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High‐latitude ionospheric conductivity variability in three dimensions
Author(s) -
McGranaghan Ryan,
Knipp Delores J.,
Matsuo Tomoko
Publication year - 2016
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 - 10.1002/2016gl070253
Subject(s) - ionosphere , geophysics , earth's magnetic field , atmospheric sciences , polar , magnetosphere , physics , solar wind , geology , magnetic field , astronomy , quantum mechanics
We perform the first ever global‐scale, altitude‐dependent analysis of polar ionospheric conductivity variability using spectrally resolved in situ satellite particle measurements. With an empirical orthogonal function analysis we identify three primary modes of three‐dimensional variability related to ionospheric footprints of the quiet and disturbed geospace environment: (1) perturbation of the quasi‐permanent auroral oval, (2) differing projections of electron precipitation during southward and northward interplanetary magnetic field, and (3) a likely imprint of variation in Alfvénic Poynting flux deposition. Together, these modes account for >50% of the total conductivity variability throughout the E region ionosphere. Our results show that height‐integrated conductance and height‐dependent conductivities are distinctly different, underscoring the importance of studying the ionosphere in three dimensions. We provide the framework for future three‐dimensional global analysis of ionosphere‐magnetosphere coupling.