The previously created one-dimensional model of wave boundary layer (hereinafter — WBL) was extended by including equations heat and vapor turbulent diffusion, formulas of heat surface flux and surface evaporation, stability functions for dissipation and turbulent coefficient. The numerical and input parameters of the model are described. The wave spectrum used in the model is considered. The set of experiment of simulating of stratified WBL structure under different condition was run. Coefficients of momentum (drag coefficient) heat and vapor exchange were evaluated. The coefficients were compared with the similar coefficients calculated by COARE algorithm; it is the commonly used method of surface turbulent flux calculation. It is shown that stratification has influence exchange in WBL in the cases of moderate and weak wind. Age of wave has an impact on momentum exchange under strong wind. The result could be used for formulating new methods of evaluating of sea surface turbulent fluxes or tuning of existed ones.

This paper presents a method for deriving turbulent stresses using a pair of ADCPs with one or two points of beam intersections. A specific experiment, which includes measurements of water temperature, under-ice irradiation levels, and velocity components in the convectively mixed layer of a shallow ice-covered boreal lake, validated the method. The experimental data allows calculations of both the pulsation intensities along the three orthogonal axes and off-diagonal components of the Reynolds tensor. The specific features of spring under-ice convection processes, in particular, the anisotropy of turbulent pulsations and the correlation of turbulence energy with the turbulence energy production (as the buoyancy flux), were described using the horizontal homogeneity assumption. Finally, the paper presents a qualitative analysis of the parameters and dynamics of energy-containing structures developing in the convective layer of small ice-covered lakes in spring.

Сlimatic quantitative relationships are established between the surface water and air temperatures, the areas of the stratified (Twsur > 4 °C) and the isothermal area (Twsur < 4 °C) in Lake Ladoga during vernal frontal zone (thermobar) period. Initial data were based on the temporal spatial distributions of the temperature of the water surface of Lake Ladoga and the upper air temperature. These empirical regression models indicate a stable relationship between the selected parameters and allow their use in the analysis of climatic variations. The climatic values (norms) of the surface water and air temperature and the dates of their occurrence during the existence of the spring thermal zone on Lake Ladoga are determined, relative to which deviations should be estimated.
The spring minimum temperature of the water surface in the deepwater part of Lake Ladoga during the appearance of the thermal frontal zone is a kind of indicator (“memory”) of the winter state of the lake and the value from which heating begins after ice melting and which largely determines the date of disappearance of the front. The approximation of the temporal course of the surface water temperature’s minimum in the deep-water zone of the lake allows us to estimate the time of onset of full thermal stratification in Lake Ladoga. Interannual variations in the date of disappearance of the isotherm on the water surface of 4 °C changes from one to four weeks in relation to norm, this is due to differences from year to year of the minimum surface temperature of the lake in the deepest part of the lake, determined by winter conditions, wind conditions, cloud cover and, therefore, the intensity of lake-atmosphere heat exchange in Lake Ladoga. The rate of increase in the water surface temperature of the stratified zone is much greater than the rate of heating of the isothermal region.

The paper presents a model of mass transfer in the Kuibyshev Reservoir, developed on the basis of a system of equations of “shallow water”, a model of convective-diffusion transfer of a dissolved substance, as well as analytical formulas for calculating the total sediment discharge and water turbidity. The model was used to assess the geoecological state of the Kuibyshev Reservoir in parts of water quality. The model parameters were evaluated using data from field changes at monitoring points. A series of simulation calculations of flows in the water area of the reservoir, the spread of tributary water plumes and the transport of suspended particles in various hydrometeorological situations in the conditions of average water content was carried out. It is shown that the velocity and trajectory of river water mass distribution depend on both the presence of wind circulation of currents and the flow regime in the water area. The formation of the spatial configuration of river water plumes in the plyos areas of the reservoir is determined by the speed and direction of circulating wind currents. The values of the specific discharge of sediment in the reservoir during strong winds change by an order of magnitude. As a result of solving this problem, the capabilities of the presented model are demonstrated and the estimation and forecast of the distribution of dissolved admixture (possibly contaminated), as well as the transport and re-deposition of river sediments in different points of the water area under different hydrometeorological conditions are given.

The problem of wave excitation on the water surface from a stationary oscillating underwater source is considered in connection with the problem of remote detection of such sources. It is shown that the attenuation of the pulse of the source with depth can be largely compensated by the waves parametric excitation of the gravitational-capillary range, that is important for radar sensing of sea surface. Threshold generating the amplitude of surface wave ξ₀ ~ 10^–2 сm, according to the model. The maximum amplitude is in the center of the gravitational-capillary region at the length of the generating gravitational-capillary wave L₀ = 1.74 сm. The generating region shifts when the frequency of the vibrator changes, and the most effective case is when the frequency of the vibrator is doubled in relation to the frequency of the excited wave F₀ =13.5 Hz. The obtained model results are important for problems related to sea surface radar. A laboratory experimental installation has been created, the measurements of electromagnetic waves scattering from the area of circular waves around the vibrating membrane (“Faraday ripples”) are conducted. Perspectives of these effects using for detect of low-frequency seismic sources, and its radar monitoring.

