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Modeling the daytime, equatorial ionospheric ion densities associated with the observed, four‐cell longitude patterns in E × B drift velocities
Author(s) -
AraujoPradere Eduardo A.,
Fang TzuWei,
Anderson David N.,
Fedrizzi Mariangel,
Stoneback Russell
Publication year - 2012
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/2011rs004930
Subject(s) - longitude , equator , daytime , ionosphere , latitude , plasmasphere , geodesy , geology , local time , geophysics , magnetic dip , anomaly (physics) , crest , atmospheric sciences , physics , magnetosphere , plasma , quantum mechanics , statistics , mathematics , condensed matter physics
Previous studies have quantified the longitude gradients in E × B drift associated with the four‐cell tidal structures and have confirmed that these sharp gradients exist on a day‐to‐day basis. For this paper, we incorporate the Ion Velocity Meter (IVM) sensor on the Communications/Navigation Outage Forecasting System satellite to obtain the daytime, vertical E × B drift velocities at the magnetic equator as a function of longitude, local time, and season and to theoretically calculate the F region ion densities as a function of altitude, latitude, longitude, and local time using the Global Ionosphere Plasmasphere model. We compare calculated ion densities assuming no longitude gradients in E × B drift velocities with calculated ion densities incorporating the IVM‐observed E × B drift at the boundaries of the four‐cell tidal structures in the Peruvian and the Atlantic longitude sectors. Incorporating the IVM‐observed E × B drift velocities, the ion density crests rapidly converge to the magnetic equator between 285 and 300°E geographic longitude, are absent between 300° and 305°, and move away from the magnetic equator between 305° and 340°. In essence, the steeper the longitude gradient in E × B drifts, the steeper the longitude gradient in the equatorial anomaly crest location.