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We discuss the computational properties of variational algorithms of mastering the data of measurements and convergency of iterative procedures of search for an optimum distribution of the input parameters of a model and consider the model of transfer of a passive admixture. The algorithm of identification is based on the variational principles, solving the conjugate problem, and minimization of the functional of quality of a prediction. We carry out the analytic verification of the efficiency of the algorithm and discuss the problems of optimum planning of experiments from the viewpoint of conditionality of the problem of identification that is being solved.

Abstract: We analyse the time variability of the fields of Cs-137 concentration in the surface waters of the Black and Mediterranean Seas in 1986–1998. It is shown that more contaminated Black-Sea waters affect the levels of concentration of this radionuclide in the east part of the Mediterranean Sea. We also study the influence of atmospheric processes and water exchange through Bosporus on the radioecological situation in the east part of the Mediterranean Sea and its coastal area.

Abstract: We discuss the current state of the problem of experimental investigation of the bottom boundary layer of the Black Sea and present the data on a new measuring complex (designed and constructed at the Marine Hydrophysical Institute and called the OLT-D profilometer of the bottom layer) together with some results of its application. On the basis of the analysis of the data on the distributions of geothermal fluxes and parameters of the bottom boundary layer in the deep-water part of the sea, we deduce and justify the relations for the evaluation of the critical thickness of the bottom boundary layer as a function of the intensities of geothermal fluxes. It is shown that the numerical results are in good agreement with the data of direct measurements of the thickness of the bottom boundary layer.

Abstract: On the basis of the analysis of the data of hydrological observations, we construct an empirical dependence of the vertical heat fluxQ on the temperature gradientT z . The integral advective-diffusive transfer is taken into account by the method of Kolesnikov. We obtain a generalized dependence of the coefficient of vertical thermal diffusivityK z onT z and note that the well-known Rossby-Montgomery relation and Kolesnikov formula are its special cases. We analyze the possibility of application of this dependence to linear and nonlinear problems of thermal conductivity and diffusion in the ocean.

Information on the depth of the sulfide onset in the Black Sea has been analyzed for the period 1910–1995. Correlation between the depth of the sulfide onset and the density structure of the layer of the main pycnocline is significant for the entire period covered. Correlation coefficients (R) between the depth of the sulfide onset and the position of isopycnal surfaces in the layer of the main pycnocline vary, on average, 0.71–0.88. The average value of density (σt) at the depth of sulfide onset, defined as a sulfide concentration equal to 3 μM, is close to 16.17. Oscillations in the average depth of the sulfide onset range over 24 m and indicate that a steady-state trend does not occur. The period of these oscillations may occur over a century timescale. The dataset for the period 1960–1995 has been used to analyze temporal variations in concentrations of sulfide inside the anoxic zone of the Black Sea. The results of isopycnal analysis demonstrate that possible temporal variations in the average position of sulfide onset versus density (σt) scale do not exceed 0.15, which is close to the limit of uncertainties for data obtained before 1988. In contrast, a prominent increase in sulfide concentration, as well as nutrient levels, within the anoxic zone is shown and is related to anthropogenic impact.

Without Abstract:

The effective gas exchange rate in whitecap formations, determined as the ratio of the total gas stream through the bubbles to the variation in the concentration of the gas dissolved in sea-water from that balanced with the atmosphere, is calculated for nitrogen and oxygen. The gas stream was determined from experimentally derived data on the distribution of air bubbles in the whitecap using remotein situ macrophotography. The dependence of the gas exchange rate on the relative saturation of the water with gas and the wind velocity is analysed. The gas exchange rate in whitecap formations for nitrogen is three times that for oxygen.

Abstract: This paper discusses the results of theoretical and experimental analysis of physical and physicochemical interactions in the ‘membrane gauge-medium’ system. The principal parameters of the system affecting measurement of the chemical field parameters under various conditions of overflow are identified. Simple computational formulae have been derived which are relevant for engineering purposes and for treatment of the observed data.

Maps of the boundary topography for anaerobic waters in the Black Sea are plotted for the summers of the 1920s and 1980s. The mean depths of the H2S boundary for this period are determined. It is shown that the variation in the distribution and average location of the hydrogen sulphide zone has remained constant for the last 60 years.

Abstract: In situ data collected by Marine Hydrophysical Institute investigators have been used to reconstruct the Black Sea paleochemistry during the period of Wrmian glaciation. The geochemical behaviour of and maps for the Cu, Zn, Mo, and U steric distribution in the New Euxinic sediments that deposited in freshwater lakes under severe climatic conditions, with salinity being virtually zero, are reported. Similar chemical processes in the New Euxinic basin and Baikal Lake are examined.

Deep drilling data, palaeobiological indicators, evidence on the sea-level, and mathematical modelling have been used to reconstruct the Black Sea palaeohydrological regime during the Karangat transgression, the new Euxinic regression, and Holocene. The mechanism responsible for salting of the sea and the accompanying processes during the inter-glacial period are studied.

