共查询到20条相似文献，搜索用时 31 毫秒
1.
通过象山港水域的潮波运动数值模拟,分析了象山港M4分潮的生成和增长机制．结果说明,潮波传播中的非线性底摩擦效应是M4分潮生成和增长的主要控制因子,M4分潮在湾内的共振现象也起着重要的放大作用二平流效应在绝大部分区域中抑制了M4分潮的发展,只有在佛渡水道中一些岛屿周围极小区域内对M4分潮有增强作用．潮滩在湾内对M4分潮的影响极其微弱． 相似文献
2.
Modeling the Tide System of the East China Sea with GIS 总被引：2，自引：0，他引：2
This article describes systematic research on the tide dynamic system under the support of the Geographic Information System and ocean fluid dynamics model. Through the high-resolution numerical simulation, we found some previously unreported phenomena, such as a low tide amplitude zone of the M2 constituent near Zhoushan isles, a low tide amplitude zone of the K1 constituent near Taiwan island, and a circular flow point band. The results of this research also show that the formation of the tide system is affected by sea-bottom friction coefficient, topography under water, and shoreline morphology. The change of shoreline morphology and significant change of topography under water play important roles in the tide system. Under specified conditions on input tide waves, shoreline morphology has a dominant impact on the formation of the tide system. With the systematically reconstructed sea level and the coastal change of 30 periods since the Pleni Glacier, the evolution process of the tide system of the East China Sea was simulated. Based on the simulation analysis of relationships among topography, shoreline and tide flow, this study concludes that the characteristic of the tide dynamic system is a dominant influencing factor on the formation of large-scale sand ridge clusters. In this article, the integration of the Geographic Information System, tide numerical simulation system, and tide movement visualization system are discussed as an example for related studies. 相似文献
3.
强人类活动目前已经成为河口演变的主要动力。阐明流量驱动下河控型河口潮波传播演变过程及机制,对河口治理及人类活动的影响评价具有重要指导意义。以珠江磨刀门河口为例,研究了径潮动力阶段性演变特征。采用流量驱动的R_TIDE数据驱动模型探究了该区潮波振幅梯度和上下游动力边界(即上游流量和口门振幅)关系的变化规律。结果表明,在强人类活动影响下,各潮位站M2分潮振幅明显上升(三灶站除外),且具有季节性差异和阶段性变化,灯笼山-马口河段的M2分潮振幅沿程平均增大约0.07 m,河段潮波振幅梯度平均增大约4.61×10–6 m–1。研究潮波振幅梯度与上下游动力边界的阈值的关系表明,阈值效应主要出现在甘竹-马口河段。在强人类活动影响下,潮波振幅梯度阈值增大,相应的流量阈值增大,而振幅阈值基本不变。在达到振幅阈值之前,由于底床摩擦效应,大潮振幅衰减效应大于小潮,而在超过振幅阈值后,地形辐聚效应成为影响潮波振幅梯度变化的主要因素,大潮振幅衰减效应小于小潮。阈值的变化主要与流量、地形、摩擦等多因子耦合作用有关,当地形辐聚效应和底床摩擦效应达到平衡时,潮波振幅梯度与上下游动力边界之间则出现阈值效应。该现象的发现可为河口海岸防灾减灾和水资源管理等实际问题提供重要理论支撑。 相似文献
4.
通过建立一维水深平均悬沙模型,对典型潮流控制的海湾内不同悬沙组分对潮流的响应关系进行了研究。模型以泥沙的水平输运、再悬浮和沉降为主要物理过程,以M2,S2分潮及余流为主要动力因素,反演了湄洲湾支水道内粉砂、淤泥组分含量的时间序列,采用2007-08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,模型分解得到的主要傅里叶分量具有M2分潮两倍的角速度与1/4日潮周期,该分量粉砂组分振幅6.1 mg/L,淤泥组分振幅1.5 mg/L;次主要傅里叶分量具有M2分潮的角速度,振幅受水平输沙、余流、M2分潮流共同影响,粉砂组分振幅4.9 mg/L,淤泥组分振幅1.2 mg/L。由于粉砂组分单位起动能力强、沉降速度高,且淤泥组分由于粘结力等因素起动条件较高,粉砂组分振幅高于淤泥组分。测站位置余流与涨潮流方向一致,余流致使涨潮过程中粉砂组分含量所占百分比上升,而落潮过程下降,淤泥组分则相反。 相似文献
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7.
