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ＭｏｄｅｌｌｉｎｇｏｆｔｈｅｂａｒｏｔｒｏｐｉｃｐｒｏｃｅｓｓｅｓｉｎｔｈｅＢｏｈａｉＳｅａ￥ＨｕａｎｇＤａｊｉ；ＣｈｅｎＺｏｎｇｙｏｎｇａｎｄＳｕＪｉｌａｎ（ＳｅｃｏｎｄＩｎｇｔｉｔｕｔｅｏｆＯｃｅａｎｏｇｒａｐｈｙ，ＳｔａｔｅＯｃｅａｎｉｃＡｄｍ... 相似文献
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The sea level variations along Visakhapatnam coast are governed by astronomical tides and nontidal oscillations including atmospheric pressure, winds, coastal currents, Ekman Pumping, and river influx. Tidal and nontidal sea level oscillations are usually studied separately because of the vastly different ways in which they are forced. In this study the tidal oscillations along Visakhapatnam are analyzed using GOTIC2 tidal model. The correlation between monthly mean sea level and monthly mean tides is 47% (r = 0.68) and increases to 54% (r = 0.74) when applied for inverse-barometric effect. The major six partial tides are computed and presented. The tidal variations from Neap tide to Spring tide are studied. 相似文献
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渤海的潮波系统及其变迁 总被引：3，自引：0，他引：3
黄祖珂 《中国海洋大学学报(自然科学版)》1991,(2)
采用二维非线性潮波微分方程对渤海M_2、S_2、K_1、O_1四个分潮进行数值模拟,得出四个分潮的潮波图,椭圆长短轴图,同潮流时图以及潮汐、潮流性质图和S_2与M_2、K_1与O_1的迟角差图。依此可以系统地了解渤海潮波系统的分布变化规律。依据30～40年代测得的渤海海图以及假设数十年后渤海的岸形对渤海进行数值模拟,从而了解过去和现在渤海潮波的变化情况,以及对未来潮波的变化作出判断。计算表明,从30年代到70年代以来,渤海南部的半日分潮波发生了很大的变化,而日分潮的潮波变化较小。 相似文献
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末次冰消期以来渤、黄、东海陆架潮汐、潮流演变过程模拟研究 总被引：1，自引：0，他引：1
朱玉荣 《中国海洋大学学报(自然科学版)》2002,32(2):279-286
末次盛冰期结束、海侵开始后渤、黄、东海陆架潮汐、潮流的演变对该区泥沙的输运与沉积 ,以及海底地貌的形成、分布以及演变等具有深刻影响。文中数值模拟末次冰消期以来 4个特定时期 ,即比现在海面低 80 m、5 2 m、30 m海面以及全新世最大海侵时渤、黄、东海陆架的潮汐、潮流。根据不同时期的潮汐、潮流分布特征得出 ,末次冰消期以来渤、黄、东海陆架潮汐、潮流的演变过程大致以全新世最大海侵为界划分为两个阶段 :1全新世最大海侵前为渤、黄、东海陆架潮汐、潮流基本分布格局的形成阶段 ;2全新世最大海侵后 ,为基本分布格局的局部调整阶段。末次冰消期以来基本海岸轮廓的变迁是渤、黄、东海陆架区潮汐、潮流演变的主要控制因素 相似文献
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The effects of tidal currents (i.e., barotropic and internal tides) are important in the biogeochemistry of a coastal shelf sea. The high-frequency of currents and near-bottom temperatures collected in three consecutive southwest monsoon seasons (May, June, July and August of 2013 until 2015) is presented to reveal the role of the tidal currents to the temperature variability in the coastal shelf sea of the east coast of Peninsular Malaysia (ECPM), south of the South China Sea (SCS). The results of a spectral density and harmonic analysis demonstrate that the near-bottom temperature variability and the tidal currents are influenced by diurnal (O1 and K1) and semidiurnal (M2) tidal currents. The spectral density of residual currents (detided data) at 5, 10 and 16 m depth also shows significant peaks at the diurnal tidal frequency (K1) and small peaks at the semidiurnal tidal frequency (M2) indicating the existence of internal tides. The result of the horizontal kinetic energy (HKE) shows a strong intermittent energy of internal tides in the ECPM with the strongest energy is found at 16 m depth during a sporadic cooling event in June and July. A high horizontal cross-shore heat flux (16 m) also indicates strong intrusions of cooler water into the ECPM in June and July. During the short duration of cold pulse water observed in June and July, a cross-wavelet analysis also reveals the strong