Abstract
Maps of the radial component of the magnetic field at the surface of Earth's core for 1715–1980 show, on average, a pattern of four lobes, placed symmetrically about the Equator, and zero flux near the poles. Time variations are largely confined to the Atlantic hemisphere (90° E to 90° W). We propose this average field to be the true dynamo-generated field; that equatorial symmetry is a fundamental consequence of the dynamo equations; and that the polar patches are because of the dynamical influence of the inner core. The main lobes are 120° apart and we propose that the flux from a missing third pair of lobes, which should appear symmetrically near the Greenwich meridian, has been re-distributed by near-surface fluid flow to generate secular variation in the Atlantic hemisphere.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Shure, L., Parker, R. L. & Backus, G. Phys. Earth planet. Inter. 28, 215–229 (1982).
Gubbins, D. Geophys. J. R. astr. Soc. 73, 641–652 (1983).
Gubbins, D. & Bloxham, J. Geophys. J. R. astr. Soc. 80, 695–713 (1985).
Shure, L., Parker, R. L. & Langel, R. A. J. geophys. Res. 90, 11505–11512 (1985).
Bloxham, J. & Gubbins, D. Nature 317, 777–781 (1985).
Doell, R. R. & Cox, A. Science 171, 248–254 (1971).
Chapman, S. & Bartels, J. Geomagnetism (Oxford University Press, 1962).
Braginsky, S. I. Sov. Phys. JETP 20, 1462–1471 (1965).
Young, R. E. J. Fluid Mech. 63, 695–721 (1974).
Gubbins, D. Geophys. J. R. astr. Soc. 42, 295–305 (1975).
Chandrasekhar, S. Hydrodynamic and Hydromagnetic Stability (Oxford University Press, 1961).
Busse, F. H. Geophys. J. R astr. Soc. 42, 437–460 (1975).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Gubbins, D., Bloxham, J. Morphology of the geomagnetic field and implications for the geodynamo. Nature 325, 509–511 (1987). https://doi.org/10.1038/325509a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/325509a0
This article is cited by
-
Intermittent non-axial dipolar-field dominance of twin Laschamp excursions
Communications Earth & Environment (2022)
-
Recent progress in identification of the geomagnetic signature of 3D outer core flows
Acta Geodaetica et Geophysica (2020)
-
Time evolution of the fluid flow at the top of the core. Geomagnetic jerks
Earth, Planets and Space (2014)
-
A study on variations of non-dipole magnetic field over Chinese mainland during 2000 BC to 1990 AD
Science China Earth Sciences (2014)
-
A sheet-metal geodynamo
Nature (2008)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
