Practical applications of spectral analysis to hydrologic time series

An Erratum has been published for this article in Hydrological Processes 17(4) 2003, 883. Fourier‐transform‐based spectral analysis and filtering techniques, although potentially very useful, have seen little practical application in hydrology. We provide an overview of the Fourier transform and spectral analysis and present examples of how these methods may be applied to practical hydrologic problems: determination of the frequency content of a time series; inference of the physical mechanisms responsible for this frequency content; and evaluation of the performance of a process‐based simulation model used for water resource management. In all cases, the methods performed well and were reasonably straightforward to implement, highlighting their general utility.