On the influence of a diurnal baroclinic tide on the diffusion of an impurity

We investigate the influence of baroclinic tidal waves on the diffusion of an impurity spot in a continuously stratified liquid. The equation of turbulent diffusion is solved numerically by taking into account the wave currents. We establish the dependences of the characteristics of the diffusion process on the parameters of the baroclinic wave and the location of the impurity spot. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Generation of internal waves by a barotropic tide in the coastal zone

Within the framework of the linear theory of long waves, we study internal waves generated by a barotropic tide in a two-layer ocean of variable depth taking into account the influence of the Coriolis force. Barotropic waves run over an extended unevenness of the bottom at an arbitrary angle. This unevenness is regarded as a model of the continental slope and shelf. We establish the dependences of the amplitudes of generated internal waves on the angle of incidence of the barotropic tide, topography of the bottom, and stratification. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Seiches in a circular basin of variable depth

Free waves (seiches) in a circular basin of variable depth are studied numerically within the framework of the linear theory of long waves taking into account the action of the Coriolis force. We determine the frequencies of axisymmetric and circular waves, study the structure of the modes of elevation of the free surface and wave velocities, and establish the dependences of the phase velocities of circular waves on the number of mode and wavelength. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Incidence of flexural gravitational waves on the line of contact of two floating ice plates of different thickness

We analyze the influence of a rift in an ice field on the propagation of flexural gravitational waves in a basin of finite constant depth. The ice cover is simulated by two floating semiinfinite elastic plates of different thickness. We studied the dependence of the amplitude coefficients of reflection and transmission of waves incident on the rift on the frequency of running waves, the thickness of ice on both sides of the rift, and the type of contact boundary conditions at the rift. Translated by Peter V. Malyshev and Dmitry, V. Malyshev     

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     

Diffusion in the ocean with diffusion coefficient depending on the scale and concentration of impurities

We solve a nonlinear problem of diffusion from a concentrated source in a moving medium with diffusion coefficient depending on the scale of the phenomenon, time, and the concentration of impurities. We obtain a family of exact solutions of this problem, which can be regarded as a generalization of the class of linear problems of diffusion considered earlier for the conditions of the ocean and atmosphere by Roberts, Ozmidov, Obukhov,et al. Translated by Peter V. Malyshev and Dmitry V. Malyshev.     

Correlation between the intensity of tsunami in the Black Sea and the magnitude of underwater earthquakes

We perform the analysis of tsunami waves in the shelf zone of the Crimean peninsula generated by underwater earthquakes whose epicentres are located near the lower boundary of the continental slope. For this purpose, we use a one-dimensional nonlinear dissipative numerical model of long waves. The investigated distributions of the depth of the basin correspond to four points of the south coast of the Crimean peninsula. We use the empirical dependences of parameters of the sources of tsunami waves on the magnitude of the earthquake obtained earlier for the Pacific Ocean. It is shown that the height, vertical climb, and duration of tsunami waves increase with the magnitude of the earthquake. For equal magnitudes of the earthquake, the highest tsunamis on the south coast of the Crimea are observed between Alushta and Yalta. We also deduced a generalized regression dependence of the height of tsunami waves near the coast on the magnitude of the earthquake. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Influence of the discharge of rivers on the formation of level of a closed sea

Within the framework of a two-layer model, we consider the process of, formation of livel in a closed basin under the action of a source with constant flow rate located on its boundary in the upper layer. The response of the level of the basin to the inflow of liquid is observed in the form of the baroclinic and barotropic modes. The baroclinic mode, has the form of an edge wave for which the deviation of level is positive for the upper layer and negative for the lower layer. The barotropic component of the level is almost spatially homogeneous and its intensity increases with time. The increase in the volume of the upper layer caused by the inflow of liquid on the boundary is almost completely attained in the barotropic mode. In the lower layer, the increase in the volume attained in the barotropic mode is completely compensated by the baroclinic edge wave. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Trapped bottom topographic waves over the inclined bottom

In the Boussinesq approximation, we study baroclinic topographic waves trapped by the flat meridional slope. The existence of these waves is explained by stratification, inclined bottom, and Earth's rotation. We deduce the evolutionary equation for the square of the envelope of a narrow-band wave packet of trapped waves. In the second order of smallness relative to the wave amplitude, we find the mean fields of velocity and density induced by the packet. It is shown that, in the limiting case of weakly nonlinear plane waves, the induced current is zonal. In the Northern hemisphere, depending on the slope of the bottom γ₁, the sign of the phase velocity σ/k (k is the zonal wave number) is either always positive (for γ₁>γ_1cr) or always negative (for γ₁<γ_1cr). If we neglect the vertical component of the Coriolis acceleration, then γ_1cr=0. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

