Multi-scale analysis of teleconnection indices: climate noise and nonlinear trend analysis
The multi-scale nature and climate noise properties of teleconnection indices are examined by using the Empirical Mode Decomposition (EMD) procedure. The EMD procedure allows for the analysis of non-stationary time series to extract physically meaningful intrinsic mode functions (IMF) and nonlinear...
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ftdoajarticles:oai:doaj.org/article:a012127efa0c41bbb755baa8d58b9fe4 2023-05-15T17:34:01+02:00 Multi-scale analysis of teleconnection indices: climate noise and nonlinear trend analysis C. Franzke 2009-02-01T00:00:00Z https://doaj.org/article/a012127efa0c41bbb755baa8d58b9fe4 EN eng Copernicus Publications http://www.nonlin-processes-geophys.net/16/65/2009/npg-16-65-2009.pdf https://doaj.org/toc/1023-5809 https://doaj.org/toc/1607-7946 1023-5809 1607-7946 https://doaj.org/article/a012127efa0c41bbb755baa8d58b9fe4 Nonlinear Processes in Geophysics, Vol 16, Iss 1, Pp 65-76 (2009) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2009 ftdoajarticles 2022-12-31T06:41:52Z The multi-scale nature and climate noise properties of teleconnection indices are examined by using the Empirical Mode Decomposition (EMD) procedure. The EMD procedure allows for the analysis of non-stationary time series to extract physically meaningful intrinsic mode functions (IMF) and nonlinear trends. The climatologically relevant monthly mean teleconnection indices of the North Atlantic Oscillation (NAO), the North Pacific index (NP) and the Southern Annular Mode (SAM) are analyzed. The significance of IMFs and trends are tested against the null hypothesis of climate noise. The analysis of surrogate monthly mean time series from a red noise process shows that the EMD procedure is effectively a dyadic filter bank and the IMFs (except the first IMF) are nearly Gaussian distributed. The distribution of the variance contained in IMFs of an ensemble of AR(1) simulations is nearly χ 2 distributed. To test the statistical significance of the IMFs of the teleconnection indices and their nonlinear trends we utilize an ensemble of corresponding monthly averaged AR(1) processes, which we refer to as climate noise. Our results indicate that most of the interannual and decadal variability of the analysed teleconnection indices cannot be distinguished from climate noise. The NP and SAM indices have significant nonlinear trends, while the NAO has no significant trend when tested against a climate noise hypothesis. Article in Journal/Newspaper North Atlantic North Atlantic oscillation Directory of Open Access Journals: DOAJ Articles Pacific |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 C. Franzke Multi-scale analysis of teleconnection indices: climate noise and nonlinear trend analysis |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
The multi-scale nature and climate noise properties of teleconnection indices are examined by using the Empirical Mode Decomposition (EMD) procedure. The EMD procedure allows for the analysis of non-stationary time series to extract physically meaningful intrinsic mode functions (IMF) and nonlinear trends. The climatologically relevant monthly mean teleconnection indices of the North Atlantic Oscillation (NAO), the North Pacific index (NP) and the Southern Annular Mode (SAM) are analyzed. The significance of IMFs and trends are tested against the null hypothesis of climate noise. The analysis of surrogate monthly mean time series from a red noise process shows that the EMD procedure is effectively a dyadic filter bank and the IMFs (except the first IMF) are nearly Gaussian distributed. The distribution of the variance contained in IMFs of an ensemble of AR(1) simulations is nearly χ 2 distributed. To test the statistical significance of the IMFs of the teleconnection indices and their nonlinear trends we utilize an ensemble of corresponding monthly averaged AR(1) processes, which we refer to as climate noise. Our results indicate that most of the interannual and decadal variability of the analysed teleconnection indices cannot be distinguished from climate noise. The NP and SAM indices have significant nonlinear trends, while the NAO has no significant trend when tested against a climate noise hypothesis. |
format |
Article in Journal/Newspaper |
author |
C. Franzke |
author_facet |
C. Franzke |
author_sort |
C. Franzke |
title |
Multi-scale analysis of teleconnection indices: climate noise and nonlinear trend analysis |
title_short |
Multi-scale analysis of teleconnection indices: climate noise and nonlinear trend analysis |
title_full |
Multi-scale analysis of teleconnection indices: climate noise and nonlinear trend analysis |
title_fullStr |
Multi-scale analysis of teleconnection indices: climate noise and nonlinear trend analysis |
title_full_unstemmed |
Multi-scale analysis of teleconnection indices: climate noise and nonlinear trend analysis |
title_sort |
multi-scale analysis of teleconnection indices: climate noise and nonlinear trend analysis |
publisher |
Copernicus Publications |
publishDate |
2009 |
url |
https://doaj.org/article/a012127efa0c41bbb755baa8d58b9fe4 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_source |
Nonlinear Processes in Geophysics, Vol 16, Iss 1, Pp 65-76 (2009) |
op_relation |
http://www.nonlin-processes-geophys.net/16/65/2009/npg-16-65-2009.pdf https://doaj.org/toc/1023-5809 https://doaj.org/toc/1607-7946 1023-5809 1607-7946 https://doaj.org/article/a012127efa0c41bbb755baa8d58b9fe4 |
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1766132713057681408 |