共查询到20条相似文献，搜索用时 31 毫秒
1.
We show that the parameters of primary radar images obtained from theSich-1 satellite depend on the mode of survey and that the time dependence of the coefficient of correction of amplification in
the channel of formation of radar signals is nonlinear. We propose to process radar images of the sea surface by using the
so-called Bragg normalization of signals, which enables one to get a physically correct dependence of specific effective scattering
surface on the elevation angle. We also consider a procedure of determination of the dependence of specific effective scattering
surface of the sea on the wind velocity on the basis of the data accumulated by the side-looking radar of theSich-1 satellite.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
2.
A. M. Chukharev 《Physical Oceanography》1999,10(2):175-182
For a one type of temperature turbulent convection observed in the ocean, i.e., for the two-dimensional roller-type convection,
we propose a model intended for the evaluation of the intensity and depth of penetration of convective motions as functions
of a given heat flow from the sea surface and the temperature gradient in the thermocline. This model is based on the methods
of the theory of turbulent jets and experimental data on the vertical distribution of temperature in the course of convection.
The comparison of the calculated dimensionless values of the depth of penetration of the thermocline in autumn and winter
shows a good qualitative agreement with the data ofin situ measurements.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
3.
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
4.
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
5.
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
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.
I. E. Timchenko A. A. Primalenny V. D. Yarin E. F. Vasechkina E. M. Igumnova 《Physical Oceanography》2001,11(4):367-378
We use many-year archival observations of hydrologic and hydrobiologic state of the Sea of Azov for the identification of
the structure of a model of its ecosystem. The ecosystem model, supplemented with expert estimates of bioresource consumption
(fish reserve), contamination level, and possible ecologic fines for violation of the sea natural state, is formalized by
the method of system dynamics. Hereat, the major part of influence functions is found in terms of observational data with
application of self-organization algorithms. We also present the results of simulated experiments with the model of the ecosystem,
which enable us to analyse scenarios of its behaviour under the influence of various external factors (wind, river discharge,
water exchange with the Black Sea, etc.).
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
8.
S. A. Grodsky V. N. Kudryavtsev A. N. Bol'shakov V. E. Smolov 《Physical Oceanography》2001,11(4):333-352
On the oceanographic platform of the Marine Hydrophysical Institute of the Ukrainian National Academy of Sciences, we performedin situ investigations of surface waves based on the analysis of the fluctuations of radar signals at a wavelength of 1.2 cm. We
analyzed both the traditional modulation transfer function used to describe variations of the scattering cross section for
the scales of surface waves and the correlation of mean variations of the level of radar signals with the group structure
of waving. This is of interest for applications in medium-resolution radar systems (−200–500m) recording the group structure
of waving in the process of its smoothing. The experimental estimations of the amplitude of variations of radar signals caused
by the group structure of waving are in good agreement with numerical results obtained with the help of a two-scale model
of scattering of radar signals by the sea surface.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
9.
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 相似文献
10.
We present the results of investigation of the transformation of a momentum flux coming from the atmosphere into a water reservoir
and establish the relationship between the surface velocity of the drift current and the dynamic velocity of wind. For the
initial stage of the development of wind waves, we propose a dependence that enables one to determine the momentum flux spent
for an increase in the intensity of waves via the momentum flux coming into the water reservoir from the wind. The behavior
of the ratio of the momentum flux spent for the increase in the intensity of waves to the total momentum flux coming from
the atmosphere into the water is studied depending on the dimensionless fetch and age of waves. In our analysis, we used both
our own experimental data and the data available from the scientific literature.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
11.
Ｅｆｆｅｃｔ ｏｆ ａｉｒ－ｓｅａ ｔｅｍｐｅｒａｔｕｒｅ ｄｉｆｆｅｒｅｎｃｅ ｏｎ ｔｈｅ ｍｏｍｅｎｔｕｍ ｅｘｃｈａｎｇｅ ｂｅｔｗｅｅｎ ａｉｒ ａｎｄ ｓｅａ ｆｏｒ ｆｅｔｃｈ－ｌｉｍｉｔｅｄ ｃａｓｅｓＣｈｅｎｇＺｈａｎａｎｄＷｕＳｈ... 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.
