Separability of seabed reflection and scattering properties in reverberation inversion
Separation of scattering properties (Lambert's mu) from reflection properties (the reflection loss angle derivative alpha) presents difficulties in the geoacoustic inversion of long range reverberation in isovelocity water, and here it is shown that there is still a problem in a refracting environment. An alternative technique is proposed where reverberation is modified by altering the source or receiverbeam pattern, for instance, using a triplet array or ring source, to provide a dipole and monopolepattern. Combinations of these two measures of reverberation then conveniently determine alpha and muindependently of other unknown quantities from long (or short) range data, in fact even from asingle range. In addition the short range ratio of the two quantities determines the critical angleindependently. The effects of refraction and other source or receiver beam patterns, including ahorizontal beam and a tilted beam, are investigated by using analytical techniques. To enhance thecredibility of these findings and demonstrate the benefits of the approach an example is posed as astandard inversion problem using a cost function based on both types of reverberation. Finally the technique is applied to some experimental data by forming simultaneous monopole and dipole beams in the vertical plane. Cop. 2007 Acoustical Society of America. [DOI: 10.1121/1.2384966]
SourceOriginally published in: Journal of the Acoustical Society of America, vol. 121, no. 1, pp. 108-119, January 2007
Harrison, Chris H.;
Nielsen, Peter L.