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Modal decomposition of tidally-forced internal waves (reconstructed from timeseries data)

  • Author / Creator
    Kaminski, Alexis K.
  • An algorithm is presented that disentangles the temporal and spatial structure of polychromatic internal wave fields generated through tidal conversion without a-priori knowledge of the topographic details. This spatial structure is relevant in estimating the location of ocean mixing. Using the (J+1) forcing frequencies associated with the wave field, a 2(J +1)×2(J +1) system is solved yielding, mode-by-mode, the frequency-specific mode strengths γjn or normalized mode strength ratios γjn/|γj1|, where j = 0, . . . , J. Both linear and nonlinear stratifications are considered. Synthetic data at laboratory and oceanographic length scales are used for verification. Excellent agreement is seen between recovered mode strengths and theoretical values from the synthetic data when using exact forcing frequencies. When forcing frequencies are determined via fast Fourier transform, the agreement is slightly less robust, with up to 18% error, although qualitative trends are still well captured. The algorithm may therefore be extended to problems of internal wave generation beyond tidal conversion.

  • Subjects / Keywords
  • Graduation date
    2012-11
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/R3K653
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
    English
  • Institution
    University of Alberta
  • Degree level
    Master's
  • Department
    • Department of Mechanical Engineering
  • Supervisor / co-supervisor and their department(s)
    • Flynn, Morris (Mechanical Engineering)
  • Examining committee members and their departments
    • Koch, Bob (Mechanical Engineering)
    • Swaters, Gordon E. (Mathematical and Statistical Sciences)