MULTIPLICATIVE PADÉ PE FORMULATION APPLIED TO SWAM'99 TEST CASES

Abstract

Accurate forward modeling of acoustic propagation is crucial in underwater sound applications that rely on coherent field predictions, such as source localization and geoacoustic inversion based on matched field processing concepts. As acoustic propagation in shallow water environments becomes important in recent years, range-dependent modeling due to environmental changes has to be considered of which parabolic equation (PE) method has received widespread use because they are accurate and relatively fast. In this paper, Seoul National University parabolic equation (SNUPE) employing a multiplicative Padé formulation is developed. Linearization of the depth direction operator is achieved via expansion into a multiplication form of Padé approximation. To approximate the depth directional equation, Galerkin's method is used with partial collocation to achieve computational efficiency. To approximate the range directional equation, Crank–Nicolson's method is used. Finally, numerical self-starter has been used to initiate the near-field solution. The Shallow Water Acoustic Modeling (SWAM'99) Workshop provides an opportunity to test SNUPE's accuracy and compare its results with others for a variety of synthetic environments. In this paper, the numerical implementation and accuracy of SNUPE is tested by comparing with RAM12 results for the SWAM'99 test cases. Numerical experiments for SWAM'99 test cases give satisfactory results in accuracy for SNUPE and show the importance of the bottom information in the shallow water acoustic modeling.