The issue is devoted to mesoscale and submesoscale processes in the ocean. Its topics cover various aspects of the dynamics of these processes. The geography of the researches is represented quite widely. Specifically, the comparative influence of the topography, β-effect, and the gradient of the meridional variability of the background flow on the propagation of barotropic topographic Rossby waves in the region of the Antarctic Circumpolar Current is analyzed. The seasonal variability of the thermohaline structure of cyclonic and anticyclonic mesoscale eddies in the Lofoten Basin is investigated based on satellite altimetry and a combined data that includes hydrological profiles from various platforms. The peculiarities of hydrophysical processes on the shelf and sea-level fluctuations in the Sea of Japan are studied. Inertial oscillations in the Black Sea are analyzed. The results of the theoretical study of the Ekman-type boundary layer over the anisotropic underlying surface are presented. The results of numerical modelling of the tsunami wave propagation in the Azov and the Black Seas from several seismic sources, which pose a potential hazard to the Kerch Strait, are presented. The variability of water quality in Lake Ladoga is analyzed based on satellite data. A new method for estimating the anisotropy parameters of small-scale turbulence from the data of acoustic profilers is proposed. A study of sea ice dynamics in the Pechora Sea in winter 2019/2020 is presented. A systematization of summer characteristics of short-period internal waves in the Kuril-Kamchatka region is given. Thus, the issue contains extensive material on the topic “Mesoscale and submesoscale processes in the ocean”, which will contribute to solving new problems in this area.
The issue is dedicated to the theoretical and applied subjects in hydrophysics. A one-dimensional model of wave boundary layer with parameterization of stratification and elements of the wind waves influence is presented. A method for deriving turbulent stresses using a pair of ADCPs with one or two points of beam intersections is shown. A 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 RAS is described. A surface waves excitation by the bottom low-frequency harmonic vibrator is studied, the possibility of their registration by the coherent radar is analyzed. The results of numerical modeling of frequency-time interference pattern (interferogram) of the broadband sound source and its 2D Fourier transformation at presence of the internal waves are considered and analyzed. The methodology for studying the effect of low-frequency high-intensity acoustic fields on marine luminous planktonic organisms is investigated based on based on determining the parameters of bioluminescence, which is one of the most important indicators of the functional state of aquatic organisms. Сlimatic quantitative relationships are established between the surface water and air temperatures, the areas of the stratified and the isothermal area in Lake Ladoga during vernal frontal zone (thermobar) period. 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 is presented. The practical recommendations are 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 by the example of burial on the bottom of the Bornholm Basin of the Baltic Sea.
The special issue of the journal contains articles devoted to solving problems of hydroacoustics and hydrooptics taking into account the influence of the marine environment. The issue opens with article that analyzes the methodological aspects of building operational oceanography systems aimed at solving practical problems of the Navy using underwater surveillance equipment. It is shown that the use of hydroacoustic models is not enough to solve problems in dynamically active areas of the ocean, including in strait zones with difficult bottom topography — it is necessary to proceed to a complete formulation of the problem. Scientific and technical approaches to the practical use of oceanological data in matters of hydroacoustic underwater observation are analyzed. The efficiency of algorithms consistent with the data processing environment is estimated. The influence of ultra-slow signal changes on the passive listening noise stability is studied. The features of impulse responses in underwater sound channels during the propagation of broadband signals are investigated. The structure and kinematic characteristics of the sound field in the infrasonic frequency range are considered. The hydroacoustic part of the issue closes with an article devoted to the diffraction of sound on an undulating surface in the middle frequency ranges.
The hydrooptical part of the issue includes articles that present the results of lidar sounding of the water of the Black Sea in order to assess the vertical structure of the environment and register internal waves. On the basis of mathematical modeling and experimental data, the analysis of the appearance of surfactant layers in the images of the Snellius circle is carried out. With the help of contact and remote measuring instruments, hydrobiological and hydrooptical characteristics of submesoscale structures in the Peter the Great Bay are obtained and analyzed.
At the end of the issue, the results of numerical modeling of the evolution of submesoscale eddies in the northern Baltic in different seasons are presented.
Another edition of the journal presents scientific articles covering fundamental and applied issues of hydrophysics. Comparative analysis of symmetric unstable perturbations of the geostrophic current with a constant vertical and horizontal velocity shear in an unbounded region and a region with lateral boundaries is discussed. In terms of the Fourier integral, a 2D analytical solution of the reference equation for the vertical focusing of the monochromatic wave is constructed, which is used to describe the dynamics of Rossby waves when they interact with shear currents. Estimated changes in freshwater content and inflows into the upper Arctic Basin from decade to decade from 1950 to 2010 and their relationship to the salinity anomaly in the North Atlantic is estimated. The spatial and temporal variability of the characteristics of the Polar frontal zone in the Barents Sea according to satellite sensing data and its relationship with global atmospheric processes are considered. Results of verification and application of automatic algorithm of upwelling detection by reanalysis data in the south-east Baltic Sea for 2010—2019 are presented. The results of experiments with a regional model of the Earth’s climate system are discussed, in which light attenuation is calculated by taking into account the feedback between water temperature and phytoplankton for the Indian Ocean. The results of the calculation of the internal phosphorus load on the ecosystem of Lake Chudsko-Pskovskoye from the secondary input of phosphorus from the sediment are presented. The processing of stereo imagery of the roughness water surface is considered, results of reconstructing of sea surface relief and spatial spectra of wind waves at several wind speeds are presented. The use of direct numerical modelling of 2D free-surface potential current is discussed to estimate sound dispersion on the water surface without imposing explicit limitations on the shape of the surface. The edition ends with an article focused to the analysis of historical information about the catastrophic flood of the Neva River in 1721.