Mode coupling and scattering in a submarine canyon environment

Acoustic propagation in a realistic ocean environment based on the Hudson Canyon is computed using an Omnidirectional Coupled Mode (OCM) and a 3-D Parabolic Equation (3DPE) approach. The 3DPE is limited by nature to one-way wave radiation, while the OCM is not. The mode coupling method accounts for omnidirectional propagation and refraction, while the forward-propagation PE model can more efficiently approximate the canyon acoustics while ignoring some of the complicated refraction. The primary motivation is to explore the differences in output between the two methods in pursuit of describing the relative importance of environmental uncertainty in model inputs. Examples of features of interest include steep bathymetric slopes, and sound speed fronts in the water column. Some methods for adapting the computational approach in the OCM model based on environmental properties are outlined, and some sensitivity analysis is presented. [Work supported by ONR.]