Water Mass and Acoustic Analysis of the East Greenland Current.

Two cluster analysis techniques, one heuristic and one iterative, are used to investigate the spatial coherence of the water masses of the East Greenland Current (EGC), in the vicinity of the East Greenland Polar Front (EGPF). Both techniques are shown to be generally reliable, although the iterativ...

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Bibliographic Details
Main Author: Clipson,James M
Other Authors: NAVAL POSTGRADUATE SCHOOL MONTEREY CA
Format: Text
Language:English
Published: 1986
Subjects:
Physical and Dynamic Oceanography
*OCEAN CURRENTS
*ACOUSTIC PROPERTIES
SOURCES
SPATIAL DISTRIBUTION
WATER
COHERENCE
FORECASTING
THESES
VARIABLES
SHALLOW WATER
CLUSTERING
PROFILES
PATTERNS
SEPARATION
ACOUSTICS
RANGE(DISTANCE)
RAY TRACING
ACOUSTIC VELOCITY
NORTH ATLANTIC OCEAN
WATER MASSES
DEEP WATER
BATHYTHERMOGRAPH DATA
TRANSMISSION LOSS
SONOBUOYS
FRONTS(OCEANOGRAPHY)
SOUND ANALYZERS
East Greenland Current
Acoustic Ducts
Greenland
East Greenland
east greenland current
North Atlantic
Online Access:http://www.dtic.mil/docs/citations/ADA175255
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA175255
Description
Summary:Two cluster analysis techniques, one heuristic and one iterative, are used to investigate the spatial coherence of the water masses of the East Greenland Current (EGC), in the vicinity of the East Greenland Polar Front (EGPF). Both techniques are shown to be generally reliable, although the iterative technique is more consistent with classical oceanographic analyses. The techniques are applied to data to explore the grouping behavior of the water masses. They are also shown to have applications to multiple and single variable data. The cluster technique is shown to have applications in planning a sonobuoy pattern and in assessing the validity of XBT data prior to an acoustic forecast. Acoustic analysis shows that acoustic reciprocity does not hold for propagation in the waters of the EGC. Ranges from shallow to deep water are far in excess of those from deep to shallow water. Propagation across the EGPF is significantly different for normal and oblique cases. Propagation loss for oblique ranges is between 60 and 80 % of perpendicular ranges, mostly due to different source sound speed profiles. Three acoustic models, FACT, RAYMODE and PE are compared and contrasted. PE is found to be the most consistent and reliable, although both FACT and RAYMODE compare satisfactorily for propagation from shallow to deep water. For the reverse case, FACT overestimates ranges by a factor of two, whereas RAYMODE is exceedingly over optimistic in its forecast ranges. Keywords: Cluster analysis; Entity attribute; Separation distance; Ducting; Ray tracing. (Theses)

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