Penalization method for WAPE adjoint based inversion of an acoustic field

Penalization methods are required for the successful use of full-field acoustic inversion methods in the assessment of a shallow water environment. Regularization incorporates additional information about the desired solution in order to stabilize ill-posed inverse problems and identify useful solutions. In this paper the application of penalization methods to the adjoint optimization formalism is investigated. A side constraint is imposed on the optimal boundary control of a Claerbout’s wide-angle parabolic equation model. The cost function is augmented into a weighted combination of the residual norm of the measured-predicted acoustic fields and the side constraint. Using an adjoint-based conjugate gradient optimization approach, penalization results are compared for different values of the regularization parameter that controls the weight given to the minimization of the side constraint relative to that of the residual