Synopses & Reviews
The generation of oceanic sound by natural physical mechanisms is a topic of scientific inquiry with a wide range of applications, both environmental and naval. Sound is generated by waves interacting, by waves breaking, by wind noise transmitted directly into, and by rain, snow and spray falling onto the water. Sound is also generated in frozen seas by ice either rubbing or cracking. This book contains the proceedings of an international conference `Natural Physical Sources of Underwater Sound' held at the University of Cambridge in July 1990. The contents of the 54 papers cover the topics of ambient noise, very low and seismic noise, noise from turbulence and bubbles singly and collectively, rain noise, ice noise, as well as thunder, cosmic ray and sea-bottom saltation. The material represents the considerable advances made by hydrodynamicists and acousticians since the first meeting on the topic held in Lerici, Italy in 1987, and published as a companion volume from Kluwer, entitled Sea Surface Sound. The material in both books is dedicated to characterizing and understanding natural, as opposed to man-made, mechanisms of underwater sound generation. Questions of propagation and scattering are included only as necessary to understanding generation itself. A reader interested either in a review of the status of this interdisciplinary field of geohydrodynamical acoustics, or with a general interest in natural acoustics, will find this book of great value.
Synopsis
To place this book in perspective it is useful for the reader to be aware of the recent history of the topic of underwater sound generation at the ocean surface by natural mechanisms. A meeting in Lerici, Italy in 1987 was convened within the NATO Advanced Research Workshop series, to bring together underwater acousticians and ocean hydrodynamicists to examine various mechanisms which generate sound naturally at the ocean surface. A record of that meeting was published in the NATO scientific publication series in 1988 under the title 'Sea Surface Sound'. That meeting was successful in inspiring and co- ordinating both participants and non-attending colleagues to examine some key issues which were raised during the course of presentations and discussions. The understanding among those present was that another meeting should be convened 3 years hence to report and review progress in the subject. Accordingly the second conference was convened in Cambridge in 1990, whose proceedings are presented here. This volume represents a very gratifying increase in only a 3 year interval in our understanding of a number of physical processes which generate sound at the peripheries of oceans. In fact it represents both the acceleration of singular effort as well as the development of interdisciplinary sophistication and co-operation. The enthusiasm, goodwill, and intense scientific curiosity which characterized the Lerici meeting carried through to Cambridge. The collegial atmosphere established by the participants was perfectly timed to foster another major advance in studies of ocean surface sound.
Table of Contents
Preface. Ambient Noise. VLF/Seismo-Acoustics. Air-Water Turbulence. Bubbles-LF Source and Scattering. Bubbles-HF Source and Scattering. Bubbles - Breaking Waves. Ice. Rain. Other Mechanisms. Subject Index.