1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Bayesian Inversion of Seabed Scattering Data

The long-term goals of this work are to improve ocean acoustic reverberation modeling and sonar performance predictions in shallow waters by developing inversion procedures to estimate seabed geoacoustic and scattering properties and their uncertainties, as well as investigating the importance of various scattering processes. Important issues include: investigating the angular and frequency dependence of scattering (defining the scattering kernel), determining the dependence of scattering on physical properties of the seabed, and establishing the relative importance between scattering due to rough boundaries at the seafloor and sub-bottom interfaces or at volume inhomogeneities. These issues are all key to the ability to invert scattering and/or reflection data for seabed geoacoustic and scattering parameters, and ultimately to the practical inversion of active source reverberation data for rapid environmental assessment applications. OBJECTIVES The specific objectives of this project are to carry out Bayesian inversion of scattering and reflection data to estimate seabed scattering and geoacoustic parameters and their uncertainties, and to investigate the relative importance of surface and volume scattering mechanisms in measured data. This involves the development and implementation of efficient forward modeling and trans-dimensional Bayesia