Geoacoustic inversion by mode amplitude perturbation
Poole, Travis L.
MetadataShow full item record
This thesis introduces an algorithm for inverting for the geoacoustic properties of the seafloor in shallow water. The input data required by the algorithm are estimates of the amplitudes of the normal modes excited by a low-frequency pure-tone sound source, and estimates of the water column sound speed profiles at the source and receiver positions. The algorithm makes use of perturbation results, and computes the small correction to an estimated background profile that is necessary to reproduce the measured mode amplitudes. Range-dependent waveguide properties can be inverted for so long as they vary slowly enough in range that the adiabatic approximation is valid. The thesis also presents an estimator which can be used to obtain the input data for the inversion algorithm from pressure measurements made on a vertical line array (VLA). The estimator is an Extended Kalman Filter (EKF), which treats the mode amplitudes and eigenvalues as state variables. Numerous synthetic and real-data examples of both the inversion algorithm and the EKF estimator are provided. The inversion algorithm is similar to eigenvalue perturbation methods, and the thesis also presents a combination mode amplitude/eigenvalue inversion algorithm, which combines the advantages of the two techniques.
Submitted to the Department of Mechanical Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Applied Ocean Sciences at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2007
Showing items related by title, author, creator and subject.
Shyu, Esther (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2015-09)Males and females may differ in stage-specific survival, maturation, fertility, or mating availability. These demographic differences, in turn, affect population growth rates, equilibrium structure, and evolutionary ...
Phenotypic diversity within two toxic dinoflagellate genera : environmental and transcriptomic studies of species diversity in Alexandrium and Gambierdiscus Pitz, Kathleen (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2016-09)Dinoflagellates are a diverse group of single-celled eukaryotic phytoplankton that are important for their unique genetics and molecular biology, the multitude of ecological roles they play, and the ability of multiple ...
Barkley, Hannah C. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2016-09)The 21𝑠𝑡 century warming and acidification of tropical oceans will impact the structure and function of coral reef ecosystems. Consequently, conservation efforts are increasingly focused on identifying and protecting ...