ASA 127th Meeting M.I.T. 1994 June 6-10

3pUW15. Sensitivity and predictability of intensity statistics for shallow-water propagation with a sediment scattering layer.

K. J. Howell

M. J. Jacobson

W. L. Siegmann

Rensselaer Polytech. Inst., Troy, NY 12180-3590

W. M. Carey

Advanced Research Projects Agency, Arlington, VA 22203-1714

It is well known that uncertainties in bottom properties are a significant factor in limiting accuracy of shallow-water acoustic predictions. In this paper, a scattering layer is introduced at a horizontal water--bottom interface to model effects of attenuation due to interface and sediment scattering. Using a wide-angle PE, formulas for intensity statistics are found for a geoacoustic model consisting of three isospeed layers. The sensitivity of these statistics to parameters such as frequency and scattering layer thickness and correlation length are then investigated analytically and numerically. Comparisons are made between intensity statistics of the three-layer model and of other isospeed and depth-dependent sediment profile models. Additional comparisons are made between three-layer model statistics and data from a recent New Jersey Shelf experiment. Results from the inclusion of a scattering layer for the prediction of relative intensity statistics are evaluated over a wide range of acoustic frequencies. Sensitivities to parameter variations are also investigated. [Work supported by ONR.]