Evaluation of the validity of the perturbation approximation for sound scattering in the sea using a Pierson - Moskowitz spectrum

Subject Areas : Marine Physics

A. Mohseni Arasteh ¹ (Faculty of Marine Science and Technology, Islamic Azad University, North Tehran Branch)
K. Lary ² (Faculty of Marine Science and Technology, Islamic Azad University, North Tehran Branch)
M. Semnaninezhad ³ (Faculty of Marine Science and Technology, Islamic Azad University, North Tehran Branch)

Received: 2008-07-27 Accepted : 2009-02-03 Published : 2009-09-22

Keywords: Sound absorption, Sound scattering perturbation theory, Pierson – Moskowitz spectrum, scattering cross section,

Abstract :

Scattering and absorption of acoustic waves is one of the important discussions in physical study of seas and oceans. In this paper, the effect of Pierson - Moskowitz spectral on the acoustic scattering in the sea have been investigated. In this study the validity of the perturbation approximations for scattering from "Pierson - Moskowitz" sea surface has been examined through comparison with typical sample. All results are for an acoustic frequency of 200 Hz and for incident grazing angles of 10 º-20 º. First–order perturbation theory, yields bistatic backscattering levels that are 1-3 dB low for the examples that have been studied, and for incident angle 20o when increased surface height, perturbation theory correspond with results of integral equation.