Ocean wave heave time series as the sum of nonharmonic sinusoids

A discrete wave displacement time-series record is usually analyzed by a Discrete Fourier Transform (DFT), which represents the record as the sum of a finite number of harmonic sinusoids. When the dominant sinusoid of the record is not one of these harmonics, DFT “leakage” produces a distorted picture of the dominant wave, particularly for records not much longer than the largest period in the record. This paper proposes a non-Fourier method for determining the dominant wave period that is applicable even when the record is short relative to the largest period present in the record.