1,ETOPO5,DBDB-V)的准确度不足以合理地模拟泰国湾潮波。 相似文献
3.
A three-dimensional isopycnic-coordinate internal tidal model is employed to investigate the generation,propagation, vertical structure and energy conversion of M2 internal tides in the Luzon Strait(LS) with mooring observations. Simulated results, especially the tidal current amplitudes, agree well with observations,demonstrating the reasonability and accuracy of the model. Results indicate that M2 internal tides mainly propagate into three directions horizontally, i.e., eastward towards the western Pacific Ocean, westward towards the Dongsha Island and southwestward towards the South China Sea Basin. In the horizontal direction, tidal current amplitudes decrease as distance increases away from the LS; in the vertical direction, they show an obvious decreasing tendency with depth. Between the double ridges of the LS, a clockwise gyre of M2 baroclinic energy flux appears, which is caused by reflections of M2 internal tides at supercritical topographies, and resonance of M2 internal tides happens along 19.5° and 21.5°N due to the heights and separation distance of the double ridges. The total energy conversion in the LS is about 14.20 GW. 相似文献
4.
南麂岛附近海域潮汐和潮流的特征 总被引：2，自引：2，他引：2
以2008年冬季在浙江近海南麂岛附近投放的4个底锚系观测的水位和流速资料为依据,分析了潮汐和潮流特征。水位谱分析结果显示半日分潮最显著,全日分潮其次;近岸的浅水分潮比离岸大。水位调和分析结果表明:潮汐类型均为正规半日潮,近岸处的平均潮差大于3m,最大可能潮差大于6m,潮汐呈现出显著的低潮日不等和回归潮特征。流速谱分析结果显示半日分潮流最强,全日分潮流其次,且比半日分潮流小得多;近岸浅水分潮流比远离岸显著。流速调和分析结果表明:潮流类型均为正规半日潮流,靠近岸的两个站浅水分潮流较显著;最显著的半日分潮流是M2分潮流,其最大流速介于0.32～0.48m/s之间,全日分潮流均很弱,最大流速小于0.06m/s。M2分潮流均为逆时针旋转,椭圆率越靠近海底越大;最大分潮流流速分布为中上层最大、表层略小、底层最小;最大分潮流流速方向的垂向变化很小,底层比表层略为偏左;最大分潮流流速到达时间随深度的加深而提前,底层比中上层约提前30min。潮流椭圆的垂向分布显示这里的半日分潮流以正压潮流为主;日分潮流则表现出很强的斜压性。 相似文献
5.
The tidal regime of Shark Bay, Western Australia 总被引：1，自引：0，他引：1
Murray C. Burling Charitha B. Pattiaratchi Gregory N. Ivey 《Estuarine, Coastal and Shelf Science》2003,57(5-6):725-735
A non-linear hydrodynamic model is used to describe the tidal dynamics of Shark Bay, Western Australia. The model is forced by tidal elevations generated by M2, S2, K1 and O1 constituent data at the open boundaries. The absence of suitable boundary data required a ‘calibration’ of the boundary condition against the known constituent data from within the model domain. The model provides a good match to the available field data, and allows the surface-level and current response to be resolved over the entire domain. Due to a near quarter-wave resonance of the semi-diurnal tide along the eastern Hopeless Reach, which increases the semi-diurnal tide by a factor of 2, the tidal characteristics on each of the Reaches are different: on the eastern Hopeless Reach the tides are mainly semi-diurnal while on the western Freycinet Reach the tides are mainly diurnal. The tidal range is also higher along Hopeless Reach. Tidal harmonics, generated by non-linearity, are important in the shallow regions. The tidal wave is shown to propagate as a progressive wave into the Bay. Substantial phase-lag, attenuation and dissipation occur over the Faure Sill, a major shallow region of the eastern reach of the Bay. Non-linear generation of the M4 and MS4 tides is also significant in this region. Depth-averaged residual currents are presented, which show a tidally generated circulation that is enhanced in regions of complex topography. Estimates of tidal dissipation indicate that although the total dissipation is small on a global scale, the areal average is comparable with the Gulf of Carpentaria and approximately one-quarter of the value estimated for the Patagonian Shelf. 相似文献
6.
