Download or read book Deep Seafloor Acoustic Backscattering Measurements Using Sea Beam written by Christian de Moustier and published by . This book was released on 1985 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multibeam echo-sounders such as Sea Beam allow investigators to carry out detailed bathymetric surveys of large areas of the seafloor. However, bathymetry only reveals the shape of seafloor features to the resolution of the sounding system, and in order to make geological interpretations one needs to characterize the nature of the seafloor surveyed. Because bottom roughness and/or variations in bottom substrate cause fluctuations in the backscattered acoustic signal received by an echo sounder such characteristics can be inferred in part by analyzing the structure and the variations of this signal over several transmission cycles. The approach taken has been to record digitally the detected echo envelopes of Sea Beam's 16 narrow beams over a variety of seafloor environments, and process these data to determine whether the acoustics held enough information to differentiate between bottom types. Significant results derived from these acoustic data concern the Sea Beam system's performance; its potential for mapping acoustic boundaries; and the display of the echoes received in a side looking sonar like picture.

Download or read book Measurements of Acoustic Backscatter of the Deep Sea Floor Using a Deeply Towed Vehicle written by M. Weydert and published by . This book was released on 1985 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1983 in area of Copper-Nickel rich manganese nodules at 14 deg 40 min N, 126 deg 25 min W (site 'E) was intensively studied with the Deep-Tow of the Scripps Institution of Oceanography, and 16 box cores were collected. Deep-Tow studies of the Thirtymile-Bank off the California Coast and the deep sea at the foot of the Patton Escarpment followed. The nodule coverage at site 'E varies from 0% to 80%. The nodule sizes vary between 1 and 13 cm. The nodule size distributions are best modeled by a Gaussian distribution. The three main nodule axes are related to each other at 1:0.8:0.5. The average density of individual nodules is 2.0 + or - 0.04 g/cu cm and the volumes increase on the average with the 2.8 power of the third root of the product of the three radii. Changes of the thickness of the upper acoustic unit of the sediment column correlate with changes in nodule coverage and concentration. The acoustic backscatter has been measured for frequencies of 4.5, 9, 15, 28, 60, 112 and 163 kHz and grazing angles from normal incidence to 5 degrees. The backscatter increases as the square of the frequency for sediments.

Download or read book Geophysics Field Measurements written by and published by Academic Press. This book was released on 1987-09-24 with total page 637 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geophysics Field Measurements

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Frequency Seafloor Acoustics written by Darrell Jackson and published by Springer Science & Business Media. This book was released on 2007-08-02 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Fundamentals of Acoustic Backscatter Imagery written by Clyde E. Nishimura and published by . This book was released on 1997-10-01 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes various multidisplinary subjects that play an important role in the operation, processing, and interpretation of acoustic backscattering systems and their data. The subject matter covered includes the physics of wave propagation and scattering, basic imaging system engineering, mode of standard survey operations, processing methodology, and marine geology and geophysics.

Download or read book Shallow Water Acoustic Backscatter and Reverberation Measurements Using a 68 kHz Cylindrical Array written by Timothy Cole Gallaudet and published by . This book was released on 2001 with total page 670 pages. Available in PDF, EPUB and Kindle. Book excerpt: The characterization of high frequency, shallow water acoustic backscatter and reverberation is important because acoustic systems are used in many scientific, commercial, and military applications. The approach taken is to use data collected by the Toroidal Volume Search Sonar (TVSS), a 68 kHz multibeam sonar capable of 360 deg imaging in a vertical plane perpendicular to its direction of travel. With this unique capability, acoustic backscatter imagery of the seafloor, sea surface, and horizontal and vertical planes in the volume is constructed from data obtained in 200 m deep waters in the Northeastern Gulf of Mexico when the TVSS was towed 78 m below the surface, 735 m astern of a towship. The processed imagery provides a quasi-synoptic characterization of the spatial and temporal structure of boundary and volume acoustic backscatter and reverberation. Diffraction, element patterns, and high sidelobe levels are shown to be the most serious problems affecting cylindrical arrays such as the TVSS, and an amplitude shading method is presented for reducing the peak sidelobe levels of irregular-line and non-coplanar arrays. Errors in the towfish's attitude and motion sensor, and irregularities in the TVSS's transmitted beampattern produce artifacts in the TVSS-derived bathymetry and seafloor acoustic backscatter imagery. Correction strategies for these problems are described, which are unique in that they use environmental information extracted from both ocean boundaries. Sea surface and volume acoustic backscatter imagery is used to explore and characterize the structure of near-surface bubble clouds, schooling fish, and zooplankton. The simultaneous horizontal and vertical coverage provided by the TVSS is shown to be a primary advantage, motivating further use of multibeam sonars in these applications.

Download or read book Fundamentals of Acoustical Oceanography written by Herman Medwin and published by Academic Press. This book was released on 1997-11-05 with total page 739 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Springer Handbook of Acoustics written by Thomas Rossing and published by Springer Science & Business Media. This book was released on 2007-06-21 with total page 1179 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Clandestine Methods for the Determination of Beach Trafficability written by Scott A. Jenkins and published by . This book was released on 1985 with total page 946 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Naval Special Warfare (NSW) units are assigned the mission of conducting reconnaissance of landing beaches in support of amphibious operations. This mission includes the determination of beach composition and trafficability available to various vehicles as they transit the beach and pass through beach exits. This report describes modern techniques, developed from soil mechanics, for determining beach trafficability. These techniques, compared to current NSW methods, require less training and shorter swimmer exposure times, and allow for a more simplified sampling, yet derive a more quantitative trafficability estimate with more repeatable results. This report recommends that these new measurement techniques be incorporated into NSW doctrine. Remote sensors for determining beach trafficability are also identified and addressed. While these methods are outside of NSW assets, they are valuable for the purpose of identifying candidate beaches before committing NSW personnel for final verification."--Abstract

Download or read book U S Geological Survey Circular written by and published by . This book was released on 1984 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 1988 Annual Report on Alaska s Mineral Resources written by and published by . This book was released on 1988 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the 1987 Exclusive Economic Zone Symposium on Mapping and Research written by Geological Survey (U.S.) and published by . This book was released on 1988 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the 1987 Exclusive Economic Zone Symposium on Mapping and Research written by John F. Elder and published by . This book was released on 1988 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Geophysical Exploration at Sea written by Richard A. Geyer and published by CRC Press. This book was released on 2018-02-06 with total page 732 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook presents advanced research and operational information about hard minerals and hydrocarbons. It provides information in an integrated, interdisciplinary manner, stressing case histories. It includes review chapters, illustrations, graphs, tables, and color satellite images that present the results of gravity, geodetic, and seismic surveys and of 3-D sea floor sub-bottom visualizations. The data was obtained using satellites, aircraft, and ships from the Atlantic and Pacific Oceans, the Gulf of Mexico, and the Caribbean Sea.Major topics addressed in these volumes include geophysical methods used to explore for hydrocarbons, advanced radiometric and electrical methods for hard mineral searches, the role of geotechnology and seismic acoustics in overcoming geological hazards in selecting drilling sites and pipeline routes, and remote sensing techniques used to determine the physical properties of hydrocarbons.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1982 with total page 916 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Annual Index written by and published by . This book was released on 1986 with total page 900 pages. Available in PDF, EPUB and Kindle. Book excerpt: