A Solution to the Inverse Problem in Ocean Acoustics

T.V. Ramana Murty; Y.K. Somayajulu; R. Mahadevan

doi:10.14429/dsj.42.4355

T.V. Ramana Murty National Institute of Oceanography, Goa
Y.K. Somayajulu National Institute of Oceanography, Goa
R. Mahadevan National Institute of Oceanography, Goa

DOI: https://doi.org/10.14429/dsj.42.4355

Keywords: Marine acoustic modelling, Geophysical inverse techniques

Abstract

The methodology and software developed to reconstruct a vertical sound speed profile as a part of studies on the marine acoustic modelling, using the ray path lengths and the travel time perturbations in tomographic layers are outlined. For a stratified ocean, considering the range independent nature of the medium, geophysical inverse techniques are employed to reconstruct the sound speed profile. The reconstructed profile for a six layer ocean, with five energetic modes, is in good agreement with that of the assumed profile thereby indicating the usefulness of the model. The effect of noise caused by the excursions of the source and receiver moorings; When expressed in terms of travel-time differences, results in the sound speed changes up to 0.1 percent.

Author Biographies

T.V. Ramana Murty, National Institute of Oceanography, Goa

Dr TV Ramana Murthy took his MSc (Applied Mathematics) from Andhra University , Waltair, in 1977 and PhD (Mathematics) from IIT, Bombay, in 1980. He worked as Post-Doctoral Fellow at the Department of Mathematics, lIT, Bombay and as a Lecturer in Mathematics at the Goa Engineering College, Farmagludi, Goa ,before joining NIO as a Research Associate , in 1982. Presently: he is working as a senior scientist. His research interests include: acoustic modelling, numerical analysis, inverse problem for ocean tomographic application, boundary layer theory, magneto hydrodynamics, non-Newtonian fluids, and heat and mass transfer problems . He has authored 29 research papers and 10 technical reports

Y.K. Somayajulu, National Institute of Oceanography, Goa

Mr YKSomayajulu took his MSc(Tech) in Meteorology and Oceanography from Andhra University, Waltair, in 1976 and joined NIO, Goa, in 1977. He received training at the Woods Hole Oceanographic Institute, USA, on the development of an operational system. 'He has been working on the physical oceanographic aspects as related to acoustic propagation and is involved in ocean acoustic model studies, computer
simulations, and development of methodology for forward and inverse aspects of tomography

R. Mahadevan, National Institute of Oceanography, Goa

Dr R Mahade van is an Associate Professor in Ocean Engineering Centre, IIT, Madras. He obtained his BE from Madras University, MTech from IIT, Kharagpu r and PhD from IISc, Bangalore. He worked at NIO, Goa ,before joining lIT, Madras, in 1984. His research interests are in the areas of ocean flow field simulation and ocean.wave hydrodynamics .