Comparison between IRI-2001 predictions and observed measurements of hmF2 over three high latitude stations during different solar activity periods

The monthly median values of the height of peak electron density of the F2-layer (hmF2) derived from ionosonde measurements at three high latitude stations, namely Narssarssuaq (NAR) (61.2 °N, 314.6 °E), Sondrestrom (SON) (67°N, 309.1°E) and College (COL) (69.9°N, 212.2°E) were analyzed and compared with the International Reference Ionosphere (IRI-2001) model, using Comité Consultatif International des Radio communications) (CCIR and Union Radio-Scientifique Internationale (URSI) options. The analysis covers hmF2 values for March Equinox (February, March, April), June Solstice (May, June, July), September Equinox (August, September, October), and December Solstice (November, December, January), during periods of high (2000–2001), medium (2004–2005) and low (2007–2008) solar activity. Generally, the IRI-2001 prediction follow fairly well the diurnal and seasonal variation patterns of the observed values of hmF2 at all the stations. However, IRI-2001 overestimates and underestimates hmF2 at different times of the day for all solar activity periods and in all the seasons considered. The percentage deviation never exceeded 20%, except during DEC SOLS at COL and SON and during MARCH EQUI at SON during low solar activity period. For all solar activity periods considered, both the URSI and CCIR options of the IRI-2001 model give hmF2 values close to the ones measured, but the URSI option performed better than the CCIR option.