| A Combined EOF/Variational Approach for Mapping Radar-Derived Sea Surface Currents |
13 JAN 2011 |
23 pages |
| Authors:
Max Yaremchuk; Alexei Sentchev; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
 | A technique for reconstruction of the 2d surface velocity field from radar observations is proposed. The method consecutively employs two processing techniques: At the first stage raw radial velocity data are subject to EOF analysis, which enables to fill gaps in observations and provides estimates of the noise level and integral parameters characterizing small-scale variability of the sea surface circulation. These parameters are utilized at the second stage when the ... |
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| Enhanced Estimation of Sonobuoy Trajectories by Velocity Reconstruction with Near-Surface Drifters |
Jan 2011 |
20 pages |
| Authors:
Y Chang; D Hammond; A C Haza; P Hogan; H S Huntley; Kirwan; A D Jr; Lipphardt; B L Jr; V Taillandier; A Griffa; T M Ozgokmen; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| An investigation to improve trajectory prediction using Lagrangian data is presented. The velocity field of a data assimilating model, EAS-16, is corrected using drifter observations taken during an experiment off Taiwan. The results are tested using another independent Lagrangian data set provided by sonobuoys launched in the same area. The latter have instrument chains that extend well into the water column. Consequently the corrected model velocities were projected into the ... |
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| Removal of Surface-Reflected Light for the Measurement of Remote-Sensing Reflectance from an Above-Surface Platform |
06 Dec 2010 |
13 pages |
| Authors:
Zhong-Ping Lee; Yu-Hwan Ahn; Curtis Mobley; Robert Arnone; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Using hyperspectral measurements made in the field, we show that the effective sea-surface reflectance (defined as the ratio of the surface-reflected radiance at the specular direction corresponding to the downwelling sky radiance from one direction) varies not only for different measurement scans, but also can differ by a factor of 8 between 400 nm and 800 nm for the same scan. This means that the derived water-leaving radiance (or remote-sensing ... |
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| Removal of Surface-Reflected Light for the Measurement of Remote-Sensing Reflectance from an Above-Surface Platform |
01 Dec 2010 |
14 pages |
| Authors:
Zhong P Lee; Yu-Hwan Ahn; Curtis Mobley; Robert Arnone; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Using hyperspectral measurements made in the field, we show that the effective sea-surface reflectance (defined as the ratio of the surface-reflected radiance at the specular direction corresponding to the downwelling sky radiance from one direction) varies not only for different measurement scans, but also can differ by a factor of 8 between 400 nm and 800 nm for the same scan. This means that the derived water-leaving radiance (or remote-sensing ... |
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| A New Mixing Diagnostic and Gulf Oil Spill Movement |
Oct 2010 |
5 pages |
| Authors:
Igor Mezic; S Loire; Vladimir A Fonoberov; P Hogan; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Chaotic advection has served as the paradigm for mixing in fluid flows with simple time dependence. Its skeletal structure is based on analysis of invariant attracting and repelling manifolds in fluid flows. Here we develop a finite-time theory for two-dimensional incompressible fluid flows with arbitrary time dependence and introduce a new mixing diagnostic based on it. Besides stretching events around attracting and repelling manifolds, this allows us to detect hyperbolic ... |
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| Eddy Resolving Global Ocean Prediction including Tides |
30 Sep 2010 |
13 pages |
| Authors:
Alan J Wallcraft; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| Use the HYbrid Coordinate Ocean Model (HYCOM) with tides, dynamic sea ice, and data assimilation in an eddy-resolving, fully global ocean prediction system with 1/25 deg horizontal resolution that will run in real time at the Naval Oceanographic Office (NAVOCEANO) starting in 2012. The model will include shallow water and provide boundary conditions to finer resolution coastal models that may use HYCOM or a different model. To develop, evaluate, and ... |
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| Flow Through the Straits of the Philippine Archipelago Simulated by Global HYCOM and EAS NCOM |
30 Sep 2010 |
11 pages |
| Authors:
