Inversion of Internal Wave-Perturbed Sound-Speed Field Via Acoustic Data Assimilation

Model-based signal processing methods, such as matched-field processing, are concerned with exploiting the combination of the sound propagation physics in an ocean waveguide and the observation data. As such, they require accurate knowledge of the ocean acoustic environment. This paper presents an approach of environmental inversion via acoustic data assimilation (ADA), intended specifically to reconstruct the sound-speed field perturbed by linear internal waves. It exploits a variety of information sources, including direct local sound-speed measurements, an internal wave model, a full field acoustic propagation model, and acoustic pressure measurements. Compared to the previous work on ADA, four important improvements have been made: 1) a linear internal wave model is included; 2) a more realistic shallow-water environment from the Shelf Break PRIMER 1996 experiment is considered in the numerical simulations; and 3) effect of the sediment on acoustic propagation is considered in the inversion algorithm. The results further demonstrate the validity of the ADA approach.