Cross-frequency coherence and pulse propagation in a turbulent atmosphere.

Cross-frequency coherence of acoustic signals in a turbulent atmosphere is an important consideration for source localization with acoustic sensor arrays and for remote sensing of the atmosphere with sodars and tomography techniques. This paper takes as a starting point recently derived, closed-form equations for the spatial-temporal correlation function of a broadband acoustic signal propagating in a turbulent atmosphere with coupled spatial-temporal fluctuations in temperature and wind velocity. This theory is employed to calculate, based on the Rytov approximation, the two-point, two-time, two-frequency mutual coherence function of plane and spherical waves in the weak scattering regime.