Comparison between RO and Digisonde bottomside electron density over Cyprus

The objective of this study is to perform a comparison between bottomside electron density measurements from the Global Navigation Satellite System (GNSS) radio occultation (RO) FORMOSAT3/COSMIC (F3/C) constellation mission along with collocated (in space and time) electron density values from bottomside electron density profile (EDP) measurements based on manually scaled ionograms from the Cyprus Digisonde. This comparison demonstrates that there is a systematic overestimation of F3/C Ne electron density (as compared to Digisonde) in the bottomside and that the relative difference between F3/C and Cyprus Digisonde electron density increases with decreasing altitude (below the Flayer peak).