Comparison between Measured and Theoretical Transmission Loss Across the Gulf Stream.
Technical note for period ending May 78,
NAVAL OCEANOGRAPHIC OFFICE NSTL STATION MS
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Acoustic transmission loss and detailed environmental measurements were made in May 1978 along a 900 km track in the Western North Atlantic transecting Slope Water, the Gulf Stream and the Sargasso Sea. The sound source was an omnidirectional 88.8 CW projector towed at a depth of 30 m. The signal was received at a bottom mounted hydrophone situated near the DSC axis in the vicinity of Bermuda. When the source was located in the Gulf Stream, sound propagation was degraded by as much as 10 dB compared to values when the source was in Slope Water or Sargasso Sea. Ray traces with the source in the Gulf Stream showed strong downward refraction, driving most of the energy into the bottom resulting high propagation loss. Transmission loss predictions from the GRASS and PE models were compared to the experimental data. The PE model successfully predicted the high transmission loss in the Gulf Stream while the GRASS model did not. Both models predicted convergence zone spacing in the Sargasso Sea to within 10 percent of the experimental data. Author
- Physical and Dynamic Oceanography