Symposium on Naval Warfare and Coastal Oceanography Naval Amphibious Base, Little Creek, Virginia, April 29-May 2, 1991 (1992) / Chapter Skim
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Science and Technology Summaries
Science and Technology Summaries
Pages 17-31
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From page 17... ...
Future requirements include beach trafficability, offshore hazards, data perishability, and acoustic coherence. To stimulate research in these areas, the Navy should maintain a central file of coastal oceanography data requirements that the research community can access.
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From page 18... ...
The possible need for a revolutionary approach to the inherently greater variability of shallow water was discussed. A revolutionary research approach may apply to the entire question of coastal ocean acoustics or perhaps only to new unfamiliar warfare regions where there are few or no prior data with which to perform classical statistical analyses.
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From page 19... ...
The present low efficiency of sweeping a mined surf zone needs to be improved by using side-scan sonars or other new techniques. Some specific actions suggested for future research include: · Develop a series of shallow-water mine detection system packages, such as magnetometers, gravimeters or acoustic subbottom side-scanning systems, · Study the mechanisms of suspended sediment seafloor scour and object burial, · Investigate the sources and mechanisms of sand transport to improve the forecast of poor nearshore visibility, · Develop ROVs for remote mine demolition with time delay activation, · Focus planned coastal data collection on areas identified by the Department of Defense as high-probability conflict areas, search the literature for existing research and data for these areas, and incorporate this data base in a GiS to share these data in map format with Navy laboratories and appropriate civilian organizations, · Develop high-frequency imaging sonars with high resolution and wider detection swaths.
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From page 20... ...
Future S&T efforts in amphibious warfare should be directed in the following · Coastal morphology models to address both along-shore currents and sediment transport mechanisms, ~ Real-time assessment of shoreline geology and geophysics from aircraft, predictive models, and soil mechanics, and · Shallow-water sensor packages for measurement of tides, atmospheric pressure, currents, and winds. These systems should be rapidly deployable and expendable, and be radio linked to command and control decision makers.
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From page 21... ...
Biological activity has a large impact on ocean optics, especially in the coastal region, where suspended sediment complicates the environment. Separating the desired signal from the background light levels requires the capability to predict and quantify the integrated reflectance from the water column and to separate out the contribution from the target (i.e., submarine or mine)
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From page 22... ...
Some problems with chemical sensing include the lack of baseline information related to chemical signatures in specific locations and the need to develop accurate real-time chemical sensors. Recent work revealed that lobsters can determine the distance of objects of interest by measuring the amount of spatial decorrelation between chemical concentrations emitted by the object as measured simultaneously by each of its antennae.
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From page 23... ...
These considerations underlie the above recommendation to focus on short, statistically independent time series of simultaneously measured variables. · Eulerian/Lagrangian discussion - A Lagrangian approach might appear most profitable in focusing attention on the biological processes of interest.
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From page 24... ...
This officer would receive training in environmental science and would serve as a liaison between the warfare and environmental science communities. One Captain indicated that many fleet commanders tend to have an inherent distrust of environmental models.
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From page 25... ...
Areas needing further study include: · Shallow-water boundary layer processes, including wave-current interaction and wave breaking phenomena, · Near shore river-shelf interactions. Whose buoyancy and density effects are of great interest to the Navy community, particularly in high-latitude areas, · The important processes that occur in areas with rough topography, · Accurate models of wave dispersion over canyons and coastlines, · Processes over the continental shelf, including internal waves, mixing, and wave breaking mechanisms, necessary for successful acoustic and electromagnetic measurements in these areas, · Three-dimensional circulation in the surf zone, · Hydraulic processes associated with atmospheric frontal regions over the shelf.
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From page 26... ...
As the location of potential conflict expands to include islands and tropical and subtropical areas, it is becoming more probable that future wars will be fought in coastal regions. Atmospheric impacts on naval operations can be either direct, such as those of surface air temperature on the range of a Tomahawk cruise missile, or indirect, when changes in the atmospheric forcing of the ocean (e.g., surface wind)
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From page 27... ...
Thus it is necessary to resort to theoretical models and the fusion of data from multiple platforms to describe and predict the microscales of coastal regions. A wide range of data products can be used in naval operations, from global climate predictions to nowcasts in a small region and descriptive analyses of coastal weather.
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From page 28... ...
This observation suggests that the phenomenon is dominated by topography and the large-scale flow and that perhaps only a few observations are needed to predict coastal weather. By contrast, an offshore flow from a land surface has been observed to induce internal boundary layers that decouple the main boundary layer {and clouds} from the ocean surface.
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From page 29... ...
Electric field measurements Ongoing Navy development projects in electromagnetic surveillance tend to concentrate on measurement of the magnetic field as opposed to the electric field. This is a natural consequence of the relatively widespread commercial availability of magnetic field sensors, whereas electric field detection in the ocean remains largely a custom technology developed by academic investigators.
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From page 30... ...
The reason, in large part, is that the Office of Naval Research terminated its electromagnetics efforts about five years ago; thus there is no clear avenue for investigators to fund the necessary exploratory basic research. Although considerable information about the electromagnetic environment in deeper water is available, including identification of sources and understanding of interactions with the seafloor, the understanding is not immediately applicable to shallow water.
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From page 31... ...
Investigation of active airborne electromagnetics Active source electromagnetic sensing from aircraft is a primary too' in mineral prospecting, and has recently been adapted to bathymetric charting by the Naval Research Laboratory {formerly NOARLl, with impressive results. However, only limited attention has been paid to the use of airborne active electromagnetic methods for direct submarine detection, despite the fact that its performance in shallow water is potentially good enough for it to be a practical tool.
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