relationship between the near-bottom temperatures and the internal tidal currents at the diurnal tidal frequency. The intrusion of this cooler water is probably related to the monsoon-induced upwelling in June. It is loosely interpreted that the interaction between the strong barotropic tides and the steep slope in the central basin of the SCS under the stratified condition in southwest monsoon has generated these internal tides. The dissipation of internal tides from the slope area probably has driven the cold-upwelled water into the ECPM coastal shelf sea when the upwelling intensity is the highest in June and July. 相似文献
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胶州湾潮汐潮流动边界数值模拟 总被引：11，自引：4，他引：7
基于普林斯顿海洋模式,通过干湿网格判别法引入潮汐潮流的漫滩过程,考虑M2,S2,K1,O1,M4和MS4六个主要分潮,建立了胶州湾潮汐潮流数值模拟和预报模型,研究了该海域潮汐潮流特征,并讨论了漫滩对潮流模拟的影响。与实测资料的对比验证表明,该模式能够对胶州湾的潮汐和潮流做出较为合理的预测。给出了胶州湾潮汐、潮流、余流等分布特征,模拟的潮流场以及余流场涡旋等现象与观测符合良好;计算了潮波能通量,从能量角度探讨了潮波的传播特性;对潮位与潮流场演变规律,以及潮能通量的分析表明,胶州湾内的潮波以驻波为主。通过数值试验发现,漫滩过程的引入对胶州湾潮流速度的模拟至关重要,不考虑漫滩过程的模式会夸大或者低估潮流流速。对于滩涂面积广阔的海域来说,潮流数值模式中考虑漫滩的影响是必要的。 相似文献
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南海北部东沙岛附近的内潮和余流特征 总被引：4，自引：2，他引：2
采用东沙岛附近的一个长达9个月的锚定潜标的观测资料对南海北部的正压潮、内潮和余流情况进行了分析,得到了当地正压潮和内潮的特征。此处正压潮流以全日潮为主,秋、冬季相对较大,春季相对较小;正压余流受海盆尺度环流和地形的限制,在潜标观测期间的秋、冬、春三季基本以偏西向的正压流为主。内潮同正压潮一样,也以全日分潮为主,潮流椭圆随水深发生旋转,在110—120m附近存在内潮非常弱的一层。斜压余流在2009年2—3月比较异常,这是由于在此其间有一个中尺度涡经过。对此潜标数据采用经验正交函数分解的方法进行分析,发现海流的各个主要EOF模态与内波的垂向模态结构有一定的关联。 相似文献
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连云港潮流的数值模拟 总被引：7，自引：1，他引：7
连云港位于江苏省东北角,海洲湾以南,是我国五大重点港口之一。为了适应四个现代化建设的需要,连云港的整治和扩建具有重要的经济意义。在连云港物理模型进行试验的同时,我们开展了数学模型的研究。由于物理模型受到场所、设备、时间及劳力的限制,因此,寻找周期短花钱少的数学模型就势在必行了。因为数学模型在复演或预演水流现象时修改模型方便,能迅速提供多种方案供人们选择,因而它可与物理模型相辅相成,取长补短。 相似文献
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横向流 (垂直于海湾主轴方向的流动) 对横向动量以及物质分布具有重要影响。已往研究表明,潮汐应变对横向流的垂向空间结构具有重要的调控作用。但这种认识仅局限于强层化海区,弱层化条件下潮汐应变对于横向流空间结构的影响仍未可知。为此,本文以象山港为例,基于实测数据阐释了弱层化条件下潮汐应变对横向流及其余环流垂向空间结构的调控作用。结果显示,象山港内湾横向流的垂向空间结构随大小潮呈现出明显的变化规律。大潮时,潮汐应变现象明显,涨潮时较强的垂向混合使得横向流在高潮阶段呈现出一层结构;落潮时垂向混合较弱,横向流在低潮时呈现两层结构。小潮时,潮汐应变受到抑制,垂向混合在涨落潮时均较弱,因此横向流在高低潮阶段均呈现出两层结构。经过潮时均进一步得到的横向余环流呈现出上层向南、下层向北的两层结构。由于潮汐应变的大小潮变化,横向余环流的反转深度反转点自大潮到小潮呈现出上升的趋势。 相似文献
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基于非结构三角形网格的FVCOM(finite-volume coastal ocean model )数值模型, 对南海北部海域的潮汐、潮流进行了精细化数值模拟研究, 并根据模拟结果详细分析了M2, S2, K1, O1 分潮的潮汐和潮流特征。研究结果表明: 神泉港到甲子港海域表现为正规全日潮性质, 珠江口附近海区潮汐以不正规半日潮为主, 其他海域主要表现为不规则全日潮; 陆架海域和深水海域主要表现为往复流, 陆架坡折区存在较强的旋转流, 陆架坡折区为不规则半日潮流和不规则全日潮流的分界线; 东沙群岛附近海域以不规则全日潮流为主, 旋转方向为顺时针; 整个海域的最大流速分布与等深线基本平行, 东沙群岛附近速度明显变大, 最大值出现在台湾浅滩附近, 最大值超过70 cm/s; 南海潮波系统以巴士海峡传入的大洋潮波为主, 分为三支潮流, 以不同的形式进出南海北部海域; 余流在台湾浅滩附近达到最大, 超过6 cm/s, 自南向北进入台湾海峡, 近岸余流自东向西沿岸流动。本研究在东沙群岛周边的模拟结果与前人基于实测资料的分析吻合较好, 并且由于采用了高精度的三角网格, 本文对东沙群岛周边海域的潮汐潮流结构和性质的刻画和分析是迄今为止较为精细的, 同时本研究还提高了对沿岸验潮站调和常数的模拟精度。 相似文献
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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
