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1.
In May 2007, the Marine Hydrophysical Institute of the Ukrainian National Academy of Sciences carried out an oceanographic
expedition in the northwest sector of the Black Sea. This expedition originates a series of surveys scheduled for this region.
It was realized within the framework of national and international projects, such as Climate, Ecoshelf, Stable Ecosystem, SESAM, ECOOP, and Oceanography. We present the data on the works carried out in this expedition and perform a brief analysis of the process of subduction
of waters on the northwest shelf. It is shown that, despite the abnormally warm preceding autumn–winter period, the wellpronounced
subduction of waters formed in the process of autumn–winter cooling was still observed over the drop of depth along the isopycnic
surfaces σt = 14.0 and σt = 14.5–14.6 in May 2007. New data on the intensity of vertical turbulent exchange over the continental slope in the northwest
part of the Black Sea are obtained. 相似文献
2.
A. A. Slepyshev 《Physical Oceanography》2005,15(5):275-288
In the Boussinesq approximation, for topographic waves entrapped by a sloping bottom, we determine mean currents induced by
a wave due to nonlinearity with regard for turbulent viscosity and diffusion. We determine the thickness of the bottom boundary
layer, the vertical turbulent exchange coefficients, and turbulent stresses on the upper boundary of the boundary layer depending
on the parameters of the wave. In the diffusion approximation, we find the vertical distribution of the concentration of sediments
suspended by the wave and the flow rates of sediments along and perpendicular to the isobaths.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 5, pp. 13–24, September–October, 2005. 相似文献
3.
S. G. Demyshev 《Physical Oceanography》2010,20(3):184-195
Within the framework of the Mellor–Yamada approach, we realize a numerical scheme for the calculation of the coefficients
of turbulent viscosity and diffusion in the z -system of coordinates for the three-dimensional model of operative prediction of currents in the Black Sea. Some discrete
analogs of the equations for turbulent kinetic energy and turbulence macroscale are studied. Their high sensitivity to the
choice of finite-difference approximations is demonstrated. On the basis of the comparison of the results of prognostic experiments
with the data of observations, we choose the best approximation of the term used to describe the generation pf turbulence
energy. 相似文献
4.
Estimates of vertical turbulent diffusion coefficient (K t ) in the Black Sea pycnohalocline have been obtained from data of simultaneous observations of seawater temperature, salinity, density, and horizontal current velocity, obtained in the northeastern part of the Black Sea during 2013–2014 with a moored Aqualog profiler. A Munk and Andersson (1948) type parameterization, adapted for the Black Sea environment, is proposed for calculating K t . Strong short-period (several days) variability of turbulent exchange is revealed, induced by vertical shear variations of the current velocity. 相似文献
5.
The influence of high vertical velocity gradients in the Black Sea Rim Current on the intensity of the vertical turbulent exchange is demonstrated on the basis of numerical modeling based on CTD data. The vertical turbulent exchange is confirmed by the anomalous distribution of the hydrochemical parameters in the redox layer. A system of equations for the kinetic energy of the turbulence and dissipation rate (k-? model) is used for the calculation of the coefficient of the vertical turbulent viscosity (diffusivity). 相似文献
6.
We construct a one-dimensional nonstationary isopycnic model of vertical exchange in the Black Sea with regard for the processes
of draining and transformation of waters of the Sea of Marmara (or “plume”), vertical diffusion, and the action of winter
convection in the upper layer. It is assumed that mixing in the basin is local in space and time and that the winter wind
action remains constant from year to year in the analyzed version of the model. The temperature of the upper mixed layer introduced
to simulate the winter conditions is regarded as the principal external variable factor. Within the framework of the accepted
restrictions, the model enables us to study the annual and interannual variability of the thermohaline characteristics and
hydrochemical parameters in the water column of the sea. As an example, we perform the numerical analysis of the periodic
action of external thermal conditions on the characteristics of the system with a period of six years.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 5, pp. 3–21, September–October, 2006. 相似文献
7.
