Anomalous low frequency sea surface reverberation

• Autorzy: Neighbors T. H. , Bjørnø L.
• Języki publikacji: EN

Abstrakty

EN

Low frequency sea surface sound backscattering from ̴100 Hz to a few kHz observed from the 1960s [A,B,C] to the 1990s [D,E] is substantially higher than explained by rough sea surface scattering theory. Alternative theories for explaining this difference range from scattering by bubble plumes/clouds formed by breaking waves to stochastic scattering from fluctuating bubble layers. Disparities remain between measurements and predictions [F] as a function of sound incidence angle, wind speed, and whitecap coverage. A first order, two dimensional approach for bubble plume scattering [G] that includes the rough sea surface shows that bubble plume shadowing dominates the backscattered signal strength at shallow grazing angles. To demonstrate the effect, scale model experiments were performed at the Technical University of Denmark [H]. The scattered signal strength fluctuations observed at shallow angles are characteristic of the predicted ocean environment. Shadowing has a first order impact on the scattering strength observed from bubble plumes and clouds.

• Wydawca: Polskie Towarzystwo Akustyczne. Oddział Gdański
• Czasopismo: Hydroacoustics
• Rocznik: 2001
• Tom: Vol. 4
• Strony: 181--192
• Opis fizyczny: Bibliogr. 13 poz., rys.

Twórcy

autor

Neighbors T. H.

• Science Applications International Corporation, 1710 SAlC Drive, MS-I-3-8 McLean, Virginia 22101, USA

autor

Bjørnø L.

• UltraTech Holding, Stendiget 19, DK-2630 Taastrup, Denmark

Bibliografia

• 1. R. P. Chapman and J. H. Harris, Surface backscattering strength measured with explosive sound sources, 1. Acoust Soc. Am., Vol. 34, 1592- I597, 1962.
• 2. R. P. Chapman and H. D. Scott, Surface backscattering strengths measured over an extended range of frequencies and grazing angles, J. Acoust Soc. Am., Vol. 36, 1735- 1737, 1964.
• 3. M. V. Brown and R. A. Saenger, Bistatic backscattering of low-frequency underwater sound from the ocean surface, 1. Acoust. Soc. Am., Vol. 52, 944-960, 1972.
• 4. P. M. Ogden and F. T. Erskine, Surface scattering measurements using broadband explosive charges in the Critical Sea Test experiments, J. Acoust Soc. Am., Vol. 95, 746- 761, 1994.
• 5. P. M. Ogden and F. T. Erskine, Surface and volume scattering measurements using broadband explosive charges in the Critical Sea Test 7 experiment, 1. Acoust Soc. Am., Vol. 95, 2908-2920,1994.
• 6. S. T McDaniel., Sea surface reverberation: A review, 1. Acoust Soc. Am., Vol. 94, 1905- 1922, 1993.
• 7. T. H. Neighbors and L Bjerne, Low frequency sea surface reverberation, in Underwater Acoustics, J. S. Papadakis (Ed.), FORTH/IACM, Heraklion, Crete, Greece 1996.
• 8. T. H. Neighbors and L Bjerne, Sea surface reverberation scale modeling, in Underwater Acoustics, A. Alippi and G. B. Cannelli (Eds.), Italian National Research Council, Rome, 1998.
• 9. B. E. McDonald, Echoes from vertically striated subresonant bubble c1ouds: a model for ocean surface reverberation, Vol. 89,1. Acoust. Soc. Am., 617-622, 1991.
• 10. F. S. Henyey, Acoustic scattering from ocean microbubble plumes in the 100 Hz to 2 kHz region, Vol. 90,1. Acoust. Soc. Am., 399-405, 1991.
• 11. R. F. Gragg and D. Wunnser, Low-frequency scattering from intermediate bubble plumes: Theory and computational parameter study, Vol. 94, 1. Acoust. Soc. Am., 3 19- 329, 1993.
• 12. K. Sarkar and A. Prosperetti, Backscattering of underwater noise by bubble c1ouds, J. Acoust, Soc. Am., Vol. 93, 3128-3138,1993.
• 13. E. B. Kraus, Atmosphere-Ocean Interaction, Oxford University Press, New York, 1972.