Fig. (4) Diurnal variations of global geomagnetic indices, ionospheric characteristics and vTEC for 7 (05:00-24:00 UT), 8 and 9 (00:00-05:00 UT) September 2017. (a) kp. (b) Dst. (c) NmF2 and (d) h’F/F2 at La Serena (LS, 29°52'S; 71°15’W) and Tucumán (TU, 26°50’; 65°14’W). (e) NmF2 and (f) h’F/F2 and hmF2 at Jicamarca (JI, 11°57’S; 78°52’W). (g) vTEC at LS and TU. Open circles, black filled circles and a black line are for LS; black filled circles are for those values scaled as “doubtful” according to international accepted rules [34]. Green lines are for TU. Black and magenta dots are for JI. Red lines are for smoothed median values plus interquartile range and blue lines are for the median minus interquartile range for 17 quiet days. The horizontal grey bars show spread-F intervals.