GNSS Atmospheric and Ionospheric Sounding – Methods and Results - Global Navigation Satellite Systems: Signal,Theory and Applications - page 374

0

￿2 0 0

￿4 0 0

0:00 8:00 16:00 24:00 8:00 16:00 24:00

9

6

3

0

0:00 8:00 16:00 24:00 8:00 16:00 24:00

3000

2000

1000

0

0:00 8:00 16:00 24:00 8:00 16:00 24:00

20 Nov. 2003 21 Nov. 2003

Fig. 12. The geomagnetic storm index (Dst) (upper), Kp (middle) and AE indices (bottom) on
20-21 November 2003

As the F2-layer peak electron density (NmF2) and its height (hmF2) are main parameters of
the ionospheric electron density profile Ne (h), the behaviour of the ionospheric F2-layer to
the storm was investigated over South Korea in terms of the NmF2 and hmF2. Here the
peak density (NmF2) and its corresponding height (hmF2) are obtained from the ground-
based GPS observations using the MART reconstructed tomography technique. The
monthly median value of GPS reconstructed electron density profiles during the quiet days
is regarded as the reference and the deviation of ionospheric NmF2 and hmF2 can reflect the
ionospheric behaviors during the geomagnetic storm. It has shown that the GPS-derived
NmF2 has a disturbance at 9:00 UT and then increases from 10:00 UT until 19:00 UT. The
corresponding hmF2 also suddenly rises from 8:00 UT when the storm just started, and
reaches the maximum height at about 16:00 UT with a maximum Kp value of 9, and then
gradually descends until 21:00 UT (Fig.13), which are also supported by anther independent
ionosonde measurement at Anyang station.