Harley E Hurlburt; E J Metzger; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| We are collaborating with other DRI participants to better evaluate and understand the dynamics seen in observations and model results within the Philippine Archipelago, a strategic region with numerous straits. The model results come from the .08 deg and .04 deg global HYbrid Coordinate Ocean Model (HYCOM) and .088 deg East Asian Seas (EAS) Navy Coastal Ocean Model (NCOM) nested in global NCOM, the .04 deg global HYCOM and some ... |
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| Compact Ocean Models Enable Onboard AUV Autonomy and Decentralized Adaptive Sampling |
30 Sep 2010 |
9 pages |
| Authors:
James Bellingham; Sergey Frolov; Igor Shulman; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Long-term goals are to improve synoptic observations and enhance ocean prediction through development of new capabilities for persistent underwater ocean surveillance. Multi-platform ocean observing systems are typically centrally controlled from shore limiting their ability to adapt to new observations which would inform more effective sampling strategies. Our objectives: 1. Enhance the ability of mobile agents to respond adaptively by providing them with a synoptic realization of the environment in the ... |
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| Variability of Irradiance in the Wave Boundary Layer |
30 SEP 2010 |
7 pages |
| Authors:
W. S. Pegau; Hemantha W. Wijesekera; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Our primary goal is improve our understanding of the role of surface waves, bubble clouds, and nearsurface oceanic processes on the spatial distribution of oceanic irradiance. |
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| Oceanographic and Atmospheric Conditions on the Continental Shelf North of the Monterey Bay During August 2006 |
17 Sep 2010 |
56 pages |
| Authors:
Steven R Ramp; Pierre F Lermusiaux; Igor Shulman; Yi Chao; Rebecca E Wolf; Frederick L Bahr; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| A comprehensive data set from the ocean and atmosphere was obtained just north of the Monterey Bay as part of the Monterey Bay 2006 (MB06) field experiment. The wind stress, heat fluxes, and sea surface temperature were sampled by the Naval Postgraduate School's TWIN OTTER research aircraft. In situ data were collected using ships, moorings, gliders and AUVs. Four data-assimilating numerical models were additionally run, including the Coupled Ocean/Atmosphere Mesoscale ... |
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| Intraseasonal Variation of Winter Precipitation over the Western United States Simulated by 14 IPCC AR4 Coupled GCMs |
01 Jun 2010 |
27 pages |
| Authors:
Jia-Lin Lin; Toshiaki Shinoda; Taotao Qian; Weiqing Han; Paul Roundy; Yangxing Zheng; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| This study evaluates the intraseasonal variation of winter precipitation over the western United States in 14 coupled general circulation models (GCMs) participating in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). Eight years of each model's twentieth-century climate simulation are analyzed. The focus is on the two dominant intraseasonal modes for the western U.S. precipitation: the 40-day mode and the 22-day mode. The results show that the ... |
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| The Distribution of Gas and Gas Hydrate at Natural Seeps Inferred from Seismic Data |
Jun 2010 |
4 pages |
| Authors:
W T Wood; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| The Naval Research Laboratory has conducted detailed seismic and acoustic investigations at natural methane hydrate seep sites at several locations worldwide. The seismic expressions of these features exhibit significant differences, such as bathymetric expression (mounds, pockmarks, pavements) and the positions of the faults that are likely acting as methanesupplying conduits. Similarities include the way in which the base of gas-hydrate stability, a pressure and temperature boundary is perturbed upward by ... |
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| A Metric for Comparing Acoustic Transmission Loss Curves |
Jun 2010 |
7 pages |
| Authors:
J P Fabre; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| A metric is presented for quantifying the difference between two acoustic transmission loss curves. This allows a fast, but more importantly, consistent way to determine how well two underwater acoustic transmission loss curves compare in terms of their end use. Two methods are proposed for different applications, the first involves comparing only the curves themselves and the second involves use of a figure of merit to compare the curves as ... |
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| A Tile-Based System for the Rapid Display of Symbolized Digital Nautical Chart Data |
