Wavelet analysis for non-stationary, nonlinear time series

Methods for detecting and quantifying nonlinearities in nonstationary time series are introduced and developed. In particular, higher-order wavelet analysis was applied to an ideal time series and the quasi-biennial oscillation (QBO) time series. Multiple-testing problems inherent in wavelet analysi...

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Main Author: J. A. Schulte
Format: Article
Language:English
Published: Copernicus Publications 2016-08-01
Series:Nonlinear Processes in Geophysics
Online Access:http://www.nonlin-processes-geophys.net/23/257/2016/npg-23-257-2016.pdf
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author J. A. Schulte
author_facet J. A. Schulte
author_sort J. A. Schulte
collection DOAJ
description Methods for detecting and quantifying nonlinearities in nonstationary time series are introduced and developed. In particular, higher-order wavelet analysis was applied to an ideal time series and the quasi-biennial oscillation (QBO) time series. Multiple-testing problems inherent in wavelet analysis were addressed by controlling the false discovery rate. A new local autobicoherence spectrum facilitated the detection of local nonlinearities and the quantification of cycle geometry. The local autobicoherence spectrum of the QBO time series showed that the QBO time series contained a mode with a period of 28 months that was phase coupled to a harmonic with a period of 14 months. An additional nonlinearly interacting triad was found among modes with periods of 10, 16 and 26 months. Local biphase spectra determined that the nonlinear interactions were not quadratic and that the effect of the nonlinearities was to produce non-smoothly varying oscillations. The oscillations were found to be skewed so that negative QBO regimes were preferred, and also asymmetric in the sense that phase transitions between the easterly and westerly phases occurred more rapidly than those from westerly to easterly regimes.
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spelling doaj.art-5c8b3699e30b43a4b1d362e3c778710d2022-12-21T18:45:21ZengCopernicus PublicationsNonlinear Processes in Geophysics1023-58091607-79462016-08-0123425726710.5194/npg-23-257-2016Wavelet analysis for non-stationary, nonlinear time seriesJ. A. Schulte0The Pennsylvania State University, University Park, Pennsylvania 16802, USAMethods for detecting and quantifying nonlinearities in nonstationary time series are introduced and developed. In particular, higher-order wavelet analysis was applied to an ideal time series and the quasi-biennial oscillation (QBO) time series. Multiple-testing problems inherent in wavelet analysis were addressed by controlling the false discovery rate. A new local autobicoherence spectrum facilitated the detection of local nonlinearities and the quantification of cycle geometry. The local autobicoherence spectrum of the QBO time series showed that the QBO time series contained a mode with a period of 28 months that was phase coupled to a harmonic with a period of 14 months. An additional nonlinearly interacting triad was found among modes with periods of 10, 16 and 26 months. Local biphase spectra determined that the nonlinear interactions were not quadratic and that the effect of the nonlinearities was to produce non-smoothly varying oscillations. The oscillations were found to be skewed so that negative QBO regimes were preferred, and also asymmetric in the sense that phase transitions between the easterly and westerly phases occurred more rapidly than those from westerly to easterly regimes.http://www.nonlin-processes-geophys.net/23/257/2016/npg-23-257-2016.pdf
spellingShingle J. A. Schulte
Wavelet analysis for non-stationary, nonlinear time series
Nonlinear Processes in Geophysics
title Wavelet analysis for non-stationary, nonlinear time series
title_full Wavelet analysis for non-stationary, nonlinear time series
title_fullStr Wavelet analysis for non-stationary, nonlinear time series
title_full_unstemmed Wavelet analysis for non-stationary, nonlinear time series
title_short Wavelet analysis for non-stationary, nonlinear time series
title_sort wavelet analysis for non stationary nonlinear time series
url http://www.nonlin-processes-geophys.net/23/257/2016/npg-23-257-2016.pdf
work_keys_str_mv AT jaschulte waveletanalysisfornonstationarynonlineartimeseries