铁山港海湾是一个遭受风暴潮灾害影响较为严重的半封闭型海湾,基于有限元海洋数学模型ADCIRC (Advanced Circulation Model)研究了1409号"威马逊"台风期间铁山港海湾的风暴潮特征及非线性作用。结果表明:当考虑天文潮与风暴潮之间的相互作用时,风暴潮水位的计算结果更加准确,只考虑纯台风影响时,计算结果会低估风暴潮增水值,高估减水值,对预报结果造成较大的误差。海湾内部的增水要远大于湾外,但是减水值则相差不大。通过对天文潮和风暴潮非线性作用的影响因子进行分析,风应力的浅水效应可以忽略,但底摩擦项和对流项影响较大。在海湾内部对流项占主导地位,与天文潮的耦合作用也较强;而在湾外,底摩擦项占优势,耦合作用在海湾内外都较强。天文潮与风暴潮相互作用产生的非线性水位在湾顶处最大可达0.94 m,出现在风暴潮最大减水时刻,风暴潮增水发生后有所减弱,非线性水位表现出从湾外向湾内递增的规律。 相似文献
8.
Mean water level setup/setdown in the inlet-lagoon system induced by tidal action-a case study of Xincun Inlet, Hainan Island in China 总被引：2，自引：1，他引：1
With the tides propagating from the open sea to the lagoon, the mean water level （MWL） in the inlet and lagoon becomes different from that at the open sea, and a setup/setdown is generated. The change of MWL （setup/setdown） in the system imposes a great impact on regulating the development of tidal marshes, on determining the long-term water level for harbor maintenance, on the planning for the water front development with the flood control for the possible inundation, and on the interpretation of the historical sea level change when using tidal marsh peat deposits in the lagoon as the indicator for open sea＇ s sea level. In this case study on the mechanisms which control the setup/setdown in Xincun Inlet, Hainan in China, the 2-D barotropic mode of Eulerian - Lagrangian CIRCulation （ELCIRC） model was utilized. After model calibration and verification, a series of numerical experiments were conducted to examine the effects of bottom friction and advection terms, wetting and drying of intertidal areas, bathymetry and boundary conditions on the setup/setdown in the system. The modeling results show that setup occurs over the inlet and lagoon areas with an order of one tenth of the tide range at the entrance. The larger the bottom friction is, a larger setup is generated. Without the advection term, the setup is reduced clue to a decrease of water level gradient to compensate for the disappearance of the advection term. Even without overtides, a setup can still be developed in the system. Sea level rise and dredging in the inlet and tidal channel can cause a decrease of setup in the system, whereas shoaling of the system can increase the setup. The uniqueness of the Xincun Inlet with respect to MWL change is that there is no evident setdown in the inlet, which can be attributed to the complex geometry and bathymetry associated with the inlet system. 相似文献
9.
David E. Cartwright 《Progress in Oceanography》1997,40(1-4)
The spring-neap cycle of global energy dissipation by ocean tides is calculated with a view to trying to explain an observed anomaly in the tidal fluctuations in the length of day. Calculations are performed in three ways: dissipation by friction linearly proportional to semidiurnal tide velocity, by quadratic friction, and by the torques of the lunar and solar tidal forces on the solar and lunar ocean tides, respectively. All methods give comparable results equivalent to an amplitude of about 0.1 μs change in the length of day with a small phase lag. These are inadequate to explain the observed anomaly of about 3 μs and 0.1 rad phase lag. Further investigations, to determine the generation of a non-equilibrium global MSf wave of equatorial amplitude 0.9 mm by nonlinear interactions in shallow seas using global tide models and observations, are suggested. 相似文献
10.
The nodal tide causes a periodic variation in the mean tidal range, with a period of 18.6 years and amplitude of about 4% of the mean range. As the cross-sectional area of the channel in an estuary has been observed to be related to the tidal prism, such a variation of the tidal range can significantly influence the morphological development of tide-dominated estuaries. Field observations from the Humber Estuary in England confirm that there is indeed an 18.6 year cycle in the total water volume of the estuary. In this estuary, with a relatively small morphological time scale, the response to the nodal tide variation appears to dominate the long-term large-scale sediment budget changes of the estuary. The semi-empirical model ESTMORF was able to reproduce these observations, in terms of the observed amplitude and phase lag (relative to the variation of the tidal amplitude) of the morphological response. It also showed good agreement with the along estuary variation in both the magnitude and phase of the response. To examine the character of the response in more detail, a simplified analytical solution has been derived from the governing non-linear equations. This has been investigated in terms of the sensitivity of the model to the various model parameters and by comparison with the historic data. The results demonstrate how the system response is strongly dependent on the morphological time scale of the estuary. Furthermore, the response is not uniform but varies along the length of the estuary, being most marked at the mouth and decaying up estuary. When examining changes in geomorphological features, such as the intertidal area, an appreciation of the role of the nodal tide is shown to be essential if historic data are to be properly interpreted. 相似文献
11.
