Water Mass and Acoustic Analysis of the East Greenland Current.
Abstract
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1986
- Accession Number
- ADA175255
Entities
People
- James M. Clipson
Organizations
- Naval Postgraduate School