Regional Variability of Influence of Small-Scale Sound-Speed Fluctuation Levels on the Acoustic Fields Formation in the Ocean

Abstract

The results presented herein are the research findings about the influence of small-scale inhomogeneity’s in water environment on the structure of acoustic fields for hydrological and acoustical conditions that are typical for the Atlantic and Pacific Oceans. Small-scale sound-speed fluctuations were modeled by adding a stochastic perturbation to the deterministic mean profile. Quantitative experiment was conducted to determine the dynamics of changes in the first three convergence zones at the depths of emission source in relation to the random componentry in the sound-speed field. Analytical dependences of increasing widths of upper convergence zones on the level of the random componentry in the sound-speed field were determined based on the results of quantitative experiment. With increasing stochasticity levels, the width of convergence zones increases in accordance with linear law, and the absolute increments grow with the increase of convergence zone number. When the values of a random componentry in the sound-speed field are fixed, the absolute increment of width of the upper convergence zones in the Atlantic Ocean is higher than in the Pacific Ocean. This said, the gradient of a smooth profile of the sound velocity by depth above the axis of hydroacoustic channel is higher in the Atlantic Ocean. Consequently, the absolute increments of width of the convergence zones depend not only on the levels of stochasticity parameters of water environment, yet, also, on the gradient size of smooth profile of the sound speed at depths above the axis of hydroacoustic channel.