HR: 15:30h
AN: OS44A-01 INVITED     [Abstracts]
TI: Multidimensional Fourier Methods: Analysis of Internal Soliton Data and Acoustic Wave Propagation
AU: * Osborne, A
EM: al.osborne@gmail.com
AF: Universita' di Torino, Dipartimento di Fisica Generale Via Pietro Giuria, 1, Torino, 10124 Italy
AB: The aggressive pursuit of a satisfactory level of physical understanding of nonlinear oceanic wave dynamics has lead to the use of multidimensional Fourier analysis as a tool for the time series analysis of both internal wave motion and acoustic wave propagation. These new tools have arisen naturally for studies using the inverse scattering transform to particular nonlinear wave equations. When applied to the Korteweg-deVries equation, for example, one finds that the approach can be extended to arbitrarily high order. There are several advantages for using multidimensional Fourier methods over ordinary Fourier analysis: (1) fully nonlinear wave dynamics can be studied, (2) solitons become a natural component in the theory and correspond to the diagonal elements of the "Riemann matrix", (3) nonlinear interactions are accounted for by the off-diagonal elements of this matrix, (4) nonlinear acoustic modes are found to also have an (albeit static) solitonic component. These surprising results lead to new interpretations of acoustic waves propagating in the presence of a nonlinear internal wave field. One of the most important results is the implication that new nonlinear filtering techniques allow for the spectral decomposition of both the internal wave field and of the acoustic field. With regard to the acoustic field, one can foresee the application of the method to the observations of phenomena in the "hidden zones", where one would normally conclude that acoustic wave propagation does not occur.
DE: 4203 Analytical modeling
DE: 4219 Continental shelf processes
DE: 4259 Ocean acoustics
SC: Ocean Sciences [OS]
MN: 2005 Joint Assembly