共查询到20条相似文献,搜索用时 15 毫秒
1.
V. F. Ivanov 《Physical Oceanography》2001,11(5):425-437
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 相似文献
2.
V. F. Ivanov 《Physical Oceanography》2001,11(3):205-219
For various stratifications and different types of bottom patterns we study the transformations of solitary perturbations
of density appearing in the depth of the sea. In the two-dimensional case, under the assumption that the average dynamic characteristics
weakly vary in time as compared with the wave characteristics, we deduce the equations for mean currents and waves taking
into account vertical and horizontal viscosity and the diffusion of density. Numerical examples show that the stratification,
bottom topography, nonlinearity, mean currents, and dissipation strongly affect both the process of splitting of a solitary
wave into wave trains and their amplitude and length. The wave currents exhibit the oscillatory (train-like) character. It
is emphasized that, in the case of propagation of solitary perturbations of density with dissipation, it is also important
to take into account the combined influence of nonlinearity, currents, bottom topography, and stratification.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
3.
We study the influence of baroclinic tidal waves on the diffusion of an impurity spot in a continuously stratified fluid.
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 parameters of baroclinic waves and the location of the impurity spot.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
4.
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 相似文献
5.
In the coastal zone, as a result of mixing of waters, it is difficult to identify turbulent phenomena with a spatial scale
of 0.1–1 km accompanied by strong vertical flows according to the data of measuring temperature. On the basis of the data
of direct measurements, it is shown that turbulent structures are well pronounced in the field of breaking of wind waves.
We deduce empirical estimates of the response of the intensity of wave breaking to the magnitude of divergence of the current
and develop a theoretical model of the influence of inhomogeneities of currents on wave breaking capable of describing the
experimental data.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
6.
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 相似文献
7.
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 相似文献
8.
N. P. Bulgakov V. V. Ukrainsky Yu. I. Popov P. D. Lomakin Yu. V. Artamonov 《Physical Oceanography》2001,11(5):447-457
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 相似文献
9.
Based mainly on TOGA COARE data, that is, the CI''D data from R/V Xiangyanghong No.5 (Pu et al.,1993),the temperature and current data from the Woods Hole mooring and other deep current data, the layered numerical profiles of buoyancy frequency and mean current components are figured out.A numerical method calculating internal wave dispersion relation without background shear current, used by Fliegel and Hunkins (1975),is improved to be fit for the internal wave equation with mean currents and their second derivatives.The dispersion relations and wave functions of the long crested internal wave progressing in any direction can be calculated inveniently by using the improved method.A comparison between the calculated dispersion relation in the paper and the dispersion relation in GM spectral model of ocean internal waves (Garret and Munk, 1972) is performed.It shows that the mean currents are important to the dispersion relation of internal waves in the western equatorial Pacific Ocean and that the currents make the wave progressing co-directional with (against) the currents stretched (shrink).The influence of the mean currents on dispersion relation is much stronger than that of their second derivatives, but that on wave function is less than that of their second derivatives.The influences on wave functions result in the change of vertical wavenumber, that is, making the wave function stretch or shrink.There exists obvious turning depth but no significant critical layer absorption is found. 相似文献
10.
O. Yu. Lavrova M. I. Mityagina K. D. Sabinin A. N. Serebryany 《Izvestiya Atmospheric and Oceanic Physics》2011,47(9):1119-1126
Results of satellite observations of surface manifestations of internal waves in the Caspian Sea are presented. It is proposed
that the possible cause of generation of the revealed internal waves is uninodal seiches with a nodal line located in the
vicinity of the Apsheron Sill. The basic parameters of internal waves in the Caspian Sea, having the form of classical soliton
trains, are determined. Seasonal variability of surface manifestations of the internal waves is revealed. The horizontal current
velocity of the solitons is assessed. According to the estimation, velocity is about 0.2 m/s, which is sufficient for wind
ripple modulation. 相似文献
11.
We the discuss the results of modelling wind currents in the system of Sevastopol bays. Numerical calculations are carried
out according to the model of Felzenbaum. It is shown that the decisive role in the formation of distinctive features of circulation
of waters and the essentially three-dimenstional character of currents in this part of the sea is played by the bottom topography
and the direction of winds. These distinctive features are demonstrated for the cases where the motion is induced by the northeast
and northwest winds. In the Sevastopol bays, we discovered the existence of jet longshore currents, vortex character of integral
circulation, and intense processes of upwelling and downwelling.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
12.
O. I. Efremov 《Physical Oceanography》2000,10(3):193-204
A method of statistical separation of fine-structure fluctuations according to their origin is applied to the analysis of
the characteristics of mixing in a layer located below the summer temperature minimum in the Black Sea. The simplification
of the procedure of numerical evaluation of the coefficient of vertical wave exchange enabled us to perform the comprehensive
fine-structure processing of the data of regular surveys of the Black Sea with an aim to determine the spatial distribution
of the field intensity of small-scale internal waves and the intensity of mixing caused by these waves in the analyzed layer.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
13.
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 相似文献
14.
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 相似文献
15.
A. A. Slepyshev 《Physical Oceanography》2000,10(5):401-418
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>γ1cr) or always negative (for γ1<γ1cr). If we neglect the vertical component of the Coriolis acceleration, then γ1cr=0.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
16.
S. F. Dotsenko 《Physical Oceanography》2000,10(6):485-493
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 相似文献
17.
The variability of the parameters of semidiurnal internal tides in Mamala Bay (Oahu Island, Hawaii) was investigated using the experimental data obtained with ADCP bottom current profilers and ther-mistor strings. It was stated that the size, shape, and orientation of the orbits, as well as the sign of the rotation of the orbital currents, are rarely similar to those characteristic of progressive internal waves on a rotating Earth. It is supposed that such unusual features of the orbital currents are related to the interference of the waves that arrive from the straits rimming Oahu Island and to the waves that, under favorable conditions, are episodically generated at the shelf edge of Mamala Bay. Due to the fact that the floor inclinations of the shelf in the bay are supercritical for semidiurnal internal tides, the local generation of internal tides is poorly efficient. 相似文献
18.
We describe a differential approach to the spectral composition of thin thermohaline inhomogeneities in the ocean depending
on the mechanisms responsible for their generation and demonstrate the possibilities of this approach in getting realistic
hydrophysical results. The statistical classification of fine-structure fluctuations according to their origin is performed
on the basis of the joint analysis of the temperature, salinity, and density spectra computed in a section of the vertical
profile where the variation of mean gradients of all three parameters is insignificant. On the basis of the constructed mean
spectrum of wave elevations, we estimate the dissipative characteristics of the convection of salt fingers and small-scale
internal waves.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
19.
With the help of a combined model of wind and waves, we study the influence of films of surfactants on the spectrum of short
wind waves and the parameters of the lowest layer of the atmosphere. It is shown that the films of surfactants decrease the
roughness of the sea surface as a result of suppression of short wind waves, which decreases the coefficient of resistance
of the sea surface and the coefficient of turbulent heat exchange. The maximum influence of films on the exchange coefficients
is attained forU∼10 m/s. In this case, the relative decrements of the coefficients of resistance and turbulent heat exchange are equal to
15 and 9%, respectively.
Translated by Peter V. Malyshev and Dmitry V. Malyshev UDC 551.46 相似文献
20.
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 相似文献