Accession Number : AD0678866

Title :   VARIATIONS IN THE GEOMAGNETIC FIELD AND IN THE RATE OF THE EARTH'S ROTATION,

Corporate Author : RAND CORP SANTA MONICA CALIF

Personal Author(s) : Ball,R. H. ; Kahle,Anne B. ; Vestine,E. H.

Report Date : OCT 1968

Pagination or Media Count : 33

Abstract : Vestine and Kahle, in a previous paper, found a strong correlation between motion of the geomagnetic eccentric dipole and changes in the earth's rotation rate, as inferred from astronomical data. This correlation suggested that the irregular change in length of day was compensated by a change in angular momentum of the outer core which is related to the eccentric dipole motion. New data are used to improve these curves, and the significance of the results is further analyzed. The observed lag in phase between the mantle and magnetically inferred core motion can be explained by diffusion of the magnetic signal through a conducting mantle, which conversely gives an independent estimate of the mantle conductivity. Results of numerical calculations for the phase lag and associated distortions of the apparent eccentric dipole motion are presented. (Author)

Descriptors :   (*EARTH(PLANET), ROTATION), (*GEOMAGNETISM, CORRELATION TECHNIQUES), ASTRONOMY, MAGNETIC MOMENTS, MOMENTUM

Subject Categories : Geomagnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE