Accession Number : ADA330699

Title :   Analysis of Ocean Wave Fields Using the Harmonic Phase Tracking Parameter Estimation Technique

Descriptive Note : Final rept. 1 Oct 92-15 Jun 97

Corporate Author : NAVAL FACILITIES ENGINEERING SERVICE CENTER PORT HUENEME CA

Personal Author(s) : Palo, P. A.

PDF Url : ADA330699

Report Date : SEP 1997

Pagination or Media Count : 427

Abstract : A uniquely new time series analysis technique called 'Harmonic Phase Tracking' (HPT) was developed and used to examine the spatial and temporal evolutionary characteristics of a hurricane wave field. The fundamental motivation was to investigate whether ocean waves were random, or if they instead self-organize into a finite number of locally stationary discrete sinusoids. Instead of the uniformly-spaced set of component frequencies inherent with the commonly-used Fourier Series (FFT) representation of a time series signal, HPT estimates the true number of harmonics along with the true frequencies, amplitudes and phases. HPT can be applied to wideband signals, and the parameters can be slowly-varying. Deterministic versus stochastic components are also readily identified. This new HPT-based representation has great promise for the better understanding of ocean waves. Two sets of ocean waves were analyzed: a control group that corresponds to stationary conditions, and a second set that corresponds to Hurricane Bob. The analysis clearly showed that there is in fact a coherent and discrete structure to the energy content in the wave field; that is, waves do 'self organize' into recognizable wave packets, with parameters that evolve very slowly over space and time.

Descriptors :   *OCEAN WAVES, *HARMONICS, SIGNAL PROCESSING, STOCHASTIC PROCESSES, PARAMETERS, ENERGY, TIME SERIES ANALYSIS, TRACKING, WAVE FUNCTIONS, TIME SIGNALS, WAVE PACKETS, HURRICANES.

Subject Categories : Physical and Dynamic Oceanography
      Theoretical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE