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

1pUW9. Modeling deterministic features in the ARSRP acoustic data.

R. A. Stephen

P. R. Shaw

R. J. Greaves

Woods Hole Oceanogr. Inst., Woods Hole, MA 02543

J. W. Caruthers

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

A preliminary study of the match-filtered beam data for the 5-s LFM chirps acquired on the Acoustic Reverberation SRP'93 acoustics cruise has been carried out. The analysis is based on a few selected segments which insonify site A at a 1/2CZ. The deterministic ``bright spot'' identified 2 years ago in the '91 data set appears in the '93 data. Although the characteristics of the event differ because of the different insonification parameters, the event appears in the same location when viewed from a number of azimthus and ranges. Other events within site A are robust when viewed from different ranges along the same azimuth, but disappear with changes in azimuth. The observations, which resolve left--right ambiguity and which account for insonification/bathymetry (TL) issues, indicate that backscatter is strongly dependent on azimuth. It is quite clear at site A that robust deterministic features are present in the 1/2CZ acoustics data. [Work supported by Office of Naval Research.]