We perform the experimental verification of the applicability of the theory of similarity to the wave boundary layer and the
assessment of wave-induced perturbations of the air flow depending on various conditions of stratification of the atmosphere
and the state of the sea. The measurements were carried out from a stationary platform located in the coastal part of the
Black Sea. The experimental procedure is based on the simultaneous measurements of the profile and fluctuations of the wind
speed at 5–6 levels in the 1.3–21-m layer, the elevations of the sea surface, the directions of waves and winds, and the mean
gradients of temperature and humidity of air. The structure of the boundary layer in the region of measurements depends on
the direction of the wind. For weak and moderate onshore winds (< 9 m/sec), the approximate balance is preserved between the
production and dissipation of turbulent energy in the cases of unstable and neutral stratification. On the average, the estimates
of friction velocity according to the profiles are higher than the dissipative estimates by 10% mainly due to the deficiency
of dissipation near the surface. For the offshore wind, the structure of the boundary layer abruptly changes and is determined
not by the local parameters but by strong turbulent eddies formed over the dry land. The intensity of low-frequency turbulent
fluctuations and the gradient of wind velocity near the surface in the coastal zone are 1.5–2 times higher than for the open
sea.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 42–61, May–June, 2007. 相似文献
8.
We propose an improvement of the algorithm of joint assimilation of the data on climatic temperature, salinity, and altimetric
sea level in a model of circulation. Unlike the previous works, the variances of the forecast errors of temperature and salinity
and the cross-covariance functions of of the forecast errors of salinity-level and temperature-level depend on the dynamics
of waters. It is shown that the structure of the fields of cross-covariance functions in the upper mixed layer is formed by
the vertical turbulent diffusion of the variances of forecast errors of temperature and salinity. At greater depths, these
statistical characteristics are mainly determined by the vertical advection. We compared the results of calculations with
and without taking into account the dynamics of the statistical characteristics. The analysis of the influence of the dynamics
of these characteristics makes it possible to reconstruct the mutually adapted climatic fields of temperature, salinity, and
horizontal and vertical current velocities in the Black Sea with the assimilation of data in the numerical model in each time
step.
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 18–31, July–August, 2008. 相似文献
9.
A. G. Zatsepin N. N. Golenko A. O. Korzh V. V. Kremenetskii V. T. Paka S. G. Poyarkov P. A. Stunzhas 《Oceanology》2007,47(3):301-312
An analysis of the data of measurements of the fine structure and microstructure fluctuations of hydrophysical fields in the upper 200-m layer of the Black Sea carried out using CTD profilers and a Baklan free falling microstructure and turbulence profiler revealed the existence of a positive correlation between the intensity of the fine structure and microstructure fluctuations and the dynamics of the currents. On the other hand, the level of the fine structure and microstructure fluctuations reflects the rate of the vertical turbulent exchange. It was shown that, in the case of the absence of the Black Sea Rim Current (BSRC) jet or clearly manifested mesoscale eddy structures, the vertical turbulent exchange in the pycnocline is weak, while, in the opposite case, it is stronger. The results obtained support the supposition that the interbasin dynamics play an important role in the maintenance of the rate of small-scale mixing in the pycnocline and halocline and provide the vertical transport of dissolved oxygen from the cold intermediate layer into the deeper layers of the sea. 相似文献
10.
The results of model calculations and experimental research of turbulent jet propagation in a stratified environment with
reference to the Sand Island wastewater outfall (Hawaii) are considered. The jet’s emergence and initial dilution were estimated
on the basis of model calculations and experimental data of the stratified environment characteristics in 2003–2004. The reason
for the appearance of the bidirectional quasi-isopycnic structure in the waste and ocean water mixing area was clarified,
and an analysis of the TS index was carried out. The jet’s features as calculated from the model and obtained from measurements with hydrophysical
and hydrooptical instrumentation were found to closely correspond. The effects of the tides and hydrophysical conditions on
the waste water’s turbulent jet characteristics (the jet’s floating-up depth level) have been revealed. The outcomes of the
study corroborate the efficiency of the model as a tool for research of deep outfall turbulent jet propagation in the stratified
environment of coastal water areas. 相似文献
11.
The results of simulating the hydrophysical fields of the Black Sea with a resolution of 1.64 × 1.64 km for January–September 2006 with the use of real atmospheric forcing are analyzed. Both vertical turbulent momentum exchange and vertical turbulent heat and salt diffusions are parameterized using the Mellor-Yamada level 2.5 scheme. The results of this numerical experiment are compared with similar data obtained with a horizontal resolution of 5 km. The features of the meso- and submesoscale dynamics of waters in individual sea regions are given. Possible physical mechanisms of forming meso- and submesoscale vortices are studied on the basis of energy analysis. It is shown that, in the absence of significant wind forcing, the main contribution to kinetic energy is made by the buoyancy force and wind-field inhomogeneities result in significant variations in both total vertical viscosity and total vertical diffusion. 相似文献
12.
