Long-Range Underwater Sound Propagation: Environmental Variability, Signal Stability and Signal Coherence
Abstract
Our long-term scientific goal is to understand the basic physics of low-frequency long-range sound propagation in the ocean, and the effects of environmental variability on signal stability and coherence. We seek to understand the fundamental limits to signal processing imposed by ocean variability to enable advanced signal processing techniques, including matched field processing and other adaptive array processing methods. The principal objective of our ongoing effort is to develop a theory of acoustic fluctuations in long-range propagation that correctly accounts for measurements. This objective is motivated by the failure (as reported by Colosi et al., 1999) of traditional approaches (see, e.g., Flatt et al., 1979) to the study of wave propagation in random media (WPRM) to predict measured time spreads and intensity statistics in recent long-range underwater acoustic experiments. Work to date strongly suggests that acoustic fluctuations are, to a surprisingly large degree, controlled by a property (the ray-based stability parameter or the asymptotically equivalent mode-based waveguide invariant ) of the background sound speed profile, rather than details of the sound speed perturbation. As a result, much of the recent theoretical work has been motivated by a desire to understand which wavefield properties are controlled by or . Over the past several years a significant part of this effort has been devoted to the analysis of measurements made during the LOAPEX experiment. A secondary objective is to better understand the limitations of the process known as noise interferometry as an ocean remote sensing tool.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2013
- Accession Number
- ADA598922
Entities
People
- Michael G. Brown
Organizations
- Rosenstiel School of Marine, Atmospheric, and Earth Science