Calculations of the ionization drift velocity by the Titheridge method,based on the data obtained at the Irkutsk Digisonde

The applicability of the method proposed by Titheridge 1995] to the estimations of the ionization vertical drift velocity V is studied. The values of the F2-layer maximum height, h _m F2, obtained from the measurements using the DPS-4 digital ionosonde at Irkutsk (Institute of Solar-Terrestrial Physics) in 2003–2006, are the initial data. The neutral gas parameters were calculated from the Hedin, 1987] thermospheric model. The obtained calculations of the vertical ionization drift velocity are estimated by comparing with the Hedin et al., 1991] empirical model. In some cases, good agreement with this model has been obtained. However, such agreement is registered not always, and the cause of such discrepancies is still unclear. The diurnal variations in the vertical ionization drift velocity in different seasons are also discussed.