Jun 2010 |
7 pages |
| Authors:
Norman Schoenhardt; John T Sample; Frank McCreedy; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| For efficient retrieval and display of Digital Nautical Chart (DNC) imagery, a tiled-based approach is presented. By preprocessing the data into persistent image tiles, the presented method can minimize or eliminate image processing steps during the retrieval process. Tile-based approaches define constant image sizes and scales for geographic regions, therefore tiles can be pregenerated and stored in a format needed for transmission to users. This greatly improves the performance of ... |
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| Using Coupled Models to Study the Effects of River Discharge on Biogeochemical Cycling and Hypoxia in the Northern Gulf Of Mexico |
Jun 2010 |
8 pages |
| Authors:
B Penta; D Ko; R Gould; R Arnone; R Greene; J Lehrter; B Schaeffer; M Murrell; J Kurtz; B Herchenroder; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| We describe emerging capabilities to understand physical processes and biogeochemical cycles in coastal waters through the use of satellites, numerical models, and ship observations. Emerging capabilities provide significantly improved ability to model ecological systems and the impact of environmental management actions on them. The complex interaction of physical and biogeochemical processes responsible for hypoxic events requires an integrated approach to research, monitoring, and modeling in order to fully define the ... |
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| Numerical Investigation of Dynamic Free-Fall Penetrometers in Soft Cohesive Marine Sediments Using a Finite Element Approach |
Jun 2010 |
9 pages |
| Authors:
Andrei Abelev; Julian Simeonov; Philip Valent; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Various branches of offshore civil and petroleum engineering, as well as the Navy, have an expressed need for tools that allow for a rapid assessment of the surficial (top 2-3m) marine sediments. Undrained shear strength of soft cohesive (clayey) deposits is one of the central parameters required in these investigations. This information is critically important in evaluations of bearing capacity of sediment under the load of objects and structures placed ... |
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| GOMEX08 - High Frequency Acoustic Propagation over the Alabama Alps |
Jun 2010 |
10 pages |
| Authors:
R L Field; P C Gallacher; D A Hebert; E Jarosz; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| The objective of this work is to diagnose high frequency acoustic propagation directly from oceanographic data and ocean models. To achieve this objective a joint acoustic and oceanographic experiment was performed in the Gulf of Mexico in the summer of 2008. This paper will show that high frequency acoustic propagation at 17.5 kHz tracks the estimated turbulent dissipation rate obtained from field measurements and that ocean modeling gives reasonable estimates ... |
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| Cluster of Sound Speed Fields by an Integral Measure |
Jun 2010 |
6 pages |
| Authors:
James K Fulford; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| A technique to cluster large area oceanic predictions of sound speed into quasi-range independent areas is presented. Oceanic models produce high fidelity predictions of the oceanic sound speed fields that enable large-scale simulation of acoustic propagation with reasonable accuracy. Unfortunately, the oceanic models can produce sound speed fields quicker than can be digested by current technologies in underwater acoustic performance prediction systems. The speed bottleneck can be broken in two ... |
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| Correlation of the Broadband Spectral Characteristics of Bottlenose Dolphin Signatures with Dolphin Behavior in the Mississippi Sound |
Jun 2010 |
10 pages |
| Authors:
Steve Stanic; Bob Brown; Edgar Kennedy; Mobashir Solangi; Delphine Vanderpool; Timothy Hoffland; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| A series of acoustic measurements and visual observations were made of Bottlenose dolphins in the Mississippi Sound. A portable acoustic monitoring system recorded dolphin echolocation clicks, wideband burst pulses and narrowband frequency modulated whistles. The signal spectra were correlated with observations of dolphin behavior. The results showed that when these dolphins are diving and traveling, the primary signals are short echolocation clicks. During what appeared to be social interactions, the ... |
