Impact of Littoral Environmental Variability on Acoustic Predictions and Sonar Performance


Book Description

The limiting influence of the environment on sonar has long been recognised as a major challenge to science and technology. As the area of interest shifts towards the lit toral, environmental influences become dominant both in time and space. The manyfold challenges encompass prediction, measurement, assessment and adaptive responses to maximize the effectiveness of systems. Although MCM and ASW activities are dom inated in different ways and scales by the environment, both warfare areas have had to consider the significantly changing requirements posed by operations in the littoraL The fundamental scientific issues involved in developing models relating acoustics to the environment are matched in difficulty by the need for data for their validation and eventual practical use for prediction. In many instances the need is for on-line adaptation of systems to changing circumstances whilst other needs are for the Ionger term planning activities. This book and the attached full-color CD are the proceedings of a conference organ ised by the SACLANT Undersea Research Centre, held at Villa Marigola, Lerici, Italy, on 16-20 September 2002. The fundamental problems associated with environmental 1 variability and sonar were explored at a previous SACLANTCEN conference in 1990. These problems have not gone away but, on the one hand are exaggerated by the move to the littoral and on the other hand, are open to treatrnent in new ways that advances in technology and computer power allow.




Marine Research


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New Techniques in Sediment Core Analysis


Book Description

In this volume, recent advances in analytical and logging technology and their application to the analysis of sediment cores are presented. Developments in providing access to core data and associated datasets, and advances in data mining technology in order to integrate and interpret new and legacy datasets within the wider context of seafloor studies are also discussed.




High-Frequency Seafloor Acoustics


Book Description

This book is a research monograph on high-Frequency Seafloor Acoustics. It is the first book in a new series sponsored by the Office of Naval Research on the latest research in underwater acoustics. It provides a critical evaluation of the data and models pertaining to high-frequency acoustic interaction with the seafloor, which will be of interest to researchers in underwater acoustics and to developers of sonars. Models and data are presented so as to be readily usable, backed up by extensive explanation. Much of the data is new, and the discussion in on two levels: concise descriptions in the main text backed up by extensive technical appendices.




In Situ Determinations of the Velocities of Compressional and Shear Waves in Marine Sediments from a Research Submersible


Book Description

In situ measurements were made of the velocity and attenuation of compressional waves and of velocities of Stoneley waves (from which shear-wave velocities were computed) at six stations in the sea floor off San Diego, California. Water depths ranged from 20 to 1130 meters, and sediment types ranged from medium sand to clayey silt. Sediment densities, porosities, and grain sizes were measured in samples taken at each station. The unique data obtained allowed tentative evaluations of models and equations, and computation of constants, for elastic and viscoelastic saturated, porous media. (Author).







Marine Research, 1973


Book Description