长江口深水航道三期工程后北槽洪枯季水沙运动特征研究 总被引：1，自引：0，他引：1
利用长江口深水航道三期整治工程前后,北槽洪枯季各测点水沙资料初步探讨了北槽洪枯季水沙运动特征。研究结果表明,北槽洪枯季潮周期平均含沙量分布自上而下总体呈"低-高-低"的分布态势,中段含沙量较高。洪季北槽各测点潮周期平均含沙量与潮周期平均流速相关性较差,北槽泥沙输运以平流输移为主。枯季两者相关较好,北槽泥沙运动则以起悬输运为主。北槽悬沙输运主要以欧拉输运为主,洪季北槽悬沙净输运率要明显大于枯季。洪季北槽中段潮泵及垂向环流作用最为明显,枯季,除北槽上段外,潮泵及垂向环流作用较小,水沙输运方向较为相近。造成洪季北槽中段潮泵作用及垂向环流输沙较大的原因是由于北槽中段滩槽泥沙交换频繁,涨潮流经南槽拦门沙及九段沙滩面后,挟带一定高含沙水体进入北槽,进而造成北槽中段潮泵及垂向环流输沙明显。 相似文献
12.
近海潮汐锋的分布和变化，主要受表层风摩擦、底层潮混合、净热通量和浮力平流的影响。基于2017年7、8月份辽东湾东部海域的实测数据，并结合ROMS（Regional Ocean Model System）模拟结果，利用考虑浮力平流效应的Stigebrandt公式对夏季辽东湾潮汐锋的位置变化进行了诊断计算，计算结果与ROMS模拟的潮汐锋位置符合较好，进一步探讨了风、净热通量和浮力平流对锋面位置变化的影响。主要结论如下：（1）位于辽东湾北部和东、西沿岸浅水区的潮汐锋呈"几"字形分布；（2）2017年6-7月潮汐锋位置变动不大，7月份仅在辽东湾东、西两岸潮汐锋位置略微向深水区移动，这主要是净热通量整体略微减小和风场略微增大造成的，浮力平流作用效果不够显著；（3）2017年8月辽东湾潮汐锋位置较7月向深水区大幅移动，最大移动距离约为20km，辽东湾8月份净热通量的大幅减弱起到了重要作用，浮力平流使潮汐锋位置向浅水区偏移，其调节效果比较显著。 相似文献
13.
修日晨 《海洋学报(英文版)》1985,4(1):1-8
This paper is devoted to the study of the propagation of tide wave in a basin with variable cross-sectional area. With the W.K.B. method an analytic solution of amplitude is obtained. It is found that the motion of co-oscillating tide wave in a basin with variable cross-section is a progressive one, depending on the cross-section as well as the frictional force. The effects of friction on the motion of tide wave is discussed in detail. 相似文献
14.
We investigated the sea level response of the Japan Sea to changes in atmospheric pressure using barotropic shallow water
models driven by idealized synoptic pressure forcing. The regional response lags behind the synoptic pressure forcing because
the adjustment is slowly established by water exchange through narrow, shallow straits. The sea level response of the realistic
Japan Sea to the idealized forcing varies with geographical location and shows zonally asymmetric variations in amplitude
and phase. The simulated response is in good agreement with the observed response of sea level recorded at Japanese coastal
tide gauges. The results of a simple one-dimensional model indicate that the zonally asymmetric pattern, with an eastward-propagating
pressure system, is essentially caused by bottom friction in shallow straits. This asymmetry arises if the typical wavelength
of the synoptic pressure system is slightly larger than the spatial scale of the Japan Sea. 相似文献
15.
We apply the second-order moment (SOM) advection scheme of (Prather, M.J. 1986. Numerical advection by conservation of second-order moments. J. Geophys. Res. 91, 6671–6681.) to the simulation of the large-scale circulation of the Arctic Ocean with a coupled ocean–sea-ice model. Compared to three other advection schemes commonly employed in ocean simulations (centred differences, flux corrected transport, and multidimensional positive definite advection transport), the SOM method helps preserve the vertical structure of Arctic water masses. The depth, thickness and hydrographic properties of the Arctic Surface Water and the Arctic Atlantic Layer are better represented with SOM than with any of the other three advection algorithms. We also present a convenient method for calculating the implicit numerical diffusivity of upstream based schemes, such as the SOM method, and discuss three approaches for improving the monotonicity properties of the SOM algorithm. 相似文献
16.
