Modeling the topside ionosphere by means of electron density values as recorded by the Swarm satellites constellation

An empirical method to model the ionospheric topside vertical electron density profile over the European region is proposed. The method is based on electron density values recorded by Langmuir Probes on board Swarm satellites, and on foF2 and hmF2 values provided by IRI UP (International Reference Ionosphere UPdate), which is a method developed to update the IRI (International Reference Ionosphere) model relying on the assimilation of ionospheric data routinely recorded by a network of European ionosonde stations. Topside effective scale heights are calculated by fitting some definite analytical functions (α-Chapman, β-Chapman, Epstein and Exponential) through the values recorded by Swarm and the ones outputted by IRI UP, with the assumption that the effective scale height is constant in the altitude range considered. Calculated effective scale heights are then modeled as a function of the F2-layer peak characteristics, foF2 and hmF2. A statistical comparison with COSMIC/FORMOSAT-3 collected Radio Occultation profiles is carried out to assess the validity of the proposed method, and to investigate which of the considered topside profilers is the best one.