Comparisons of in situ ionospheric density using ion velocity meters onboard FORMOSAT-7/COSMIC-2 and ICON missions

Abstract We report the preliminary inter-satellite comparisons of in situ ion density measurements by velocity meter (IVM) onboard FORMOSAT-7/COSMIC-2 (F7/C2) and Ionospheric Connection Explorer (ICON) missions, during solar minimum period December 2019 to November 2020. The initial reveal identical diurnal, seasonal, latitude/longitude variations two ion-density measurements, with F7/C2 consistently yielding stronger values than ICON, which could partly result from difference their orbit altitudes. diurnal variation equatorial region did not show any effect pre-reversal enhancement (PRE) 2019–2020. daytime plasma distributions larger densities over a narrow latitudinal belt around geomagnetic equator all seasons, low-latitude signatures hemispherical asymmetry, occurring summer hemisphere. observations also distinct wavenumber-4 longitudinal modulation, is most prominent equinox becomes less distinguishable solstice months. simultaneous IVM ICON provide opportunities study spatial configuration time evolution ionospheric irregularities low latitude regions. simultaneously observed bubbles (EPBs) Taiwan on 18 October 2020, are consistent each other. EPBs were an all-sky imager located Taiwan, comparing satellite observations. Graphical