It is well known that as long as variations in the ionosphere follow regular patterns, the latest version of the International Reference
Ionosphere IRI-2001 model estimates sufficiently accurate NmF2 and other parameters relevant for the ionospheric effects on radio wave
propagation. During geomagnetic storms, it is desirable that for the IRI-2001 model to be tested against available observations. This
paper presents the comparison of the IRI-2001-generated electron density (N(h)) profiles with those updated using measured values over
European area during October and November 2003 geomagnetic super storms. Ionospheric stations involved in this study are Athens,
Chilton, Rome, Juliusruh and Tromso. These stations provide real-time ionospheric characteristics and N(h) profiles regularly within the
framework of the EU COST271 Action on ‘‘Effects of the upper atmosphere on terrestrial and earth-space communications’’. Comparative
analysis shows that significant discrepancies do exist predominantly during the storm main phase. The model not always estimates
correctly the phase and the magnitude of intense geomagnetic storm effects on the daytime F2 layer peak electron density at different
European latitudes. Results are discussed in the context of real-time N(h) profile updating capabilities and effectiveness.
2006 COSPAR. Published by Elsevier Ltd. All rights reserved