“…Negative CG flashes typically outnumber positive ones by 10 to 1; however, the vast majority of documented sprites were observed during ground observations and found by a margin of at least 1,000 to 1 to be triggered by positive CG lightning (Williams et al, 2007). So far, only 22 sprites have been linked to negative ground flashes unambiguously (Barrington-Leigh & Inan, 1999;Boggs et al, 2016;Lang et al, 2013;Li et al, 2012;Liu et al, 2016;Lu et al, 2012;Lu et al, 2016;Lyons, 2011;Taylor et al, 2008). This sprite polarity paradox was further deepened by reports that exceptional, strong negative CG flashes generally failed to produce sprites (Williams, 2001;Williams et al, 2007).…”