Research of the MOF Variation at the Mid-latitude Path of Oblique Sounding

The results of oblique sounding (OS) are presented for the 2,770 km-long longitudinal radio path. Estimates have been obtained for the fast and slow fluctuations of the maximal observable frequency (MOF) and for the day-to-day variation of MOF. Special attention has been given to assessing the effectiveness of error reduction of the maximal usable frequency (MUF) on-line forecast which can be reached for the International Reference Ionosphere (IRI) model-based forecast by correcting the model using current VS data at the center of the path.