| Route Survey Periodicity for Mine Warfare |
Sep-2009 |
73 pages |
| Authors:
Coke; Hartwell F V; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
 | One of the Navy's most long standing challenges has been conquering the mine warfare threat. As mines and mine warfare techniques evolve and become more sophisticated, so does the United States' ability to counter the threat. The United States newest technique for countering a potential mined harbor, or route, is a process known as change detection. This concept uses previous side scan sonar images of the area prior to a ... |
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| Heavy Oil Detection (Prototypes) |
Jun-2009 |
74 pages |
| Authors:
Kurt A Hansen; Michele Fitzpatrick; Penny R Herring; Mark VanHaverbeke; COAST GUARD RESEARCH AND DEVELOPMENT CENTER NEW LONDON CT
|
| Current methods for locating and recovering submerged oil spills are inadequate. Detection methods are often improvised on-scene, and recovery techniques are labor intensive and not always successful. The U.S. Coast Guard Research and Development Center has embarked on a multi-year project to develop a complete approach for dealing with spills of submerged oils. This report describes the assessment of detection techniques using sonar, laser fluorometry, real-time mass spectrometry, and in-situ ... |
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| Underwater Detonations at the Silver Strand Training Complex: Effects on Marine Mammals |
30-Apr-2009 |
87 pages |
| Authors:
Glenn H Mitchell; Tiffini J Brookens; Stephen A Jordan; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| The Commander of the U.S. Pacific Fleet is preparing an environmental impact statement (EIS) for activities at the Silver Strand Training Complex (SSTC). Training often involves the use of small explosives for various purposes, such as to disable underwater mines or defend ports. Explosions release very brief, intense sound energy with spectral characteristics spanning a wide band of frequencies. As a part of the SSTC EIS development, a quantitative analysis ... |
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| Vertical Structure of Bottom Ekman Tidal Flows: Observations, Theory, and Modeling From the Northern Adriatic |
17-Apr-2009 |
26 pages |
| Authors:
Milivoj Kuzmic; Ivica Janekovic; Paul J Martin; Jeffrey W Book; M Wimbush; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| From September 2002 to May 2003, fifteen bottom-mounted, acoustic Doppler current profilers measured currents of the northern Adriatic basin. Tidal fluctuations at all seven of the major Adriatic frequencies were synthesized from a response tidal analysis of these measurements. Most observed tidal current ellipses were nearly reversing, but near the bottom, tidal current ellipses all shortened and broadened, semidiurnal currents led upper water column currents, and diurnal tidal current ellipse ... |
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| Multi-Static Detection and Localization of Buried Targets using Synthetic Aperture Iterative Time-Reversal Processing |
18-Mar-2009 |
26 pages |
| Authors:
H C Song; Karim Sabra; W A Kuperman; W S Hodgkiss; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE PHYSICAL LAB
|
| The objective of this project is to develop bi-static applications of the iterative time reversal techniques to focus along the ocean bottom. Iterative time-reversal provides a simple solution for self-adaptive focusing on strong reflectors (i.e. scattering targets) located on the ocean bottom without relying on predictive or modeling capabilities of the environment and of the target of interest. These robust focusing properties are crucial for mapping large and uncharted areas ... |
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| Characterization of a Mud Deposit Offshore of the Patos Lagoon, Southern Brazil |
Feb-2009 |
13 pages |
| Authors:
K T Holland; Allen H Reed; Richard W Faas; Mead A Allison; Lauro J Calliari; S E O'Reilly; W C Vaughan; A Alves; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOACOUSTICS DIV
|
| Rapid deposition of mud on the beach along the shoreface of Rio Grande do Sul, Brazil dramatically influences the normal operations in the littoral zone. In the surf zone, fluid and suspended mud opposes water-wave movement and dissipates water-wave energy; on the beach, mud limits trafficability. As part of a multinational, multidisciplinary program to evaluate the influence of mud strength, density and viscosity on water-wave attenuation, sediments were evaluated in ... |
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| Toward an Arctic Strategy |
