Fig. 4From: Statistical analysis of short-wave fadeout for extreme space weather event estimationHistograms of a SWF event number and b occurrence ratio as a function of SWF event duration, and histograms of SWF event number as a function of c LT (= UT + 9 h) and d solar zenith angle for SWF events with the criteria of dfmin ≥ 2.5 MHz (blue lines), dfmin ≥ 3.5 MHz (light blue lines), and blackout (red dashed lines)Back to article page