Comparisons of IRI TEC predictions with GPS and digisonde measurements at Ebro

Vertical TEC measurements obtained with GPS satellite signals (GPSTEC) and total electron content derived from ionograms (ITEC) are compared with the latest version of the International Reference Ionosphere, IRI-2000 (IRITEC). Digisonde data from the Ebro station (40.8°N, 0.5°E) recorded during two years of high solar activity 2000 (Rz12 = 117) and 2001 (Rz12 = 111) are used in the study. The results obtained with the three techniques are similar, and as expected, the GPS TEC values are greater than those obtained with the digisonde measurements. The IRI predictions generally overestimate the ITEC values. The diurnal and seasonal variations of the plasmaspheric electron content are also analyzed.