Silva, L, Jackson, LP and Mound, J (2012) Assessing the importance and expression of the 6-year geomagnetic oscillation. Journal of Geophysical Research. Solid Earth, 117 (B10). ISSN 2169-9313
Abstract
The first time derivative of residual length-of-day observations is known to contain a distinctive 6 year periodic oscillation. Here we theorize that through the flow accelerations at the top of the core the same periodicity should arise in the geomagnetic secular acceleration. We use the secular acceleration of the CHAOS-3 and CM4 geomagnetic field models to recover frequency spectra through both a traditional Fourier analysis and an empirical mode decomposition. We identify the 6 year periodic signal in the geomagnetic secular acceleration and characterize its spatial behavior. This signal seems to be closely related to recent geomagnetic jerks. We also identify a 2.5 year periodic signal in CHAOS-3 with unknown origin. This signal is strictly axially dipolar and is absent from other magnetic or geodetic time series.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2012 American Geophysical Union. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | Core surface flows; Geomagnetic secular acceleration; Length of day |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 31 Oct 2014 12:12 |
Last Modified: | 02 Nov 2014 04:30 |
Published Version: | http://dx.doi.org/10.1029/2012JB009405 |
Status: | Published |
Publisher: | American Geophysical Union/Wiley |
Identification Number: | 10.1029/2012JB009405 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:80889 |