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1.
LOU Angang） ）* HU Yuebo） KUANG Liang） ZHANG Xueqing） DU Peng） ）） College of Environmental Science Engineering Ocean University of China Qingdao P. R. China ） Key Lab of Marine Environmental Science Ecology P. R. China 《中国海洋大学学报(英文版)》2009,8(1)
The 3-D ECOMSED ocean model was applied to establish a time-dependent boundary model for Jiaozhou Bay (JZB), in which the operator-splitting technique was used and the ‘dry and wet’ method was introduced. The influence caused by JZB reclamation on the surface level, residual currents, tidal system and tidal energy of M2 tidal system were predicted and analyzed. The results show that JZB reclamation has slight impact on the M2 tidal system, in which the variation of amplitude and phase is less than 1%.The ch... 相似文献
2.
吴德星 《中国海洋湖沼学报》1997,15(4):314-321
ImODUcnONThedeepequatorialoceanhasobvioussignilicantflowapparentlycarryinghacelsa1ongandacrosstheequator(WissCtal.,l985).RmtfloatmsurementSshoWedthattheflowishigh1yvariable(Richardsonetal.,l993).ThomPsonandKawase(l993)pro-posedthatthelargeinstantaneousandfloatvelocitiesasWellasthevariabilitysuggestthatthetracersignaIsreflCCtreCtificationoftimedependentmotionsandniinginsteadofrneanEulerianflow.TheresultSoftheirstudyonthegenerationofmeancurrentSbyperi-odicfordngintheequatorialoceaninasir… 相似文献
3.
There are two different modeling approaches which have been proposed and utilized to derive residual currents: the first approach
is equivalent to deducing residual currents from current-meter records using filtering techniques or time averages of time-series
records to remove tidal variations; in the second approach, filters or time averages over several tidal cycles are applied
to the hydrodynamic equations to generate the governing equations for residual circulation. Based on the latter, both the
baroclinic dynamic models of residual circulation are proposed, of which one is a two-dimensional transport model and the
other is a three-dimensional model with variable eddy viscosity. The two-dimensional transport model is a direct generalization
from the barotropic model of residual circulation presented by Nihoul and Randy (1975) and Heaps (1978) to the baroclinic
model. In the three-dimensional model with variable eddy viscosity, using a Sturm-Liouville system adopted in the reference
[5], the nondimensional problem for residual circulation reduces to the nondimensional problem of the elevation and the expression
of residual currents.
It should be pointed out that both the baroclinic models developed in the present paper are confined to describe the Eulerian
residual circulation only. 相似文献
4.
The 3-D ECOMSED ocean model was applied to establish a time-dependent boundary model for Jiaozhou Bay (JZB), in which the
operator-splitting technique was used and the ‘dry and wet’ method was introduced. The influence caused by JZB reclamation
on the surface level, residual currents, tidal system and tidal energy of M2 tidal system were predicted and analyzed. The results show that JZB reclamation has slight impact on the M2 tidal system, in which the variation of amplitude and phase is less than 1%.The changes of the currents and residual currents
in Qian Bay and near the reclamation areas are greater, but in other areas the changes are smaller, in which the currents
have a change of around 1%, while the residual currents change ranges from 1.82%–9.61%. After reclamation, the tidal energy
fluxes increase by 2.62%–5.24% inside and outside the JZB mouth, but decrease by 20.21%–87.23% near Qian Bay and the reclamation
area. 相似文献
5.
利用宜川-泰安剖面高精度重力观测和GPS数据测量结果,对观测数据进行各项改正和处理,得到剖面的布格重力异常,并采用高斯低通滤波获得剩余重力异常。以诸城-宜川深地震测深（DSS）速度剖面为约束,对沿该剖面得到的高精度布格重力异常数据进行拟合,获得剖面地壳密度结构。结果表明,趋势异常主要反映该剖面地壳厚度的变化,太行山重力梯级带是地壳厚度的陡变带。结合前人相关研究,对剩余重力异常结合剖面经过的隆起、凹陷等地质问题进行讨论,进一步揭示出,剩余重力异常主要反映浅部地质构造和低密度地质体,剩余重力异常与地质构造不仅具有良好的对应关系, 而且其幅值能体现地质体的基本特征,比布格重力异常反映得更清晰、更细致。 相似文献
6.
