M.B. Porter email@example.com
Dep. of Applied Mathematics, New Jersey Institute of Technology, NJ, USA
S.M. Jesus firstname.lastname@example.org
UCEH - Universidade do Algarve, Faro, Portugal
Y. Stephan and X. Demoulin email@example.com , firstname.lastname@example.org
Centre Militaire Oceanographique - SHOM, Brest, France
E. Coelho email@example.com
Instituto Hidrografico, Lisboa, Portugal
Comments: download pdf
Ref.: in Experimental Acoustics Inversion Methods for Exploration of the Shallow Water Environment, Caiti, Hermand, Jesus and Porter (eds.), KLUWER, (ISBN 0-7923-6305-1) pp. 19-38, March 1999.
Abstract : In the summer of 1996, an experiment was conducted off the coast of Portugal to study the effects of internal tides on sound propagation. This experiment -called INTIMATE'96 (Internal Tide Investigation by Means of Acoustic Tomography Experiments) - has provided a great deal of insight about the variability of pulse transmission over space and time. In contrast to a common view of shallow water propagation as complicated and unpredictable, we find a steady pattern of echoes. The echo pattern stretches ans shrinks in a systematic way with tides and allows us to infer the components of the first few oceanographic modes. We also used the echo-pattern to track the source over a period of several days. During this period the isotherms in the ocean wavered by 20 m as a results of the tides, providing a challenge for model-based tracking. We will discuss these acoustic results with emphasis on the source tracking.
ACKNOWLEDGMENT: this work was partially supported by project INTIMATE from FCT (Portugal).