湍流扩散过程导致的硝酸盐垂向输运对海水表层的浮游植物生长和初级生产力的大小有着重要影响。本文基于2018年夏季黄、东海水文环境、硝酸盐浓度和湍动能耗散率的同步、原位数据，分析了海域温度、盐度和硝酸盐的空间分布特征，结果表明营养盐含量丰富的黄海冷水团、长江冲淡水、东海北部底层混合水与黑潮次表层水是影响研究海域硝酸盐分布的主要水团。利用垂向湍扩散硝酸盐通量公式，计算了三个选定断面上的硝酸盐垂向扩散通量，其高值区与湍流扩散系数的高值区的位置基本一致。针对存在明显硝酸盐跃层的站位，计算得到跨硝酸盐跃层的垂向通量FND的范围在-9.78—36.60mmol/（m2·d）之间，在黄海冷水团区，夏季温跃层限制了该区营养盐向近表层的湍流垂向扩散；东海北部底层混合水区，湍流垂向扩散向上层补充了大量硝酸盐，促进了跃层之上浮游植物的生长；黑潮次表层水影响海区，夏季中层水体混合较弱，跨跃层的垂向通量也普遍偏低。开展硝酸盐垂向扩散通量的计算与分析，对进一步明确营养盐的输运机制有着重要研究意义。 相似文献
13.
D. V. Alekseev V. A. Ivanov E. V. Ivancha V. V. Fomin L. V. Cherkesov 《Physical Oceanography》2005,15(6):336-345
By the method of mathematical simulation, we study the evolution of local discharges of pollutants on the northwest shelf
of the Black Sea induced by the motion of a cyclone. We use the nonlinear equations of motion of a homogeneous viscous fluid
in the hydrostatic approximation and the equation of turbulent diffusion. A cyclonic formation is represented by a moving
axisymmetric area of low pressures. The discharges of pollutants are caused by the action of instantaneous sources located
on the sea surface. We perform the analysis of dependences of the paths of motion of polluted regions, the periods of their
dissipation, and the depths of penetration of pollutants on the bottom topography and the intensity of diffusion processes.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 6, pp. 17–27, November–December, 2005. 相似文献
14.
By analyzing, as an example, the data of observations of the Black Sea from the space in autumn 1998, we conclude that, in
some cases, the atmospheric distortions manifest themselves in all measuring channels of SeaWiFS instruments and lead to significant errors in determining the concentration of chlorophyll according to the standard NASA algorithm. After additional rejection of the data with negative values of the spectral brightness of the sea surface at a
wavelength of 412 nm, the results of evaluation the concentration of chlorophyll are in good agreement with the available
data of direct measurements. We also present a detailed discussion of some specific features of operation of the NASA algorithm of atmospheric correction playing an important role in the interpretation of the data of observations of the Black
Sea.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 68–79, March–April, 2008. 相似文献
15.
V. M. Kushnir E. Hansen L. A. Petrenko V. K. Pavlov A. N. Morozov S. V. Stanichnyi S. V. Fedorov 《Physical Oceanography》2007,17(5):278-295
The numerical analysis of the stationary field of current velocity on the upper boundary of the bottom boundary layer in the
Barents Sea is performed on the basis of a simplified model taking into account the fields of wind velocity and density of
water for the principal periods of the seasonal cycle and the bottom topography. The analysis is based on the climatic BarKode database and the data on the wind velocity over the Barents Sea for the last 50 yr. The numerical results demonstrate that
the field of bottom currents is fairly nonuniform and the current velocities vary from several fractions of 1 cm/sec to 5
cm/sec in the zones with noticeable slopes of the bottom. The estimates of the thickness of the bottom boundary layer are
obtained for the constant coefficient of bottom friction C
f
= 0.04. In the major part of the water area of the Barents Sea, the thickness of the bottom boundary layer is close to 1
m. In the regions with significant slopes of the bottom, it increases to 2–2.5 m and, in the two zones of intensification
of the bottom currents, becomes as large as 5 m. The maximum estimate of the coefficient of turbulent viscosity is close to
5 cm2/sec. The mean value of the coefficient of vertical density diffusion K
S
is equal to 2.34 cm2/sec and its standard deviation is equal to 1.52 cm2/sec.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 31–49, September–October, 2007. 相似文献
16.
