Finestructure in NAPOLI 85, an ocean/acoustic experiment

NAPOLI 85 was an ocean/acoustic experiment carried out in the Tyrrhenian Sea to investigate acoustic propagation variability due to inhomogeneities in the ocean medium. The variability in the pulse arrival times has already been presented. This article presents the analysis of the environmental conditions. Data are available from various instruments, including a towed oscillating body (TOB), which was equipped with sensors that provide sound speed. The TOB allows oceanic features to be mapped in the vertical–horizontal plane. These maps show significant finestructure features (typically 4 km long by 40 m deep) that can be tracked through 10-TOB casts over a 3-day period. In contrast to an oceanographer’s viewpoint, the analysis of these features is carried out in terms of their impact on acoustic propagation. A procedure for separating finestructure into internal-wave and non-wave components is extended from previous work and applied. This procedure provides a means to identify the mechanism generating th...