This study was conducted on the spatial distribution characteristics of surface tidal currents in the southwestern Taiwan Strait based on the quasi-harmonic analysis of current data obtained by two high frequency surface wave radar (HFSWR) systems. The analysis shows that the tidal current pattern in the southwestern Taiwan Strait is primarily semi-diurnal and influenced significantly by shallow water constituents. The spatial distribution of tidal current ellipses of M2 is probably affected by the interaction between two different systems of tide wave, one from the northern mouth of Taiwan Strait and the other from the Bashi Channel. The directions of the major axes of M2 tidal current ellipses coincide roughly with the axis of the Taiwan Strait. The spatial distribution of the magnitudes of the probable maximum current velocity (PMCS) shows gradual increase of the velocity from northeast to southwest, which is in accordance with the spatial distribution of the measured maximum current velocity (MMCS). The directions of the residual currents are in accordance with the direction of the prevailing monsoon wind at the Taiwan Strait and the direction of the Taiwan warm current during summer. The bathymetry also shows a significant effect on the spatial distribution characteristics of tidal currents. 相似文献
7.
Feng Shizuo 《中国海洋湖沼学报》1986,4(2):139-158
In recent years, studies of the environmental hydrodynamics in coastal seas and tidal estuaries have placed focus on the processes
which determine the “fate” of longer-term transport. The lagrangian residual current has been recognized as an important factor
which affects the longer term transport processes since it is more relevant to use a Lagrangian mean velocity rather than
an Eulerian mean velocity to determine the origin of Water masses. In the present paper, an attempt is made to formulate a
three-dimensional dynamics on the tideinduced Lagrangian residual current and mass-transport based upon a three-dimensional
weakly-nonlinear model of tides. The Lagrangian residual velocity is shown to be the sum of the mass-transport velocity, which
is the sum of the Eulerian residual velocity and the Stokes’ drift velocity, and the Lagrangian residual drift velocity which
is dependent on the tidal current phase. This reveals that it is the mass-transport velocity which is the tidal cycle Eulerian
mean of the Lagrangian residual velocity and that the mass-transport velocity is correct to the second order of approximation
rather than to the first order. And then, a new longer-term transport equation which correctly describes the Lagrangian nature
of transport processes without introducing the Fickian hypothesis for tidal dispersion is derived. In fact, the convection
can be correctly represented by the Eulerian mean of the Lagrangian residual velocity, as the convective velocity in the longer-term
transport equation is nothing but the mass-transport velocity.
Submitted for IAMAP/IAPSO Joint Assembly, August 5–16, 1985, Honolulu, Hawaii U.S.A. 相似文献
8.
Spatial and seasonal variabilities of submesoscale currents in the northeastern South China Sea are investigated by employing a numerical simulation with a horizontal resolution of 1 km. The results suggest that submesoscale currents are widespread in the surface mixed layer mainly due to the mixed layer instabilities and frontogenesis. In horizontal, submesoscale currents are generally more active in the north than those in the south, since that active eddies, especially cyclonic eddies, mainly occur in the northern area. Specifically, submesoscale currents are highly intensified in the east of Dongsha Island and south of Taiwan Island. In temporal sense, submesoscale currents are more active in winter than those in summer,since the mixed layer is thicker and more unstable in the winter. The parameterization developed by FoxKemper et al. is examined in terms of vertical velocity, and the results suggest that it could reproduce the vertical velocity if mixed layer instability dominates there. This study improves our understanding of the submesoscale dynamics in the South China Sea. 相似文献
9.
