Table 2 The signal characteristic and D-region parameters for four nighttime NPM signal anomaly events
No. of events | Date (dd/mm/yy) | Time (hh:mm UT) | ΔAmplitude (dB) | Δϕ (deg) | ΔH′ (km) | Δβ (km−1) |
|---|---|---|---|---|---|---|
1 | 13/12/20 | 13:09 | − 10.664 | + 97 | − 18.0 | − 0.070 |
2 | 14/12/20 | 13:25 | − 14.297 | + 148 | − 19.2 | − 0.050 |
3 | 16/12/20 | 10:47 | − 11.831 | + 137 | − 17.7 | − 0.008 |
4 | 17/12/20 | 11:07 | − 7.710 | + 100 | − 13.2 | − 0.011 |