Algorithm of Reflection Coefficient for Unbounded Media in Beam-Displacement Ray-Mode Theory

The beam-displacement ray-mode theory is a normal mode method for propagation modeling in common horizontally stratified shallow water. Computation of the reflection coefficient for unbounded media is the key of the theory. In this paper, on the basis of the WKBZ eigenfunction, a kind of algorithm for computing the reflection coefficient for unbounded media is proposed. And the algorithm is universal to any sound speed profile with complex surface layer. Numerical simulations show that the beam-displacement ray-mode theory results with this algorithm are in good agreement with the KRAKEN normal mode results, and computational speed of this algorithm excels that of the other methods.