Acoustic effect caused by a deep thermohaline stepped structure in the Mediterranean Sea

Abstract

Recent oceanographic observations in the Tyrrhenian Sea and Sardinian Channel show a well-defined stepped thermohaline structure below the core of the Levantine water (∼500 m). Such a stepped structure has also been found under the Mediterranean outflow west of Gibraltar. The effects of the Tyrrhenian Sea stepped structure on sound propagation are examined qualitatively using ray tracing techniques. The predominant effect occurs for energy that has travelled along rays that have vertexed in the steps. Shadow zones, regions of high propagation loss, and caustics are then generated.