Oceanography and Naval Special Warfare Opportunities and Challenges (1997) / Chapter Skim
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4 Oceanography and Naval Special Warfare
4 Oceanography and Naval Special Warfare
Pages 25-62
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From page 25... ...
The Naval Special Warfare Mission Planning Guide identifies a number of environmental parameters, including lunar illumination, water temperature, bathymetry, wave height, water clarity, humidity, current direction and speed, that must be considered throughout mission planning and execution. These factors affect many aspects of mission planning, including transportation and communications.
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From page 26... ...
Although the environment plays an important role in any military operation, missions conducted by special operations forces in general, and NSW forces in particular, are extremely environmentally sensitive. Environmental conditions are an important consideration in mission planning as demonstrated by the importance placed on them in the NSW Mission Planning Guide (prepared by the Naval Special Warfare Center)
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From page 27... ...
Because NSW missions can be highly varied and complex, this one hypothetical example cannot fully demonstrate the potential impact of all the environmental factors discussed in the NSW Mission Planning Guide on the breadth of potential NSW missions. Consequently, summaries of working group discussions that took place during the symposium (i.e., Bioluminescence and Toxins Working Group, Waves and Surf Working Group, Currents and Tides Working Group, EM/JR "Above Surface" Signal Propagation and Coastal Winds Working Group, EO/Acoustic "Below Surface" Signal Propagation Working Group)
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From page 28... ...
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From page 29... ...
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From page 31... ...
Research Issues Long Term Goals Signature Reduction To adequately address the problem of detection or vulnerability of divers and undersea vehicles, two types of activities were initiated in 1991 at Naval Research and Development (NRaD) , San Diego, following a request for supporting research in this area from the Naval Special Warfare Center (NSWC)
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From page 32... ...
Units ~ ~7 1 1 1 1 1 of photons per unit volume are used when the residence time of the bioluminescent organism in the detection chamber is long enough for a whole flash to occur. Under such circumstances the average photon flux measured by the light detector is a function of the concentration of bioluminescent organisms, the total photons per flash, and the volumetric flow through the detection chamber.
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From page 33... ...
bUnits of Photons 1-1. Measurements were made with HIDEX-BPs CUnits of Photons s-1 1-l for short residence time bathyphotometers 33 average photon flux measured by the light detector is a function of detection chamber volume rather than volumetric flow.
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From page 34... ...
More specifically, discussions centered on conducting field exercises that address detection of combat swimmers and their vehicles, using swimmers to determine detection at various depths. Overall, eight specific suggestions were offered by symposium participants to limit the adverse impacts of bioluminescence on NSW operations: · Characterize optical signatures at night for SEAL vehicles such as Combat Rubber Raiding Craft (CRRC)
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From page 35... ...
In addition, some recent evidence suggests that outbreaks of certain infectious diseases, such as cholera, may be associated with algal blooms. It was not clear, based on the limited discussions at the symposium, in what specific ways additional research on infectious diseases could be made to benefit NSW operations.
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From page 37... ...
To improve prediction, research is needed both to identify the environmental conditions that regulate the distribution, abundance, and impact of harmful algal blooms and to improve identification methods and protocols for early detection of blooms. In addition, flexibility in mission planning could be improved if data bases were developed that include bloom incidence, mass mortality events, and epidemiology.
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From page 38... ...
The ingress and egress routes of these operations place NSW in several environmentally distinct domains of wave dynamics and kinematics: the surf zone, the inner shelf offshore of the surf zone, inlets, and harbors. Wave characteristics that are relevant to NSW operations in wave domains are: heights (distance from trough to crest of the waves)
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From page 39... ...
Ingress and egress routes pass through the inner shelf and through either a surf zone or an inlet and harbor. Advance knowledge of wave characteristics along the route through these distinct wave domains is needed for mission planning and can be critical to mission success.
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From page 40... ...
Solutions Wind-wave climate information in a shallow water operational region can be obtained from: model predictions with knowledge of the underlying bathymetry and the offshore wave conditions, direct observation using in situ sensors, and indirect observation using remote sensing platforms and concomitant transfer function models.
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From page 41... ...
The complexity of the bathymetry on the inner shelf limits the applicability of local wave-climate measurements to other locations; wave-climates can change dramatically over as little as 100 m because of refraction and diffraction of waves by bathymetry and currents. However, using the local wave climate measurements with wave propagation models and bathymetry data can alleviate this inherent limitation.
