Estimating equivalent bottom geoacoustical parameters from broadband inversion

X. Demoulin, L. Pelissero, Y. Stephan,,
CMO - SHOM, Brest, France
S.M. Jesus
UCEH - Universidade do Algarve, Faro, Portugal
M.B. Porter
SAIC, La Jolla, USA
E. Coelho
Instituto Hidrografico, Lisboa, Portugal

Comments: download pdf file .
Ref.: Proc. ECUA 2000, (ISBN 92-828-9530-0), pp. 191-196, Lyon, France, June 2000.

Abstract : A simple and fast approach to retrieve equivalent geoacoustic parameters is presented in this paper. The method is based upon the processing of 300-800 Hz broadband signals on a single hydrophone.Two stable characteristics of the impulse response of the shallow water waveguide are estimated: the time dispersion and the bottom reflection amplitudes. This two features are analytically linked to the compressional speed and to the attenuation coefficient of the medium. The inversion of the two latter geoacoustic parameters is straightforward since it relies on an analytical expression. The method is tested on INTIMATE96 data. The results show an excellent agreement between the reflection of the true medium and the reflection coefficient of the equivalent medium.

ACKNOWLEDGMENT: this work was partially supported by project ATOMS from FCT (Portugal).