Abstract
Recently Wiener chaos derived stochastic expansion methods, especially polynomial chaos (PC), have caught great attention in the underwater acoustics community for its success in modeling random properties of underwater acoustic field. However, most research until now concern a Gaussian random field, while fluctuations in ocean medium are not always Gaussian. For non‐Gaussian probability density function (PDF) with a finite support, it is reported that a Wiener chaos decomposition, which use wavelets as basis functions instead of orthogonal polynomials, is more suitable than PC. This paper concentrates on non‐Gaussian high frequency internal waves [T. Wang and T. Gao, Chin. J. Ocean. Limnol. 20, 16–21 (2002)] and presents a multi‐resolution stochastic expansion approach to handle acoustic field fluctuation in a non‐Gaussian internal wave field. The depth dependent PDF of sound speed fluctuation is determined empirically from experiment results. Spatial coherence function and scintillation index of acoustic field were calculated for Gaussian and non‐Gaussian cases. In addition, a comparison between both situations was made, which shows that in the non‐Gaussian case, the acoustic field has a more complex coherence structure. [Work partially supported by NSFC.]
Published Version
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