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Currents on either side of Well Bank were recorded for 41 days in May–June 1981, in order to distinguish locally tidally-generated asymmetries (pertinent to maintenance of the bank) from larger-scale and wind-driven flows.Semi-diurnal currents were dominant, nearly rectilinear and slightly inclined to the bank axis.Fourth-diurnal currents were consistent with previously observed and computed fourth-diurnal tides for the area overall; amplitudes varied as the square of the semi-diurnal amplitude. Hence they appear to be generated by tides, but only a small part locally.Residual currents (average over a tidal cycle) were always in the sense of clock-wise circulation around the bank, consistent with simple models and giving strong evidence of local generation by tides. This circulation combines with the semidiurnal currents to maintain the bank. The slow increase of the residuals with the semi-diurnal amplitude is interpreted as an effect of strong semi-diurnal currents. A persistent component onto the bank 7 m above the bottom at one position may indicate distortion of the frictional layer by the sloping bottom or by bank curvature. 相似文献
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The principal characteristics of the tides are investigated by a shipborne acoustic Doppler current Profiler at a fixed station located in the Beibu Gulf from 4 to 14 April 2003. Data analysis indicates that the diurnal tidal currents dominate local current variations at the observing site. Except the barotropic M_2 constituent, four principal tides comprise both back-and-forth barotropic and baroclinic tidal currents. The baroclinic tidal ellipse parameters vary with depth, showing complicate features, rather than monotonous features being figured. For baroclinic tidal constituents, vertical modes are different to each other. Similarly, the semi-major axes of the tidal constituents vary with depth. In the lower layer, a nonlinear regression approach is used to calculate and obtain the SEMA profiles of diurnal tidal constituents. Results show that in the thin bottom boundary layer, all of the parameters vary drastically with depth, totally distinguished from the vertical profiles above. 相似文献
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Time series of velocity and water temperature were measured at three stations on the continental shelf, on the shelf margin and on the slope off the northwest Tokunoshima in December 1980 to study influences of the slope on tides.Tidal currents with semidiurnal periods were dominant at the stations on the shelf and shelf margin. However, semidiurnal components in temperature fluctuations were dominant at the stations on the shelf margin and the slope. We estimated horizontal currents due to semidiurnal internal tides from the vertical distribution of water density and temperature, assuming that the temperature fluctuations were caused by the vertical displacement of water particles due to semidiurnal internal tides. The tidal ellipses at the station on the shelf and the phase relation of the tidal currents between the two stations on the shelf and shelf margin indicated that the M2 surface tide on the shelf was a Sverdrup wave propagating to the northwest.Semidiurnal tidal currents on the slope were also caused by tides of surface and internal modes. Furthermore, the axis of the tidal ellipse was not perpendicular to the co-tidal line estimated by Ogura (1934) but rather parallel to the isobaths on the slope, which shows a striking effect of the bottom topography on the tidal currents. 相似文献