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| Using Acoustic Tomography to Monitor Deep Ocean Currents in the Eastern Gulf of Mexico |
Jun 2010 |
3 pages |
| Authors:
D A Rosenfield; J W Caruthers; D A Nechaev; N A Sidorovskaia; G E Ioup; J W Ioup; M I Yaremchuk; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Toward the improved prediction and monitoring of deep-water currents and eddies in the Gulf of Mexico, the Gulf Eddy Monitoring System group (GEMS; researchers from University of Southern Mississippi, University of New Orleans, University of Louisiana at Lafayette, and the Naval Research Laboratory) proposes that a network of acoustic transmitter receiver pairs be deployed in the northeastern Gulf of Mexico. Acoustic travel times are inverted to recover temperature and velocity ... |
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| A WAVCIS Based Ocean Observing Station to Provide Hydrodynamic Data off Eglin Air Force Base, Fort Walton, Florida, USA |
Jun 2010 |
9 pages |
| Authors:
Gregory W Stone; Felix Jose; Yixin Luo; Seyed M SiadatMousavi; Todd Holland; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| A new coastal ocean observing station has been established for the west Florida shelf, off Eglin Air Force Base, with an upward looking ADCP deployed at the approximate 11 m isobath for measuring the coastal currents, waves and tide. Hourly processed data were communicated to the WAVCIS station, through secured cellular communication. Vertical profiles of current speed and direction were continuously monitored until summer 2008. Also, directional wave spectra, bulk ... |
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| The Numerical Solution of Acoustic Propagation through Dispersive Moving Media |
Jun 2010 |
6 pages |
| Authors:
Guy V Norton; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| As the Navy expands its dependence on underwater communication between sensors, operating in areas where turbulent turbid water layers are present; there exists a need to accurately predict prior to sensor deployment how they will operate in these environments. The benthic nepheloid layer (BNL) is an example of a moving turbid water layer in the ocean. The BNL is characterized by changing vertical thickness, concentration and speed of the suspended ... |
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| Synthetic Aperture Sonar Low Frequency vs. High Frequency Automatic Contact Generation |
Jun 2010 |
4 pages |
| Authors:
J R Dubberley; M L Gendron; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Synthetic Aperture Sonar (SAS) bottom mapping sensors are on the verge of entering operational use. Here we examine the utility of both the low and high frequency output of SAS systems recorded from trials to determine their utility in the automatic contact generation scheme described in the companion paper Automated Change Detection using Synthetic Aperture Sonar Imagery [1]. The survey area covered by the trial has contacts called separately by ... |
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| NASA Satellite Monitoring of Water Clarity in Mobile Bay for Nutrient Criteria Development |
Jun 2010 |
7 pages |
| Authors:
Slawomir Blonski; Kara Holekamp; Bruce A Spiering; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Water clarity controls the loss of sunlight reaching the underwater habitats. Because many organisms living in estuarine and coastal waters rely on photosynthesis, water clarity needs to be incorporated into protective water quality standards for these valued ecosystems. To develop the protective standards, a better understanding of causes and effects of water clarity variability at local and regional scales is needed. To that end, NASA remote sensing data are being ... |
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| An Evaluation of Methods for Characterizing the Air/Water Interface for Parabolic Equation Transmission Loss Modeling |
Jun 2010 |
8 pages |
| Authors:
J P Fabre; Guy Norton; Robert Zingarelli; Richard Keiffer; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Proper characterization of underwater acoustic transmission loss (TL) relies on proper treatment of the air/water and water/sediment interfaces. This paper will focus on how the air/water interface is treated in parabolic equation (PE) models such as the range dependent acoustic model (RAM) [Collins, M. D., Applications and time-domain solution of higher-order parabolic equations in underwater acoustics, J. Acoust. Soc. Am., 86 (3), 1097-1102, 1989] and the finite element parabolic equation ... |
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| Coverage Metric for Acoustic Receiver Evaluation and Track Generation |
Jun 2010 |
6 pages |
| Authors:
