Abstract:

The problem of predicting the high-frequency forward propagation loss due to the near-surface bubble layer, called the surface bubble loss (SBL), is solved by use of the full-field University of Miami parabolic equation (UMPE) acoustic model. Curves of SBL versus grazing angle are presented for many wind speeds and frequencies. These results demonstrate the importance of surface-image interference at small grazing angles, an effect that ray-tracing models do not predict. It is also found that the effective surface is displaced downward by the lossy bubble layer, a novel effect that also is not predicted by ray-tracing models. [Work supported by ONR.]