Generation of internal waves in the region of a bottom ridge with continuously varying height

Internal waves generated by a barotropic wave impinging on a bottom ridge with continuously varying height are studied within the framework of the linear theory of long waves. We consider the case where the diurnal tide travels at an arbitrary angle to the axis of the ridge located in the area of a geostrophic flow caused by tilting of the free sea surface and the interface of a two-layer ocean. We study the dependences of the amplitudes of internal waves on the velocity of the geostrophic flow, the direction of propagation of the barotropic tide, and the geometry of the ridge. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Generation of internal waves in a three-layer ocean

Within the framework of the linear theory of long waves taking into account the action of the Coriolis force, we solve the problem of generation of internal waves by a barotropic tide impinging on a bottom irregularity of the sea-ridge type. The cross section of the ridge is assumed to be rectangular and the stratification of the ocean is regarded as stepwise with two thermoclines (three-layer model). We study the dependences of the characteristics of generated waves on the parameters of stratification and the period of the impinging barotropic tide. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Investigation of transformations of barotropic tides in the coastal zone

Within the framework of the linear theory of long waves, we perform the numerical investigation of transformations of a barotropic diurnal tide in the process of its motion from the deepwater region of the sea into the region of continental slope and shelf zone at any angle to the coast line. For a linear profile of the bottom of the continental slope and shelf, we establish dependences of the amplitudes and velocities of waves on the direction of propagation of the tidal wave and the latitude of the place. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

The impact of stratification on the wave velocity field generated by a barotropic tide impinging upon an oceanic ridge

The horizontal wave velocity field generated by a barotropic tide impinging upon a subwater ridge is considered in the linear theory assumptions for long waves. The ocean is assumed to be twolayered, with the tidal wave on-running at an arbitrary angle to the ridge axis. The dependence of the horizontal velocity amplitudes on stratification, the angle of barotropic tide impinging, and the bottom feature geometry is studied.Translated by V. Puchkin.     

The effect of a current upon the generation of internal waves by a semi-diurnal tide in the vicinity of a ridge with a continuously changing height

In the framework of the linear theory for long waves, the paper studies internal waves generated by a semi-diurnal barotropic tide impinging on a bottom ridge at an arbitrary angle. The ocean is assumed to be double-layered. In the vicinity of the ridge, whose height is continuously changing, geostrophic flows occurring due to the inclination of the free surface and interface are considered. The dependencies of the generated wave's amplitudes on the angle of incidence of the tide and on the magnitude and direction of the geostrophic current velocity are determined, allowing a conclusion that the current contributes to the generation of internal waves. Translated by Vladimir A. Puchkin.     

The effect of currents on the generation of internal waves by a barotropic tide near an underwater ridge

In the frame of the linear theory for long waves, the paper studies long waves generated by a barotropic tide running at an arbitrary angle over a bottom ridge. The ocean is assumed to be two-layered. In the area of a ridge with a rectangular cross section, geostrophic flows are considered, coupled with the inclinations of the free surface and interface. Wave amplitudes are shown to depend on the angle of an onrunning tide and this allows us to reach a conclusion about the influence of a geostrophic current on the generation of internal waves. Translated by Vladimir A. Puchkin.     

The generation of internal waves by the barotropic tide at an oceanic ridge

The generation of internal waves by the barotropic tide in a two-layer ocean of variable depth is studied within the framework of the linear theory of long waves in view of the Coriolis force. The relationships between the internal wave amplitude, the angle of climb of the barotropic tide, and the bottom elevation geometry are studied.Translated by Mikhail M. Trufanov.     

The generation of internal waves by the diurnal barotropic tide in the area of extensive irregularity of the bottom topography

The generation of internal waves by the barotropic tide in a two-layer ocean of variable depth is studied within the framework of the linear theory of long waves in view of the Coriolis force. A barotropic wave climbs at an arbitrary angle to the axis of the extensive ridge with constantly varying profile. The relationships between the amplitudes of the generated internal waves, the location of the ridge, and the angle of climb of the barotropic tide are studied. The analogous research is given in refs 1 and 2.Translated by Mikhail M. Trufanov. UDK 532.59.     

Generation of long barotropic waves by moving baric disturbances in a system of basins connected by a channel

We consider long barotropic waves in a system of two rectangular basins connected by a channel in the case where waves are generated by the moving region of disturbances of atmospheric pressure passing above one of the basins. By using a numerical model, we compute the characteristics of the wave process for various values of the parameters of this system. The results of numerical calculations are compared with the corresponding characteristics obtained for the case of a closed basin. We also analyze the distinctive features of long-wave processes induced in the presence of the channel. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Non-linear model for the generation of baroclinic tides over extensive inhomogeneities of the seabed relief

A numerical model is developed for the generation of internal waves induced by a barotropic tidal wave travelling over large bottom features. Motion equations consider the non-linear terms, as well as the terms responsible for horizontal turbulent exchange. The fluid is assumed to be continuously stratified. In the framework of the developed model, a packet of short non-linear internal waves is shown to occur together with a long baroclinic tide. In the absence of non-linear terms in the equations of motion, the model data are qualitatively and quantitatively consistent with the data provided by known linear models.Translated by V. Puchkin.     

Investigation of internal waves generated by a diurnal barotropic tide in the vicinity of an oceanic ridge

Internal waves occurring near an oceanic ridge as a result of impingement of a barotropic tide are scrutinized in terms of the long theory for long waves. The ocean is assumed to be double-layered, the relief continuously changing, and the tidal wave on-running at an arbitrary angle. The dependences of the wave amplitudes and horizontal velocities on the ridge's latitude, the angle of tide running, and the depth of the density jump layer are obtained. Similar investigations for the model bottom relief have been conducted in refs 1 and 3.Translated by Vladimir A. Puchkin.     