本文通过建立一维水深平均悬沙模型,对典型潮流控制的水道内悬沙运动特征进行研究。模型以泥沙再悬浮、沉降和平流为主要物理过程,动力因素包含M2、S2分潮及余流,采用湄洲湾2007年8月潮位、潮流、悬沙、底质同步观测资料进行分析和验证。通过三角傅里叶分析,将悬沙的时间序列分解为12个主要的谐波分量,其中主要分量包括:M2分潮作用下产生的具有M2倍潮角速度的1/4日分潮项,M2与S2分潮共同作用下且角速度为两分潮角速度之和的1/4日分潮项,及水平悬沙梯度、余流与M2分潮共同作用下具有M2分潮角速度的半日潮项。悬沙在时间上的平均值受到余流、悬沙水平梯度、M2分潮流及悬沙起动条件等因素控制。余流导致了悬沙序列中相邻周期之间的不对称性。反映泥沙特性的参量对悬沙的曲线特征具有重要影响,泥沙沉降速度影响悬沙的相位,并影响其振幅;再悬浮有关的参量仅影响各谐波分量的振幅,但不影响相位。 相似文献
7.
Takeshi Matsuno 《Journal of Oceanography》1991,47(4):138-151
Analysis of current velocity and temperature records obtained from moored buoy systems deployed off the east coast of Japan
reveals the intermittent occurrence of semi-diurnal internal tides and their manner of propagation. The internal tidal waves
clearly propagate toward the shore, which is confirmed by cross-correlation of the onshore current velocity and temperature
between neighboring stations. The propagation speed of the internal tide increases with water depth except in the area furthest
offshore. In this area, motions near the second mode seem to occur occasionally, while in the nearshore area the motions for
the most part consist of the first mode.
Through harmonic analysis, it is shown that theM
1 internal motions were not vertically homogeneous. That is, the internal motions are greater at the lower level in the nearshore
area while they are greater at the upper level in the offshore area. Pathways along which the energy of the internal tide
should propagate are estimated in such a way that the characteristic curves pass through the area over which relatively large
onshore/offshoreM
2 velocity is distributed. The movement of the characteristic ray of a certain phase explains the observed phase velocity estimated
from the cross-correlation diagrams. Internal motions around the characteristic ray were pronounced in a rather wide area.
Thus, it is suggested that the generation region of the internal tide in the present study area might be relatively wide. 相似文献
8.
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
9.
《Deep Sea Research Part I: Oceanographic Research Papers》2007,54(4):533-556
ADCP measurements of the velocity structure in the permanent thermocline at two locations over the continental slope in the Bay of Biscay are presented. The vertical variation of the contribution of the inertia-gravity waveband to the kinetic energy, vertical motion, and current shear are analysed. The semi-diurnal tides together with near-inertial waves appear to provide over 70% of the high-frequency kinetic energy (>1/3 cpd). Over the vertical range of the ADCP observations the phase of the harmonic M2 tide changes up to 155°, while the kinetic energy varies in the vertical by a factor of 3.8, showing the importance of the contribution of internal waves to the observed tidal motion. Both semi-diurnal internal tidal waves and near-inertial waves have a vertically restricted distribution of the variance of the horizontal and vertical velocity, as in internal wave beams. The short-term 14-day averaged amplitude and phase lag of the M2 tide shows large temporal changes, with a characteristic 40–45 day time scale. These changes are probably related to variations in generation sites and propagation paths of the internal tide, because of changes in the temperature and salinity stratification due to the presence of meso-scale eddies. The relatively large shear in the inertia-gravity wave band, mainly at near-inertial frequencies, supports low-gradient Richardson numbers that are well below 1 for nearly half of the time. This implies that the large shear may support turbulent mixing for a large part of the time. 相似文献
10.
基于FVCOM(Finite Volume Coast and Ocean Model)模型,建立北印度洋海域(31°~102°E,16°S~31°N)的M2和S2分潮潮波数值模式,研究北印度洋半日潮潮汐、潮流分布特征。对底摩擦系数进行数值试验,利用代价函数梯度下降法,得到分潮调和常数向量均方根偏差(RMSE)的变化曲线,逼近并确定最优的底摩擦系数。将采用该系数的模拟结果与TOPEX/Poseidon卫星高度计交叉点的调和常数数据、国际海道测量组织(IHO)及部分文献中的验潮站数据进行比较与验证,一致性较好。其中对比卫星数据的振幅偏差为2~4 cm、迟角偏差为7°~8°,与验潮站数据的振幅偏差为3~6 cm、迟角偏差为8°~9°。根据模拟结果,分析了北印度洋海域M2和S2分潮潮波传播特征和潮流椭圆的空间分布特征等。M2分潮潮波在阿拉伯海南部有1个无潮点,在波斯湾内有2个无潮点,最大振幅超过80 cm;潮流在西北印度洋和孟加拉湾中部大多为顺时针旋转,其余海域大多为逆时针旋转;流速在阿拉伯海东北部、安达曼海、波斯湾和孟加拉湾北部较大,最大流速为160 cm/s,其他海域较小。S2分潮的潮波传播特征、无潮点的位置和潮流椭圆的空间分布特征等都与M2分潮类似,但潮波振幅和潮流流速等都相对M2分潮较小。研究完善了北印度洋海域2个主要半日分潮M2和S2的整体特征。 相似文献
11.
