Spiesberger John L.

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Spiesberger
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John L.
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  • Technical Report
    Multipath variability due to the Gulf Stream
    (Woods Hole Oceanographic Institution, 1981-06) Spindel, Robert C. ; Spiesberger, John L.
    A phase-coded signal with 64-ms resolution was transmitted at 10-min intervals for a 19-day period over two ~300-km ranges. The acoustic source was moored at 2000-m depth northwest of Bermuda. One receiver was moored at 2000-m depth to the northeast of the source and the other receiver was bottom mounted at ~1000- m depth near Bermuda. The large (~0.6 s) travel time change at the Bermuda receiver is probably due in large part to motion of the source mooring in the presence of currents. The multipath arrival pattern at the moored receiver undergoes significant modification due to the presence of a southern meander of the Gulf Stream which intersects this transmission path.
  • Technical Report
    Ocean acoustical ray-tracing : Software Ray
    (Woods Hole Oceanographic Institution, 1992-10) Bowlin, James B. ; Spiesberger, John L. ; Duda, Timothy F. ; Freitag, Lee E.
    A new computer program for accurate calculation of acoustic ray paths through a range-varing ocean sound channel has been written. It is based on creating a model of the speed of sound in the ocean, consistent with input data, that produces the smoothest possible wavefronts. This scheme eliminates "false caustics" from the wavefront. It may be useful in calculating an approximate solution to the full wave equation at megameter ranges.
  • Technical Report
    Evaluation of electromagnetic source for ocean climate acoustic thermometry at Lake Seneca
    (Woods Hole Oceanographic Institution, 1993-02) Slavinsky, Mark ; Bogolubov, Boris ; Alelekov, Igor ; Pigalov, Konstantin ; Spiesberger, John L. ; Boutin, Paul R.
    A compact electromagnetic monopole source, requiring pressure equalization, was evaluated at the Naval Underwater Systems Center at Lake Seneca during July 1992 by scientists from the Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS) and from the Woods Hole Oceanographic Institution and other American organizations. The titaium source was developed at the IAP RAS. The source has a mass of 123 kg and a diameter of .54 m. The source cannot be thought of as a single unit; rather the characteristics of the transmitted signal depend on a transmission system consisting of the source, the power amplifier, and a computer. The computer and the amplifier send specially adapted signals to the source to produce the desired acoustic signals. Measurements indicate the acoustic system as a center frequence of 225 Hz, a bandwidth of about 50 Hz, an associated pulse resolution of about 0.02 s, a source level of about 198 dB re 1 μpa @ 1 m, with an efficiency of about 50%. The system has an efficiency of about 67% near 225 Hz, the resonant frequence. The source is suitable for mounting on autonomous ocean moorings for several years as part of a system of monitoring climatic temperature changes over basin scales.