This thematic issue presents the results of ocean optics researches. The main features of seasonal and inter-annual variations of bio-optical characteristics in the surface layer of the Barents, White, Black and Caspian Seas calculated from data of satellite scanners are discussed. The experimental results of spatial distribution of dissolved organic matter and chlorophyll-a fluorescence intensity in the Western Black Sea are given. A method of improving the underwater optical communication quality based on amplitude-modulated laser beam is suggested. Luminescent methods of investigation of uranium (VI) complexes in natural waters are theoretically studied. New approaches for estimation of photosynthetic efficiency and primary productivity in water are examined. The new results in problem of underwater objects imaging correction through a rough water surface are presented. The experimental data for correction of satellite sensing results are shown. The issue also includes some papers on the problems of applied hydroacoustics and hydrodynamics of marine objects.
For scientists, engineers, students, post-graduate students and universities specializing in ocean optics.
This issue includes papers showing modern ways in numerical modeling of hydrophysical field dynamics; the hydrooptics, hydroacoustics and bioacoustics matters are discussed; the reviews of microbiotesting of aquatic environments toxicity are presented as well. The results of modeling of thermohaline structure in the Gulf of Finland obtained using the three-dimensional eddy-resolving hydrodynamic model based on the model complex NEMO are given. The boundary-value problem for equations of two-layer fluid (water-landslide material) for calculation of coastal wave dynamics generated by a landslide in random three-dimensional field is considered. The review of underwater imaging problem is presented. The calculation of interferential structure of the low-frequency hydroacoustic fields in shallow sea is discussed. The problem of detection with adaptive algorithms in passive sonar is considered. The possibility of estimation of distance to noise signal source by two-frequency method with the use of band-pass filters is analyzed. The method of hydrobionts acoustic emission signals detection is described. The review of modern foreign and native microbiotests for control of harmful factors influence on the hydrosphere is given; the problems that arise at ecotoxicological control of natural waters are shown.
This thematic issue is dedicated to the 70th anniversary of the famous Russian hydrophysicist Efim Pelinovsky. The issue contains results of the studies that reflect the current state of hydrophysics in the field of in situ and laboratory measurements, analytical and numerical modeling of surface and internal waves. A review of studies on the transformation of surface and internal waves over the bottom step is presented. A revision of an asymptotic derivation of the rotation-modified Kadomtsev-Petviashvili equation taking into account the background shear flow as well as the background stratification is given. Results of numerical calculations of internal gravity waves fields in a stratified fluid layer of variable depth by exact and asymptotic formulae are presented. Results of analytical and numerical solutions as well as laboratory experiments describing the evolution of solitary waves over an uneven bottom are considered. Dynamics and energetics of a frontal collision of internal solitary waves of high amplitude propagating in a two-layer stratified fluid are studied. Distinctive features of a particle transport during the propagation of long nonlinear localized wave packets (breathers) are investigated in three modes: a linear mode, a weakly nonlinear approximation and a weakly nonlinear weakly dispersive approximation. The evolution of internal waves field in the Pechora Sea is observed by means of the model based on the Gardner equation, the bore record is used as initial condition. A stationary circulation and semidiurnal surface and internal tides in the region of the Kara Gates Strait are reproduced within the framework of a three-dimensional finite-element hydrostatic model. A comparison of moored measurements of currents and temperature in the Gibraltar and Bab-el-Mandeb Straits is given, vertical displacements in both straits are caused by semidiurnal internal waves.
The round-table discussion «Fundamental Science to The Navy» within the Seventh International Maritime Defence Show (IMDS-2015)
The issue presents topics of the round-table discussion «Fundamental Science to the Navy» within the Seventh International Maritime Defence Show (IMDS−2015). The main subjects of the discussion were the problems of marine situations surveillance for marine objects detection by space, aviation and ship’s systems for monitoring of the World Ocean. The matters of countermeasures and security for underwater sensor network systems were analyzed. The researches devoted to the theoretical and experimental problems of dynamics of hydrophysical fields were discussed, including a problem of high-speed motion of supercavitating bodies in water. The issue also contains scientific papers devoted to the various aspects of hydrophysics. The results of experimental study of interaction of background internal waves and processes caused by the movement of the sphere in stratified fluids are presented. The modern approach to the calculation of wave climate (mode disturbances) is shown. The task of minimization of number of spectral channels of modern hyperspectral optoelectronic systems for remote sensing of the ocean is discussed. The estimation of biooptical characteristics in the Black Sea is given, the results of modeling of biogeochemical processes in the Gulf of Finland are considered.