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While the project was deemed a failure (see below), does the upper atmospheric acoustic waveguide exist?

What are the propagation losses for low-frequency sounds?

Where can one find further information on the acoustical characteristics of the upper atmosphere?

PROJECT MOGUL

Project MOGUL was first conceived by Dr. Maurice Ewing of Columbia University, NY, and Woods Hole Oceanographic Institution, MA. Dr. Ewing had conducted considerable research for the Navy during World War II, studying, among other things, the "sound channel" in the ocean. He proved that explosions could be heard thousands of miles away with underwater microphones placed at a predetermined depth within the sound channel. He theorized that since sound waves generated by explosions could be carried by currents deep within the ocean, they might be similarly transmitted within a sound channel in the upper atmosphere. The military application of this theory was the long-range detection of sound waves generated by Soviet nuclear detonations and the acoustical signatures of ballistic missiles as they traversed the upper atmosphere. He presented his theory to General Carl Spaatz, Chief of Staff of the Army Air Forces, in the fall Of 1945. ...

...By December 1948, serious concerns had arisen regarding the feasibility of the project as first conceived. Even though the principle on which the project was based was determined to be sound, questions concerning cost, security, and practicality were discussed-that ultimately led to the disbandment of the project, and Project MOGUL as first conceived was never put into operational use. ...

...The primary scientist for MOGUL was Dr. James Peoples, assisted by Albert P. Crary, the Field Operations Director. Both scientists had previous associations with Dr. Ewing: Dr. Peoples at Columbia, and A.P. Crary at Woods Hole. Both scientists were assigned to MOGUL for the entire length of the project. ...

References

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More than a year later, I'm doing a preliminary literature survey (noting that infrasound propagation is used in nuke test ban treaty verification):

... and a ton of others. When I have enough time, will study. Others may surely use the leads I collected to post an answer before that.

Things to keep in mind: anomalous propagation, whether acoustic or electromagnetic, below the surface or above it, is based on speed inversions. Whenever there are countervailing trends in salinity (for water)/water content (for air), density, and temperature, natural waveguides may exist.

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  • $\begingroup$ I'll look for a reference of a talk I saw on elephants using infrasound from distant thunderstorms to find water. $\endgroup$ – casey♦ Jul 19 '15 at 17:47
  • $\begingroup$ @casey - would be v. grateful. Should I make the post community wiki in the meantime? $\endgroup$ – Deer Hunter Jul 19 '15 at 17:49
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    $\begingroup$ Here is one 10.3390/ani3020349. IIRC this work stems from research into elephant communication via infrasound and the possible use of lightning generated infrasound for finding stormwater over distances of 100+ km. This article is quite short, but take a look at its references. $\endgroup$ – casey♦ Jul 22 '15 at 19:22
  • $\begingroup$ @casey - the refs are almost exclusively elephant-centered 8-) Thanks a lot! $\endgroup$ – Deer Hunter Jul 22 '15 at 19:40

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