(Upper row of plots) Comparison between the observed (dashed line) and model (solid line) rVTEC at the geographic point (20° N, 130° W) for the geomagnetic storm in November 2004 (left plot and December 2005 (right plot); (bottom row of plots) Comparison between the measured Kp-index (tick solid line with dots) and modified Kp_Ts – (dashed line) and Kp_Tl – (solid line) indices for November 2004 (left plot) and December 2005 (right plot) (Andonov et al. 2011).