Observed periodicities and the spectrum of field variations in Holocene magnetic records

S. Panovska, Chris Finlay, A.M. Hirt

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

In order to understand mechanisms that maintain and drive the evolution of the Earth's magnetic field, a characterization of its behavior on time scales of centuries to millennia is required. We have conducted a search for periodicities in Holocene sediment magnetic records, by applying three techniques: multitaper spectral estimation, wavelet analysis and empirical mode decomposition. When records are grouped according to their geographical locations, we find encouraging consistency amongst the observed periods, especially in nearby inclination records. No evidence was obtained for discrete, globally observed, periods. Rather we find a continuous broadband spectrum, with a slope corresponding to a power law with exponent of -2.3 ± 0.6 for the period range between 300 and 4000 yr. This is consistent with the hypothesis that chaotic convection in the outer core drives the majority of secular variation. © 2013 Elsevier B.V.
Original languageEnglish
JournalEarth and Planetary Science Letters
Volume379
Pages (from-to)88-94
ISSN0012-821x
DOIs
Publication statusPublished - 2013

Keywords

  • Spectrum analysis
  • Wavelet analysis
  • Geomagnetism

Cite this

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keywords = "Spectrum analysis, Wavelet analysis, Geomagnetism",
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Observed periodicities and the spectrum of field variations in Holocene magnetic records. / Panovska, S.; Finlay, Chris; Hirt, A.M.

In: Earth and Planetary Science Letters, Vol. 379, 2013, p. 88-94.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Observed periodicities and the spectrum of field variations in Holocene magnetic records

AU - Panovska, S.

AU - Finlay, Chris

AU - Hirt, A.M.

PY - 2013

Y1 - 2013

N2 - In order to understand mechanisms that maintain and drive the evolution of the Earth's magnetic field, a characterization of its behavior on time scales of centuries to millennia is required. We have conducted a search for periodicities in Holocene sediment magnetic records, by applying three techniques: multitaper spectral estimation, wavelet analysis and empirical mode decomposition. When records are grouped according to their geographical locations, we find encouraging consistency amongst the observed periods, especially in nearby inclination records. No evidence was obtained for discrete, globally observed, periods. Rather we find a continuous broadband spectrum, with a slope corresponding to a power law with exponent of -2.3 ± 0.6 for the period range between 300 and 4000 yr. This is consistent with the hypothesis that chaotic convection in the outer core drives the majority of secular variation. © 2013 Elsevier B.V.

AB - In order to understand mechanisms that maintain and drive the evolution of the Earth's magnetic field, a characterization of its behavior on time scales of centuries to millennia is required. We have conducted a search for periodicities in Holocene sediment magnetic records, by applying three techniques: multitaper spectral estimation, wavelet analysis and empirical mode decomposition. When records are grouped according to their geographical locations, we find encouraging consistency amongst the observed periods, especially in nearby inclination records. No evidence was obtained for discrete, globally observed, periods. Rather we find a continuous broadband spectrum, with a slope corresponding to a power law with exponent of -2.3 ± 0.6 for the period range between 300 and 4000 yr. This is consistent with the hypothesis that chaotic convection in the outer core drives the majority of secular variation. © 2013 Elsevier B.V.

KW - Spectrum analysis

KW - Wavelet analysis

KW - Geomagnetism

U2 - 10.1016/j.epsl.2013.08.010

DO - 10.1016/j.epsl.2013.08.010

M3 - Journal article

VL - 379

SP - 88

EP - 94

JO - Earth and Planetary Science Letters

JF - Earth and Planetary Science Letters

SN - 0012-821X

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