We report on a new method to calibrate the FORMOSAT-7/COSMIC-2 (F7/C2) ion velocity meter (IVM) in-situ ion density data using the Tri GNSS (Global Navigation Satellite System) Radio-occultation System (TGRS) differential total electron content (TEC) data. This calibration is made using collocated measurements from the IVM and TGRS instruments on the same satellite. We found that the IVM ion density is about 8-15% lower than the TGRS derived density at the insertion orbit (~ 710 km) and 5% higher at the mission operation orbit (~ 540 km). Using a linear correction specific to orbit altitude and satellite, an adjustment is implemented for the IVM density data. These corrections remove the offsets between the IVM and TGRS density measurements. We believe the corrected densities eliminate any inter-spacecraft discrepancy in the IVM density data, making it suitable for use in multi-satellite scientific investigations of longitudinal and local time variations and space weather operational applications.

Simultaneous measurements of F-region neutral winds near 250 km and topside interhemispheric plasma flow near 600 km, made by the ICON satellite, allow the connection between these parameters to be observationally established for the first time. The largest variations in the topside plasma flows are seen as a function of season and are shown to depend on trans-equatorial neutral winds below the F peak in a manner that is essentially the same during the daytime and the nighttime for the solar minimum conditions that prevail in 2020. This finding is consistent with established principles of a servo model of the ionosphere for which both production and loss rates in the topside are specified by the O/N2 ratio at the F-peak height. The intermediate relationships, describing how the neutral wind influences the F-peak height and how the O+ plasma pressure gradient across the equator influences the interhemispheric plasma flow are also investigated and found to be consistent with expectations.