Steven M Dennis; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Acoustic receiver track generation has been the subject of active research, both academic and operational, since at least 1946. In general, track generation algorithms operate by maximizing some measure of effectiveness or performance for a particular receiver in a particular environment. Current probability-based receiver performance measures are difficult to visualize, time consuming to calculate and are not easily subject to strict scientific analysis. Although great strides have been made in ... |
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| Magnetic Noise Associated with Ocean Internal Waves |
Jun 2010 |
4 pages |
| Authors:
W E Avera; Patrick C Gallacher; W J Teague; Robert Liang; J B Nelson; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Environmental noise can be a major limitation on the performance of magnetic sensor systems in continental shelf regions. Previous work has predicted the magnetic influence from internal waves and indicates that these could be important components of ambient ocean magnetic noise. Existing electric and magnetic field sensor technology has an instrument noise floor well below the ambient magnetic noise in shallow water applications. Model predictions indicate that internal oceanographic features, ... |
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| Mixture Theory Model Sensitivity to Effective Viscosity in Simulations of Sandy Bedform Dynamics |
Jun 2010 |
9 pages |
| Authors:
Allison M Penko; Joseph Calantoni; Donald N Slinn; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| We perform a sensitivity analysis on a three-dimensional bottom boundary layer model (SedMix3D) that uses mixture theory to simulate the flow and sediment transport over rippled sand beds. SedMix3D treats the fluid-sediment mixture as a single continuum with effective properties that parameterize the fluid-sediment and sediment-sediment interactions using several closures for the sediment phase. The effective viscosity is one such closure that includes three adjustable parameters: the intrinsic viscosity, the ... |
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| Technical Metrics for Acoustic Evaluation |
Jun 2010 |
6 pages |
| Authors:
J P Fabre; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| A Technical Metrics Workshop was held at NRL Stennis Space Center, MS, by the NRL Acoustics Division April 29 - May 1, 2008. The primary goal of the workshop was to identify the state-of-the-art technical and scientific metrics for the acoustic and oceanographic research and development communities. A second goal was to relate scientific metrics to engineering and performance metrics, and outline the inclusion of uncertainties in various parameters using ... |
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| The Naval Research Laboratory's Ongoing Implementation of the Open Geospatial Consortium's Catalogue Services Specification |
Jun 2010 |
9 pages |
| Authors:
Frank P McCreedy; David B Marks; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| The Naval Research Laboratory's (NRL) Digital Mapping, Charting and Geodesy Analysis Program (DMAP) team, located at Stennis Space Center, conducts research involving the online storage and manipulation of geospatial data. One aspect of this research concerns metadata. Metadata is data about data or simply put, various bits of information that provide an understanding of certain aspects of the data such as source, resolution, date created, geographic location and many others. ... |
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| Weakly Nonlinear Harmonic Acoustic Waves in Classical Thermoviscous Fluids: A Perturbation Analysis |
Jun 2010 |
5 pages |
| Authors:
P M Jordan; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Using regular perturbation analysis, we investigate the propagation of a time-harmonic acoustic signal, generated by a sinusoidal boundary condition, in a half-space filled with a classical thermoviscous fluid. It is assumed that the flow is described by a recently introduced, weakly nonlinear partial differential equation (PDE) that, unlike earlier models, exhibits a Hamiltonian structure in the lossless limit. |
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| Strain-Rate Dependency of Strength of Soft Marine Deposits of the Gulf of Mexico |
Jun 2010 |
10 pages |
| Authors:
Andrei Abelev; Philip Valent; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Many marine civil engineering applications require knowledge and understanding of the behavior and strength properties of soft cohesive marine sediments under high strain-rate conditions, typically encountered during impact penetration events of sediment probes and other objects as a result of free fall through the water column. In order to investigate these effects, a series of variable rotational rate vane shear tests were performed using a precision rheometer and spanning the ... |