The characteristics of the spatial structure of the Atlantic north equatorial countercurrent (NECC) have been determined from the analysis of observations of the subsatellite buoy tracers (surface drifters LOBAN-TM) launched during cruises of the research vessels operated by the Marine Hydrophysical Institute of the Ukrainian Academy of Sciences. A comparison with the data obtained by other methods of current measurement has been carried out. The region of and the time of discontinuity of the NECC and of the reconstruction of its continuous zonal structure have also been determined.

The hydrological and hydrochemical structures of the upper 300 m water column of the Black Sea in autumn 1988 have been studied. Regularities in the distribution of the physico-chemical characteristics in the zone of interaction between aerobic and anaerobic waters as well as the topography of the H2S zone boundary and its connection with a certain density gradient have been found.

The concentrations of137Cs and134Cs were measured using the sorption method in the waters of the Black Sea during 1986–1987. An inhomogeneous character of the contamination of the surface waters in the Black Sea due to the Chernobyl disaster is shown. The subsequent migration and redistribution of caesium radionuclides in the various seasons of the year were studied. The amount of137Cs and134Cs in the upper 50 m layer was estimated. The results of measuring the concentration of caesium radionuclides in the near-water atmospheric layer over the Black Sea and Mediterranean Sea in 1986–1987 are also reported.

The results obtained point to a relation between the possibility of employing the rheological model (1) for describing the viscous flow of a material and the validity of the Mackenzie equation. Two limiting cases may arise. In one of them, where pore healing in a material occurs through a mechanism of viscous change in shape of the nonporous part of the material, the Mackenzie relation (2) or its generalized variant (15) is applicable. The rheological model for an isotropic solid is described by Eq. (1). When the Nabarro-Herring diffusional creep mechanism is operative, the coefficients of viscosity are calculated with Eqs. (19) and (20).

Abstract: Using thein situ currents measurements conducted during Cruise 41 of the R/VAkademik Vernadsky, we have considered the structure of the Guiana Current in winter over the shelf, continental slope and in the deep-water part of the ocean, adjoining the Brazilian coast. Regular variations of the current velocity with depth have been identified, and the current velocity's stability and variability determined. The paper examines how the barocline component of the hydrostatic pressure horizontal drop influences the current velocity's vertical profile. An attempt has been made to evaluate the current's transport.

Abstract: 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 (σt∼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.

Abstract: Using variational algorithss, computations aiming at the reconstruction of the initial passive impurity field have been performed. The likely areas of impurity propagation from various sources in the Black Sea have been identified. The paper discusses different aspects of the application of variational methods of data assimilation in the course of modelling passive impurity propagation.

Abstract: The paper discusses the parameters derived through deep-sea precision CTD-probings, characteristic of the structure of the near-bottom boundaries layer, specifically, the depth of the layer's upper boundary and the mean vertical potential temperature/salinity gradients, as well as the density ratio over the layer of the near-bottom convection. The peculiarities of the parameters' spatial distribution have been identified. The conclusion derived from the analysis of the model implies that the near-bottom boundary layer occurs, aside from the presence of the bottom geothermal heat flux, due to the strong dependence of the Bosphorus salt flux on stratification. The dependence of the Black Sea buoyancy flux and vertical diffusion coefficient on depth has been estimated.

Abstract: A mathematical model is applied to study the transformation of the Post-Karangate Sea into a brackish New Euxinic basin during the ‘Würmian’ glaciation period. Halocline destruction and the leveling of salimity of surface and deep waters took place at the beginning of that period. The paper examines the evolution of the salinity field and vertical exchange over a period of ten thousand years, starting from the time of degeneration of the Bosphorus undercurrent. The thermal effect of the New Euxinic basin prevented the progress of the glaciation toward south-eastern Europe. The small organic matter content in the New Euxinic deposits is the result of severe climatic conditions and intensive terrigenous deposition, as well as of the sorption of phosphates by iron and aluminium hydroxides and their subsequent sedimentation.

Abstract: On the basis of the measurements collected by MHI and other scientific institutions during expeditions in various parts of the Black Sea and in various seasons, the variability of the upper boundary of the hydrogen sulphide zone and the respective isopycnic surface is considered, as well as the relationship between the latter parameters and the index of atmospheric circulation. Correlation between the studied processes in the Black Sea and atmosphere has been found to be very high.

Peculiarities of the dynamics and the structure formation in the estuary run-off lenses have been analysed based on field data obtained at the Guinean coast (the central eastern Atlantic Ocean). Attention was paid to the processes of restratification, internal mixing, and exchange in the areas of the frontal zone of the run-off lens and the tidal frontal zone. The stabilization of the front of the estuary run-off lens by means of the periodic ‘washing out’ of its forepart by tidal upwelling is described. The mechanisms of the energy transformation in the leading part of the lens have been revealed. Effects of ‘run-off’ and loczalization of transformed waters in the small-scale frontal zones are found. The energy estimations represented will be useful in considering analogous phenomena in other coastal regions.

