Lightning Superbolts Detected By Satellites
The Vela satellites carry optical sensors for the detection of terrestrial nuclear explosions. Four Vela satellites keep the entire earth under constant surveillance. In addition to nuclear explosions, these satellites register many intense lightning flashes. Some of the flashes are over 100 times more brilliant than average. Only about five of these "superbolts" occur for every 10 million flashes registered.
Superbolt flashes have relatively long durations (about one thousandth of a second) and do not appear to be confined to the upper levels of the clouds. A large fraction of the superbolts are recorded over Japan and the northeast Pacific during intense winter storms. Ground observations during these storms reveal occasional very powerful discharges of long duration from positively charged regions near the cloud tops to the ground. In contrast, typical lightning arises from negatively charged regions of clouds.
(Turman, B.N.; "Detection of Lightning Superbolts," Journal of Geophysical Research, 82:2566, 1977.)
Reference. Many of lightning's anomalies are described in Chapter GLL in our Catalog: Lightning, Auroras. For ordering information, visit: here.