Abstract
Uncertainties in noise level, and in signal level after long-range (42 km) acoustic shallow water transmissions, from a pulsed source, are determined from the summer shelfbreak PRIMER experiment. Fluctuations over the 10-day period are not stationary, but are rendered so by tracking the wandering of their means. Then narrow-sense stationary probability density functions are obtained of ambient noise and signal peak transmissions from a match-filter output with time-bandwidth product = 1. The data are centered at 400 Hz, in a 100 Hz bandwidth, and analyzed from three individual hydrophones of a vertical line array. The ambient noise fluctuations closely follow the phase-random Log-Rayleigh density, with standard deviation σ = 5.6 dB. Signal peak statistics are determined from demeaned 50 s samples. The signal statistics over an 8-h period are approximately similar, but not identical, to those over the entire 10-day period. The signal has narrower histograms (σ ≈ 0.8 dB) than the noise. Log Chi-Square densities, fit to the signal histograms, suggest that about 30 equal intensity components contribute to the fluctuations, many more than can be attributed to the idealized modal structure in the shelfbreak duct. This suggests that either strong scattering affects the signal transmission, or the signal process is not fully phase-random.
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References
Abbot, P. and Dyer, L, Sonar performance predictions based on environmental variability. In Impact of Littoral Environmental Variability on Acoustic Predictions and Sonar Performance, edited by N.G. Pace and F.B. Jensen (Kluwer Academic, The Netherlands, 2002) pp. 611–618.
Dyer, I., Statistics of sound propagation in the ocean, J. Acoust. Soc. Amer. 48, 337–345 (1970).
Dyer, I., Statistics of distant shipping noise, J. Acoust. Soc. Amer. 53, 564–570 (1973).
Lynch, J., Gawarkiewicz, G., Chiu, C., Pickart, R., Miller, J., Smith, K., Robinson, A., Brink, K., Beardsley, R., Sperry, B. and Potty, G., Shelfbreak PRIMER-An integrated acoustic and oceanographic field study in the mid-Atlantic Bight. In Shallow-Water Acoustics, edited by R. Zhang and J. Zhou (China Ocean Press, 1997) pp. 205–212.
Miller, C., Estimating the acoustic modal arrivals using signals transmitted from two sound sources to a vertical line hydrophone array in the 1996 Shelfbreak PRIMER Experiment. Naval Postgraduate School M.Sc. Thesis, 1998.
Colosi, J., Lynch, J., Beardsley, R., Gawarkiewicz, G, Chiu, C. and Scotti, A., Observations of nonlinear internal waves on the New England continental shelf during summer shelfbreak PRIMER, J. Geophys. Res. (in press 2002).
Chiu, C., Realistic simulation studies of acoustic signal coherence in the presence of an internal soliton wavepacket. In Proc. IOS/WHOI/ONR Internal Solitary Wave Workshop, Victoria, B.C., Canada, October 27–29, 1998.
Chiu, C., Lynch, J., Gawarkiewicz, G., Miller, C., Sperry, B. and Newhall, A., Measurement and analysis of the propagation of sound from the continental slope to the continental shelf, (in preparation).
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© 2002 Springer Science+Business Media Dordrecht
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Abbot, P., Gedney, C., Dyer, I., Chiu, CS. (2002). Ambient Noise and Signal Uncertainties During the Summer Shelfbreak Primer Exercise. In: Pace, N.G., Jensen, F.B. (eds) Impact of Littoral Environmental Variability of Acoustic Predictions and Sonar Performance. Springer, Dordrecht. https://doi.org/10.1007/978-94-010-0626-2_32
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DOI: https://doi.org/10.1007/978-94-010-0626-2_32
Publisher Name: Springer, Dordrecht
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