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Modeling Backscattering from a Rough Seafloor with Sediment Inhomogeneities.

ADA292025

Publication Date	1995
Personal Author	Novarini, J. C.; Caruthers, J. W.
Page Count	25
Abstract	Current models used to predict the backscattering strength of the ocean floor are either very involved, requiring geoacoustic parameters usually unavailable for the site in practical applications, or overly simplistic, relying mainly on empirical terms such as Lambert's law. In any case, solutions are very approximate and the problem is still far from being solved. In this work, a model is presented that avoids empirical functional forms, yet requires only a few physical parameters to describe the surficial sediments, often tabulated for typical sediments. The aim of the work is to develop a simple algorithm for operational prediction of bottom reverberation with only one free parameter, i.e., the volume scattering coefficient. The algorithm combines a two-scale surface scattering model with scattered contributions originating from inhomogeneities within the sediments, taking into consideration the rough interface. No specific mechanism is assumed for scattering at the volume inhomogeneities; however, the inhomogeneities are assumed to be uniform and isotropic. The volume scattering coefficient, combined with the bottom attenuation and density and referenced to the surface, plays a role similar to the Lambert's constant in empirical models. The model is exercised on a variety of published datasets for low and moderately high frequency. In general, the model performs very well for both fast and slow sediments, showing a definite improvement over Lambert's law. (AN).
Keywords	Backscattering Underwater acoustics Ocean bottom Mathematical models Algorithms Parameters Surface roughness Oceanographic data Shallow water Geoacoustics Mathematical prediction Heterogeneity Acoustic attenuation Acoustic scattering Reverberation Sonar Sediments Bragg scattering
Source Agency	Non Paid ADAS
NTIS Subject Category	46A - Acoustics 63A - Acoustic Detection 47C - Physical & Chemical Oceanography
Corporate Authors	Naval Research Lab. Detachment, Stennis Space Center, MS.
Supplemental Notes	Prepared in collaboration with Planning Systems Inc., Slidell, LA 70458.
Document Type	Technical Report
Title Note	Final rept.
NTIS Issue Number	199520

Modeling Backscattering from a Rough Seafloor with Sediment Inhomogeneities.

Modeling Backscattering from a Rough Seafloor with Sediment Inhomogeneities.
ADA292025

Publication Date	1995
Personal Author	Novarini, J. C.; Caruthers, J. W.
Page Count	25
Abstract	Current models used to predict the backscattering strength of the ocean floor are either very involved, requiring geoacoustic parameters usually unavailable for the site in practical applications, or overly simplistic, relying mainly on empirical terms such as Lambert's law. In any case, solutions are very approximate and the problem is still far from being solved. In this work, a model is presented that avoids empirical functional forms, yet requires only a few physical parameters to describe the surficial sediments, often tabulated for typical sediments. The aim of the work is to develop a simple algorithm for operational prediction of bottom reverberation with only one free parameter, i.e., the volume scattering coefficient. The algorithm combines a two-scale surface scattering model with scattered contributions originating from inhomogeneities within the sediments, taking into consideration the rough interface. No specific mechanism is assumed for scattering at the volume inhomogeneities; however, the inhomogeneities are assumed to be uniform and isotropic. The volume scattering coefficient, combined with the bottom attenuation and density and referenced to the surface, plays a role similar to the Lambert's constant in empirical models. The model is exercised on a variety of published datasets for low and moderately high frequency. In general, the model performs very well for both fast and slow sediments, showing a definite improvement over Lambert's law. (AN).
Keywords	Backscattering Underwater acoustics Ocean bottom Mathematical models Algorithms Parameters Surface roughness Oceanographic data Shallow water Geoacoustics Mathematical prediction Heterogeneity Acoustic attenuation Acoustic scattering Reverberation Sonar Sediments Bragg scattering
Source Agency	Non Paid ADAS
NTIS Subject Category	46A - Acoustics 63A - Acoustic Detection 47C - Physical & Chemical Oceanography
Corporate Authors	Naval Research Lab. Detachment, Stennis Space Center, MS.
Supplemental Notes	Prepared in collaboration with Planning Systems Inc., Slidell, LA 70458.
Document Type	Technical Report
Title Note	Final rept.
NTIS Issue Number	199520