Intradecadal variations in length of day and their correspondence with geomagnetic jerks.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32385238.
- Also identified by DOI 10.1038/s41467-020-16109-8 and PMC identifier 7210880.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Earth's core oscillations and magnetic field inside the liquid outer core cannot be observed directly from the surface, we can infer these information from the intradecadal variations in Earth's rotation rate defined by length of day. However, the fine time-varying characteristics as well as relevant mechanisms of the intradecadal variations are still unclear. Here we report that the intradecadal variations present a significant 8.6-year harmonic component with an unexpected increasing phenomenon, besides a 6-year decreasing oscillation. More importantly, we find that there is a very good correspondence between the extremes of the 8.6-year oscillation with geomagnetic jerks. The fast equatorial waves with subdecadal periods propagating at Earth's core surface may explain the origin of this 8.6-year oscillation.