Modeling the effect of bubble plumes on high frequency acoustic propagation in shallow water

In this paper we model the effect of bubbles on high frequency acoustic propagation in shallow water under strong winds. Underwater bubble clouds provide locally significant modifications of the sound speed field. The modified sound speed field contributes to a major transmission loss to sound propagation and scattering of the signals. We adopt the bubble field model developed by Norton, et al., generate range dependent discrete bubble plumes and compute the sound speed profile of each bubble plume. We expand our previous work on modeling the effect of rough sea surface and bubble plumes, to include both β- and γ-plumes in the model. We particularly compare cases where the random distribution of β- and γ-plumes are generated differently. With a bubble perturbed sound speed field, we model the communication channel using a rough surface parabolic equation model to generate a complex pressure field at a selected set of ranges and depths. These pressure fields form the basic frequency response of the channel. Our results show that under strong winds, bubbles contribute to large transmission loss and cannot be neglected. The dominant contribution to attenuation is due to β plumes rather than γ plumes. However γ plumes cannot be ignored because their existence affects the spacing between β plumes. And the spacing between β plumes is a significant factor, which results in less attenuation compared to closely spaced β plumes.