Improved High-Frequency Bottom Loss Characterization

We propose development of an improved bottom database suitable for use in the frequency range of 1-10 kHz. Measured transmission loss (TL) and reverberation level (RL) will be jointly processed in building the database. The influence of the rough sea surface, rough seafloor, as well as subbottom heterogeneity will be accounted for during database generation. The rough sea surface will be characterized by wind speed and wind direction, and the seafloor by a layered sediment where each interface is allowed to be rough and each layer allowed to be heterogeneous. A suite of models (e.g., rough surface PE, rough surface transport equation, or rough surface ray tracing, the GABIM model for characterization of bottom backscatter, and reverberation models based on perturbation theory) will be jointly applied to process measured wideband data in order to populate the database. Numerical simulations and field data with companion environmental data (TREX13) will be used to test the procedure, parameterization, and resulting database. The new procedure will then be applied to existing and new NAVOCEANO data sets to check consistency of the data basing results across regions with similar sediment types.