Feb-2009 |
36 pages |
| Authors:
Alan L Kollien; ARMY WAR COLL CARLISLE BARRACKS PA
|
| Rising temperatures and a corresponding ice pack melt in the Arctic accelerates to levels not previously envisioned. The rapidly receding polar ice pack opens a new Arctic area of opportunity in ways not witnessed until this century. This emerging area of operations holds new economic opportunity recognized by many nations, but especially Arctic border nations rushing to stake their claims in the Arctic Ocean and its seabed. Despite the accelerating ... |
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| A Model-Coupling Framework for Nearshore Waves, Currents, Sediment Transport, and Seabed Morphology |
Jan-2009 |
16 pages |
| Authors:
H S Tang; T R Keen; R Khanbilvardi; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| This paper presents a framework for synchronously coupling wave, current, sediment transport, and seabed morphology for the accurate simulation of multi-physics coastal ocean processes. The governing equations, which represent models that are commonly adopted in practical simulations, are discretized using finite-difference methods. The resulting system is validated against analytical solutions. In order to test the performance of the proposed framework and the numerical methods, dam-break flow over a mobile-bed and ... |
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| Quantifying In Situ Metal and Organic Contaminant Mobility in Marine Sediments |
Jan-2009 |
45 pages |
| Authors:
Stephen Lieberman; Bart Chadwick; ENVIRONMENTAL SECURITY TECHNOLOGY CERTIFICATION PROGRAM OFFICE (DOD) ARLINGTON VA
|
| Contaminants enter shallow coastal waters from many sources, including ships, shoreside facilities, municipal outfalls, spills, and nonpoint source runoff. Sediments are typically considered a primary sink for these contaminants. Sediments in many bays, harbors, and coastal waters used by the Department of Defense (DoD) are contaminated with potentially harmful metal and organic compounds. DoD is required by the Comprehensive Environmental Resource Conservation and Liability Act (CERCLA), as amended by the ... |
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| A Study of Dissipation of Wind-Waves by Mud as Cassino Beach, Brazil: Prediction and Inversion |
Jan-2009 |
16 pages |
| Authors:
W E Rogers; K T Holland; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| The impact of a non-rigid seafloor on the wave climate at Cassino Beach, Brazil, May-June 2005 is studied using field measurements and a numerical wavemodel. The measurements consist of wave data at four locations; rheology and mud thickness from grab samples; and an estimate of the horizontal distribution of mud based on echo-soundings. The dissipation of waves by a non-rigid bottom is represented in the wave model by treating the ... |
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| Toward Cooperation or Conflict on the Moon? Considering Lunar Governance in Historical Perspective |
Jan-2009 |
23 pages |
| Authors:
James C Moltz; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF NATIONAL SECURITY AFFAIRS
|
| The question of how the moon will be governed once humans return to it in about a decade and begin to establish permanent bases matters greatly to the future of international security. Already, a range of major powers have plans to participate in the moon's further scientific exploration, commercial exploitation, and possible permanent settlement. If we count both manned and robotic activities, this list currently includes the United States, China, ... |
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| Acoustic Image Models for Navigation with Forward-Looking Sonars |
Dec-2008 |
69 pages |
| Authors:
Masek; Theodore D Jr; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Cost and miniaturization of autonomous unmanned vehicles (AUV) drive component reuse and better sensor data analysis. One such component is the forward looking sonar (FLS) which can be used for obstacle avoidance and to extract vehicle state information. However, autonomous feature extraction of images from the FLS is difficult due to the noise inherent in the sensor and the sensor's susceptibility to interference from other acoustic devices. This thesis investigated ... |
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| Assessing Potential Sites for Undersea Warfare Training Ranges: The Effects of Active Sonars on Marine Mammals |
28-Oct-2008 |
84 pages |
| Authors:
Yadira V Gilchrest; Thomas N Fetherston; Bert E Neales; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| The U.S. Navy is preparing a draft environmental impact statement/overseas environmental impact statement (DEIS/OEIS) for what will be the proposed site for an undersea warfare training range (USWTR). The DEIS includes an assessment of the effects of Navy active acoustic sonars on marine mammals during range exercises as required by the Marine Mammal Protection Act (MMPA). The Naval Undersea Warfare Center Division, Newport, RI, has assessed four sites: Jacksonville, FL; ... |
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| Testing and Evaluation of the Mobile Inspection Package |
01-Oct-2008 |
11 pages |
| Authors:
John Kloske; SRI INTERNATIONAL MENLO PARK CA
|
| The goal of this contract (N00014-07-C-0722) is to develop a portable system for underwater port security focusing on ship hull scanning. This, and previous efforts, have been to develop a system that meets the requirements of the Coast Guard, the Navy Explosive Ordnance Disposal Team (EOD) and local law enforcement. The result is a Mobile Inspection Package (MIP), capable of surveying ship hulls, seawall, pilings, and seafloors. The MIP can ... |
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| Influence of Atmospheric and Sea-Surface Corrections on Retrieval of Bottom Depth and Reflectance Using a Semi-Analytical Model: A Case Study in Kaneohe Bay, Hawaii |
01-Oct-2008 |
11 pages |
| Authors:
ZhongPing Lee; James A Goodman; Susan L Ustin; MIAMI UNIV FL
|
| Hyperspectral instruments provide the spectral detail necessary for extracting multiple layers of information from inherently complex coastal environments. We evaluate the performance of a semi-analytical optimization model for deriving bathymetry, benthic reflectance, and water optical properties using hyperspectral AVIRIS imagery of Kaneohe Bay, Hawaii. We examine the relative impacts on model performance using two different atmospheric correction algorithms and two different methods for reducing the effects of sun glint. We ... |
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| U.S. Deep-Sea Tsunameter Network Fully Operational |
Sep-2008 |
11 pages |
| Authors:
William Hansen; Douglas Maxwell; Shannon McArthur; Richard Bouchard; Ian Sears; Jack Higgs; Mark Webster; NATIONAL DATA BUOY CENTER STENNIS SPACE CENTER MS
|
| In March 2008, the National Oceanic and Atmospheric Administration's (NOAA) National Data Buoy Center (NDBC) completed the deployment of the last of the 39-station network of deep-sea tsunameters. This effort was an integral part of the National Tsunami Hazard Mitigation Program. The Tsunami Program is part of a cooperative effort to save lives and protect property through hazard assessment, warning guidance, mitigation, research capabilities, and international coordination. NOAA's National Weather ... |
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| Observations of the R Reflector and Sediment Interface Reflection at the Shallow Water '06 Central Site |
28-Aug-2008 |
8 pages |
| Authors:
Jee Woong Choi; Peter H Dahl; J A Goff; HANYANG UNIV SEOUL (KOREA)
|
| Acoustic bottom-interacting measurements from the Shallow Water '06 experiment (frequency range 1-20 kHz) are presented. These are co-located with coring and stratigraphic studies showing a thin (20 cm) higher sound speed layer overlaying a thicker (20 m) lower sound speed layer ending at a high-impedance reflector (R reflector). Reflections from the R reflector and analysis of the bottom reflection coefficient magnitude for the upper two sediment layers confirm both these ... |
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| Improving Accuracy of Acoustic Prediction in the Philippine Sea through Incorporation of Mesoscale Environmental Effects |
01-Jun-2008 |
69 pages |
| Authors:
Kimberly M Freitas; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| An understanding of ocean acoustic fields, their statistics, and relation to the oceanographic environment is the sine qua non of undersea warfare. In the tactically important Philippine Sea, powerful mesoscale eddies can have strong effects on acoustic fields. To quantify eddy effects, a mesoscale sound-speed model was developed and interfaced with a parabolic equation acoustic simulation. Eight combinations of frequency (20Hz/250Hz), wavenumber spectra (Stammer/Lorentzian) and source depth (50m/200m) were simulated ... |
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| 2007 Program of Study: Boundary Layers |
Jun-2008 |
|
| Authors:
Claudia Cenedese; John A Whitehead; Joseph Pedlosky; Steven Lentz; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
