The air sea boundary interaction zone is described in terms of nondimensional variables requisite for future experiments. Noise field coherency, rare directional measurements, and unique basin scale computations and methods are presented. The use of satellite measurements in these basin scale models is demonstrated. A series of appendices provides in-depth mathematical treatments which will be of interest to graduate students and active researchers.
Contents:Applications of Natural Ocean Noise:Oceanographic Applications of Natural Sea Surface Sound (W K Melville)Applications of Matched-Phase Noise Reduction to Wind-Wave Generated Noise (B E McDonald & G J Orris)Wind and Precipitation Noise:Laboratory Acoustical Studies of Micro-Scale Sea Surface Activity During Wind and Rain (H Medwin)Ambient Noise Dependence on Local and Regional Wind Speeds (D H Cato et al.)Breaking Waves:New Insights into Breaking Waves and Bubble Entrainment (M S Longuet-Higgins)High Frequency Noise Emitted from Ocean Breaking Waves (P H Dahl)Bubbles:Unresolved Issues in Bubble-Related Ambient Noise (L A Crum)Artificial Bubble Cloud Targets (P A Hwang et al.)Spatial/Temporal Characteristics of Natural Ocean Noise:Source Localization in Noisy Ocean Environments (M D Collins et al.)A Comparison of Deep and Shallow Water Ambient Noise Measurements at Selected Sites Off Western Vancouver Island Using a Multi-Element Vertical Array (P Scrimger et al.)Ice Noise:Acoustical Tracking of Ice Failure Processes (Y-B Xie)Ridge Source Localization Through Matched-Field Processing (P Zakarauskas et al.)and other papers
Readership: Applied physicists.
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
Acoustic techniques provide the most effective means for remote sensing of ocean and sea floor processes, and for probing the structure beneath the sea floor. No other energy propagates as efficiently in the ocean: radio waves and visible light are severely limited in range because the ocean is a highly conductive medium. However, sound from breaking waves and coastal shipping can be heard throughout the ocean, and marine mammals communicate acoustically over basin scale distances.
The papers in this book indicate a high level of research interest that has generated significant progress in development and application of experimental acoustic inversion techniques. The applications span a broad scope in geosciences, from geophysical, biological and even geochemical research. The list includes: estimation of geotechnical properties of sea bed materials; navigation and mapping of the sea floor; fisheries, aquaculture and sea bed habitat assessment; monitoring of marine mammals; sediment transport; and investigation of natural geohazards in marine sediments.
This book is primarily intended for physicists and engineers working in underwater acoustics and oceanic engineering. It will also be of interest to marine biologists, geophysicists and oceanographers as potential users of the methodologies and techniques described in the book contributions.
The invited contributions explore the use of acoustics to measure bottom properties and morphology, as well as to probe buried objects within the sediment. Within the water column, sound is applied to imaging of oceanographic features such as currents and tides or monitoring of marine life. Another key theme is the use of sound to solve geometric inverse problems for precise tracking of undersea vehicles.
Audience: This volume should be useful both to the novice seeking an introduction to the field and to advanced researchers interested in the latest developments in acoustic sensing of the ocean environment.
The workshop was sponsored by the Fundação para a Ciêcia e a Tecnologia (Portuguese Foundation for Science and Technology).
The pseudo-Stoneley wave is most sensitive to permeability: both the impedance and the attenuation are controlled by the fluid flow. Also from reflected-wave modes unique estimates for permeability and porosity can be obtained when the reflection coefficients of different reflected modes are combined. In this case the sensitivity to permeability is caused by subsurface heterogeneities generating mesoscopic fluid flow at seismic frequencies. The results of this thesis suggest that estimation of in-situ permeability is feasible, provided detection is carried out with multi-component measurements. The results of this thesis argely affect geotechnical and reservoir engineering practices.