Positive and negative GPS‐TEC ionospheric storm effects during the extreme space weather event of March 2015 over the Brazilian sector

TLDR

The study employed a network of 102 GPS‑TEC stations, including two latitudinal chains spanning equatorial to low latitudes in the east and west Brazilian sectors, to investigate ionospheric response and equatorial ionization anomaly behavior during the March 2015 extreme space‑weather event. During the March 2015 storm, vertical total electron content was severely disturbed, exhibiting a three‑peak wavelike oscillation that narrowed from 0°S–30°S to 13°S–25°S during the main phase, followed by a strong low‑latitude negative VTEC phase in recovery that suppressed the equatorial ionization anomaly.

Abstract

Abstract We studied the response of the ionosphere ( F region) in the Brazilian sector during extreme space weather event of 17 March 2015 using a large network of 102 GPS‐ total electron content (TEC) stations. It is observed that the vertical total electron content (VTEC) was severely disturbed during the storm main and recovery phases. A wavelike oscillation with three peaks was observed in the TEC diurnal variation from equator to low latitudes during the storm main phase on 17–18 March 2015. The latitudinal extent of the wavelike oscillation peaks decreased from the beginning of the main phase toward the recovery phase. The first peak extended from beyond 0°S to 30°S, the second occurred from 6°S to 25°S, whereas the third diurnal peaks was confined from 13°S to 25°S. In addition, a strong negative phase in VTEC variations was observed during the recovery phase on 18–19 March 2015. This ionospheric negative phase was stronger at low latitudes than in the equatorial region. Also, two latitudinal chains of GPS‐TEC stations from equatorial region to low latitudes in the east and west Brazilian sectors are used to investigate the storm time behavior of the equatorial ionization anomaly (EIA) in the east and west Brazilian sectors. We observed an anomalous behavior in EIA caused by the wavelike oscillations during the storm main phase on 17 March, and suppression of the EIA, resulting from the negative phase in VTEC, in the storm recovery phase.