Fourth Moments of Acoustic Waves Forward Scattered by a Rough Ocean Surface
Abstract
Three types of statistical fourth moments of acoustic waves forward scattered by a randomly rough ocean surface are derived and numerically evaluated. The first one is related to the scintillation index which characterizes intensity fluctuations. The second one is the two-position intensity correlation function which describes the spatial correlation of wave intensity. The third is the two-position coherence function which carries information on the phase fluctuations of the scattered wave. In the range of weak scattering, the ratio of the absolute value of the two-position coherence function over the two-position intensity correlation exactly describes the mean square fluctuation of the relative phase between the two positions. The acoustic frequency is high so that the Kirchhoff approximation can be used. Two types of spectral functions for surface-height fluctuations are considered: a Gaussian spectrum and the Donelan/Pierson spectrum. The latter is obtained from a model for the fluctuations of the ocean surface height which are controlled by the wind at the ocean surface. Keywords: Forward scattering, Ocean surface, High frequency scattering statistics.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 09, 1990
- Accession Number
- ADA227469
Entities
People
- Chen Yang
- S. T. Mcdaniel
Organizations
- Pennsylvania State University