A Multifrequency Acoustic Sounding System for Studying the Acoustic Characteristics of the Upper Layer of the Sea

A method and acoustic sounding hardware complex for studying the acoustic characteristics of the upper layer of the sea with the use of broadband highly directional inverted radiators, which are installed on the bottom, are described. The method is based on the principle of registering backscattering and reflection of acoustic pulses of different frequencies from the water surface, thus allowing simultaneous measurements of the sound scattering and absorption by sea water. Multifrequency sounding allows acoustic spectroscopy of bubbles in near-surface sea layers, assessment of the gas content, and obtaining data on the scattering and absorbing properties of the upper layer of sea water in various sea conditions up to a storm. Some of the results that were obtained during multiday sounding of the upper sea layer on the shelf of the Sea of Japan are presented.