Analysis of the Parameters of the Upper Atmosphere and Ionosphere Based on Radio Occultation, Ionosonde Measurements, IRI and NeQuick Model Data

In April 2006, a new satellite system FormoSat-3/COSMIC (Taiwan's Formosa Satellite Mission #3 and Constellation Observing System for Meteorology, Ionosphere and Climate) was put into operation. The system consists of 6 low-orbital satellites with an orbital altitude of the order of 800 km. FormoSat-3/COSMIC satellites are capable of receiving radio signals transmitted from GPS navigation system. The Formosat-3/COSMOS radio occultation measurements provide, on average, 1800 electron density profiles of the ionosphere worldwide per day. We present the results of verifying the FormoSat-3/COSMIC radio occultation electron density profiles with the measurements by ionosondes in different regions of the world during 2006-2008. In many cases, the necessary (or missing) information on the ionosphere is derived from global empirical ionospheric models, the IRI (International Reference Ionosphere), and NeQuick. The aim of our work is to compare the data provided by the IRI-2001, IRI-2007 and NeQuick models with the radio occultation electron density profiles from the data of FormoSat-3/COSMIC system. The results of this comparison are valuable for the elaboration and improvement of ionospheric models, as well as for many radiophysical and geophysical applications. The results of comparisons of the IRI-2001, IRI-2007, NeQuick models with the radio occultation profiles for different geomagnetic conditions are reported.