 | The topic of the Principal Lectures for the forty-ninth year of the program was Boundary Layers. The subject centers around those problems in which the boundary conditions lead to a large gradient near the boundary. Nine of this year's principal lectures were given by Joe Pedlosky and the tenth was given by Steve Lentz. The fluid mechanics of boundary layers was reviewed, first starting from its classical roots and then ... |
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| Shallow Water Mid-Frequency Research and FY07 Experiment |
05 MAY 2008 |
7 pages |
| Authors:
Dajun Tang; WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB
|
| Long-term goals: To understand mid-frequency (1-10 kHz) acoustics in shallow waters through measurements and modeling, including propagation, reflection, and forward- and backscatter. The top-level goals of this effort are to understand the important environmental processes, which impact mid-frequency sonar performances in shallow water environments; and to develop means to efficiently collect those environmental data. The LEAR (Littoral Environmental Acoustics Research) acoustics field experiment, part of Shallow Water 2006 (SW06) project, ... |
|
| The Effect of Pressure and Time on Information Recall |
01-Apr-2008 |
28 pages |
| Authors:
J B Morrison; J K Zander; SHEARWATER HUMAN ENGINEERING NORTH VANCOUVER (BRITISH COLUMBIA)
|
| Mine countermeasures divers are required to investigate mines located on the seabed. The diver is required to first locate, then to memorize details about the mine for later reporting to the dive supervisor. This study evaluated the effects of diving to 40 msw and elapsed time on the processing and recall of information. Ten divers viewed detailed images of mine-like objects on six occasions in air and in dives to ... |
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| Assessment of the Performance of the Near-Bottom Hydrophones of the U.S. Navy Southern California Offshore Range in Detecting, Localizing and Reconstructing 10-20 kHz Odontocete Whistles |
01-Mar-2008 |
81 pages |
| Authors:
Carl A Hager; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A series of 10 to 20 kHz, frequency-sweeping signals synthesizing whistles of vocalizing Odontocetes was transmitted from a J-9 sound projector suspended from the Research Vessel Pt Sur while over the U.S. Navy Southern California Offshore Range (SCORE) Underwater Acoustic Range from 11 to 13 August 2004. The transmissions were recorded by a group of seven near-bottom hydrophones of the Range. Using statistical analysis on ensembles of the repeated transmissions, ... |
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| Bedforms and Mine Burial in the Nearshore |
MAR 2008 |
8 pages |
| Authors:
Edith L. Gallagher; Rob Holman; FRANKLIN AND MARSHALL COLL LANCASTER PA BIOLOGY DEPT
|
| The threat of mines has an enormous impact on Naval operations. Methods exist for search and identification of proud mines, but the potential existence of buried mines is of considerable concern. This work will help to describe the process of mine burial owing to bottom bedform movement by quantifying the expected time scales and depths of disturbance of the natural bed in the nearshore. As waves work the sediments on ... |
|
| A Quantitative Approach to Determine Analogous Areas Using Environmental Parameters |
MAR 2008 |
159 pages |
| Authors:
Christopher L. Bryan; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The backbone of the success of the United States Naval Forces has been its ability to train for future events. By conducting successful training operations, the Navy has prepared for real-world operations. The principle, "fight like you train, train like you fight," has no less significance today than it did in the past. The purpose of this thesis is to develop a new, robust analogous area determination tool for the ... |
|
| Australian DefenceScience. Volume 16, Number 1, Autumn |
Jan-2008 |
|
| Authors:
DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION CANBERRA (AUSTRALIA)
|
| This volume contains the following articles: Is high-fidelity best for depicting situation awareness?; A cool-headed robot built for hot radiological work; Easing the strain on replenishment at sea; MURLIN defeats the deadly gaze of IR missile eyes; Scanning the seafloor for maritime operations; Better ways to link people securely by satellite; An improved tool for countering mine attack at sea; ADF frontline personnel to benefit from sports technology Personal radar ... |
|
| Investigating the Relationship Between Fin and Blue Whale Locations, Zooplankton Concentrations and Hydrothermal Venting on the Juan de Fuca Ridge |
