Extreme Low-Latitude Total Electron Content Enhancement and Global Positioning System Scintillation at Dawn

We report on an extreme ionospheric plasma density enhancement and Global Positioning System (GPS) scintillation at dawn, observed within the expanding equatorial ionization anomaly (EIA). The total electron content (TEC) in central America reached 50 TECu at sunrise, the value almost twice as high as the normal afternoon peak. The enhanced EIA expanded poleward and westward from just below 20 degrees magnetic latitude (MLAT) to beyond 30 degrees MLAT at sunrise. The chief ramification of the enhanced EIA was strong GPS scintillation which was observed poleward of 30 degrees northern MLAT and lasted until 8:00 local time. In total, the amplitude scintillation and phase fluctuations lasted for similar to 5 h at latitudes north of 20 degrees MLAT in central America.