Variations of TEC over Iberian Peninsula in 2015: effects of geomagnetic storms, solar flares, and solar eclipse

The total ionospheric content (TEC) over the midlatitudinal area of Iberian Peninsula was studied using data from two locations on the west and east coasts of the peninsula. The data are obtained both by the GNSS receivers and an ionosonde. The principal component analysis applied to the TEC data allowed us to extract two main modes.

The variations of these modes as well as the original TEC data were studied in relation to geomagnetic disturbances observed in March, June, October, and December of 2015. Seven of eight analyzed geomagnetic events were associated with positive-negative ionospheric storms (seen both in TEC daily cycle amplitude and in Mode 1).

Four out of eight analyzed geomagnetic events were associated with variations of Mode 2 that can be described as the appearance of the second daily peak on the 1^st day of the storm and a deep in TEC variations on the 2^nd day.

Besides, we analyzed the effects of solar flares and overall variations of the solar UV and XR fluxes on the TEC variations during those months. Since a partial solar eclipse was observed in March 2015, the TEC variations during this event were also studied. Only the amplitude of the daily TEC cycle (Mode 1) was found to respond to these types of events.