Comparison of the main ionospheric characteristics measured by the digisonde at Irkutsk in 2003 with IRI 2001 model data

Diurnal and seasonal variations of F2 layer characteristics over Irkutsk during the decrease in solar activity in 2003–2006: Observations and IRI-2001 model predictions

“…Currently (Bilitza, 2001), IRI has two options for the thickness parameter BO: (1) a set of values based on the data from a few representative ionosonde stations, and (2) a formula for the half-density height, developed by Gulyaeva (1987), based on mid-latitude ionosonde data; half-density is defined as the height for which Ne(z) = NmF2/2. For the Irkutsk station, Oinats et al (2005Oinats et al ( , 2006 found systematic differences between the predicted and observed foF2 diurnal behavior for the summer months of 2003 and 2004. The main feature is the observational absence of the predicted morning foF2 peak, and a significant underestimation by the IRI model of the observed diurnal range.…”

Influence of the 27-day solar flux variations on the ionosphere parameters measured at Irkutsk in 2003–2005

“…The regular character of the observations enables us to investigate the character of ionosphere parameter variations and to study the influence of geomagnetic disturbances and solar activity on the ionosphere. The analysis of the day-to-day foF2 variations obtained at Irkutsk showed a good correlation between the observed daily mean critical frequencies and daily F10.7 index values for winter months (Oinats et al, 2006). This fact has motivated us to research the influence of the 27-day solar flux variations on the ionosphere parameters.…”

“…Since 2003 the regular ionospheric observations have been performed at Irkutsk (52.3N, 104.3E) with the modern DPS-4 ionosonde (Reinisch et al, 1997). The regular character of the observations enables us to investigate the character of ionosphere parameter variations and to study the influence of geomagnetic disturbances and solar activity on the ionosphere.…”

Testing of the international reference ionosphere model using the data of dual-frequency satellite altimeters “Topex”/“Poseidon” and “Jason-1”

“…As a rule, the reference model is tested with the use of isolated data, including measurements of the maximum height and critical frequency of the F 2 layer at separate points for the vertical and oblique sounding [10,11], electron number density profiles obtained on the basis of the incoherent scattering method [12], measurements of the total electron content on the basis of data from a separate GPS receiving station [13], etc. Calculations of the total electron content with the use of IRI compared with the results of GPS radio tomography are presented in [14,15].…”