Hartley transform: Basic theory and applications in oceanographic time series analysis

Abstract

The Hartley transform, a real valued alternative to the complex Fourier transform, is presented as an efficient tool for data analysis in physical oceanography. Basic theoretical properties of this real-valued transform are briefly reviewed. Similarities and differences between Fourier and Hartley integral transforms and their discrete versions, as well as computational benefits or disadvantages between numerical algorithms used to evaluate their discrete versions are presented. The Hartley transform is used to estimate the spectral density function of ocean surface waves and coastal current time series.