Full wave-field simulation of the autocorrelation of a low-frequency broadband signal in an ocean with a layered sediment bottom

Abstract

From low-frequency acoustic measurements carried out over the Tufts Abyssal Plain of the Northeast Pacific Ocean, it was found that the correlations between the multipath arrivals from a broadband source can be greatly affected by the bottom sediment. As an aid to explaining these effects, the pulse version of the safari full wave-field propagation model was modified to simulate the autocorrelation of the received signal. As with the original model, the bottom environment is input in the form of a geoacoustic profile. However, the inputs to the modified model also include the source level, realistic ambient noise and sea state conditions, noise due to distant shipping, and the self-noise levels of the receiving array. Simulations were carried out using the environment of the Tufts Abyssal Plain, including a geoacoustic profile that has been developed for the area. It was found from these simulations that the distortions observed in the measured correlograms can be predicted reliably.