The current paper considers the results of the numerical simulations fulfilled with a three-dimensional non-hydrostatical model of water–air interaction, with use of the method of large eddy simulations (LES) for aver-aging the full system of Navier-Stokes equations, and the volume of fluid method (VOF) – for describing water-air interface and their interaction. The results of the numerical simulations on the underwater obstacle over-flow are compared with the laboratory data. The preliminary results of the investigation of internal and free surface wave generation as well as the wave interaction, are presented.

The hypothesis is made that it is not the progressive waves but the standing-progressive gradient-vortex Ross-by waves that are really dominating in the ocean. These waves can be detected through analysis of the satellite altimetry maps as a system of node lines where the sea-surface level does not vary, while the sea level oscilla-tion phase is subject to an immediate change by 180 grad. The node lines form a pattern of cells, the progres-sive waves of Rossby propagating between the cells nodes. On the basis of the altimetry data series covering the northwestern Pacific Ocean over the period of 1992–2009, the average estimates of the following Rossby wave parameters are obtained: wavelengths, periods, phase velocities of waves propagating between nodes, as well as node-to-node distances.

The existing models reproduce a contradictory pattern of tides in the region of the Franz-Josef Land (FJL) and Svalbard archipelagos. To refine it, we used the 3D finite-element hydrostatic model QUODDY-4. The region of interest was considered not as an isolated area, but as an element of the tidal dynamics of the entire Barents Sea. It is shown that in this region there are no other amphidromes, except for the degenerated amphidrome with its center at the Spitsbergen Island. There are two more peculiarities of this region such as the anticyclonic gyre of the horizontal wave flux of the barotropic tidal energy, as well as an increase (approximately, by one order of magnitude) of values of this gyre in the vicinity of Svalbard compared to the given values in the vicin-ity of FJL.

We discuss the interannual variability of the ocean heat content (OHC) from the mid-20th century to the present, using the data of different authors. An average trend of OHC is 0.22·1022 J/year, which covers 75 % variance of the source time series. A strong oscillation with the period of 23 years was detected using the wavelet analysis throughout the whole time interval under consideration. On the basis of reanalysis and the satellite sea surface temperature the statistical models accurately describing OHC changes, were designed. It is shown that since 2003 there is a certain stabilization in the variability of OHC.

An attempt was made to study the long-term variability of the average sea level and a range of hydrometeoro-logical characteristics of the eastern part of the Gulf of Finland, the Baltic Sea. The time series of observations carried out at the marine meteorological stations over the period of 1958-2009 were used as the initial data. The results of the analysis showed an increase of the air temperature in winter-time by 2.8С, while the summer-time temperature increased by 1.2С. The sea surface temperature increased by 1.6С over the past 20 years, while the ice cover period duration in the eastern part of the Gulf of Finland became shorter by 15 days. At the same time the sea level rise made 5 mm over the past 50 years The largest anomalies of the parameters were registered over the period of 1991-2005.

Experimental investigations of the wave processes performed in the coastal zone near the settlement Vzmorye Sakhalin Isl.) allowed obtaining a digital record of a rare occurrence extreme negative surge observed during cyclone passage over the northern part of the island. The analysis of the meteorological conditions of the negative surge and its spectral characteristics was performed. The dynamics of the wind waves and swell was considered. It was discovered that in the process of the negative surge there was a significant decrease of the wave amplitudes until the end of the negative surge period, after which even a noticeable rise was recorded.

The features of the weak signals resolution by suggested algorithms are considered, taking into account the combination of factors appropriate to every particular implementation case: dimensions and parameters of antennae; a time interval of the spectral analysis; application of focusing matrices to correct samples at different frequencies; a sample length required for adaptation; a process spread of the reception path parameters; the parameters and the type of the algorithms used including the classic adaptive algorithms (MUSIC, Johnson) and the normalized versions of proper structural and projection algorithms.

The current work is analyzing an interference situation in the presence of a significant scattering component within the strong interfering signals. The order of magnitude of the interval of fluctuation frequency correlation in sea environment is estimated. Simulations of direction-finding contours of the adaptive algorithms (classical and those based on the orthogonal projection with valuation of the strong signals) are carried out for resolution of the weak signals masked by the strong local source signals in the presence of the scattering component in their structure. An influence of the physical parameters of the acoustic field (the interval of fluctuation frequency correlation) as well as the parameters of the receiving channels is studied.

Two versions of a new modification of the hydrostatic method for the in-situ measurements of sea-water density are offered. The first version is based on co-processing of the signals of three differential pressure sensors, their inputs being located on three non-orthogonal (a general case) axes. The second version is based on co-processing of the signals of four rigidly connected non-differential pressure sensors. In both cases after co-processing an output signal of the pressure sensor system is insensitive to inclination of the system in the sea environment, which increases accuracy of the in-situ sea water density measurements.