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
14.
N. A. Panteleev 《Physical Oceanography》1999,9(6):405-416
We present an analytic survey of a series of works devoted to the direct methods for the investigation of turbulence in natural
basins originated under the guidance of A. G. Kolesnikov in the 50s. We describe the principal results of the early stage
which formed the basis for future investigations. The main scientific directions of the latest period are also considered
from the viewpoint of the development of Kolesnikov's ideas: investigation of the processes of generation and energy supply
of small-scale turbulence, relationship between turbulence and the fine vertical structure and internal waves, and the mechanisms
of vertical turbulent exchange in the ocean. A model of vertical exchange under the conditions of intermittent “source” turbulence
is distinguished. We also discuss the directions of development and prospects of the investigation of turbulence.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
15.
根据 1 994年 9月 1 8— 30日南沙群岛海域渚碧礁的近海面大气湍流观测实验资料 ,分别计算了该海域光滑海面和粗糙海面上的空气动力粗糙度 (z0 )、中性曳力系数 (CDN)。利用Brutsaert的假定 ,推导了一组求取标量粗糙度 (zT,zQ)、整体输送系数 (感热交换系数CHN、水汽交换系数CEN)的公式。在此基础上分别计算和分析了该海域近海面光滑海面和粗糙海面上z0 ,zT,zQ,CDN,CHN,CEN 及它们关于水平风速u分量的分布 ,并得到了一些有意义的结论。 相似文献
16.
Paul A. Hwang 《Journal of Oceanography》2005,61(1):91-107
Depending on the choice of reference wind speed, the quantitative and qualitative properties of the drag coefficient may vary. On the ocean surface, surface waves are the physical roughness at the air-sea interface, and they play an important role in controlling the air-sea exchange processes. The degree of dynamic influence of surface waves scales with wavelength. Drag coefficient computed with the reference wind speed at an elevation proportional to the wavelength (for example, U
λ/2) is fundamentally different from the drag coefficient computed with the wind speed at fixed 10 m elevation (U
10). A comparison has been carried out to quantify the difference in wind stress computation using several different parameterization functions of the drag coefficient. The result indicates that the wind stress computed from U
10 input using a drag coefficient referenced to U
λ/2 is more accurate than that computed with drag coefficient functions referenced to U
10. 相似文献
17.
A parameterization of subgridscale surface fluxes over the marginal sea ice zone which has been used earlier in several studies is modified and applied to a nonhydrostatic mesoscale model. The new scheme accounts for the form drag of ice floes and is combined with a so-called flux averaging method for the determination of surface fluxes over inhomogeneous terrain. Individual fluxes over ice and water are calculated as a function of the blending height. It is shown by comparison with observations that the drag coefficients calculated with the new parameterization agree well with data. The original scheme strongly overestimates the form drag effect. An improvement is mainly obtained by an inclusion of stratification and by use of a more adequate coefficient of resistance for individual ice floes. The mesoscale model is applied to off-ice flows over the polar marginal sea ice zone. The model results show that under certain meteorological conditions the form drag can have a strong influence on the near-surface wind velocity and on the turbulent fluxes of momentum. Four case studies are carried out. The maximum influence of form drag occurs in the case with strong unstable stratification and with wind oblique to the ice edge. Under these conditions the wind stress on sea ice is modified by at least 100% for ice concentrations less than 50% if form drag is taken into account. 相似文献
18.
É. N. Mikhailova V. A. Ivanov A. I. Kubryakov N. B. Shapiro 《Physical Oceanography》2000,10(4):305-311
We use mathematical simulation to study the response of the sea in the region of the Zmeiny Island to the action of winds
of various directions. We describe the processes of reconstruction of circulation and thermohaline structure of waters and,
in particular, the location and dimensions of the zones of upwelling and downwelling caused by water surges depending on the
direction of the wind.
Translated by Peter V. Malyshev and Dmitry V. Malyshev 相似文献
19.
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 相似文献
20.
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 相似文献