Premium
Longitudinal Structure of the Midlatitude Ionosphere Using COSMIC Electron Density Profiles
Author(s) -
Li Qiaoling,
Liu Libo,
Balan N.,
Huang He,
Zhang Ruilong,
Chen Yiding,
Le Huijun
Publication year - 2018
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2017ja024927
Subject(s) - middle latitudes , ionosphere , solstice , longitude , geology , atmospheric sciences , southern hemisphere , magnetic declination , northern hemisphere , declination , latitude , solar wind , climatology , physics , geodesy , geophysics , earth's magnetic field , astrophysics , plasma , magnetic field , quantum mechanics
Longitudinal variations of electron density ( Ne ) near zero magnetic declination lines at midlatitude ionosphere have been disclosed earlier in some longitude regions. However, its global picture remains unclear. In this study, Ne at midlatitudes (40–50° magnetic latitude) within 170‐ to 550‐km altitudes obtained from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites for low solar activity (2006–2011) are used to investigate the local time, seasonal, altitudinal, and hemispheric variations of Δ Ne (difference between Ne and its zonal mean). Results indicate (1) Δ Ne showing different patterns below 180 km and above 220 km and (2) an eastward phase shift of Δ Ne above 220 km. The Δ Ne above 220 km shows wave‐1 longitudinal structure during forenoon in northern winter, which differs from the wave‐2 longitudinal structure in other seasons. The Δ Ne below 180 km presents solstice asymmetries and wave‐1 longitudinal structures. (3) On average, Δ Ne above 220 km is stronger in North American sector (30–150°W) by 32% compared to Europe‐Asian sector (30–150°E), and it is also stronger in Southern Hemisphere by 35% than in Northern Hemisphere. The wave‐1 longitudinal structure below 180 km is due to the latitudinal difference of solar zenith angle in magnetic coordinates. The Δ Ne above 220 km has high consistency with that of Δ h m F 2 (peak height) indicating significant effects of neutral wind dynamics. Results of the empirical model Horizontal Wind Model 14 further disclose that the vertical drifts due to zonal wind (via magnetic declination) and meridional wind (via its zonal difference) are responsible for the longitudinal structures in Δ Ne above 220 km.