Effect of dispersion on the convergence rate for Green's function retrieval

• Published in: The Journal of the Acoustical Society of America 2017-05, Vol.141 (5), p.3590-3590
• Main Authors: Yoritomo, John Y., Weaver, Richard
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4987671

Much information about wave propagation in a variety of structures has been obtained from Green's function retrieval by noise correlation. Here we examine how dispersion affects Green's function retrieval and, in particular, its signal-to-noise ratio (SNR). On recalling how the inherent spread of a signal due to band limitation is augmented by spread due to dispersion and propagation distance, and how both affect amplitude, we argue that SNR in highly dispersive media can be substantially lowered by strong dispersion. We argue this is most relevant for gravity waves over large propagation distances in the ocean or atmosphere. In particular, we argue that dispersion could explain recent retrieval failure from surface gravity wave noise in the ocean. Lastly, we consider methods to ameliorate the poor SNR due to dispersion. We use numerical simulation to substantiate our analytic results.