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Chinese Journal of Oceanology and Limnology 2015年第5期33卷 1279-1285页

作者：蔺飞龙梁楚进侯一筠刘亚豪刘泽胡珀 Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography

During the observational period of our study, Typhoon Hagupit passed over the mooring site and induced strong near-inertial waves （NIWs）, which provided an opportunity to investigate the interactions between internal tides （ITs） and NIWs. Based on the mooring data, we compared the current spectra during the typhoon period and non-typhoon period in the northern South China Sea, and found that the high- frequency waves （fD1 and fD2） were evident during the former. Moreover, the observations of the current revealed that fD1 and fD2 occurred near the depth of strong vertical shear in the NlWs. In order to confirm the generation mechanism of fD1 and fD2, we compared the positions of strong vertical shear in the NIWs and strong vertical velocity in the ITs. It was established that the vertical shear of the horizontal current of the NIWs and the vertical current of the ITs contributed to the generation of fDt and fD2.

关键词： internal tides near-inertial waves typhoon nonlinear interaction South China Sea

Three-dimensional numerical simulation of internal tides that radiated from the Luzon Strait into the Western Pacific

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Chinese Journal of Oceanology and Limnology 2017年第6期35卷 1275-1286页

作者：刘昆徐振华尹宝树 Institute of Oceanology Chinese Academy of Sciences Key Laboratory of Ocean Circulation and Waves (KLOCAW) Chinese Academy of Sciences University of Chinese Academy of Sciences Laboratory for Ocean and Climate Dynamics Qingdao National Laboratory for Marine Science and Technology

Recent satellite altimeter observations have indicated that internal tides （ITs） from the Luzon Strait （LS） propagate more than 2 500 km into the Western Pacific （WP）. This study used a high-resolution three-dimensional numerical model to reproduce and examine the ITs radiation process. The propagation of diurnal and semidiurnal ITs showed different patterns and variations. Diurnal ITs with lower frequency were affected more by the earth＇s rotation and they were bent more toward the equator than semidiurnal ITs. ITs phase speeds are functions of latitude and diurnal ITs showed greater distinctions of phase speeds during propagation. For M2 ITs, the wavelength remained nearly unchanged but the beam width increased significantly during propagation away from the LS. For diurnal ITs （K1 and O0, the wavelength decreased noticeably with latitude, while the beam width varied little during propagation because of blocking by land. Baroclinic energy was also examined as a complement to satellite results reported by Zhao （2014）. The magnitude of the generated baroclinic energy flux reduced remarkably within 300 km from the generation site but it then decayed slowly when propagating into abyssal sea. Baroclinic energy of diurnal ITs was found to dissipate at a slower rate than semidiurnal ITs along the main propagation path in the WP.

关键词： internal tides numerical simulation Luzon Strait Western Pacific

A Model Study on the Generation of internal tides by Tidal Flows Over a Submerged Seamount in the Channel

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Communications in Computational Physics 2010年第6期8卷 95-114页

作者： Shuqun Cai Junliang Liu Xiaomin Long LED South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou510301China Graduate School of the Chinese Academy of Sciences Beijing100049China

It is known that the submerged seamount/ridge is a source for the generation of internal *** this paper,a three-dimensional two-layer model is set up to study the generation of internal tides by tidal flows over a submerged seamount/ridge in the *** numerical experiments with different topographic features,upper layer depths,tidal flows and background currents are carried out to study the variations of the induced internal *** is shown that,for the specific stratification,the seamount feature,the slope,the initial upper layer depth and the imposing driven force determine the Froude number near the seamount *** when the Froude number is supercritical,the associated maximum amplitude of the induced internal tide is so large that the internal tide begins to disintegrate,which brings about severe variations of the current velocity and the water elevation fields,and the associated induced baroclinic tidal energy around the seamount peak is much larger than the barotropic *** Richardson number greater than 1/4 is a criterion for stability of shear *** the maximum tidal velocity changes within 0∼360◦with time in a period around the seamount peak,the induced internal tide does not stride the seamount peak before it disintegrates,which is different from the two-dimensional modeled *** asymmetrical slope of the submerged seamount is a mechanism for the asymmetrical internal tide generation.

关键词： internal tides numerical modeling two-layer model sill channel

internal tides in the northern South China Sea from 20-day in-situ mooring observations in 1998

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Marine Science Bulletin 2012年第2期14卷 12-23页

作者：蔡扬郭朴方文东国家海洋局南海预报中心广州510300 中国科学院南海海洋研究所热带海洋环境国家重点实验室广州510301

20-day in-situ ADCP current and CTD data are used to investigate the characteristics and energy of the internal tides in the northern South China Sea （NSCS）. The results show that the O1, K1, M2 and S2 constituents of internal tides are energetic and diurnal constituents （O1 and K1） are dominating. In the observational period, the current vectors of these four constituents all rotate clockwise and the maximum semi-major axe of internal tidal ellipses is more than 14 cm/s. The variation of ocean temperature shows that the internal tides present obvious quasi-diurnal oscillation and the average amplitude reaches 50 m. Furthermore, these internal tides carry high energy and appear to be intermittent. The maximum values of KE （PE） during the observational period are up to 2 （3.5） k J/m^2 for diurnal internal tides, and up to 1 （1.5） k J/m^2 for semidiurnal internal tides.