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Remarkable tidal currents associated with temperature fluctuations in the subsurface layer have been observed in Uchiura Bay. In order to study the characteristics of these tidal currents, we carried out current measurements in November 1972 and October 1974. It was confirmed from the first set of observations in 1972 that the tidal currents above and below the seasonal thermocline oscillate out of phase with each other and the tidal currents are associated with internal tides.In the second set of observations in 1974 not only current measurements but also serial BT lowerings were made. The phase of the thermocline displacements lagged behind the tidal currents by 81 for the semidiurnal constituent and by 83 for the diurnal constituent, and it is thus concluded that the internal tides in Uchiura Bay behave as standing waves. 相似文献
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The offshore tide becomes strongly distorted as it propagates into shallow estuarine systems. Observations of sea surface elevation and horizontal currents over periods ranging from three days to one year, at nine stations within Nauset inlet/estuary, document the non-linear interaction of the off-shore equilibrium tidal constituents. Despite strong frictional attenuation within the estuary, the overtides and compound tides of M2, S2 and N2, in particular, reach significant amplitude, resulting in strong tidal distortion. High frequency forced constituents in sea surface are phase-locked, consistently leading the forcing tides by 60–70°, resulting in a persistent distortion where falling tide is longer than rising tide. Forced constituents in currents are more nearly in phase with equilibrium constituents, producing flood currents which are shorter but more intense than ebb currents. A compound fortnightly tide, MSf, modulates the mean water level such that lowest tides occur during neap phase instead of spring phase. This fortnightly tide can be contaminated by storm surge, changing the phase characteristics of this constituent. Implications of the overtides, compound tides, and lower frequency tides on near-bed, suspended and dissolved material transport are profound. 相似文献
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本文根据实测资料和潮汐学基本理论,分析了福建海区潮波结构和特征、潮汐和潮流主要特征值的分布规律。结果表明,泉州湾以北海区潮汐很强,为半日潮;港湾区因受地形影响潮流很强,性质为半日潮;外海区潮流很弱,性质多为混合潮。福建南部海区潮汐很弱,性质多数是混合潮;潮流很强,性质为半日潮。 相似文献
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C.M. Davies 《Marine Geology》1974,16(2):M31-M38
Two separate current systems have been identified in Swansea Bay — a rotatory current system, located in the northern part of the embayment, and a rectilinear current system, offshore. The amount of fine-grained sediment suspended in the rotatory currents varies with both direction during a tide cycle and tidal range. Measurements of suspended sediment indicate that the suspended load is higher on neap tides than spring tides. This is due to a change in axial orientation of the rectilinear system, which directs ebb-tide currents towards the northern part of the embayment on neap tides, but “deflects” ebb-tide currents from the northern area on spring tides. 相似文献