Rapid calculations of acoustic propagation loss in range dependent oceans

Calculation of transmission loss in range-dependent ocean environments usually involves CPU-intensive models that offer little insight into the problem. The authors present a new approach based on hybrid ray and mode concepts. A set of incoherent intensity formulas is given for different acoustic components of the propagation. The key points are the conservation of energy flux and the exploitation of the ray invariant to model weak range dependence. Predictions from these formulas are compared with benchmark solutions to demonstrate both their accuracy and the insight provided by the individual components