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From page 42... ...
Currents flowing in the alongshore direction can be driven by obliquely incident waves or can form in regions where there are longshore variations in wave height, perhaps due to nonuniform bathymetry (Longuet-Higgins, 1970~. The presence of these surf zone currents can have a variety of impacts on NSW operations.
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From page 44... ...
STOIC courtesy of the Warfighting Support Center, Naval Oceanographic Office (NAVOCEANO) , Stennis Space Center, .
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From page 45... ...
Both cross-shore and longshore current strengths are quite dependent on details of the nearshore bathymetry. River or Harbor Tides and Currents Commonly, the ultimate objective of NSW missions is industrial or military sites located along a navigable estuary or river or involving significant transit along an estuary or river.
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From page 46... ...
With respect to postprocessing and analysis, tools should include those areas specific to Special Warfare missions, such as salinity gradients in the vertical and horizontal, tidal velocity vectors, and wind fields. With regard to visualization packages, all model products should be visualized in a useful 3-D fashion to present these results in a fashion that is immediately and easily understood by NSW personnel not conversant in scientific issues.
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From page 47... ...
, Stennis Space Center, Mississippi.
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From page 48... ...
Indirect effects can be the bathymetric influence on the location and height of breaking wind waves and on the location, direction, and strength of the currents. Nearshore bathymetry issues can be divided into two regional categories: surf zone and offshore of the surf zone (inner shelf)
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From page 50... ...
The inner shelf can also be a region of complicated physical oceanography. Unlike deeper water, the bottom and surface boundary layers begin to merge due to the shallowing of the inner shelf.
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From page 51... ...
Toward the surf zone, the Beach Probing System (BPS) offers the potential for using inner shelf instrument packages to estimate surf zone bathymetry based on wave signals that propagate out from nearshore.
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From page 52... ...
Summary it, Although not considered a critical mission parameter, the importance of determining bathymetry pervades NSW operations. For ingress and egress, bathymetry may represent an obstacle in the form of a sandbar and adjacent deeper trough in the nearshore or perhaps some unknown bathymetric obstruction.
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From page 53... ...
Research Issues To deal with EM-propagation effects, SEALs need a specification of the propagation conditions in the operational area as a function of time and location for the duration of the operation. For mission planning purposes, this specification is required well before the actual mission in other words a forecast of propagation conditions is necessary, with continual updates and evaluations through the planning and execution of the mission.
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From page 54... ...
. ATMOSPHERIC VISIBILITY Naval Special Warfare operations involve both the water and the land portions of the littoral zone.
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From page 55... ...
Since NSW operations routinely take place in denied areas, satellite-sensed data are often the only real-time data sources. Over water, multi-spectral upwelling radiance can be used to infer optical depth and boundary-layer aerosol properties.
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From page 56... ...
Existing mine countermeasures shallow water sonar performance prediction models could be used to provide SDV teams with a range-of-the-day prediction for mission planning. Although such models provide a rough measure of performance, they are limited by the fidelity of environmental acoustic models describing boundary interactions at high frequencies.
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From page 57... ...
in very shallow water, underwater acoustic research issues most relevant to NSW missions include both small-scale characterization of the boundaries and the development of models for acoustic boundary interactions at high frequency. Sea Surface Scattering Although surface roughness and wind-generated bubbles are relevant to acoustic surface provements to modeling the acoustical effects of bubbles constitute the most important research issue.
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From page 58... ...
The critical mission thresholds included in the NSW Mission Planning Guide indicate that swimmer or SDV operations should not be conducted when water clarity allows the swimmer
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From page 59... ...
Thus, knowledge of the time-varying changes in underwater optical properties could be an excellent asset in mission planning and execution. Nearshore, Riverine, and Estuarine Optics Water clarity can vary rapidly in the near coastal zone, within rivers, estuaries, or bays, as a consequence of tidal changes, river flow, surf action, and watershed rainfall.
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From page 60... ...
. Solutions Various disciplines have been developing advanced measurement tools and models of relevance to predicting the time and space mission-critical parameters included in the NSW Mission Planning Guide.
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From page 61... ...
STOIC courtesy of the Warfighting Support Center, Naval Oceanographic Office (NAVOCEANO) , Stennis Space Center, Mississippi.
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From page 62... ...
Predictive capabilities are also limited by the validity of the initialization parameters (e.g., errors in the input data can be propagated through the model) and the spatial resolution of the model.
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