back again Card che ground at ranges froa 200 to 500 ailes. “‘Repetitions of
this ionmospoeric ducting process could lead to dececeadility at great ranges.
Past experience has shown, bovever, that attenuition is very great for sourd
propagated in the extresely low-density ionosphere, and pwidentifiable signals
Rave been recorded beyond the second or third cycle strixe.
A possibility existed that strong sound signals cucted near the Teak source
level would scatter or difirace detectable signals to the ground.
There is po
adequate theory nor any previous observation to check this phenocenon; quactitative predictions of long-range noise froa this source were not attexpted.
Pressure-wave recordings were planned in the aicrcbarography of Operation
Hardtack at various ranges to peasure and observe detectability and to prove or
qualify the inconclusive theories which existed for ultrahigh-altitude bursts.
Sandia aicrobarographs were located on Johastan Island” and at stations 500
and G00 piles away.
projects.
Soce airborne pressure seasurenents were nade by other
AFTAC attempted pressure recordings at aany points around the world.
Since each station consisted of two or more sensing units planned to be
about a aile apart along 2 tine frou Gz, the incidence angle of each soundwave front couid be established.
With oeasured ceaperature am! winds along
souod-ray paths to various stations, it was anticipated that some definition
of a source size, shape, and location could be calculated by acoustic-ray trace
ing to blast-wave source.
With equipment in place for the Teak event, microbarograph measureaents
were also sade on the Orange event.
[t was hoped that results would give an
intermediate point for interpreting Teak data and checking the Shelton theory.
Long-range detectability estimares could also be verified.
6.1.2
Predictions
Odvicusly,
2
Johnston [sland stations were planned at 7 niles froa intended CZ, but
bucse-position erroc placed close stations cnls one-halr aile fret’ actual c2.
Tie is realized chae application of this theory ty Teak i» 2 gross over-
extension af eho choory snd, o3 pointed wil by Sueitun, tne tacury Turt be surpect bys the tine ambient densicy at burse aleitude is oneeune FundredcA of that
at sea level.
Teak density eas less than one ten-thousandta of sea level dense...