Long-range sound propagation in the central part of the Barents Sea

Abstract

The data of the experiments on long-range propagation of explosion-generated and tonal sound signals, which had been performed in different years in the central part of the Barents Sea in summertime conditions, are used to analyze the space structure of the sound field intensity, to estimate the attenuation coefficient due to the sound energy loss in the bottom sediments, and to determine the frequency dependence of this coefficient. A comparison of the data on the long-range propagation of explosion-generated signals is performed between two experiments carried out on the same 230-km-long path crossing the Central Basin of the Barents Sea, several years in succession. The two experiments differ in the propagation conditions: in the first experiment, a near-bottom sound channel extends along the entire path, and in the second experiment, the path crosses a frontal zone characterized by fairly complex variations of the sound speed field. Calculations are carried out to show that the specific behavior of the frequency dependence of attenuation can be explained by the powerlaw frequency dependence (with an exponent of 1.4) of the sound absorption in the water-saturated upper layer of the bottom sediments. It is also shown that the difference in the decay laws obtained for the sound field levels in the two experiments is caused by the difference in the corresponding hydrological conditions.