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| Numerical Investigation of Dynamic Freefall Penetrometers in Soft Cohesive Marine Sediments Using a Finite Difference Approach |
Jun 2010 |
12 pages |
| Authors:
Andrei Abelev; Kevin Tubbs; Philip Valent; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Rapid assessments of undrained shear strength of marine sediments are often of great interest in various branches of offshore civil and petroleum engineering, as well as the Navy. Dynamic free-fall penetrometers offer a potential for such rapid strength assessment, but have typically been employed in conjunction with mostly empirical relationships to investigate the undrained shear strengths of sediments. In this work, we analyze the behavior of STING (Sea Terminal Impact ... |
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| Automated Change Detection Using Synthetic Aperture Sonar Imagery |
Jun 2010 |
4 pages |
| Authors:
Marlin Gendron; Maura Lohrenz; John Dubberley; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| When resurveying a seafloor area of interest during change detection operations, an automated method to match found bottom objects with objects detected in a previous survey allows the surveyor to quickly sort new objects from old. The change detection system developed at the Naval Research Laboratory contains modules for automatic object detection, feature matching using shadow outlining, scene matching using control-point matching, and visualization capabilities. This system was developed for ... |
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| Flow Interpretation Implications for Poro-Elastic Modeling |
Jun 2010 |
6 pages |
| Authors:
James K Fulford; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| The basis of poro-elastic modeling is a set of assumptions about the nature of the porous media and the fluid that fill its void spaces. The basic assumptions are: (1) the solid matrix is homogenous, elastically deformable , and chemically inert with respect to the fluid, (2) the fluid is single phase and Newtonian, (3) the flow is in the laminar range, (4) there is an explicit one-to-one relationship between ... |
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| Measuring Coastal Sea-Surface Salinity of the Louisiana Shelf from Aerially Observed Ocean Color |
Jun 2010 |
5 pages |
| Authors:
V J Maisonet; J Wesson; D Burrage; S Howden; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| We have demonstrated the ability of airborne radiance and irradiance sensors to detect the persistent salinity gradient of the Atchafalaya plume and corresponding color fronts as observed by in-situ shipboard measurements as well as STARRS. We used an empirical algorithm A(sub cdom) (412) = 0.227 x (R(sub rs)510/R(sub rs)555)exp -2.022 (1) for CDOM from D'Sa et al. 2006. Their study was conducted in the same region (Louisiana Shelf) and time ... |
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| Optimizations for Fourier Synthesized Time Domain Pulse Propagation Calculations |
Jun 2010 |
5 pages |
| Authors:
Robert A Zingarelli; Stanley A Chin-Bing; Michael D Collins; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Fourier transform methods are the standard way for determining time-domain pulse structure and arrival time from a set of continuous wave (discrete frequency) underwater acoustic model calculations. This technique requires a large number of computer model runs at closely spaced frequencies, often making it computationally expensive. It has the advantages of including the correct attenuation at each frequency component, and of correctly treating continuity requirements at the water/sediment interface. Direct ... |
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| The Coastal Dynamics of Heterogeneous Sedimentary Environments: Numerical Modeling of Nearshore Hydrodynamics and Sediment Transport |
10 May 2010 |
145 pages |
| Authors:
Timothy R Keen; K T Holland; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| This report discusses details of the numerical models used to simulate wave, tide, and wind-driven hydrodynamics and sedimentation in water depths less than 10 m. These simulations have used the Princeton Ocean Model (POM), the Navy Coastal Ocean Model (NCOM), the SWAN wave model, and the Littoral Sedimentation and Optics Model (LSOM). The problems include: (1) nearshore erosion and mass conservation on the shoreface; (2) coastal erosion during a hurricane; ... |
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| Anaerobic Metabolism of Biodiesel and Its Impact on Metal Corrosion |
