Abstract:

Strong correlation between acoustic ambient noise and backscattering strength was observed during analysis of data from the acoustic surface reverberation experment (ASREX) [Williams et al., J. Acoust. Soc. Am. 97, 3404 (1995)]. Traditional empirical formulas for acoustic backscattering strength, such as those of Chapman and Harris [R. P. Chapman and J. H. Harris, J. Acoust. Soc. Am. 34, 1592--1597 (1962)] and Ogden and Erskine [P. M. Ogden and F. T. Erskine, J. Acoust. Soc. Am. 95, 746--761 (1994)], utilize wind speed, frequency, and grazing angle as their input variables. An alternative approach which utilizes ambient noise in place of wind speed is presented here. Unlike wind speed, ambient noise measurements are easily made from subsurface platforms and this technique may therefore be advantageous for certain applications (i.e., submarines and covert operations). [Work supported by ONR.]