Sporadic E S Layers at High Latitudes During a Magnetic Storm of March 17, 2015 According to the Vertical and Oblique Ionospheric Sounding Data

We consider the behavior of the parameters of the ionospheric E (s) layers according to the vertical sounding at the Sodankyla observatory and oblique sounding at the Lovozero (Murmansk region)-Gor'kovskaya station (Leningrad region) path during a superstorm of March 17, 2015. Temporal and spatial behavior of these parameters is compared. It was found that the storm significantly distorted the normal course of variations of the sporadic E (s) layer characteristics. Specific behavior of the layers during a storm at points separated by about 300 km was detected. With the help of ray tracing calculations using the IRI model, oblique sounding ionograms were constructed for the radio path analyzed. Primary attention is given to the maximum usable frequency of the F (2) layer-MUF-F (2). Additionally, for the disturbed conditions where there is only a high-power E (s) layer on the experimental ionograms, the values of MUF-E (s) and the ratio K =MUF-E (s)/f (o) E (s) for various cutoff frequencies f (o) E (s) of the E (s) layer and its altitudes are calculated within the framework of the well-known approximations. Calculations for the case of weak disturbance and semitransparent E (s) layers are carried out with the IRI model adapted to the current diagnostics parameters. It was found that the calculated and experimental values of MUF-F (2) are close to each other or coincide, while this cannot be said about MUF-E (s). The calculated and experimental values of MUF-E (s) can be matched in the model of mirror reflection from a flat layer for intense layers and the model of the E layer for thick E (s) layers of low intensity.