Generation of internal waves resulting from the interaction of a barotropic tide with a horizontallyinhomogeneous density field and bottom topography

This paper addresses the problem of the generation of internal waves by a barotropic tide propagating in a uniformly stratified sea across the frontal zone overlying a submerged ridge or a continental slope. Using Riemann's technique, we have performed computations and analysed the wave fields' spatial characteristics and have defined the dependences of the generated wave amplitudes, bottom topography parameters, and density field. It is shown that the presence of a horizontally-inhomogeneous density region over a subwater feature may lead to substantial alteration of the maximum amplitudinal values of internal waves, both inside and around the frontal zone.Translated by Vladimir A. Puchkin.     

The influence of stratification on the field of wave disturbances generated by a barotropic tide in the vicinity of the Mid-Atlantic ridge

In the framework of the linear theory for the long waves occurring in a fluid with a density gradient, the paper concentrates on the field of wave disturbances generated by a barotropic tide in the vicinity of the Mid-Atlantic ridge. Dependences of the wave amplitudes and velocities on the stratification parameters, the angle of onrunning and the period of the barotropic tide have been obtained. A similar study for a model ridge relief of paraboloidal shape has been conducted in ref. 1. Translated by Vladimir A. Puchkin.     

Generation of internal waves by a semidiurnal barotropic tide in the Mid-Atlantic ridge area

Internal waves occurring in the specific Mid-Atlantic ridge area as a result of the impinging of a barotropic tide are studied in the terms of the linear theory for surface waves. The ocean is assumed to be double-layered, with a tidal wave running onto it at an arbitrary angle. The dependences of the wave amplitudes and horizontal velocities on the angle of run-on of a tidal wave are derived. Similar studies for the model bottom topography have been reported in refs 1–3. Translated by Vladimir A. Puchkin.     

底地形变化对内潮产生影响的数值研究

本文结合南沙群岛海域出现内潮的水文背景,建立了一个两层数值模式,并通过数值试验来探讨由正压潮波作用下的内潮产生机制。结果表明：底形效庆是促使内潮产生的重要因子;内潮心要在大陆坡产生,然后分别沿着大陆架和深海平原两个方向传播;内潮斜压流速的量级可与正压流速的相比拟。     

南海东沙岛西南大陆坡内潮特征

2008年4月-10月,在南海东沙岛西南大陆坡底部布放了1套全剖面锚系,同时沿大陆坡底部布放了3套近底锚系,应用谱分析和调和分析方法分析温度和海流连续观测资料,进而研究该海域的内潮特征.结果表明,东沙岛西南大陆坡存在强内潮现象,大陆坡底部温度变化受到内潮波的影响,上层海洋存在强日潮周期的内潮波振动;正压潮和斜压潮均以O...     

The generation of non-linear internal waves by a barotropic tide in the area of a solitary bottom elevation

A mathematical model is suggested for calculating current, density, and pressure fields in the area of a solitary bottom rise (seamount). The model is based on a set of non-linear differential equations governing the motion of an inviscid continuously stratified fluid. The algorithm for solving the equations is based on the splitting technique. The model has been used to compute non-linear baroclinic waves generated by a barotropic tide in the seamount area. Translated by Vladimir A. Puchkin.     

Analysis of the intensification of tsunami waves near the South Coast of Crimea

We perform the numerical analysis of the intensification of tsunami waves in the course of their propagation from the open part of the Black Sea to the shelf zone. For this purpose, we use a one-dimensional model of nonlinear long waves taking into account the effect of bottom friction. We study four profiles of the bottom corresponding to the south coast of the Crimean Peninsula and establish the predominant role of the bottom pattern and insignificant contribution of nonlinearity to the transformation of waves in the process of their propagation in the direction of the coast. Down to depths of 50 m, all changes in the height of waves are described by the Green law. For the evaluation of vertical run-up of waves, it is important to take into account nonlinear effects. The highest vertical run-ups of waves are observed in the parts of the shelf zone located near Yalta and Alushta. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Generation of internal waves by barotropic tidal flow over a steep ridge

A three-dimensional nonhydrostatic numerical model is used to study the generation of internal waves by the barotropic tidal flow over a steep two-dimensional ridge in an ocean with strong upper-ocean stratification. The process is examined by varying topographic width, amplitude of the barotropic tide, and stratification at three ridge heights. The results show that a large amount of energy is converted from the barotropic tide to the baroclinic wave when the slope parameter, defined as the ratio of the maximum ridge slope to the maximum wave slope, is greater than 1. The energy flux of internal waves can be normalized by the vertical integral of the buoyancy frequency over the ridge depths and the kinetic energy of the barotropic tides in the water column. A relationship between the normalized energy flux and the slope parameter is derived. The normalized energy flux reaches a constant value independent of the slope parameter when the slope parameter is greater than 1.5. It is inferred that internal wave generation is most efficient at the presence of strong upper-ocean stratification over a steep, tall ridge. In the Luzon Strait, the strength of the shallow thermocline and the location of the Kuroshio front could affect generation of internal solitary waves in the northern South China Sea.     

Generation of geostrophic vortices caused by displacements of a part of the bottom of a basin

Within the framework of the general linear statement of the problem, we determine the conditions of generation of a geostrophic current in a layer of uniform rotating fluid for small displacements of the bottom of a basin. We deduce an equation relating the equilibrium shape of the surface of the fluid with residual deformations of the bottom and find its general solution. It is shown that the geostrophic current is generated only in the presence of residual deformations. We present numerical estimates of the intensity of the generated geostrophic formation for a model of motion of the bottom. The investigated mechanism of generation of geostrophic vortex fields is especially efficient in the shelf zone of the ocean. Translated by Peter V. Malyshev and Dmitry V. Malyshev