This book has been written to encourage a new generation of
scientists,
engineers, and entrepreneurs to break the constraints of traditional disciplines
and to apply the modem methods of acoustical physics to probe the mysterious
sea. In order to assist the reader, we have included a large number of references
that are of either historical or immediate importance. The inspired reader will
keep up to date in applied ocean acoustics by referring to the most prominent,
appropriate technical periodicals such as The Joual of the Acoustical Society
of America and The Joual of Geophysical Research." Oceans and
Atmospheres.
We are both applied physicists-one originally a physical acoustician, the
other a geophysicist. We use the tools of applied mathematics, physical acoustics,
noise control, seismology, signal theory, and wave propagation to lea about the
sea. The reader will find on these pages various techniques to solve the direct
problem-that is, to predict the propagation of sound from an essential
knowledge of the physical and biological characteristics along the ocean
propagation path. He or she will also find examples of inverse problem solutions,
in which the vagaries of underwater sound propagation are used to measure the
physical and biological characteristics of the sea and its boundaries. Our methods
include laboratory scale models of ocean-acoustic environments as well as
experiments at sea, and solutions based on theoretical analysis and numerical
simulations.
When we published our first book (C. S. Clay and H. Medwin, Acoustical
Oceanography, 1977), the broad application of acoustics to lea about the
sea and its boundaries had barely been defined. Now, two decades later, this
exciting field is expanding in several directions. A broad range of imaginative specialists have used the methods of underwater acoustics to open new areas of
ocean engineering, oceanography, marine biology, and even, unexpectedly,
meteorology.
Following a brief survey of recent successes in acoustical oceanography
(Chapter 1), we explain the principles of underwater sound propagation (Chapters
2-6). We then describe how both actively probing sonars and passively listening
hydrophones can reveal what the eye cannot see over vast ranges of the turbid
ocean. The goal is to use acoustical remote sensing, variations in sound
transmission, in-situ acoustical measurements, computer models, or laboratory
models to identify the physical and biological parameters and processes in the sea
(Chapters 7-14).
For the reader's convenience, we give brief derivations, summaries, and
formulas in several sections and subsections that are marked with an asterisk (*).
We will use material given there, but readers may wish to skip those entire
sections or omit some of the details.
Both of us have contributed to each of the chapters; however, the principal
author of Chapters 1, 2, 4, 5, 8, 12, and 13 was H. Medwin, and that of Chapters 3,
6, 7, 9, 10, 11, 14 was C. S. Clay. We invite you to direct comments and questions
to the principal authors: Herman Medwin, Physics Department, Naval
Postgraduate School, Monterey, Califoia; Clarence S. Clay, Department of
Geology and Geophysics, University of Wisconsin, Madison, Wisconsin.
engineers, and entrepreneurs to break the constraints of traditional disciplines
and to apply the modem methods of acoustical physics to probe the mysterious
sea. In order to assist the reader, we have included a large number of references
that are of either historical or immediate importance. The inspired reader will
keep up to date in applied ocean acoustics by referring to the most prominent,
appropriate technical periodicals such as The Joual of the Acoustical Society
of America and The Joual of Geophysical Research." Oceans and
Atmospheres.
We are both applied physicists-one originally a physical acoustician, the
other a geophysicist. We use the tools of applied mathematics, physical acoustics,
noise control, seismology, signal theory, and wave propagation to lea about the
sea. The reader will find on these pages various techniques to solve the direct
problem-that is, to predict the propagation of sound from an essential
knowledge of the physical and biological characteristics along the ocean
propagation path. He or she will also find examples of inverse problem solutions,
in which the vagaries of underwater sound propagation are used to measure the
physical and biological characteristics of the sea and its boundaries. Our methods
include laboratory scale models of ocean-acoustic environments as well as
experiments at sea, and solutions based on theoretical analysis and numerical
simulations.
When we published our first book (C. S. Clay and H. Medwin, Acoustical
Oceanography, 1977), the broad application of acoustics to lea about the
sea and its boundaries had barely been defined. Now, two decades later, this
exciting field is expanding in several directions. A broad range of imaginative specialists have used the methods of underwater acoustics to open new areas of
ocean engineering, oceanography, marine biology, and even, unexpectedly,
meteorology.
Following a brief survey of recent successes in acoustical oceanography
(Chapter 1), we explain the principles of underwater sound propagation (Chapters
2-6). We then describe how both actively probing sonars and passively listening
hydrophones can reveal what the eye cannot see over vast ranges of the turbid
ocean. The goal is to use acoustical remote sensing, variations in sound
transmission, in-situ acoustical measurements, computer models, or laboratory
models to identify the physical and biological parameters and processes in the sea
(Chapters 7-14).
For the reader's convenience, we give brief derivations, summaries, and
formulas in several sections and subsections that are marked with an asterisk (*).
We will use material given there, but readers may wish to skip those entire
sections or omit some of the details.
Both of us have contributed to each of the chapters; however, the principal
author of Chapters 1, 2, 4, 5, 8, 12, and 13 was H. Medwin, and that of Chapters 3,
6, 7, 9, 10, 11, 14 was C. S. Clay. We invite you to direct comments and questions
to the principal authors: Herman Medwin, Physics Department, Naval
Postgraduate School, Monterey, Califoia; Clarence S. Clay, Department of
Geology and Geophysics, University of Wisconsin, Madison, Wisconsin.