Comments: download file (cintal_rep).
Ref.: SiPLAB Report 03/17, SiPLAB, University of Algarve, February 2017.
Abstract
The WiMUST Project envisions using a team of autonomous underwater vehicles towing
short acoustic arrays for seismic surveying of sea-bottom geo-acoustic properties. The
idea is to invert the acoustic array data by means of a Matched-Field Inversion (MFI)
technique. While there is great deal of experience in MFI and the so-called focalization
applied to horizontal propagation scenarios, in near vertical propagation scenarios, with
a source receiver horizontal distance limited a few tens of meter or less, there is little
understanding terms of feasibility of the acoustic inversion of bottom properties. In
particular, when the objective is to simultaneously invert bottom properties (soundspeed,
density and attenuation) of multiple bottom layers. The actual simulation study, carried
out with an environmental scenario and geometric set up based on the Peljesac data set,
models a shallow water acoustic propagation scenario with a short array. A sensitivity
analysis in MFI provides understanding on the observability of the unknown parameters
of interest. A mismatch analysis indicate that water-column mismatch (soundspeed and
depth) may cause the MFI procedure to break down. Based on the conclusions taken from
the sensitive and mismatch analysis, an iterative acoustic inversion concept with feedback
of intermediate parameter estimates is developed and tested with simulated data.