Perth-Bermuda (1960) revisited global scale acoustic propagation

• Published in: The Journal of the Acoustical Society of America 2008-10, Vol.124 (4_Supplement), p.2598-2598
• Main Authors: Heaney, Kevin D., Murray, James J.
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4783267

A recent paper in Geophysical Research Letter [Dushaw, Geophys. Res. Lett. 35, L08601 (2008)] commented on the Perth-Bermuda Sound Propagation Experiment (1960): An Adiabatic Mode Interpretation JASA 95, November 1991, by Kevin D. Heaney, William S. Kuperman, and B. E. McDonald. Dushaw raises questions about the validity of the approach and conclusions of Heaney et al. In particular, the validity of the adiabatic mode assumption for long-range propagation in the presence of internal wave scattering and seafloor interaction is challenged. Dushaw finds no other explanation for the observed double pulse arrival in the original 1960 experiment. The approach and conclusions of Heaney et al. will be presented. The range of validity of the adiabatic mode approximation in global scale acoustics will be addressed. The original computations of Heaney et al. were for a single mode at 10 Hz due to the computational power available at the time. Broadband results (10–50 Hz) using multiple modes summed coherently will be presented.