Affiliation:
1. School of Earth Sciences, University of Leeds, Leeds LS2 9JT, UK.
Abstract
Slow temporal variations in Earth's magnetic field originate in the liquid outer core. We analyzed the evolution of nonaxisymmetric magnetic flux at the core surface over the past 400 years. We found that the most robust feature is westward motion at 17 kilometers per year, in a belt concentrated around the equator beneath the Atlantic hemisphere. Surprisingly, this motion is dominated by a single wavenumber and persists throughout the observation period. This phenomenon could be produced by an equatorial jet of core fluid, by hydromagnetic wave propagation, or by a combination of both. Discrimination between these mechanisms would provide useful constraints on the dynamics of Earth's core.
Publisher
American Association for the Advancement of Science (AAAS)
Reference27 articles.
1. Geodynamo theory and simulations
2. D. Gubbins, J. Bloxham, Geophys. J. R. Astron. Soc.80, 695 (1985).
3. Four centuries of geomagnetic secular variation from historical records
4. E. Dormy, J.-P. Valet, V. Courtillot, Geochem. Geophys. Geosyst.1, 2000GC000062 (2000).
5. M. Kono, P. H. Roberts, Rev. Geophys.40, 2000RG00102 (2002).
Cited by
152 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献