Jan-2008 |
10 pages |
| Authors:
William S Wilcock; Richard E Thomson; WASHINGTON UNIV SEATTLE SCHOOL OF OCEANOGRAPHY
|
| We are investigating the potential correlation between whale tracks, enhanced zooplankton concentrations and hydrothermal vents above the Juan de Fuca Ridge with the long-term goal of understanding such correlations in terms of the influences of globally distributed hydrothermal plumes on the trophic ecology of the deep ocean. We are conducting a retrospective study using existing seismic and bio-acoustical data sets from the Juan de Fuca Ridge with the following four ... |
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| Layered Organization in the Coastal Ocean: Acoustical Data Acquisition, Analyses and Synthesis |
Jan-2008 |
10 pages |
| Authors:
D V Holliday; C F Greenlaw; RHODE ISLAND UNIV NARRAGANSETT GRADUATE SCHOOL OF OCEANOGRAPHY
|
| The long-term goal of our research is to improve our ability to observe the ocean's plants, animals, and their physical and chemical environment at the scales that control how they live, reproduce, and die. We are working with our colleagues in the ONR-sponsored research program on Layered Organization in the Coastal Ocean (LOCO) to jointly analyze data collected in Monterey Bay, CA during FY2002, 2005 and 2006. Our work this ... |
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| Autonomous Sensing of Layered Structures in Hawaiian Waters |
Jan-2008 |
6 pages |
| Authors:
Margaret A McManus; HAWAII UNIV AT MANOA HONOLULU DEPT OF OCEANOGRAPHY
|
| Our long-term goals are (1) to determine the spatial and temporal scales of thin layers, (2) to identify the processes responsible for the formation, maintenance and dissipation of vertically thin layers, and (3) to develop the capability to predict thin layer formation and presence in the sea. The central focus of our research is to investigate: the spatial and temporal scales of thin layers, the relationship between physical processes (from ... |
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| Measuring the Spatial Distribution of Ripples Using REMUS AUV |
10 OCT 2007 |
|
| Authors:
Wayne R. Geyer; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
|
| The long term goal of this work is to increase our understanding of bedform geometry and processes associated with bedforms on the continental shelf. To do this we have been developing novel measurement techniques, conducting observations of both the spatial and temporal variability of ripples and developing a variety of model approaches. |
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| Wave Modelling - The State of the Art |
27 SEP 2007 |
73 pages |
| Authors:
L. Cavaleri; Erick Rogers; Hendrik L. Tolman; Fabrice Ardhuin; Igor V. Lavrenov; J-H. G. Alves; A. Babanin; M. Banner; K. Belibassakis; M. BENOIT; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
|
| This paper is the product of the wave modelling community and it tries to make a picture of the present situation in this branch of science, exploring the previous and the most recent results and looking ahead towards the solution of the problems we presently face. Both theory and applications are considered. The many faces of the subject imply separate discussions. This is reflected into the single sections, seven of ... |
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| Cross-Shelf Circulation and Momentum and Heat Balances Over the Inner Continental Shelf Near Martha's Vineyard, Massachusetts |
SEP 2007 |
268 pages |
| Authors:
Melanie R. Fewings; MASSACHUSETTS INST OF TECH CAMBRIDGE JOINT PROGRAM IN APPLIED OCEAN SCIENCE AND ENGINEERING
|
| The water circulation and evolution of water temperature over the inner continental shelf are investigated using observations of water velocity, temperature, density, and bottom pressure; surface gravity waves; wind stress; and heat flux between the ocean and atmosphere during 2001-2007. When waves are small, cross-shelf wind stress is the dominant mechanism driving cross-shelf circulation. The along-shelf wind stress does not drive a substantial cross- shelf circulation. The response to a ... |
|
| Modeling of High-Frequency Acoustic Propagation in Shallow Water |
JUN 2007 |
150 pages |
| Authors:
Juan C. Torres; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This research involves numerical modeling of acoustic signals through shallow water channels. The sound is computationally modeled in a vertical plane as a dense fan of beams radiating from the transmitter location. The cross section of each 2-dimensional beam is represented as a Gaussian distribution of acoustic energy. The Gaussian beam travels axially along rays governed by Snell's Law, dispersing in width as a function of travel distance. At arbitrary ... |
