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Data Assimilation Applied to Ocean Acoustic Tomography

Phd thesis by Paulo Felisberto,

Abstract: This thesis discusses the application of data assimilation methods to the estimation of space-time disturbances of the temperature/sound speed field in coastal environments. The proposed method is based on the assimilation of data measured in-situ and data provided by acoustic tomography, in accordance with an acoustic field correlation model commonly used in oceanography. The assimilation method developed herein uses information provided by classical ray tracing acoustic tomography. In order to overcome the stringent requirements imposed by ray tracing based acoustic tomography regarding source-receiver geometry knowledge, an alternative method of data assimilation based on range independent matched field tomographic inversions is proposed. This method is applied to an acoustic data set acquired during an internal wave devoted study: the INTIMATE´98 sea trial. The analysis of the experimental data set acquired during INTIMATE'98, allowed for realistic setup of a simulated temperature/sound speed space-time disturbances field, than used as input to the data assimilation simulation study. This work is a contribution to implement a strategy of sampling oceanographical processes, combining methods of underwater acoustics and methods of oceanography, in order to simplify acquisition systems and provide faster access to oceanographic information.