Open AccessThe Conductivity of Spherically Symmetric Layered Earth Models determined by Sq and longer Period Magnetic Variations *
Author(s) -
Jady R. J.
Publication year - 1974
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1974.tb03647.x
Subject(s) - conductivity , harmonics , earth (classical element) , variation (astronomy) , spherical harmonics , shell (structure) , inverse , electromagnetic induction , computational physics , physics , surface conductivity , geophysics , mathematical analysis , geometry , materials science , mathematics , quantum mechanics , composite material , voltage , astrophysics , mathematical physics , electromagnetic coil
Summary An approach to the inverse problem of electromagnetic induction in spherically symmetric layered Earth models is described. In the first case single periodic variations alone are considered and it is assumed that the conductivity is uniform in a single thick shell which surrounds a perfectly conducting sphere. The conductivity and thickness of the shell are determined for each variation separately by using the observed value of the ratio of internal to external parts of the magnetic potential at the surface of the Earth. Results have been obtained by using a variational technique, for Sq variations, the 27‐day variation and its harmonics, and the annual variation. In the second case several variations are used simultaneously to obtain a multilayered model. Finally the method is used to give an estimate of the maximum screening effect of the oceans.