Acoustic propagation uncertainty in internal wave environments using an ocean-acoustic joint model

Abstract

An ocean-acoustic joint model is developed for research of acoustic propagation uncertainty in internal wave environments. The internal waves are numerically produced by tidal forcing over a continental slope using an ocean model. Three parameters (i.e., internal wave, source depth, and water depth) contribute to the dynamic waveguide environments, and result in stochastic sound fields. The sensitivity of the transmission loss (TL) to environment parameters, statistical characteristics of the TL variation, and the associated physical mechanisms are investigated by the Sobol sensitivity analysis method, the Monte Carlo sampling, and the coupled normal mode theory, respectively. The results show that the TL is most sensitive to the source depth in the near field, resulted from the initial amplitudes of higher-order modes; while in middle and far fields, the internal waves are responsible for more than 80% of the total acoustic propagation contribution. In addition, the standard deviation of the TL in the near field and the shallow layer is smaller than those in the middle and far fields and the deep layer.