Planetary Scale Flow in the Earth's Core and Geodetic Observations

  1. D. E. Smylie and
  2. Raymond Hide
  1. J. B. Merriam

Published Online: 29 MAR 2013

DOI: 10.1029/GM046p0073

Structure and Dynamics of Earth's Deep Interior

Structure and Dynamics of Earth's Deep Interior

How to Cite

Merriam, J. B. (1988) Planetary Scale Flow in the Earth's Core and Geodetic Observations, in Structure and Dynamics of Earth's Deep Interior (eds D. E. Smylie and R. Hide), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM046p0073

Author Information

  1. University of Saskatchewan, Saskatoon, Saskatchewan S7N-0W0

Publication History

  1. Published Online: 29 MAR 2013
  2. Published Print: 1 JAN 1988

ISBN Information

Print ISBN: 9780875904504

Online ISBN: 9781118666562

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Keywords:

  • Earth—Core—Congresses;
  • Geodynamics—Congresses

Summary

The westward drift of the geomagnetic field implies fluid velocities in the outer core of 4×10−4 m s −1. The pressure associated with this flow is small (about 104 Pa) but it is shown that this is sufficient to produce observable deformations of the mantle. Changes in J 2, polar motion, and the length-of-day, are all measured with sufficient accuracy that these data could contain a component due to pressure anomalies, of this magnitude, at the core-mantle boundary. Relations between pressure at the core-mantle boundary and geodetic quantities such as J 2, polar motion, and the length-of-day are derived and the unexplained residual in each is used to set an upper limit on the decade-scale pressure fluctuations at the core-mantle boundary. The polar motion observations supply the most severe upper bound (< 2×103 Pa) but satellite observations of J 2 could soon prove to be more useful. It is evident that not more than 10% of the decade changes in the length-of-day can be due to pressure core-mantle coupling.