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

1pUW8. Comparison of acoustic model predictions with reverberation data from the ARSRP reconnaissance experiment.

Stanley A. Chin-Bing

Naval Res. Lab., Stennis Space Center, MS 39529-5004

Joseph E. Murphy

Gongqin Li

Univ. of New Orleans, New Orleans, LA 70148

Reverberation measurements from the mid-Atlantic ridge region were made during the Acoustic Reverberation Special Research Program (ARSRP) 1991 reconnaissance cruise. Ocean acoustic models have been used to investigate acoustic backscatter from a sedimented seafloor overlying an anelastic subbottom typical of this seafloor region. Computer simulations of the reverberant field were generated and compared with the ARSRP measured reverberation. Computer simulations were made using high-resolution ocean acoustic and seismoacoustic cw computer models. The parabolic equation model, fepe, was used to propagate the long-range acoustic fields to and from the vicinity of the mid-Atlantic ridge region, and the seismoacoustic finite-element model, safe, was used to determine the scattered fields from the rough seafloor and anelastic subbottom. Time-domain calculations were obtained from FFTs of the backscattered cw fields. Several realizations of the range-dependent sediment and subbottom were used. The bathymetric data for the sedimented regions were generated by the Webb--Jordan sediment distribution model. The bathymetric data for the subbottoms were generated by the Goff--Jordan fractal seafloor/basement model. The envelope of the simulated reverberation compared favorably with the measured reverberation data. Results support the conclusion that seafloor reverberation can be accurately simulated using high resolution ocean acoustic-seismoacoustic computer models together with high-resolution seafloor bathymetric data obtained from geomorphological models. [Work supported by the Office of Naval Research, Acoustic Reverberation SRP.]