Cross-correlation of shipping noise: Refraction and receiver-motion effects.

The spatial correlation of a diffuse isotropic noise field generated from a uniform distribution of uncorrelated noise sources contains information about the time-domain Green's function ( TDGF) corresponding to propagation between the correlated locations. The distribution of noise in the ocean due to shipping-the prevailing origin of continuous low-frequency noise-is far from uniform. Besides the location of noise sources, the propagation conditions and the hydrophone locations have a significant influence on whether the TDGF can be reliably reconstructed through the cross-correlation procedure. A wave-theoretic scheme is implemented to simulate the cross-correlation function of a noise field in the time domain for arbitrary distributions of deterministic or random noise sources in refractive environments, and it is used to study the influence of propagation conditions and receiver motion on the efficiency of the cross-correlation procedure to obtain the TDGF from shipping noise. (C) 2019 Acoustical Society of America.