Acoustic detection of microbubbles and particulate matter near the sea surface

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Author
Buxcey, Stanley
McNeil, James E.
Marks, Robert H.
Date
1965Metadata
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A pulse-echo system using an electrostatic transducer and
steel reflector was operated over the frequency range 24-192 Kcps
in the sea and in the laboratory. Excess attenuations from 0.15 to
1.1 db/M due to absorption and scattering by inhomogeneities were
made over the full frequency range with a maximum error of less than
0.05 db/meter. Backscattering at sea was detected in the frequency
range 24-60 Kcps with an average scattering cross-section per unit
volume of 4.00 cm /m^ at a depth of 10 feet. Scattering was not
detected abbve 60 Kcps. Variation of sound velocity with frequency
was measured from 24-192 Kcps. The accuracy of these values was 0.03
percent for frequencies over 40 Kcps.
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