Geoacoustic Inversion Using Time Reversal of Ocean Noise
Ji-Xing Qin1**, Boris Katsnelson2, Oleg Godin3, Zheng-Lin Li1
1State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190 2Department of Marine Geosciences, School of Marine Sciences, University of Haifa, Haifa 31905, Israel 3Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Colorado 80309, USA
Abstract：We present a passive geoacoustic inversion method using two hydrophones, which combines noise interferometry and time reversal mirror (TRM) techniques. Numerical simulations are firstly performed, in which strong focusing occurs in the vicinity of one hydrophone when Green's function (GF) is back-propagated from the other hydrophone, with the position and strength of the focus being sensitive to sound speed and density in the bottom. We next extract the GF from the noise cross-correlation function measured by two hydrophones with 8025-m distance in the Shallow Water '06 experiment. After realizing the TRM process, sound speed and density in the bottom are inverted by optimizing focusing of the back-propagated GF. The passive inversion method is inherently environmentally friendly and low-cost.
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2017, Vol. 34 
