Download Free Measurements Of Acoustic Backscatter Of The Deep Sea Floor Using A Deeply Towed Vehicle Book in PDF and EPUB Free Download. You can read online Measurements Of Acoustic Backscatter Of The Deep Sea Floor Using A Deeply Towed Vehicle and write the review.

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.
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.
Discoveries of new types of marine mineral occurrences during the last decade, and specifically the massive sulfide deposits at spreading ridges on the ocean floor, have significantly advanced geologic concepts about the origin of ore deposits in a very short period of time. These discoveries also renewed interest in all marine mineral occurrences including the well-known manganese nodules, and led to more wide-ranging and thorough examination of cobalt-rich manganese crusts, expanded mapping of phosphorites of continental shelves, and the initiation of several new surveys for placer minerals in shallow waters. The result of these activities is already noticeable in an increasingly broader variety of minerals being found on and below the ocean floor. This upsurge of scientific interest and research in marine minerals provided the impetus to organize an Advanced Research Workshop under auspices of the NATO Science Council and its Special Program Panel on Marine Sciences. The workshop was held in the United Kingdom at Gregynog Hall of the University of Wales, June 10-16, 1985, under the theme "Marine Minerals--Resource Assessment Strategies. " The timing of this workshop was propitious in many ways. First, marine surveys and expeditions to chart the mineral resources of the world's oceans had increased in number in recent years, involving a growing number of nations interested in obtaining firsthand information.
Reprints from various publications
"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
A beautifully illustrated reference providing fascinating insights into the hidden world of the seafloor using the latest deep-sea imaging.
Reprints from various publications.