A hydro-dynamic model is established on basis of MIKE21 FM to simulate the hydro-dynamic characteristics of Xinghua Bay and investigate the influence of reclamation project on the tidal elevation and tidal currents. Tidal elevation data was obtained at the six tide gauge stations around the Xinghua Bay, and another six current stations were established to observe the tidal current velocity and direction. Validation shows that the model-simulated tidal elevation and tidal currents agree well with observations made at different stations. Predictions are made according to the reclamation project proposed in the regional marine planning of Hanjiang Industrial Park around the port in Putian City. The variations of hydro-dynamic factors, such as tide, current velocity and direction and tidal influx are obtained, and the adverse effect of reclamation on marine environment is discussed. It is shown that the tidal level inside the Xinghua Bay during high tide decreases after the reclamation project is completed. The tidal currents during flooding tide generally decrease in the southeast of the reclamation region, with the maximum decreasing amplitude reaching 0.44 m s-1. On the other hand, the tidal currents during flooding tide increase around the southeast and southwest corners of the reclamation region. The tidal currents during ebb tide increase around the southeast and southwest corners of the reclamation region, with the maximum increasing amplitude attaining 0.18 m s-1. The results in this paper can give some guidance for the marine environment management and the effective utilization of land in Putian. 相似文献
10.
《中国海洋大学学报(英文版)》2021,(3)
The shipboard measurements of whitecap coverage(W) and the meteorological and oceanographic information from two cruises in the South China Sea and Western Pacific are explored for estimating W. This study aims at evaluating how to improve the parameterizations of W while considering the effects of currents and swells on wave breaking. Currents indeed affect W in a way that winds with following currents can decrease W, whereas winds with opposing currents can increase W. Then, 10-m wind speed over sea surface(U_(10)) is calibrated by subtracting the current velocity from U_(10) when the propagating directions of winds and currents are aligned. By contrast, when the direction is opposite, U_(10) is calibrated by adding the parallel velocity component of the opposing current to U_(10). The power fits of W dependence on the U_(10)-related parameters of U_(10), friction velocity, wind sea Reynolds number in terms of this calibrated-U_(10) obtain better results than those directly fitted to U_(10). Different from the effect of currents on W, wind blowing along the crest line of swells may contribute to the increase in W. The conclusions suggest that U_(10) should be calibrated first before parameterizing W in areas with a strong current or some swell-dominant areas. 相似文献
11.
While the Antarctic Slope Current(ASC) has been intensively studied for the East Antarctica slope area and the Weddell Sea, its fate in the western Antarctic Peninsula(WAP) region remains much less known. Data from two cruises conducted near the South Shetland Islands(SSIs) and the Elephant Island(EI), one in austral summer of 2004 and one in austral winter of 2006, were analyzed to provide a broad picture of the circulation pattern over the continental slope of the surveyed area, and an insight into the dynamical balance of the circulation. The results indicate that southwestward currents are present over the upper slope in the study area, indicating the ASC in the WAP region. Near the Shackleton Gap(SG) north of the EI, the southwestward slope currents near the shelf break are characterized by a water mass colder and fresher than the ambient water, which produces cross-slope density gradients and then vertical shear of the along-slope(or along-isobath) velocity. The vertical shear is associated with a reversal of the along-slope current from northeastward at surface to southwestward in deeper layers, or a depth-intensification of the southwestward slope currents. The water mass with temperature and salinity characteristics similar to the observed cold and fresh water is also revealed on the southern slope of the Scotia Sea, suggesting that this cold and fresh water is originated from the Scotia Sea slope and flows southwestward through the SG. Over the shelf north of the SSIs, the cold and fresh water mass is also observed and originates mainly from the Bransfield Strait. In this area, vertical structure of the southwestward slope currents is associated with the onshore intrusion of the upper Circumpolar Deep Water that creates cross-slope density gradients. 相似文献
12.
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13.
《中国海洋大学学报(英文版)》2016,(6)
Bottom currents at about 1000 m depth in and around a submarine valley on the continental slope of the northern South China Sea were studied by a 14-month long experiment from July 2013 to September 2014. The observations reveal that bottom currents are strongly influenced by the topography, being along valley axis or isobaths. Power density spectrum analysis shows that all the currents have significant peaks at diurnal and semi-diurnal frequencies. Diurnal energy is dominant at the open slope site, which is consistent with many previous studies. However, at the site inside the valley the semi-diurnal energy dominates, although the distance between the two sites of observation is quite small(11 km) compared to a typical horizontal first-mode internal tide wavelength(200 km). We found this phenomenon is caused by the focusing of internal waves of certain frequencies in the valley. The inertial peak is found only at the open slope site in the first deployment but missing at the inside valley site and the rest of the deployments. Monthly averaged residual currents reveal that the near-bottom currents on the slope flow southwestward throughout the year except in August and September, 2013, from which we speculate that this is a result of the interaction between a mesoscale eddy and the canyon/sag topography. Currents inside the valley within about 10 mab basically flow along slope and in the layers above the 10 mab the currents are northwestward, that is, from the deep ocean to the shelf. The monthly mean current vectors manifest an Ekman layer-like vertical structure at both sites, which rotate counter-clockwise looking from above. 相似文献
14.
To investigate the mechanism of secondary circulations in rip current systems, and to explore the relationship between wave conditions and secondary circulation intensity, a series of numerical experiments is performed using coupled nearshore wave model and circulation model. In these experiments, the rip currents and secondary circulations generated above barred beaches with rip channels are simulated. A comparison experiment is conducted to investigate the formation and hydrodynamics of the secondary circulations. Model results indicate that the secondary circulations consist of alongshore flows driven by wave set-up near the shoreline, part of the feeder currents driven by the wave set-up over the bars, and onshore flows at the end of the rip channel driven by wave breaking and convection. The existence of the secondary circulation barely affects the rip current, but narrows and intensifies the feeder currents. Three groups of experiments of varying incident wave conditions are performed to investigate the relationship between wave conditions and secondary circulation intensity. The velocity of the alongshore flow of the secondary circulation is sensitive to the variation of the incident wave height and water depth. It is also found that the alongshore flow intensity is in direct proportion to the alongshore variation of the wave height gradient between the bars and the shoreline. 相似文献
15.
Current data from a moored Acoustic Doppler Current Profiler(ADCP) deployed at 69?30.155′N,169?00.654′W in the central Chukchi Sea during 2012 summertime is analyzed in the present paper.Characteristics of tidal and residual currents are ob-tained with Cosine-Lanczos filter and cross-spectral analyses.The main achievements are as follows:1) Along with the local inertial frequency of 12.8 h,two other peaks at ~12-h and ~10-d dominate the time series of raw velocity;2) The M_2 dominates the 6 resolved tide constituents with significant amplitude variations over depth and the ratios of current speed of this constituent to that of the total tidal current are 54% and 47% for u and v components,respectively.All the resolved tidal constituents rotate clockwise at depth with the exception of MM and O1.The constituents of M_2 and S_2 with the largest major semi-axes are similar in eccentricity and orientation at deeper levels;3) The maximum of residual currents varies in a range of 20–30 cms~(-1) over depth and the current with lower velocities flow more true north with smaller magnitudes compared to the current in surface layer.The ~10 d fluctuation of residual current is found throughout the water column and attributed to the response of current to the local wind forcing,with an approximate 1.4 d lag-time at the surface level and occurring several hours later in the lower layer;4) Mean residual currents flow toward the north with the magnitudes smaller than 7 cms~(-1) in a general agreement with previous studies,which suggests a relatively weaker but stable northward flow indeed exists in the central Chukchi Sea. 相似文献
16.
选取2008~2018年茅山断裂带及周边82个测震台站记录到的516个近震Pg、Sg到时数据,采用双差地震层析成像方法对茅山断裂带及邻区进行地震重定位和三维P波速度结构的联合反演,并分析溧阳历史上两次破坏性地震与速度结构的关系。结果表明,地震重定位后残差显著降低,研究区大部分地区横向分辨率可达0.2°。P波的速度结构横向差异变化比较明显,反演后的速度与初始速度模型之间的变化率基本在±10%左右。茅山断裂带两端呈现高速特征,中段表现为低速结构。溧阳震源区1974年MS5.5地震发生在深变质岩系内的低速层上,而1979年MS6.0地震发生在深变质岩系与浅变质岩系边界上,这两次地震的发震原因可能与具有塑性流变特性的低速体和速度梯度较大的转换复合位置容易产生应力集中有关。 相似文献
17.
