Sound Propagation through the Stochastic Ocean

Abstract

The ocean is opaque to electromagnetic radiation and transparent to low-frequency sound. So acoustical methodologies are an important tool for sensing the undersea world. Stochastic sound-speed fluctuations in the ocean, such as those caused by internal waves, result in a progressive randomization of acoustic signals as they traverse the ocean environment. This signal randomization imposes a limit to the effectiveness of ocean acoustic remote sensing, navigation, and communication. At the same time, signal fluctuations can be used as an important probe to better understand stochastic ocean processes. Sound Propagation through the Stochastic Ocean provides a comprehensive treatment of developments in the field of statistical ocean acoustics over the last thirty-five years. This book will be of fundamental interest to oceanographers, marine biologists, geophysicists, engineers, applied mathematicians, and physicists. Key discoveries in topics such as internal waves, ray chaos, Feynman path integrals, and mode transport theory are addressed with illustrations from ocean observations. The topics are presented at an approachable level for advanced students and seasoned researchers alike.

Training a U-Net based on a random mode-coupling matrix model to recover acoustic interference striations

“…The mode-coupling matrix method [16,17] is used to describe the mode coupling induced by horizontal inhomogeneities in ocean waveguides.…”

“…where the subscript denotes the mode number and the superscript``T'' denotes the matrix transpose, can be expressed as [16,17]…”

“…is the mode-coupling matrix which is caused by the horizontal inhomogeneity, such as NLIW, between 1 r and 2 r [16,17]. Mode-coupling effects introduce many additional components in AISs [13] which results in the distortion of the AISs.…”

Acoustic Tomography in the Canary Basin: Meddies and Tides

“…First, the predictions from climatology obtain almost no acoustic energy consistent with the broad, stochastic overture that extends from about 205.25 to 205.6 s. Second, the weak last arrival at about 207.25 s was not obtained. The nature of these data and the environment suggested these arrivals could be accounted for by adding stochastic sound speed effects to the sound speed section (Colosi, 2016;Dushaw et al, 2016;Van Uffelen et al, 2010).…”

“…The observed acoustic scattering that characterizes the overture is a general feature of acoustic arrival patterns obtained elsewhere, although it has been most often associated with the finale of midlatitude arrival patterns (Colosi, 2016;Colosi et al, 2005;Worcester et al, 1999). Two phenomena have been employed to account for Journal of Geophysical Research: Oceans 10.1002/2017JC013356 acoustically scattered signals like these.…”