Characteristics of the Hydrodynamic Portraits of Acoustic Fields of the Shallow Areas of Peter the Great Bay of Sea of Japan

Abstract

An approach to solve the problem of improving the technological methods of forming the means of investigation of the underwater environment through comprehensive studies of acoustic fields created by objects of artificial origin against the background of noise fields from natural phenomena of shallow areas is presented. The object of research is hydrodynamic acoustics, arisen from several scientific branches, including hydrodynamics, oceanology, hydrography and acoustics of the ocean. The subject of the research is a set of consistent theoretical, analytical and experimental results in the study of the basic concepts of hydrodynamic acoustics: the sea areas of Peter the Great Bay; geographical contours, allowing on a number of parameters to carry out their deterministic or uniquely prede-fined classification; hydrodynamic portraits of acoustic fields in order to identify their distinctive parameters. The multilevel systematics of the dynamics of hydrometeorological characteristics and its influence on the acoustic fields of geographic regions makes it possible to carry out field observation in a fractal-attractor way at those points that determine the structure of the aquatic environment. In this case, the fractal-attractor method of monitoring the environment and hydrodynamic portraits of acoustic fields can be used to study the various processes in the water environment whatever their nature. According to the research results it was noted that the occurrence of random variations of physical phenomena gradients considered in the paper is balanced on average by the processes of their dissipation and the appearance of fine structures in the marine environment; longterm continuous measurements and their analysis showed that changes in the acoustic field parameters, especially the acoustic signal phase, are associated not only with the geographical area of the equipment installation, but also with the influence of tidal forces, the bottom structure and natural and anthropogenic processes; tracks as "external influences" affect acoustic waves propagation in the marine environment due to the creation of an acoustic background on them that activates the environment and makes it possible to detect irregular acoustic changes in the shelf zone; the biological factors are sometimes crucial at the analysis of the acoustic field of the shallow sea. For the shelf waters of Sea of Japan, the parameters of internal waves, fluctuations of the thermohaline wedge, Brunt-Väisälä frequencies values can be considered dependent on the complex structure and size of bays and coves in the shelf zone. This negatively affects the equipment issues solution of marine areas with formed specific portraits on seiche of internal (gravitational) waves and the instrument constructions for solution of hydrodynamic acoustics problems. Such an object-subject approach depending on the totality of the obtained characteristics allows us to solve the problem of marine areas equipment with the instrument constructions at implementation of hydrodynamic aco...