[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-P12] The lunar phase effects on the equatorial ionization anomaly crest and ionospheric electron density structure

*Tsung-Yu Wu¹、Jann-Yenq LIU^1,2,3、CHIYEN LIN^1,2、Loren Chang^1,2 (1.Center for Astronautical Physics and Engineering, National Central University, Taoyuan, Taiwan、2.Department of Space Science and Engineering, National Central University, Taoyuan, Taiwan、3.Center for Space and Remote Sensing Research, National Central University, Taoyuan, Taiwan)

The total electron content (TEC) of global ionosphere maps, and the electron density profiles observed by global navigation satellite system (GNSS) radio occultation (RO) measurements from the FORMOSAT-3/COSMIC (F3/C) and FORMOSAT-7/COSMIC-2 (F7/C2) are utilized to find the ionosphere response to lunar gravitational force. The results show that the appearance time and latitudinal location of the equatorial ionization anomaly (EIA) crest yield prominent lunar phase signature with 14.76-day period. The EIA crests on the new moon or full moon lead those of the overall average by about 20–40 minutes. By contrast, the EIA crests on the first quarter or third quarter lag those of the overall average by about 20–40 minutes. Meanwhile, EIA crests move the furthest poleward and equatorward with 1° latitude 2–5 days after the new moon or full moon and the first quarter or third quarter, respectively. The electron density further depicts global three-dimensional plasma flows in the ionosphere due to the lunar gravitational force.