05 May 2010 |
6 pages |
| Authors:
Deniz F Aktas; Jason S Lee; Brenda J Little; Richard I Ray; Irene A Davidova; Christopher N Lyles; Joseph M Suflita; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Biodiesels have gained widespread acceptance because they are domestically produced carbon-neutral fuels that ultimately decrease greenhouse gas emissions and reduce dependence on fossil imports. While they are chemically and physically stable fuels, their susceptibility to biological degradation in the absence of oxygen is underexplored. We incubated five anaerobic inocula with biodiesel. The microorganisms originated from fresh and marine environments with differing histories of exposure to hydrocarbons, biodiesel, and oxygen. All ... |
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| Simulated and Observed Circulation in the Indonesian Seas: 1/12 deg Global HYCOM and the INSTANT Observations |
14 Apr 2010 |
62 pages |
| Authors:
E J Metzger; H E Hurlburt; X Xu; Jay F Shriver; A L Gordon; J Sprintall; R D Susanto; H M van Aken; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| A 1/12 degree global version of the HYbrid Coordinate Ocean Model (HYCOM) using 3-hourly atmospheric forcing is analyzed and directly compared against observations from the International Nusantara STratification ANd Transport (INSTANT) program that provides the first long-term (2004-2006) comprehensive view of the Indonesian Throughflow (ITF) inflow/outflow and establishes an important benchmark for inter-basin exchange, including the net throughflow transport. The simulated total ITF transport (-13.4 Sv) is similar to the ... |
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| A Modeling Study of Circulation and Eddies in the Persian Gulf |
Apr 2010 |
14 pages |
| Authors:
Prasad G Thoppil; Patrick J Hogan; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| The circulation and mesoscale eddies in the Persian Gulf are investigated using results from a high-resolution (1 km) Hybrid Coordinate Ocean Model (HYCOM). The circulation in the Persian Gulf is composed of two spatial scales: basin scale and mesoscale. The progression of a cyclonic circulation cell dominates the basin-scale circulation in the eastern half of the gulf (52 deg-55 deg E) during March-July. This is primarily the consequence of density-driven ... |
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| Observation Platform in Long Island Sound for Calibration/Validation of Multi-and Hyperspectral Ocean Color Satellite Sensing of Coastal Waters |
Apr 2010 |
3 pages |
| Authors:
S A Ahmed; R A Arnone; A Gilerson; S Hlaing; A Weidemann; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Improving satellite retrievals of inherent optical properties (IOPs) is increasingly focused on coastal waters because of adjacent population concentrations and susceptibility to anthropogenic impacts. However, their complexity has presented more retrieval challenges than open ocean waters. To address these concerns, and support multi- and hyper-spectral development of new retrieval techniques and algorithms for coastal waters, we have established a new scientifically comprehensive offshore platform, the Long Island Sound Coastal Observatory ... |
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| Forecasting the Coastal Optical Properties using Satellite Ocean Color |
Apr 2010 |
17 pages |
| Authors:
Robert Arnone; Brandon Casey; Sherwin Ladner; Dong Ko; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| Satellite ocean color has been providing a monitoring capability for bio-optical properties along the coastal line using several ocean color sensors for a number of years. Applications of these data for coastal managers and researchers are limited by coverage and the ability to forecast the changing conditions. We examine the capability to couple satellite bio-optical properties with physical forecast circulation models to provide a real-time prediction of 24 hour bio-optical ... |
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| Pore-Scale Study of the Collector Efficiency of Nanoparticles in Packings of Nonspherical Collectors |
15 Jan 2010 |
|
| Authors:
Wei Long; Haiou Huang; Jasmine Serlemitsos; Elizabeth Liu; Allen H Reed; Markus Hilpert; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
 | Pore-scale simulations of flow and transport through a filter were used to predict clean-bed filtration of nano-particles from a 3D image of the filter. X-ray micro-computed tomography was used to obtain the geometry and topology of the filter consisting of flattened half-spherical collectors. A Lattice-Boltzmann method was used to model fluid flow and particle transport in the volumetric image of the filter. Nano-particles are considered that are so small that ... |
