Open AccessDerivation of A Geomagnetic Model to N = 63
Author(s) -
Cain Joseph C.,
Wang Zhigang,
Kluth Christopher,
Schmitz Dave Ray
Publication year - 1989
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1989.tb00513.x
Subject(s) - earth's magnetic field , longitude , geophysics , geodesy , least squares function approximation , ionosphere , mathematics , latitude , data set , interval (graph theory) , mathematical analysis , geology , magnetic field , physics , statistics , combinatorics , quantum mechanics , estimator
Summary A high degree model of the geomagnetic field is derived using an integral technique to extend coefficients beyond the limits allowable with least squares approaches. A previously derived model to n = 29 was first updated with new secular change data for the interval 1979 September‐1980 June combined with the previously obtained analysis set of Magsat vector data. Residuals of a new selection of observed vector Magsat data were then analysed by solving for ionospheric‐magnetospheric variations and removing their effect. the reduced B r , components were then averaged over approximately 3°× 3° blocks of latitude and longitude, and coefficients derived using the Neumann method. These coefficients, when combined with those from the least squares solution, were seen to show significantly greater detail in the structure of the geomagnetic field which appeared to be realistic to n = 50.