Study on the applicability of the international ionospheric model IRI 79 for obtaining electron density profiles

The International Reference Ionosphere model, IRI 79, was implemented for the B6800 computer of INPE, allowing to obtain average profiles of the ionospheric electron density. In order to verify the validity of the utilizationn of the IRI 79 model in the Brazilian region, a comparison was made between IRI 79 profiles and profiles from ionograms obtained in Cachoeira Paulista (23 S, 45 W). Very good agreement was observed between profiles predicted (IRI 79) and observed for all the analyzed months and hours, except in small height intervals and in the lower parts of the Cachoeira Paulista profiles, where disagreement was observed. The implications of the use of the IRI model in propagation studies is briefly analyzed.