Open AccessThe source of the longitudinal asymmetry in the ionospheric tidal structure
Author(s) -
Kil H.,
Kwak Y.S.,
Oh S.J.,
Talaat E. R.,
Paxton L. J.,
Zhang Y.
Publication year - 2011
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011ja016781
Subject(s) - crest , longitude , solstice , ionosphere , geology , asymmetry , superposition principle , physics , geodesy , latitude , atmospheric sciences , geophysics , optics , quantum mechanics
We examine the source of the longitudinal asymmetry in the ionospheric tidal structure by using the measurements of the plasma density and vertical plasma drift by the first Republic of China satellite. The consistent feature in plasma density and vertical plasma drift in all months is the development of the wave crests near 0°–10°E and 90°–100°E longitude. The appearance of the global wave‐4 or wave‐3 structure is determined by the morphology between 150°E and 300°E longitude. Two crests are pronounced in July–September, and only one crest appears during the December solstice in that longitude region. The crests of the wave‐4 structure between 150°E and 300°E longitude are much weaker than the crests near the longitudes of 0° and 90°E during July–September. The wave‐3 structure is pronounced in all months. The phase difference between the wave‐3 and wave‐4 structures is small near the longitudes of 0° and 90°E, and thus the superposition of the wave‐3 structure amplifies the wave‐4 crest intensity in those regions. The phase difference is large between 150°E and 300°E longitude, and thus the destructive superposition of the wave‐3 component weakens the wave‐4 crest in that region. The wave‐3 and wave‐4 structures are the permanent ionospheric features, and the significant portion of the longitudinal asymmetry is explained by the phase difference of the two structures.