Comparisons of low latitude F region peak densities, heights and equatorial ExB drift from IRI with observational data and the Sheffield University Plasmasphere Ionosphere Model

Observed values of the critical frequency and real height of the ionospheric F-region peak (foF2 and hmF2, respectively) over Fortaleza (4degrees S, 38degrees W) and Cachoeira Paulista (22.5degrees S, 45degrees W) near solar minimum are compared with their values calculated by the International Reference Ionospheric Model (IRI). A comparison between the equatorial ExB drift velocities represented by IRI and those obtained by a method that uses the Sheffield University Plasmasphere Ionosphere Model (SUPIM) has also been carried out. In general, the values of foF2 and hmF2 calculated by IRI using the International Radio Consultive Committee (CCIR) maps show better agreement with the observed values than do those obtained using the International Union of Radio Science (URSI) maps for both stations, Fortaleza and Cachoeira Paulista. Equatorial ExB drift velocities calculated by IRI/Scherliess and Fejer (1999) have presented values different from those calculated by SUPIM mainly during evening and nighttime for December solstice and equinox conditions. (C) 2003 COSPAR. Published by Elsevier Science Ltd. All rights reserved.