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| Experimental and Seismological Constraints on the Rheology, Evolution, and Alteration of the Lithosphere at Oceanic Spreading Centers |
FEB 2007 |
|
| Authors:
Brian J. deMartin; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
| Oceanic spreading centers are sites of magmatic, tectonic, and hydrothermal processes. In this thesis I present experimental and seismological constraints on the evolution of these complex regions of focused crustal accretion and extension. Experimental results from drained, triaxial deformation experiments on partially molten olivine reveal that melt extraction rates are linearly dependent on effective mean stress when the effective mean stress is low and non-linearly dependent on effective mean stress ... |
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| Geoacoustic Inversion by Mode Amplitude Perturbation |
FEB 2007 |
|
| Authors:
Travis L. Poole; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
| This thesis introduces an algorithm for inverting for the geoacoustic properties of the seafloor in shallow water. The input data required by the algorithm are estimates of the amplitudes of the normal modes excited by a low-frequency pure-tone sound source, and estimates of the water column sound speed profiles at the source and receiver positions. The algorithm makes use of perturbation results, and computes the small correction to an estimated ... |
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| High-Resolution Mapping of Mines and Ripples at the Martha's Vineyard Coastal Observatory |
Jan-2007 |
18 pages |
| Authors:
Peter Traykovski; Larry A Mayer; Michael D Richardson; Arthur C Trembanis; Richard Raymond; Gerd Glang; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOACOUSTICS DIV
|
| High-resolution multibeam sonar and state-of-the-art data processing and visualization techniques have been used to quantify the evolution of seafloor morphology and the degree of burial of instrumented mines and mine-shapes as part of the U.S. Office of Naval Research (ONR, Arlington, VA) mine burial experiment at the Martha's Vineyard Coastal Observatory (MVCO, Edgartown, MA). Four surveys were conducted over two years at the experiment site with a 455-kHz, Reson 8125 ... |
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| Mine Burial Experiments at the Martha's Vineyard Coastal Observatory |
Jan-2007 |
|
| Authors:
Peter Traykovski; Larry A Mayer; Michael D Richardson; James D Irish; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
| Several experiments to measure post impact burial of seafloor mines by scour and fill have been conducted near the Woods Hole Oceanographic Institution's Martha's Vineyard Coastal Observatory (MVCO, Edgartown, MA). The sedimentary environment at MVCO consists of a series of rippled scour depressions (RSDs), which are large scale bedforms with alternating areas of coarse and fine sand. This allows simultaneous mine burial experiments in both coarse and fine sand under ... |
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| Scour and Burial Mechanics of Objects in the Nearshore |
Jan-2007 |
14 pages |
| Authors:
Michael D Richardson; Thomas F Wever; Scott A Jenkins; Douglas L Inman; Joseph Wasyl; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA MARINE PHYSICAL LAB
|
| A process-based, numerical, hydrodynamic vortex lattice mine scour/burial model (VORTEX) is presented that simulates scour and burial of objects of arbitrary shape resting on a granular bed in the nearshore. There are two domains in the model formulation: a far-field where burial and exposure occur due to changes in the elevation of the seabed and a near-field involving scour and transport of sediment by the vortices shed from the object. ... |
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| Multibeam Observations of Mine Burial Near Clearwater, FL, Including Comparisons to Predictions of Wave-Induced Burial |
Jan-2007 |
17 pages |
| Authors:
Michael D Richardson; Monica L Wolfson; David F Naar; Peter A Howd; Stanley D Locker; Brian T Donahue; Carl T Friedrichs; Arthur C Trembanis; Thomas F Wever; UNIVERSITY OF SOUTH FLORIDA SAINT PETERSBURG
|
| A Kongsberg Simrad EM 3000 multibeam sonar (Kongsberg Simrad, Kongsberg, Norway) was used to conduct a set of six repeat high-resolution bathymetric surveys west of Indian Rocks Beach (IRB), just to the south of Clearwater, FL, between January and March 2003, to observe in situ scour and burial of instrumented inert mines and mine-like cylinders. Three closely located study sites were chosen: two fine-sand sites, a shallow one located in ... |
