Analysis of the ionosphere/plasmasphere electron content variability during strong geomagnetic storm

• The PEC variations during strong geomagnetic storms were studied.
• The combination of ISR and GPS TEC measurements were used for PEC estimation.
• The GPS TEC was strongly contributed by the PEC under certain conditions.
• The PEC to GPS TEC contribution during strong negative storm can reach up to 90%.
• Results can be explained by effects of electric fields, winds and movement plasma.

The ionosphere/plasmasphere electron content (PEC) variations during strong geomagnetic storms in November 2004 were estimated by combining of mid-latitude Kharkov incoherent scatter radar observations and GPS TEC data derived from global TEC maps. The comparison between two independent measurements was performed by analysis of the height-temporal distribution for specific location corresponding to the mid-latitudes of Europe. The percentage contribution of PEC to GPS TEC indicated the clear dependence from the time with maximal values (more than 70%) during night-time. During day-time the lesser values (30–45%) were observed for quiet geomagnetic conditions and rather high values of the PEC contribution to GPS TEC (up to 90%) were observed during strong negative storm. These changes can be explained by the competing effects of electric fields and winds, which tend to raise the layer to the region with lower loss rate and movement of the ionospheric plasma to the plasmasphere.