ASA 127th Meeting M.I.T. 1994 June 6-10

3aUW3. Comparison of various parabolic equation methods in a shallow water environment.

F. J. Ryan

Ocean and Atmospheric Sci. Div., Code 541, NRaD, San Diego, CA 92152-5000

The parabolic wave equation (PE) is a powerful numerical method for computing the full-wave complex acoustic pressure field in range-dependent environments. Various PE implementations have been proposed including those based on finite element Pade (FEPE) and split-step Fourier PE (SSFPE) algorithms. Numerical results from these algorithms will be presented for a range-dependent bottom-limited shallow water environment off San Diego, CA. These simulations will be compared to experimental data collected during the SWellEX-1 experiment in August 1993. Among the issues to be discussed are (1) computational efficiency versus model accuracy, (2) effects of environmental (water column and bottom properties) spatial sampling on model output, (3) treatment of PE grid boundary conditions, and (4) reciprocity. [Work supported by NRaD IR program.]