1. Comparisons of in situ ionospheric density using ion velocity meters onboard FORMOSAT-7/COSMIC-2 and ICON missions.
- Author
-
Choi, Jong-Min, Lin, Charles Chien-Hung, Panthalingal Krishanunni, Rajesh, Park, Jaeheung, Kwak, Young-Sil, Chen, Shih-Ping, Lin, Jia-Ting, and Chang, Min-Ti
- Subjects
- *
ION migration & velocity , *LATITUDE , *DENSITY , *GEOMAGNETISM , *ORBITS (Astronomy) , *LONGITUDE , *VELOCITY measurements - Abstract
We report the preliminary inter-satellite comparisons of the in situ ion density measurements by the ion velocity meter (IVM) onboard FORMOSAT-7/COSMIC-2 (F7/C2) and Ionospheric Connection Explorer (ICON) missions, during the solar minimum period of December 2019 to November 2020. The initial comparisons reveal identical diurnal, seasonal, and latitude/longitude variations in the two ion-density measurements, with F7/C2 consistently yielding stronger values than ICON, which could partly result from the difference in their orbit altitudes. The diurnal variation in the equatorial region did not show any effect of pre-reversal enhancement (PRE) during 2019–2020. The daytime plasma distributions show larger ion densities over a narrow latitudinal belt around the geomagnetic equator in all seasons, and the low-latitude densities reveal signatures of hemispherical asymmetry, with larger values occurring in the summer hemisphere. The observations also reveal distinct wavenumber-4 longitudinal modulation, which is most prominent in equinox and becomes less distinguishable during December solstice months. The simultaneous observations from F7/C2 IVM and ICON IVM also provide opportunities to study the spatial configuration and time evolution of ionospheric irregularities in the equatorial and low latitude regions. The F7/C2 and ICON simultaneously observed the equatorial plasma bubbles (EPBs) occurring around Taiwan on 18 October 2020, and the observations are consistent with each other. The EPBs were also observed by an all-sky imager located in Taiwan, comparing the satellite observations. Key points: F7/C2 IVM shows similar patterns of diurnal, seasonal and latitude/longitude variations of ion density to ICON IVM but with stronger magnitudes. Distinct latitudinal and longitudinal variations of plasma distributions along seasons were observed during 2019-2020. Simultaneous observations by the multi-satellite constellation of F7/C2 and ICON and all-sky imager provide opportunity to monitor evolutions of EPBs. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF