Methods of forecasting and detection of rogue waves in numerical experiments are considered. Methods of operational forecast of freak waves, as well as the methods of remote sensing of the sea surface and application of computing experiments to validation of in-situ measurements, are suggested and analyzed.

The results of investigation of the Pechora Sea tidal dynamics sensitivity to variations of the external governing parameters, obtained with the use of the 3D finite-element hydrostatic model QUODDY-4, are considered in this paper. It is shown that the tidal characteristics are weakly sensitive to variations of the critical depth separating the subdomains of  rough and incompletely rough bottoms, and are strongly sensitive to variations of hydrodynamic roughness of the bottom.

The information on the expedition of St. Petersburg branch of the Institute of Oceanology is provided. The purpose of work is accumulation of meteorological data to study variability of the local hydrophysical fields, produced by the tidal variations, in the White Sea areas differing in hydrological conditions.

The presence of an internal tidal bar and intensive internal wave packets with the period of 10-20 minutes were detected from the in-situ data obtained on the White Sea shelf. Along with the standard methods the wavelet analysis was applied to describe the internal wave characteristics. A well-grounded choice of a wavelet basis and its construction method was carried out. Different options of wavelet transformation are shown while describing nonlinear waves.

Algorithms and results of the calculations of the apparent contrast of oil films on the sea surface are given for the case of observations from space in visual, ultraviolet and infrared spectral ranges (300–800 nm). The calculations were carried out for different water types and optical thicknesses of the maritime atmosphere and for various solar altitudes and wind velocities. It is shown that the oil films on the sea surface can be detected if the wind velocity ranges from 6 to 20 m/s and the solar zenith angle varies from 0 to 45 degrees. The greatest values of the contrast correspond to the highest wind velocities and solar zenith angle.

This paper considers numerical simulation of a moving ice keel in a two-layer fluid. The immersed boundary method is used for modeling of the non-stationary complex geometry on the rectangular grids. The results of the drag force computations for various Froude numbers are presented in comparison with the laboratory experiments.

An initial stage of high-speed penetration of a needle-shaped metal body into the water and its interaction with the metal target are considered. The calculations are carried out in the frame of the continuum mechanics: for a solid body an elastic-plastic model, with allowance for destruction, is suggested, while for the water fluid mechanics equations are used.  Over the considered range of speeds of 1.0.2.5 km/s, when the body is entering the water, a mode of developed cavitation occurs; the plastic deformation of the head part of the striker, and in some cases, its destruction, are observed, which leads to increase of the penetration resistance.

For filtration of the tone echo-signals in the presence of reverberation interference, a narrow-band filter is synthesized, with the AFC being at a low level beyond the passband. The given property of the filter is reached due to introduction of a weighing window in the process of the spectral analysis. A traditional choice of a spectral decomposition interval, as well as the choice of the parameters of a specified window, results in the width of a filter passband being unmatched with duration of an echo-signal. The paper considers a problem of synthesis of an improved filter, with no defect described above. 

The new version of the program complex intended for numerical modeling of propagation and transformation of internal gravity waves in the ocean, with a finalized unit calculation of a ray of internal waves and with a paralleling of the program, which can significantly speed up the ongoing computation is presented. As a practical example of the proposed study addictive properties of the shelf of the Baltic Sea from the point of view of long internal waves on the basis of the ray approach is offered. The values of the coefficient of capture are calculated and the corresponding maps are constructed.

The paper considers a way of weight coefficients optimization for a ship broadside extended multi-element antenna, with allowance for a number of requirements for its parameters, with the non- uniform noise level distribution over the antenna elements.