A numerical experiment of the M2 tide in the Yellow sea 总被引：1，自引：0，他引：1
Hui Soo An 《Journal of Oceanography》1977,33(2):103-110
Semi-diurnal tides in the Yellow Sea are calculated by integrating the shallow water wave equations with frictional and inertial terms.It is found that the results depend on the bottom friction. In the frictionless case the tidal range is unstably amplified because of the occurrence of resonance of the semi-diurnal tidal component in Inchon Bay. When the bottom friction is in the form of the square of velocity, the results agree fairly well with the observations.The following results are obtained. First, the tidal range is larger at the coast of the Korean Peninsula than at the China Coast. Second, resonance of the semi-diurnal tide occurs in Inchon Bay. Third, bottom friction is very important in the shallow ocean,i.e., when the bottom friction become large, the phase lag is retarded and the tidal range decreases.The amplitude and the phase lag calculated in this study agree well with the observations in the case of
b
=b
2
V¦V¦,
b
2=0.0026, especially in the coast of the Korean Peninsula. 相似文献
17.
ABSTRACTThe performance of global tide models in China's seas is far worse than in deep water, owing to generally larger and more complex tides. An ocean tide model (named CST1) was developed by Princeton Ocean Model (POM) and blending assimilation technique, which includes 13 major constituents with a 1.2' × 1.2' spatial resolution. The nautical charts over the Chinese continental shelves and ETOPO1 database are used to generate the bathymetric grid model. The bottom friction coefficient is parameterized through a linear dependency on the depth of each grid. The weight parameter in blending assimilation is a function of the amplitude of constituent. Compared with 33 tide gauges along the Chinese coastline, the Root Sum Square (RSS) error of 8 major constituents is 12.09 cm, and the RSS of 4 major constituents (M2, S2, K1, O1) is 10.76 cm. CST1 with spatially interpolated residual water level was used to provide water level reducers for bathymetric survey. An example near amphidromic point of semi-diurnal constituents in the Yellow Sea demonstrated its process. Assessment showed that it can meet the required accuracies of standards of hydrographic surveys in China. The application proved that CST1 can predict adequately precise astronomical tide level, and is potentially economical and the best approach to provide water level reducers, although some checks should be made in survey planning stage. 相似文献
18.
长江口浑浊带核心区北槽水动力特征研究 总被引：4，自引：2，他引：2
本文根据2015年长江口洪季浑浊带水域座底三脚架全水深范围观测数据,对北槽中下段纵横向流、余流结构、边界层特征等进行了深入研究,结果显示:（1）大潮潮流矢量特征在垂向上的变化差异最为显著;北槽中下段水流出现明显的横向输移,指向航槽北面;（2）横向流速在大潮期间的变化（垂线平均）为-0.10~0.39 m/s,小潮期间的变化为-0.13~0.25 m/s;横向平流对于北槽纵向物质输运有显著调整作用;（3）余流垂向差异大,底部几乎为0,小潮期间余流更强;周期性再悬浮的细颗粒泥沙可作为北槽最大浑浊带的重要物质来源;（4）传统六点对数流速拟合法获得摩阻流速误差较大,近底1 m区域高分辨流速剖面是准确获取底边界层参数的有效途径。 相似文献
19.
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
20.
B. A. Kagan O. lvarez A. Izquierdo R. Maanes B. Tejedor L. Tejedor 《Estuarine, Coastal and Shelf Science》2003,56(5-6):989-1000
The formulation of weak wind-wave/low-frequency current interaction is extended to the case of suspended sediment-stratified flow. The influence of suspended sediment stratification on flow dynamics is described in terms of a sediment stratification parameter defined as von Karman's constant times a depth-independent function of the relative friction velocity and the relative settling velocity of suspended particles that is specified by a solution for the problem on the vertical structure of the suspended sediment-stratified near-bottom logarithmic layer. This ‘extended’ formulation is inserted in a two-dimensional non-linear, finite-difference, high-resolution hydrodynamic model and the modified model is applied to clarify the roles of wind-wave/tide interaction and suspended sediment stratification—individually and in combination—in the formation of the M4 and M6 overtides in Cádiz Bay. It is shown that the predictions for the M4 and M6 overtides have much in common and much in contrast with the M2 tide. For the M2 tide the influence of suspended sediment stratification shows up most vividly in the spatial variability of the tidal characteristics, but is not evident in changes in the M4 and M6 overtides. On the other hand, the influence of wave-induced changes on the M2 tidal amplitude and phase is only of minor importance, but for the M4 and M6 overtides these changes are quite significant. When taken together, the effects of the two factors under investigation are very nearly balanced. This, however, does not mean that the conventional assumption of ignoring these factors is valid in shallow-water dynamics. Simply, that their resulting effect vanishes. 相似文献