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Rates of change of the earth's magnetic field measured by recent analysesTypical rates of change of the earth's magnetic field are presented as a function of the earth's spherical harmonics. Harmonics up to the eight degree are analyzed. With the increase in the degree of the harmonics an increase in the relative rate of change can be observed. For higher degrees, the rate of change can be predicted. This enables a differentiation between harmonics originating in the core and harmonics caused by crustal magnetization. The westward drift of the magnetic field depends on the longitudinal gradient of the field. In order to determine the longitudinal motions, harmonics up to degree 20 can be utilized. The average rate of secular acceleration increases with the degree of harmonics from 0.001 deg/sq yr for a dipole term to an average of 0.05 deg/sq yr for degree eight harmonics.
Document ID
19910029943
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Harrison, C. G. A.
(Miami Univ. FL, United States)
Huang, Qilin
(Miami, University FL, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1990
Publication Information
Publication: Journal of Geomagnetism and Geoelectricity
Volume: 42
Issue: 8, 19
ISSN: 0022-1392
Subject Category
Geophysics
Accession Number
91A14566
Distribution Limits
Public
Copyright
Other

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