关键词： internal tides in-situ mooring observations northern South China Sea energy

Characteristics of Semi-diurnal internal tides in the Western Equatorial Pacific Ocean Around 1°45′S,156°E

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Marine Science Bulletin 2006年第2期8卷 12-20页

作者：鲍献文张义钧孙丽杜涛方欣华中国海洋大学物理海洋实验室山东青岛266003 国家海洋信息中心天津300171

The analyses of a data series obtained during TOGA- COARE show the existence of remarkable semi-diurnal intemal tides in the western equatorial Pacific Ocean around 1°45＇S, 156°E. Some characteristic parameters of the internal tides are vertical wavenumber -1.6×10^-3 m^-1, horizontal wavenumber （wavelength） 3.3×10^-2 km^-1 （210 km）, vertical propagation speed -3.8 cm/s and horizontal propagation speed 2.0 m/s. The waveforms propagate downwards slantingly, that is, the wave energy transfers upwards slantingly. Depth-distribution of the＇rotary spectral levels is a saddle-shape. The depths of the trough and the deeper peaks are almost coincident with those of the south boundaries of the South Equatorial Current and the Equatorial Undercurrent, respectively. The mean orientation of the rotary spectral ellipse changes with depth： 30° from north to east at 40 m, and changes into 14° from east to south at 324 m, and generally, it points to northeastward, which indicates ＂that waves come from the southwest.

关键词： internal waves internal tides western equatorial Pacific Ocean TOGA-COARE

The influence of background waves on internal solitary waves after the transit of Typhoon Neast in the northern South China Sea

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Acta Oceanologica Sinica 2014年第12期33卷 40-47页

作者： LIN Feilong HOU Yijun LIU Ze HU Po FANG Yong DUAN Yongliang Institute of Oceanology Chinese Academy of Sciences Key Laboratory of Ocean Circulation and Waves (KLOCAW) Chinese Academy of Sciences University of Chinese Academy of Sciences Center for Ocean and Climate Research First Institute of Oceanography State Oceanic Administration

On the basis of the time series observations from a temperature chain and an acoustic Doppler current profiler on the continental shelf of the northern South China Sea, a sequence of internal solitary waves （ISWs） and background waves （BWs, including internal tides and near-inertial waves） on the continental shelf were captured simultaneously after the transit of Typhoon Neast in October 2011. These measurementsprovided a unique opportunity to explore the influence of BWs on the ISWs. The BWs appeared a conversion on the current strength and vertical mode structure during the observational period. The BWs were dominated by weak and mode-one waves before October 2 and then turned to strong and high-mode waves after that time. Meanwhile, the ISWs displayed different wave structures before and after October 2, which was closely related to BWs＇ changes. According to the current profiles of BWs, the high-mode wave structure with strong current could significantly strengthen the vertical shear of ISWs in the near-surface layer and promote the breaking of ISWs, and thus it may play an important role in affecting the background current condition.

关键词： internal solitary wave shear instability near-inertial waves internal tides

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An isopycnic-coordinate internal tide model and its application to the South China Sea

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Chinese Journal of Oceanology and Limnology 2011年第6期29卷 1339-1356页

作者：苗春葆陈海波吕咸青 Laboratory of Physical Oceanography Ocean University of China

A three-dimensional isopycnic-coordinate ocean model for the study of internal tides is presented. In this model, the ocean interior is viewed as a stack of isopycnic layers, each characterized by a constant density. The isopycnic coordinate performs well at tracking the depth variance of the thermocline, and is suitable for simulation of internal tides. This model consists of external and internal modes, and barotropic and baroclinic motions are calculated in the two modes, respectively. The capability of simulating internal tides was verified by comparing model results with an analytical solution. The model was then applied to the simulation of internal tides in the South China Sea （SCS） with the forcing of M2 and K1 tidal constituents. The results show that internal tides in the SCS are mainly generated in the Luzon Strait. The generated M2 internal tides propagate away in three different directions （branches）. The branch with the widest tidal beam propagates eastward into the Pacific Ocean, the most energetic branch propagates westward toward Dongsha Island, and the least energetic branch propagates southwestward into the basin of the SCS. The generated KI internal tides propagate in two different directions （branches）. One branch propagates eastward into the Pacific Ocean, and the other branch propagates southwestward into the SCS basin. The steepening process of internal tides due to shoaling effects is described briefly. Meridionally integrated westward energy fluxes into the SCS are comparable to the meridionally integrated eastward energy fluxes into the Pacific Ocean.

