The viability of reflection loss measurement inversion to predict broadband acoustic behavior

The viability of using reflection loss measurements for the determination of sediment parameters and the predictions of broadband acoustic behavior is studied as a function of frequency for a dispersive ocean bottom. For this study, a deterministic set of reflection loss values from an idealized dispersive sediment is calculated as a function of grazing angle over a large frequency band 100Hz–1MHz. In each of the four decades of frequency a simulated annealing optimization process is used to invert for the sediment parameters. In addition, a set of rotated coordinates is calculated that reveals the the relative sensitivities of the reflection data to each of the sediment parameters and therefore the ability of the inversion process to converge. The accuracy and precision of each estimate is analyzed. The predicted broadband acoustic behavior from the inverted parameters from each decade band was compared to the original model. Only the estimates obtained from data that include frequencies in the transition region can successfully predict broadband behavior.