The method of two-dimensional isopycnic analysis is applied to study the distribution of inorganic phosphates and nitrates
in the Black Sea. The effect of winter-time ventilation in the central sea on the formation of chemical fields is examined,
as well as the outcropping of biogenic elements from the layer of high concentrations (σ
t∼14.5–16.0). It is demonstrated that the amount of nitrates entering the upper active layer of the sea as a result of winter-time
convective ventilation may attain values comparable with their overall annual input by river discharge, and that they control
the intensity of winter-spring phytoplankton blooming in the central sea. The spatial variability of the vertical phosphate
distribution is analysed. For the annual cycles with fairly cool winter conditions, an occurrence of three peaks on the phosphates
vertical profile in spring has been documented over a vast sea area where the rim current represents an external dynamic boundary.
Translated by Vladimir A. Puchkin. 相似文献
17.
We present the results of numerical experiments aimed at the simulation of the circulation of waters and transport of impurities
in the Balaklava Bay for typical wind conditions established on the basis of the analysis of the data of in-situ measurements. The currents are computed by using the nonlinear σ-coordinate model. The specific features of the integral
circulation and three-dimensional structure of the current field are investigated. The statistical characteristics of currents
are estimated on the basis of the in-situ data on winds and model calculations. Possible scenarios of propagation of impurities from the coastal sources are analyzed
for various hydrodynamic conditions. It is shown that the localized eddy structures in the current fields (in combination
with the zones of intense vertical motion) can result in a complex character of the transport of substances in the bay and
lead to the formation of local regions of maximum concentrations of impurities on the boundary of the north and central parts
of the bay.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 43–58, July–August, 2005. 相似文献
18.
We demonstrate the importance of investigation of the behavior of methane as a source of energy and an element of the Black-Sea
ecosystem affecting the global behavior of the climate. We describe the genesis of methane and the processes of its aerobic
and anaerobic oxidation. An especially important biogeochemical and ecological role is played by the anaerobic oxidation of
methane guaranteeing the formation of its effective sink inside the anaerobic zone and preventing its penetration into the
atmosphere as a greenhouse gas. On the basis of the analysis of the experimental data available from the literature, we also
discuss the principal regularities of the distribution of concentration of methane and its flows. It is shown that the formation
of methane hydrates at the bottom in the abyssal part of the Black Sea and the events of jet gas release on the periphery
of the basin can be regarded as the components of a single global process of gas release from the bottom of the Black Sea.
We present estimates of the components of methane budget in the Black Sea. The results of simulation of the dynamics of methane
bubbles and the processes of their gas exchange with the medium are analyzed. The data of hydroacoustic measurements are used
to evaluate the distribution of methane bubbles in sizes and the mass transfer of methane through the ocean–atmosphere interface.
Finally, we consider the methods of mathematical simulation of the distribution of methane in the ecosystem of the Black Sea.
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 5, pp. 40–56, September–October, 2008. 相似文献
19.
For the first time, an acoustic Doppler current profiler (ADCP) produced by the RDI is used in the water area of the Black
Sea in the lowered mode. This direction in the application of acoustic Doppler current profilers is now in the stage of development
and verification of various procedures of measurements with subsequent data processing and enables one to get the distributions
of current velocities down to depths of 1000–6000 m depending on the modification of the instrument. We describe the procedures
of measurements performed with the help of the ADCP in the lowered mode in the course of an expedition and the stages of processing
of the primary data based on the experience of application of similar acoustic current profilers at the Marine Hydrophysical
Institute of the Ukrainian National Academy of Sciences accumulated in the 1980s. We generalize the experience of application
of ADCP under the hydrological conditions of the Black Sea, propose the algorithms of data processing, present the profiles
of absolute current velocity at several stations, compare these profiles with the geostrophic velocities, and determine the
deep-water structure of the field of currents in a shelf-open-sea section made along 31.17°E.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 4, pp. 31–48, July–August, 2006. 相似文献
20.
V. A. Dulov V. N. Kudryavtsev V. I. Shrira V. E. Smolov A. N. Bol’shakov 《Physical Oceanography》2007,17(1):29-40
We describe the procedure of field experiments aimed at measuring the vertical profiles of the vectors of a drift current
with the help of quasi-Lagrangian drifters. We present the data on the vertical shears of the current at depths of 0.5–5 m
obtained under the conditions of neutral stratification in the upper 5-m layer of the sea in the presence of weak and moderate
winds. The correspondence of the obtained data to the concept according to which the subsurface layer of the sea is regarded
as a near-wall turbulent layer with Ekman current located below is analyzed. A conclusion is made that the results of measurements
correspond, on the average, to the classical concepts demonstrating both the region of logarithmic sublayer and its transition
into the Ekman spiral.
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Translated from Morskoi Gidrofizicheskii Zhurnal, No. 1, pp. 32–44, January–February, 2007. 相似文献