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| Irregular Wave Forces on Heavily Overtopped Thin Vertical Walls |
JAN 2007 |
14 pages |
| Authors:
Steven A. Hughes; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
|
| The Coastal and Hydraulics Engineering Technical Note (CHETN) described herein provides empirical equations to estimate irregular wave forces and overturning moments on thin, vertical walls extending from the seafloor and having a top elevation that is below the still-water level. In this situation, the majority of the wave crest passes over the vertical wall. A worked example illustrates application of the empirical equations. |
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| Time-Frequency Modeling of Shallow Water Environments: Rigid vs. Fluid Seabed |
2007 |
6 pages |
| Authors:
Jun Zhang; Bertrand Gottin; Antonia Papandreou-Suppappola; Cornel Ioana; ARIZONA STATE UNIV TEMPE DEPT OF ELECTRICAL ENGINEERING
|
| When the ocean seabed is considered to be rigid, the ideal waveguide model can be used to model the shallow water environment. However, a more realistic ocean waveguide model treats the ocean floor as a boundary between two different fluid media. In this paper, a frequency-domain characterization of shallow water environments is proposed based on this realistic waveguide model with a fluid boundary. First, the time-frequency characteristics of this model ... |
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| Determining the Properties and Capabilities of an Existing Experimental Large Loop EM61 Underwater UXO Detector |
DEC 2006 |
54 pages |
| Authors:
DILLON CONSULTING LIMITED CAMBRIDGE (CANADA)
|
| In response to UXSON-04-03, Dillon Consulting Ltd (DCL) investigated the response of a prototype Large Loop EM61 Marine System. The system was originally conceived in 2002 for a marine UXO survey of Wright's Cove near Halifax, Nova Scotia, to detect accumulations of metal on or below the sea floor at depths of 1 to 15 meters of water. The survey presented new challenges in that the water depths required that ... |
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| The Automated Change Detection and Classification - Real-Time (ACDC-RT) System |
Dec-2006 |
16 pages |
| Authors:
Geary Layne; CHARLES MARTIN; Martin L Gendron; Christy Gautre; James Hammack; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| In support of Military Mine Warfare (MIW) clearance operations for safe vessel passage, analysts perform change detection by visually comparing historical high-resolution sidescan sonar imagery (SSI) with newly collected SSI in an attempt to identify newly placed objects. The objective of MIW change detection is to match objects detected in new SSI with historical objects stored in a database. Any newly detected objects not successfully matched are flagged for investigation. ... |
|
| Design and Analysis of Side-Looking Sonar Experiments |
DEC 2006 |
129 pages |
| Authors:
Konstantinos Tsaprazis; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This research concerns the design and analysis of different Side-Looking Sonar experiments in order to satisfy different operational requirements. The different designs and analysis have been done via computer simulation. Side-Looking Sonar (also known as side-scan sonar) is known for very high quality, high resolution, ocean bottom imaging. Hence, it is used for bathymetric surveys commonly called seafloor mapping. It is able to rapidly survey large ocean areas for bottom ... |
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| Analysis and Modeling of Surfzone Turbulence and Bubbles |
29 NOV 2006 |
6 pages |
| Authors:
Falk Feddersen; SCRIPPS INST OF OCEANOGRAPHY LA JOLLA CA INTEGRATIVE OCEANOGRAPHY DIV
|
| Turbulence in the surfzone and nearshore mixes momentum vertically, transmits stress to the sea bed, influences the structure of the cross- and alongshore currents, and controls the suspension of sediment from the sea bed. In many coastal and shelf environments, the sea-bed is the primary source of turbulence due to bottom induced shear. In the surfzone, the breaking-wave generated turbulence likely dominates over bottom generated turbulence. However, the dynamics of ... |
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| Short-Timescale Strata Formation on a Canyon-Dominated Margin: Assessing the Link between Shelf and Slope Systems |
25 SEP 2006 |