The physical and mathematical principles of hologram formation in the oceanic environment at presence of intense internal waves is considered. It is assumed that intense internal waves are reason of the sound field modes coupling. The presented research is based on the analysis of the frequency-time interference pattern (interferogram) of the broadband sound source and its 2D Fourier transformation (hologram). The relationship between the interferogram and hologram structures and the unperturbed and scattered fields parameters is obtained in the paper. The hologram spectral density consists of the two disjoint regions corresponding to the scattered and scattered fields. The filtering of these regions allows us to transmit the non-distorted information through inhomogeneous ocean environment. The numerical simulation results of interferograms and holograms at presence of the internal waves are considered. The relative error of the reconstructed interferogram for unperturbed sound field is estimated. The applying of obtained results to the hydroacoustic communication are proposed.

«Acoustic pollution» is a dangerous anthropogenic load on the ecosystems of the World Ocean. At present, hydroacoustic emitters are widely used to solve a variety of scientific and applied problems, no longer limited to the traditional tasks of long-distance sound underwater communications, remote control, illumination of the underwater environment, acoustic thermometry of the ocean climate, monitoring of underwater objects, geological, seismic and fishery exploration. In many of the above mentioned applications, in particular in the tasks of providing long-distance sound underwater communication as well as in conducting geological and seismic exploration, powerful sources of low-frequency hydroacoustic fields are needed. The sound pressure created by such hydroacoustic emitters reaches several thousand, and in some cases — tens of thousands of Pa (reduced to 1 m). The effect of sound fields of such intensity on aquatic organisms has hardly been studied. The main problem of such studies is the difficulty in recording the impact of powerful acoustic fields on marine ecosystems. This work is devoted to the development of a methodology for researching the influence of powerful low-frequency sound fields on luminous planktonic marine organisms. The methodology is based on determining the parameters of bioluminescence, which is one of the most important indicators of the functional state of aquatic organisms.

This article is devoted to the development and application system for Particle Image Velocimetry (PIV) measurements of velocity fields in a turbulent boundary layer within experiments carrying out on the modified hydrodynamic flume of the Atlantic Branch of the Shirshov Institute of Oceanology of the Russian Academy of Sciences. This study is concerned with the preparation of laboratory setup for investigations on the initiation of motion of microplastic particles from the bottom covered with natural bottom sediment. The conditions of three types of bottom material (coarse sand (1–1.5 mm), amber grains (3–4 mm), pebbles (1–2 cm)) were investigated. The developed system of PIV-measurements uses a digital camera of medium framerate and continuous wave laser illumination. The experiments were performed in a wide range of flow velocities, up to 2 m/s, controlled by a pump rate and a control valve position. Average velocity profiles were measured, and the slope of their logarithmic part was used to calculate the corresponding friction velocity. The friction velocity and the bottom roughness are the crucial parameters for the assessment of sedimentation/initiation of motion processes. Friction velocities over sand and amber appear to be similar and significantly smaller than that for pebbles. The pebble roughness scale turned out to be the maximum, as expected. The amber simulated the bottom of intermediate roughness. For this case, due to its relatively low density (1.07 g/cm3), we observed the beginning of particle motion at velocities lower than those necessary for the initiation of sand grain movement. There was a good agreement between the observed threshold of motion for amber with available data obtained by A. Shields. The advantage of PIV-measurements for further investigations of the microplastic dynamics is the possibility of simultaneous measurement of almost instant velocity parameters in the boundary layer together with the observation of microplastic particles added at the bottom surface.

Under subterranean economic operations (geological prospecting, fishing, ecological control of the Nord Stream pipeline), a specific problem arises in the Baltic Sea due to the presence of a mass accumulation of captured chemical amunition on the bottom of the Bornholm Basin flooded after the World War II.
Shirshov Institute of Oceanology of the Russian Academy of Sciences periodically conducts expeditions to survey submarine potentially dangerous objects using ship geophysical and geochemical means. The paper analyzes the features of conducting underwater economic operations in a number of water areas of the Baltic Sea associated with the presence of submerged chemical munitions. Theoretical aspects of the search for underwater potentially dangerous objects in shallow water areas are presented. In the process of prospecting, it became possible to classify underwater potentially hazardous objects according to their magnetograms. An analysis of the magnetograms of the detected underwater object allows us to classify it as a «set of chemical munitions» or as a «sunken ship».
Practical recommendations have been developed on the integrated use of sonar and magnetometric means for detecting chemical bombs, taking into account the specificity of the bottom relief and soil characteristics.
According to the concept of environmental monitoring, the location of flooded ships and vessels, as well as the burial of chemical warfare agents — chemical amunition are considered as zones of especially dangerous natural and technogenic complexes at the bottom of the Baltic Sea.