关键词： internal tides isopycnic coordinate numerical simulation South China Sea (SCS)

Is the small-scale turbulence an exclusive breaking product of oceanic internal waves

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Acta Oceanologica Sinica 2011年第6期30卷 1-11页

作者： FAN Zhisong College of Physical and Environmental Oceanography Ocean University of China Qingdao 266100 China

On the basis of the theoretical research results by the author and the literature published up to date, the analysis and the justification presented in this paper show that the breaking products of oceanic internal waves are not only turbulence, but also the fine-scale near-inertial internal waves （the oceanic reversible finestructure） for inertial waves and the internal solitary waves for internal tides respectively. It was found that the oceanic reversible finestructure may be induced by the effect of the horizontal component f （f = 2Ωcosφ） of the rotation vector on inertial waves. And a new instability of the theoretical shear and strain spectra due to the effect of f occurs at critical vertical wavenumber β c ≈ 0.1 cpm. It happens when the levels of shear and strain of the reversible finestructure are higher than those of inertial waves, which is induced by the effect of f along an ＂iso-potential-pycnal＂ of internal wave. If all breaking products of internal waves are taken into account, the average kinetic energy dissipation rate is an order of magnitude larger than the values of turbulence observed by microstructure measurements. The author’s theoretical research results are basically in agreement with those observed in IWEX, DRIFTER and PATCHEX experiments. An important impersonal fact is that on the mean temporal scale of thermohaline circulation these breaking products of internal waves exist simultaneously with turbulence. Because inertial waves are generated by winds at the surface, and internal tides are generated by strong tide-topography interactions, the analysis and justification in this paper support in principle the abyssal recipes Ⅱ：energetics of tidal and wind mixing by Munk Wunsch in 1998, in despite of the results of microstructure measurements for the turbulent kinetic energy dissipation rate and the diapycnal turbulent eddy diffusivity.

关键词： internal waves inertial waves internal tides turbulence oceanic interior mixing

Analysis of internal tidal characteristics in the layer above 450 m from acoustic Doppler current profiler observations in the Luzon Strait

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Science China Earth Sciences 2011年第7期54卷 1078-1094页

作者： LIAO GuangHong YUAN YaoChu Kaneko ARATA YANG ChengHao CHEN Hong Taniguchi NAOKAZU Gohda NORIAKI College of Information Science and Technology Ocean University of China Qingdao 266100 China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China Graduate School of Engineering Hiroshima University Higashi-Hiroshima 739-8527 Japan

The characteristics of internal tides in the upper layer of the Luzon Strait are investigated on the basis of direct-observation current data recorded on April 25 and September 26, 2008 by an acoustic Doppler current profiler. Spectral analysis and energy estimation show that the diurnals and semidiurnals carry most of the energy of internal tides. Values of the depth-integrated total energy E for the three frequency bands of diurnal, semidiurnal, and high frequencies are 31, 6.9, and 3.4 kJ. m, respectively. Near-inertial peaks are only present in the baroclinic component. The behavior of typical tidal frequencies （i.e., O1, K1, M2, MK3, and M4） and the near-inertial frequency is basically consistent with linear internal wave theory, which predicts E＋（ω）/E_（ω）=（ω-f）2/（ω＋f）2 at depths above 66 m, while not all prominent tidal components coincide well with the relation of the linear internal wave field at other depths. Examinations of depth structures of the baroclinic tides and temporal variations show that the surface tides and internal tides are both of mixed type, having diurnal inequality and spring-neap fortnight periods. The K1 and O1 tides have comparable cross- and along-shelf components, while the M2 and S2 tides propagate toward the shelf in the northern South China Sea as wave beams. The amplitude and phase of internal tides vary with time, but M2 and S2 tides appear to have structures dominated by the first mode, while the K1 and O1 tides resemble second-mode structures. The minor to major axis ratios are close to expected values of flω in the thermocline.

关键词： current observation acoustic Doppler current prof'fler internal tides internal waves Luzon Strait

Plane wave fitting of the internal tidal sea-surface height signatures extracted from the TOPEX/Poseidon altimeter data along satellite tracks

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Acta Oceanologica Sinica 2012年第4期31卷 31-45页

作者： CHEN Haibo LV Xianqing WANG Bin Laboratory of Physical Oceanography Ocean University of ChinaQingdao 266100China

The sea-surface height （SSH） signatures of internal tides extracted from the TOPEX/Poseidon （T/P） altimeter data along satellite tracks are fitted with superposition of several plane waves which have different wavenumber vectors. The key problem of plane wave fitting with iterative method is how to determine the initial value of wavenumber of each plane wave. The previous solving method is to analyze the internal tidal SSH signatures along each track with wavenumber spectrum. But it is found that the problem cannot be solved completely with the wavenumber spectrum analysis method only. The method based on the combination of wavenumber spectrum analysis method and the exhaustive method is proposed to determine the initial values of wavenumbers for iteration. Numerical results indicate that the proposed method is not only reasonable and feasible but also better than the previous method. The proposed method is an improvement of the previous one, which is beneficial to improving the precision of plane wave fitting of the T/P internal tidal SSH signatures and deepening the understanding of the internal tides in ocean.

关键词： plane wave fitting internal tides TOPEX/Poseidon altimeter data