Acoustic Green's function extraction from ambient noise in a coastal ocean environment

Abstract

We report on the results of an underwater acoustic field experiment conducted in December 2012 on the continental shelf off the Florida Keys in water of approximately 100 m depth. Ambient noise was recorded concurrently on three moored near-bottom instruments with horizontal separations of approximately 5 km, 10 km, and 15 km. We focus in this letter on instrument pairs with 5 km and 10 km separations. Consistent with theoretical predictions, coherent sums of many realizations of cross correlations of ambient noise records at two measurement locations are shown to yield approximations to deterministic acoustic Green's functions that describe propagation between those two locations. The results presented demonstrate the feasibility of extracting information suitable for use in tomographic inversions from measurements of underwater acoustic ambient noise. Key Points Noise interferometry is feasible in a challenging coastal ocean environment Ambient noise-based remote sensing of the ocean is feasible © 2014. American Geophysical Union. All Rights Reserved.