Optimized extraction of coherent arrivals from ambient noise correlations in a rapidly fluctuating medium

Abstract

Ambient noise correlations can be used to estimate Green's functions for passive monitoring purposes. However, this method traditionally relies on sufficient time-averaging of the noise-correlations to extract coherent arrivals (i.e., Green's function estimates), and is thus limited by rapid environmental fluctuations occurring on short time scales while the averaging takes place. This letter demonstrates with simulation and data that the use of a stochastic search algorithm to correct and track these rapid environmental fluctuations can significantly reduce the required averaging time to extract coherent arrivals from noise correlations in a fluctuating medium.