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Mathematical representation of the auroral oval
Author(s) -
Holzworth R. H.,
Meng C.I.
Publication year - 1975
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl002i009p00377
Subject(s) - geodesy , earth's magnetic field , interplanetary magnetic field , fourier analysis , physics , quiet , offset (computer science) , geology , geophysics , magnitude (astronomy) , magnetic field , fourier transform , astrophysics , solar wind , astronomy , quantum mechanics , computer science , programming language
A curve fitting procedure for mathematically representing the auroral oval is described. It is shown that the Feldstein ovals and quiet auroral ovals of the night side in DMSP photographs can be approximated by an offset circle, plus a small (≲ 1° magnitude) Fourier component in corrected geomagnetic coordinates. Parameters are introduced, Θ and (θ o , ϕ o ), that indicate the dynamic motion of the auroral oval size and center location, respectively. Using the parameter Θ, an analysis of several DMSP photographs shows a strong correlation between the southward interplanetary magnetic field (−B z ) and the size of the auroral oval.