The continents of our planet have already been exploited to a great extent. Therefore man is turning his sight to the vast spaciousness of the ocean whose resources - mineral, biological, energetic, and others - are just beginning to be used. The ocean is being intensively studied. Our notions about the dynam ics of ocean waters and their role in forming the Earth's climate as well as about the structure of the ocean bottom have substantially changed during the last two decades. An outstanding part in this accelerated exploration of the ocean is played by ocean acoustics. Only sound waves can propagate in water over large distances. Practically all kinds of telemetry, communication, location, and re mote sensing of water masses and the ocean bottom use sound waves. Propa gating over thousands of kilometers in the ocean, they bring information on earthquakes, eruptions of volcanoes, and distant storms. Projects using acoustical tomography systems for exploration of the ocean are presently be ing developed. Each of these systems will allow us to determine the three-di mensional structure of water masses in regions as large as millions of square kilometers.

Publisher Description

This is an unparalleled modern handbook reflecting the richly interdisciplinary nature of acoustics edited by an acknowledged master in the field. The handbook reviews the most important areas of the subject, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest research and applications are incorporated throughout, including computer recognition and synthesis of speech, physiological acoustics, diagnostic imaging and therapeutic applications and acoustical oceanography. An accompanying CD-ROM contains audio and video files.

This book presents a comprehensive overview of hydroacoustics and describes the physical basis of acoustic processes observed in the sea. In addition, it discusses the basic concepts and provides simplified models of sound propagation and acoustic phenomena at the boundary between environments. Lastly, the book examines in detail a number of applications of ocean acoustics and methods. The ocean is the last reserve of natural resources. It is also an essential element in the biosphere, ensuring the latter’s balance, and plays a pivotal role in the Earth’s climate system and global warming. Consequently, studying the ocean is one of humankind’s most critical scientific tasks, but penetrating its mysteries is no mean feat. Acoustics (hydroacoustics) is one of the most powerful tools for examining the water layer and beyond, since sound waves are the only type of radiation that can propagate over distances of hundreds and even thousands of kilometers in the ocean. This unique resource appeals to specialists working in the fields of ocean and atmosphere physics, students and postgraduate students studying sea physics and oceanology, and anyone who is interested in the problems the ocean is currently facing.

For the 119 species of marine mammals, as well as for some other aquatic animals, sound is the primary means of learning about the environment and of communicating, navigating, and foraging. The possibility that human-generated noise could harm marine mammals or significantly interfere with their normal activities is an issue of increasing concern. Noise and its potential impacts have been regulated since the passage of the Marine Mammal Protection Act of 1972. Public awareness of the issue escalated in 1990s when researchers began using high-intensity sound to measure ocean climate changes. More recently, the stranding of beaked whales in proximity to Navy sonar use has again put the issue in the spotlight. Ocean Noise and Marine Mammals reviews sources of noise in the ocean environment, what is known of the responses of marine mammals to acoustic disturbance, and what models exist for describing ocean noise and marine mammal responses. Recommendations are made for future data gathering efforts, studies of marine mammal behavior and physiology, and modeling efforts necessary to determine what the long- and short-term impacts of ocean noise on marine mammals.

A systematic study of chaotic ray dynamics in underwater acoustic waveguides began in the mid-1990s when it was realized that this factor plays a crucial role in long-range sound propagation in the ocean. The phenomenon of ray chaos and its manifestation at a finite wavelength — wave chaos — have been investigated by combining methods from the theory of wave propagation and the theory of dynamical and quantum chaos.This book is the first monograph summarizing results obtained in this field. Emphasis is made on the exploration of ray and modal structures of the wave field in an idealized environmental model with periodic range dependence and in a more realistic model with sound speed fluctuations induced by random internal waves. The book is intended for acousticians investigating the long-range sound transmission through the fluctuating ocean and also for researchers studying waveguide propagation in other media. It will be of major interest to scientists working in the field of dynamical and quantum chaos.

The developments in the field of ocean acoustics over recent years make this book an important reference for specialists in acoustics, oceanography, marine biology, and related fields. Fundamentals of Acoustical Oceanography also encourages a new generation of scientists, engineers, and entrepreneurs to apply the modern methods of acoustical physics to probe the unknown sea. The book is an authoritative, modern text with examples and exercises. It contains techniques to solve the direct problems, solutions of inverse problems, and an extensive bibliography from the earliest use of sound in the sea to present references.Written by internationally recognized scientists, the book provides background to measure ocean parameters and processes, find life and objects in the sea, communicate underwater, and survey the boundaries of the sea. Fundamentals of Acoustical Oceanography explains principles of underwater sound propagation, and describes how both actively probing sonars and passively listening hydrophones can reveal what the eye cannot see over vast ranges of the turbid ocean. This book demonstrates how to use acoustical remote sensing, variations in sound transmission, in situ acoustical measurements, and computer and laboratory models to identify the physical and biological parameters and processes in the sea.* Offers an integrated, modern approach to passive and active underwater acoustics* Contains many examples of laboratory scale models of ocean-acoustic environments, as well as descriptions of experiments at sea* Covers remote sensing of marine life and the seafloor* Includes signal processing of ocean sounds, physical and biological noises at sea, and inversions* resents sound sources, receivers, and calibration* Explains high intensities; explosive waves, parametric sources, cavitation, shock waves, and streaming* Covers microbubbles from breaking waves, rainfall, dispersion, and attenuation* Describes sound propagation along ray paths and caustics* Presents sound transmissions and normal mode methods in ocean waveguides

Rated the most up-to-date source on underwater sound propagation in the current literature. The book covers these topics and more: Basic theory; velocity of sound in the ocean; attenuation and absorption; computer models of sound propagation; reflections and scattering by the sea surface and the sea bottom; temporal and spatial coherence; and multipath in the sea.