Higher-Order Boundary and Rough Surface Treatment of the MMPE Model in the Evaluation of Scattering Effects
Naval Postgraduate School Monterey United States
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This research aims to improve the Monterey-Miami Parabolic Equation model MMPE by incorporating a higher-order hybrid boundary treatment and Fred D. Tapperts field transformational model to add surface scattering to the existing models. The impact of these two additions is investigated for improvements in accuracy and stability to the current MMPE model under rough surface conditions. Both models were treated with a Pierson-Moskowitz rough surface spectrum. It was hoped that the hybrid model would provide a reduction of the phase errors inherent to the MMPE at long range however, no improvements were seen, and the sensitivity to depth mesh size was not reduced. This could be the result of errors in the derivation of the higher-order algorithm.The transformational model used Tapperts field transformation to incorporate surface scattering and is thought to perform better when compared with the hybrid model by capturing higher modes of propagation.The inclusion of rough surface scattering in both models was evaluated for energy transmission across the airwater interface and beam dispersion. It was observed that the rough surface had minimal impact on energy transmission.