Regional variability of the phenomenon of sound penetration into shadow zones in the ocean with fine-structure stratification

The regional variability of the phenomenon of the shadow zone insonification in the ocean is manifested in the variability of the main parameters of the sound signals that penetrate into these zones because of the scattering by the fine-structure inhomogeneities of the refractive index. The intensity of the phenomenon is governed by a combination of the vertical distribution of intensity of the fine-structure inhomogeneities and the caustics that exist in the insonified domains, along with the caustic intensity and position, both of which depend on the mean sound speed profile and on the geometry of the experiment. For the chosen typical regions of the ocean, the characteristics of the fine structure are systematized, and the phenomenon under study is analyzed. The results obtained offer a justified approach to solving inverse problems and a way to perform practical-purpose studies aimed at improving the ultimate performance of underwater observation and monitoring systems.