Internal waves play a crucial role in ocean mixing, and density perturbation and energy flux are essential quantities to investigate the generation and propagation of internal waves. This paper presents a methodology for calculating density perturbation and energy flux of internal waves only using a velocity field that is based on linearized equations for internal waves. The method was tested by numerical simulations of internal waves generated by tidal flowing over a Gaussian topography in a stratified fluid. The density perturbations and energy fluxes determined using our method that only used velocity data agreed with density perturbations and energy fluxes determined by the equation of state based on temperature data. The mean relative error (MRE) and root mean square error (RMSE) between the two methods were lower than 5% and 10% respectively. In addition, an experiment was performed to exam our method using the velocity field measured by Particle Image Velocimetry (PIV), and the setup of the experiment is consistent with the numerical model. The results of the experiments calculated by the methods using PIV data were also generally equal to those of the numerical model. 相似文献
18.
三峡库首区最小一维速度模型研究 总被引：3，自引：0，他引：3
根据三峡台网2001～2006年记录的490个地震事件中的7 330条P波和3 524条S波到时资料,利用Kissling方法得到了三峡库区最小一维P波和S波速度模型以及台站校正值,并应用于地震的精定位.重新定位后地震走时残差均方根从原来的0.56 s下降到0.41 s,地震定位精度在经度、纬度、深度方向上有了较大提高. 相似文献
19.
Estimation of S-wave velocity using logging data has mainly been performed for sandstone,mudstone and oil and gas strata,while its application to hydrate reservoirs has been largely overlooked.In this paper we present petrophysical methods to estimate the S-wave velocity of hydrate reservoirs with the P-wave velocity and the density as constraints.The three models used in this paper are an equivalent model(MBGL),a three-phase model(TPBE),and a thermo-elasticity model(TEM).The MBGL model can effectively describe the internal relationship among the components of the rock,and the estimated P-wave velocities are in good agreement with the measured data(2.8% error).However,in the TPBE model,the solid,liquid and gas phases are considered to be independent of each other,and the estimation results are relatively low(46.6% error).The TEM model is based on the sensitivity of the gas hydrate to temperature and pressure,and the accuracy of the estimation results is also high(3.6% error).Before the estimation,the occurrence patterns of hydrates in the Shenhu area were examined,and occurrence state one(the hydrate is in solid form in the reservoir) was selected for analysis.By using the known P-wave velocity and density as constraints,a reasonable S-wave velocity value(ranging from 400 to 1100 m s~(-1) and for a hydrate layer of 1100 m s~(-1)) can be obtained through multiple iterations.These methods and results provide new data and technical support for further research on hydrates and other geological features in the Shenhu area. 相似文献
20.
针对当前大规模GNSS网在数据预处理、组织管理、基准站选取、处理策略、分区方案、质量检核与评估以及现有研究中速度场模型数据量小、连续性不佳、现势性不强等问题,首先基于2011~2017年陆态网260多个连续运行基准站的观测数据探讨大网解算的一体化数据处理流程,给出适用于大规模GNSS网数据处理的优化原则与质量评估方案,并着重分析不同的数据解算成果评估策略,其对大规模GNSS站网的高精度数据解算具有借鉴和参考意义;然后基于解算得到的ITRF2014框架下高精度速度场成果,采用克里金插值构建中国大陆水平格网速度场模型,并利用国内IGS站和陆态网区域站的精确速度值,对格网内插结果进行外部检验,结果表明,东、北方向速度残差的平均误差和中误差均小于2 mm/a,验证了模型的准确性、可靠性、简便性与现势性。 相似文献