North Brazil Current: Variability, stability and transport of waters

On the basis of the data of thein situ measurements of current velocities and other basic hydrophysical parameters (temperature and salinity) performed in the course of Cruise 41 of the R/VAkademik Vernadsky, we analyze the variability and stability of the North Brazil Current in winter. We also study the possibility of the influence of the baroclinic component of the horizontal drop of hydrostatic pressure on the vertical profile of the current velocity and estimate the intensity of the transport of waters. 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     

Modelling of the propagation of passive impurities in Sevastopol bays

We discuss the results of numerical experiments modelling the process of propagation of passive impurities from the Karantinnaya Bay caused by steady wind currents and turbulent diffusion. The currents are computed according to the Felzenbaum model for the cases of northeast and north-west winds [1, 2]. We analyse specific features of the space and time distribution of the impurities caused by the three-dimensional character of the currents. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Generation of internal waves in the sea by local perturbations of wind and density flows on the surface

On the basis of a nonlinear model taking into account viscosity, density diffusion, and currents, we perform the numerical analysis of propagation of perturbations formed in the abyssal part of the Black Sea as a result of the action of tangential wind stresses or density flows in the form of a strip on the sea surface. It is shown that, in the course of time, in the region of the bottom slope, these perturbations generate a train of waves in the sea, which causes oscillations of the fields of density and currents. There are some differences between the generation of internal waves by the flows of density and the wind. Unlike the wind action, in the presence of flows of density in the upper layer in the region of the strip, the initial period of generation is characterized by the formation of intense perturbations without train structure. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Mass transfer by nonlinear waves in a basin with floating broken ice

We study the influence of floating broken ice on the mean nonzero displacements of liquid particles in nonlinear running surface waves. The analysis is performed on the basis of a uniform asymptotic expansion (up to the quantities of the third order of smallness as compared with the potential of the velocity of motion of liquid in a basin of finite depth) obtained by the method of multiple scales. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

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     

Propagation of passive impurities in the northwest part of the Black Sea under the action of cyclones moving to the north

We perform the theoretical analysis of the turbulent diffusion of impurities in the sea in the presence of long waves. The role of generators of long-wave motions is played by moving cyclonic baric formations. At the initial time, the zone of pollution is specified in the form of a spot of a passive substance localized near the Karkinitskii Bay in the Black Sea. The results of our investigations enable us to estimate the contribution of long waves to the process of diffusion of the spot of impurity depending on the trajectory of motion of the cyclonic formation. It is shown that, under the action of waves induced by the cyclone, the maximum concentration in the spot decreases more rapidly only for a certain period of time. Moreover, we observe a northwest displacement of the spot specified by the structure of the wave field.Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 3–18, July–August, 2004.     

Structure and kinematics of waters in the region of the Argentine Islands in the autumn of 1998

On the basis of the data of the complex oceanographic experiment carried out in the course of the second Ukrainian Antarctic expedition in March 1998, we study the structure and kinematics of waters in the region of the archipelago of Argentine Islands. The regularities of thermohaline stratification of waters are discovered. We determine the most important environmental parameters premoting the variability of hydrophysical fields on time scales varying from several days up to a week, analyse the data of actual observations over the currents, and estimate the relative contribtions of diurnal and semidiurnal tidal waves to the total dispersion of hydrophysical parameters of the environment. The residual currents are filtered out. We propose a hypothesis about the mechanism of their formation. Various types of tidal currents are revealed and the directions of propagation of diurnal and semidiurnal tidal waves are determined. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Evolution of waves induced by periodic variations of pressure in a bounded basin of variable depth

Within the framework of the linear theory of long waves, we study the evolution of a wave process caused by the action of surface pressure periodically varying in time in a bounded basin of variable depth without vertical walls. We assume that the basin is filled with a homogeneous liquid nonperturbed at the initial time and take into account the action of dissipative forces. We obtain the analytic solution of the posed problem. It is used to perform the detailed analysis of the influence of the dissipative forces and the frequency of perturbing pressure on the characteristics of the process of evolution of waves. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

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     

Distributed thermoprofilometers and their capabilities in oceanographic investigations

We describe the principles of design of distributed thermoprofilometers and analyze their characteristics and the required hardware, algorithms, and software. The capabilities of these instruments in the investigation of temperature fields, vertical displacements, and the parameters of internal waves are evaluated. The results of measurements and numerical calculations are presented. Translated by Peter V. Malyshev and Dmitry V. Malyshev