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
12.
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
13.
《Oceanologica Acta》1998,21(3):429-446
With the application of a two-dimensional nonlinear hydrodynamical-numerical semi-implicit model, the principal tides M2, S2, K2, N2, K1, P1 and O1 were studied. Energy budgets of the semi-diurnal M2 and S2 were calculated separately. The linear sum of these budgets was compared with the tidal energy budget obtained when these two tidal constituents interact. Since a quadratic form for the bottom friction was used, remarkable differences were found. The results show that in the area of the Colorado River delta, the dissipation of tidal energy is very strong. Intense tidal currents were observed in the same region and over the Salsipuedes Sill. Energy budgets calculated for forcing waves of different periods, but of the same amplitude, were used to estimate the principal periods of resonance. Although the topography of the Gulf is very complex, the model reproduced observed sea-surface elevation and current patterns. To study spring tide conditions, the above seven tidal constituents were simulated. Estimates of residual currents reveal the presence of several intense cyclonic and anticyclonic gyres. Over the Salsipuedes Sill, residual currents of the M2 tide reach values of more than 15 cm s−1. Horizontal distributions of dissipation rates of tidal energy and of kinetic energy were also obtained. 相似文献
14.
吕宋海峡由于剧烈变化的地形成为内潮产生的源地,内潮是海洋混合的重要原因。为了认知南海的内潮能通量分布,对南海的内潮有更好的理解,本文利用21世纪以来发射的多颗高度计卫星:J2、J1T、GFO以及EN,提取了吕宋海峡附近内潮的能通量。研究使用了调和分析和高通滤波等方法来提取第一模态内潮,主要提取K_1,K_2,M_2,N_2,O_1,P_1,Q_1和S_2八个分潮。同时结合WOA数据对能通量进行计算。结果表明,目标区域潮汐以全日分潮为主,所选区域的全日分潮中K_1所占比例最大;半日分潮中M_2分潮最强,而内潮的能通量则是M_2分潮所占最大,在吕宋海峡区域M_2能通量为6.45GW。内潮主要产生在地形变化剧烈的地方,海域的大部分地区内潮能量很小。在吕宋海峡中部,全日分潮能通量要小于南部地区,而半日分潮则有较大值。 相似文献
15.
16.
Numerical study of baroclinic tides in Luzon Strait 总被引：6，自引：1，他引：5
The spatial and temporal variations of baroclinic tides in the Luzon Strait (LS) are investigated using a three-dimensional
tide model driven by four principal constituents, O1, K1, M2 and S2, individually or together with seasonal mean summer or winter stratifications as the initial field. Barotropic tides propagate
predominantly westward from the Pacific Ocean, impinge on two prominent north-south running submarine ridges in LS, and generate
strong baroclinic tides propagating into both the South China Sea (SCS) and the Pacific Ocean. Strong baroclinic tides, ∼19
GW for diurnal tides and ∼11 GW for semidiurnal tides, are excited on both the east ridge (70%) and the west ridge (30%).
The barotropic to baroclinic energy conversion rate reaches 30% for diurnal tides and ∼20% for semidiurnal tides. Diurnal
(O1 and K1) and semidiurnal (M2) baroclinic tides have a comparable depth-integrated energy flux 10–20 kW m−1 emanating from the LS into the SCS and the Pacific basin. The spring-neap averaged, meridionally integrated baroclinic tidal
energy flux is ∼7 GW into the SCS and ∼6 GW into the Pacific Ocean, representing one of the strongest baroclinic tidal energy
flux regimes in the World Ocean. About 18 GW of baroclinic tidal energy, ∼50% of that generated in the LS, is lost locally,
which is more than five times that estimated in the vicinity of the Hawaiian ridge. The strong westward-propagating semidiurnal
baroclinic tidal energy flux is likely the energy source for the large-amplitude nonlinear internal waves found in the SCS.
The baroclinic tidal energy generation, energy fluxes, and energy dissipation rates in the spring tide are about five times
those in the neap tide; while there is no significant seasonal variation of energetics, but the propagation speed of baroclinic
tide is about 10% faster in summer than in winter. Within the LS, the average turbulence kinetic energy dissipation rate is
O(10−7) W kg− 1 and the turbulence diffusivity is O(10−3) m2s−1, a factor of 100 greater than those in the typical open ocean. This strong turbulence mixing induced by the baroclinic tidal
energy dissipation exists in the main path of the Kuroshio and is important in mixing the Pacific Ocean, Kuroshio, and the
SCS waters. 相似文献
17.
