日本財団 図書館


Development of Acoustic Tomography and Future Prognosis

 

Bob Spindel

Director of Applied Physics Laboratory University of Washington

 

Acoustic tomography developed largely as a result of underwater acoustic research sponsored by the US Navy during the 1960's and early 1970's. The Navy problem was the passive detection and localization of submarines at long ranges. Numerous experiments revealed important unexplained signal amplitude and phase variations and sound speed variations. The problem was addressed with little real success by underwater acousticians who sought to discover relationships between ocean processes and observed acoustic variability. The term acoustic oceanography was coined during this era, and the field of ocean acoustics, rather than underwater sound, began to emerge. However, it was mainly a small group of physicists and oceanographers, many of whom were gathered together by the US defense department, that significantly advanced the field. They developed theories to explain observed acoustic effects in terms of known ocean processes. This, coupled with both an interest at that time in inverse theory and its application to oceanography, and a growing realization among oceanographers that the controlling scales of oceanic variability were impossible to observe with conventional ships and moorings, led directly to the development of acoustic tomography, and eventually to acoustic thermometry. Today, a time in which global oceanic observation is the goal of a plethora of national and international programs, it would seem that acoustic methods, with their inherent ability to provide long-range, basin-scale, in situ integrated measurements ―ideal for the task― would be embraced. It is interesting to speculate on whether they will be.

 

 

 

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