Fig. 3: Examples of lightning sferics.
From: Whistler echo trains triggered by energetic winter lightning
a Waveform of the lightning sferics radiated by a positive CG occurring on 01:31:12.886259UT at 10.3951°E and 44.0589°N. b Waveform belonging to the lightning sferics radiated by a negative CG detected on 05:07:36. 565981 UT at 14.6317°E and 43.8039°N. c Waveform of the lightning sferics emitted by a negative CG occurring on 05:18:35. 068414 UT at 19.9121°E and 32.6886 °N. d Waveform of the lightning sferics radiated by a positive CG occurring on 06:42:03. 548862UT at 8.7698°E and 63.7329°N. The N-S component of the magnetic field is shown by the black line and the W-E component is plotted by coloured lines (Northern thunderstorm – blue, Central Mediterranean – green, and Eastern and African Mediterranean – orange). The N-S component is inverted in all panels to prevent the overlapping of curves. Grey dashed horizontal lines indicate the saturation level of the receiver. The ground waves, sky waves, preliminary breakdown pulse trains and tweek oscillations are identified in individual panels. Source data are provided as a Source Data File.