西北太平洋的一种潮汐数值同化模型 总被引：1，自引：1，他引：0
利用FVCOM海洋数值模式,在球坐标系统下考虑非线性效应和天体引潮力的影响,基于非结构的三角形网格建立了包括中国近海、日本海、鄂霍次科海和部分西北太平洋海域的高分辨率海洋潮汐数值模型,并采用趋近法同化84个沿岸验潮站的观测资料。模拟结果与175个验潮站的实测结果拟合良好,M2,S2,K1,O1四个主要分潮振幅和迟角的绝对平均误差分别为4.0 cm和5.6°,2.4 cm和7.5°,2.6 cm和6.3°,1.5 cm和5.0°。依据调和分析结果给出了4个主要分潮的同潮图分布,得到8个半日分潮和5个全日分潮的无潮点,证实了宗谷海峡全日潮无潮点的存在,首次模拟得到津轻海峡的全日潮无潮点;还给出了整个计算海域内最大可能潮差和潮汐余水位的分布特征。 相似文献
18.
Numerical simulation on diurnal and semidiurnal tidal currents is made for the eastern and southern parts of the East China Sea bounded by the Tsushima, islands of Kyushu and Ryukyu in the east and extending to the central Taiwan Strait in the south. The numerical computation shows that the rapid variation in the seabed topography near the Okinawa Trough may cause computational instability and this instability can be removed by setting a suitable lateral eddy viscosity. The computed results are in good agreement with the observations and indicate that the tidal currents in the greater part of the area studied rotate clockwise. An M2 current-amphidromic point exists in the southern part of the Korea Strait and another one appears in the west of Okinawa with less certainty. K1 and M2 cotidal charts based on the observed and computed tidal currents in the sea and the observed tides on the coast are also given. 相似文献
19.
We adopt a parameterized internal tide dissipation term to the two-dimensional (2-D) shallow water equations, and develop the corresponding adjoint model to investigate tidal dynamics in the South China Sea (SCS). The harmonic constants derived from 63 tidal gauge stations and 24 TOPEX/Poseidon (T/P) satellite altimeter crossover points are assimilated into the adjoint model to minimize the deviations of the simulated results and observations by optimizing the bottom friction coefficient and the internal tide dissipation coefficient. Tidal constituents M2, S2, K1 and O1 are simulated simultaneously. The numerical results (assimilating only tidal gauge data) agree well with T/P data showing that the model results are reliable. The co-tidal charts of M2, S2, K1 and O1 are obtained, which reflect the characteristics of tides in the SCS. The tidal energy flux is analyzed based on numerical results. The strongest tidal energy flux appears in the Luzon Strait (LS) for both semi-diurnal and diurnal tidal constituents. The analysis of tidal energy dissipation indicates that the bottom friction dissipation occurs mainly in shallow water area, meanwhile the internal tide dissipation is mainly concentrated in the LS and the deep basin of the SCS. The tidal energetics in the LS is examined showing that the tidal energy input closely balances the tidal energy dissipation. 相似文献
20.
为了研究人工鱼礁区基本水动力特征,本文利用人工鱼礁投放区的座底海床基获取半年以上的水动力观测资料,通过谱分析、调和分析、滤波等方法分析了该海区潮汐、潮流特征,并讨论了余流特征。结果表明,该海域属于不规则半日潮,具有显著的全日潮周期和半日潮周期,潮汐性质指数为0.98,平均潮差为0.95m,最大可能潮差为2.25m。潮流为典型的往复潮,潮流主向为NNE-SSW,优势分潮为M2分潮。垂向上,流速大小随深度增加显著降低,海底1m的流速较表层降低约30%,流向向沿鱼礁布设方向偏转。该海域余流较小,欧拉余流与斯托克斯余流大小相当,分别为1.35cm/s,1.41cm/s,均为向岸输运,欧拉余流表层受风影响较大,拉格朗日余流为2.76cm/s,方向SEE。该海域流场垂向结构与人工鱼礁投放后底摩擦增加、鱼礁对近底层水流的阻滞作用有关。底层温度具有显著的季节变化与日变化特征,短期高频变化存在显著的全日周期与半日周期,冬春季由于垂向混合加强,全日信号更为显著。底层浊度的升高主要由大风过程加强垂向混合的引起。 相似文献