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| Upper-Ocean Processes under the Stratus Cloud Deck in the Southeast Pacific Ocean |
Jan 2010 |
20 pages |
| Authors:
Yangxing Zheng; Toshiaki Shinoda; George N Kiladis; Jialin Lin; E J Metzger; Harley E Hurlburt; Benjamin S Giese; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| The annual mean heat budget of the upper ocean beneath the stratocumulus/stratus cloud deck in the southeast Pacific is estimated using Simple Ocean Data Assimilation (SODA) and an eddy-resolving Hybrid Coordinate Ocean Model (HYCOM). Both are compared with estimates based on Woods Hole Oceanographic Institution (WHOI) Improved Meteorological (IMET) buoy observations at 208S, 858W. Net surface heat fluxes are positive (warming) over most of the area under the stratus cloud ... |
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| Evaluating the Impact of the Number of Satellite Altimeters Used in an Assimilative Ocean Prediction System |
Jan 2010 |
21 pages |
| Authors:
Robert W Helber; Jay F Shriver; Charlie N Barron; Ole M Smedstad; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| The impact of the number of satellite altimeters providing sea surface height anomaly (SSHA) information for a data assimilation system is evaluated using two comparison frameworks and two statistical methodologies. The Naval Research Laboratory (NRL) Layered Ocean Model (NLOM) dynamically interpolates satellite SSHA track data measured from space to produce high-resolution (eddy resolving) fields. The Modular Ocean Data Assimilation System (MODAS) uses the NLOM SSHA to produce synthetic three-dimensional fields ... |
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| Littoral Environmental Reconnaissance Using Tactical Imagery From Unmanned Aircraft Systems |
Jan 2010 |
9 pages |
| Authors:
K T Holland; David M Lalejini; Steven D Spansel; Robert A Holman; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
|
| The dynamic nature of littoral regions requires a reconnaissance approach that can rapidly quantify environmental conditions. Inadequate estimation of these conditions can have substantial impacts on the performance of Naval systems. Given that expeditionary warfare operations can occur over timescales on the order of hours, exploitation of video imagery from tactical vehicles such as Unmanned Aircraft Systems (UAS) has proved to be a reliable and adaptive solution. Tactical littoral products ... |
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| Observed Dispersion Relation of Yanai Waves and 17-Day Tropical Instability Waves in the Pacific Ocean |
Jan 2010 |
5 pages |
| Authors:
Toshiaki Shinoda; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| Using sea surface height (SSH) data derived from recent satellite observations, we present the observed dispersion relationship of mixed Rossby Gravity (Yanai) waves in the Pacific Ocean. A wavenumber-frequency spectral analysis of SSH fields shows prominent spectral peaks along the dispersion curves of first and second baroclinic mode oceanic Yanai waves. Also, salient features of tropical instability waves (TIWs) with a period of 17 days can be effectively isolated based ... |
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| High Sea-Floor Stress Induced by Extreme Hurricane Waves |
Jan 2010 |
19 pages |
| Authors:
Hemantha W Wijesekera; David W Wang; William J Teague; Ewa Jarosz; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| Strong surface waves and currents generated by major hurricanes can produce extreme forces at the seabed that scour the seafloor and cause massive underwater mudslides. Our understanding of these forces is poor due to lack of concurrent measurements of waves and currents under these storms. Using unique observations collected during the passage of a category-4 hurricane, Ivan, bottom stress due to currents and waves over the outer continental shelf in ... |
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| Negotiation as Creative Social Interaction Using Concept Hierarchies |
Jan 2010 |
10 pages |
| Authors:
Frederick E Petry; Ronald R Yager; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
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| Negotiation is a process that ranges from international issues to common society interactions. We present approaches to facilitate the process by exploring alternative spaces for this process. We base the approach on exploring alternative terminology that can resolve conflicts in the negotiation solution. Concept hierarchies can provide higher level concepts that can be used to obtain agreement between parties in the negotiation. |
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