The variation algorithm of data assimilation is considered which is based on the minimization of some quadratic functional of the prediction quality and the solution of a conjugated problem. Numerical experiments of the model have been carried out which demonstrate the potentialities of this approach and the prospects of its employment for solving practical problems.

The result of research into the distribution of artificial radionuclides of137Cs in the Black Sea and the Mediterranean Sea are reported. The data obtained permits consideration of the peculiarities of distribution of this radionuclide in the areas under investigation. The contribution of the ‘Chernobyl’ radiocaesium to the total radioactivity of these water areas is estimated.

A quasi-periodic (wave) spatial-temporal structure of the intrannual variability of the climatic fields of the seawater geostrophic motion within the constant halocline in the Black Sea (75–300m) has been revealed on the basis of generalized archival data on hydrological observations in the main Black Sea current (MBSC) near the Crimea and Caucasus. The variability with annual and semi-annual periods has the character of standing quasi-geostrophic waves at 2- to 4-month periods which become progressive as the direction of their propagation changes during the year. The energy characteristics for the forms of variability revealed are discussed and interpreted from the viewpoint of gradient-eddy waves and the hydrodynamic instability of the MBSC.

Computations involving a complete baroclinic model for the Black Sea are analysed. Monthly climatic temperature and salinity data were used. Dynamic fields were derived for each of the 12 months. The characteristics of the cold intermediate layer, which represents an essential feature of the Black Sea thermal structure, are examined.

Spectral analysis of the climatic circulation in the upper 10 m layer of the Black Sea has been carried out. The current field was calculated from a three-dimensional baroclinic non-linear model. The mode composition of the circulation was derived. It is shown that the surface climatic circulation can be represented as the superposition of a finite number of ‘elementary’ currents of two types:n- andm-modes. Only 4n-modes are shown to be energy-dominant throughout the year. A relation is established between the different sources of energy supply of currents and the modes which assimilate this energy. Problems concerning the nature of the classical Black Sea currents such as the main Black Sea current (MBSC) and the Knipovich ‘spectacles’ are discussed. A ‘scenario’ of the field large-scale experiment is suggested which allows the reconstruction of the amplitudes of the first 10n- and the first 10m-modes from mooring data.

This paper discusses the conclusion derived during a joint U.S—Turkey expedition on the R/VKrorr on the ‘dramatic’ variations of the O2−H2S zone in the Black Sea observed over the last 20 years. This conclusion is shown to be invalid since it was based on a comparison of data obtained at two stations only (in 1969 and 1988) that was made in various regions and in different seasons. Examples are provided for the inter-seasonal and mesoscale variations of hydrophysical and hydrochemical characteristics in the O2−H2S zone which, as to their scales, are comparable to or even exceed the variations registered during the expedition ofKrorr.

T-clones specific for purified protein derivative of tuberculin are derived from mice with genetically different sensitivity to tuberculosis. The absolute majority of resultant T-clones express the T-helper phenotype and are restricted for the class II H-2 gene products. T-clones exert different effects on the bacteriostatic activity of syngeneic macrophages. A relationship between the described characteristics of T-clones and the allele composition of their H-2 is hypothesized.

Abstract: Regularities of oxygen and hydrogen sulfide are examined, using the method of spatial isopycnic analysis. The contribution that ventilation of winter-time surface waters over the domes of cyclonic gyres makes to the transfer of O2 towards the upper boundary of the constant pycnocline and to the oxicline layer is demonstrated. The paper provides spatial scales of this phenomenon and indicates the areas where the upper boundary of the anoxic layer in the Black Sea, relative to the conventional density, is located much higher compared with the rest of the sea. The suboxic zone is shown to be a specific feature of the O2/H2S distribution in the Black Sea waters, typical, at least, of the northern part of the basin. Analysis of the suboxic spatial variability in the vertical has been conducted.

The liver of mice with implanted cancer produces mitogenetic radiation; its spectral analysis shows that the protein molecules of the cell substrate become smaller in size. After implantation of a piece of tumor in mice, the mitogenetic radiation of the liver and cancer “extinguisher” was detected in its cells in 20–22 hr, whereas endogenous cancerogenic substance was detected only after 4 days.

The authors present data which broadens the concept of the regulatory effect exerted by the spinal cord centers on the molecular substrate of muscles. Evolution of mitogenetic spectra of the resting rabbit gastrocnemius (connected with age) and the prevalence of mitogenetic radiation of degradational type in adult animals point to the gradual formation of the nonbalanced structural state of the substrate.