A sensitivity study for full-field inversion of geoacoustic data with a towed array in shallow water

Jesus, S. M.

http://hdl.handle.net/10400.1/5176

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Authors

Jesus, S. M.

Abstract(s)

This paper presents some of the preliminary work aimed at estimating the ocean bottom morphological structure in coastal waters using a towed array. In order to obtain an idea of the expected performance of the system and draw some conclusions on its operation this study presents the sensitivity of three processors to variations of: array length, source and receiver positions, sensor noise, source frequency and frequency band. Conclusions tend to demonstrate that cost function sensitivity to sound speed variations is higher on the bottom top layers and it increases with array length. An increased sensitivity is generally acompanied by a cost function non-monotonic behavior creating local minima and making it more di cult to reach the global minimum. Attenuations have in general small in uence on the acoustic eld structure and are therefore di cult to estimate. Increasing the signal frequency band by incoherent module averaging has no signi cant in uence on sensitivity. A cost function relaying on the conventional matched lter has shown low sensitivity to sensor noise and is being extended to matching directional data from bottom arrivals at several frequencies. Mismatch cases, mainly those related to array/source relative position, will be also presented.