Evidence for the chaotic origin of Northern Annular Mode variability

Osprey, S. M. and Ambaum, M. H. P. ORCID: https://orcid.org/0000-0002-6824-8083 (2011) Evidence for the chaotic origin of Northern Annular Mode variability. Geophysical Research Letters, 38 (15). L15702. ISSN 0094-8276 doi: 10.1029/2011GL048181

Abstract/Summary

Exponential spectra are found to characterize variability of the Northern Annular Mode (NAM) for periods less than 36 days. This corresponds to the observed rounding of the autocorrelation function at lags of a few days. The characteristic persistence timescales during winter and summer is found to be ∼5 days for these high frequencies. Beyond periods of 36 days the characteristic decorrelation timescale is ∼20 days during winter and ∼6 days in summer. We conclude that the NAM cannot be described by autoregressive models for high frequencies; the spectra are more consistent with low-order chaos. We also propose that the NAM exhibits regime behaviour, however the nature of this has yet to be identified.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/22646
Item Type	Article
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Geophysical Union
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