7 pages |
| Authors:
Beth L. Mullenbach; TEXAS A AND M UNIV COLLEGE STATION DEPT OF OCEANOGRAPHY
|
| Recent studies have shown that significant amounts of sediment can escape the shelf break during sea-level highstands, particularly on tectonically active margins (e.g., Kineke et al., 2000). These studies reveal the importance of off-shelf sediment exchange during present conditions in certain environments. However, the specific characteristics (e.g., shelf morphology, regional circulation) that permit significant sediment export from the continental shelf are not well understood, particularly near canyon heads. The long-term ... |
|
| Advances in Group Filter Applications to Sea Mine Detection |
Sep-2006 |
6 pages |
| Authors:
J T Cobb; M An; B Shenefelt; R Tolimieri; PROMETHEUS INC PANAMA CITY BEACH FL
|
| Automatic detection of sea mines in coastal regions is a difficult task due to the highly variable sea bottom conditions present in the underwater environment. Detection systems must be able to discriminate objects which vary in size, shape, and orientation from naturally occurring and man-made clutter. Additionally, these automated systems must be computationally efficient to be incorporated into unmanned underwater vehicle (UUV) sensor systems characterized by high sensor data rates ... |
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| Computer-Assisted Analysis of Near-Bottom Photos for Benthic Habitat Studies |
Sep-2006 |
|
| Authors:
V L Ferrini; H Singh; M E Clarke; W Wakefield; K York; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
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| This paper reports on a methodology developed for the analysis of near-bottom photographs collected for fisheries habitat studies. These tools provide a framework for conducting minimally invasive in-situ investigations of benthic organism abundance, diversity, and distribution using high-resolution optical datasets integrated with high precision navigational data. Utilizing these techniques with near-bottom photos collected with a precision navigated survey platform greatly increases the efficiency of image analysis and provides new insight ... |
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| The Ocean Observatories Initiative: Wiring the Ocean for Interactive Scientific Discovery |
Sep-2006 |
8 pages |
| Authors:
Alexandra R Isern; NATIONAL SCIENCE FOUNDATION ARLINGTON VA DIV OF OCEAN SCIENCES
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| The National Science Foundation's Division of Ocean Science has established the Ocean Research Interactive Observatory Networks (ORION) Program to operate and manage existing and future ocean observing sites funded by NSF including those constructed by the Ocean Observatories Initiative (OOI). The OOI is an integrated observatory system with three elements: (1) deep-sea buoys with capabilities appropriate to the experiments they will host with some designs capable of deployment in harsh ... |
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| Assessment of an Active Electromagnetic Sensor for Hunting Buried Naval Mines, Part II |
Sep-2006 |
9 pages |
| Authors:
P J Carroll; W M Wynn; J W Purpura; NAVAL SURFACE WARFARE CENTER PANAMA CITY FL
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| The US Navy is investigating the use of broadband electromagnetic (EM) sensors as a candidate technology for its Buried Minehunting (BMH) sensor suite. New Navy tactics are being pursued, where short-range sensors are incorporated into reacquisition minehunting systems for short-range classification. The current approach includes study of use of active EM sensors that employ multi-frequency sources for target illumination which can provide valuable multi-spectral discrimination for the classification of buried ... |
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| Mapping Clutter In Situ: Broadband Results from T-MAST 02 and Boundary 2004 |
Sep-2006 |
7 pages |
| Authors:
R C Gauss; J M Fialkowski; NAVAL RESEARCH LAB WASHINGTON DC
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| This paper presents experimental results of applying two methods to help mitigate the seabed clutter problem by spatially isolating significant reverberant features in situ: 1) a clutter mapping technique applied to broadband (400 to 2500 Hz) acoustic data collected in the vicinity of the Stanton Banks off of Scotland during the T-MAST 02 experiment; and 2) the use of a cardioid receiver array on the Malta Plateau off of Sicily ... |
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Reports by Keyword(s)
OCEAN BOTTOM
