Fig. 1

The figure shows three panels with the variation of the D_st index on the top, the variation of the f_bE_s (green line) and f_tE_s (brown line) at São Luís in the middle panel, and the variation of the X-ray solar radiation intensity measured in the range 1.0–8.0 Å (blue line) from December 12 to 18, 2006 (bottom panel).