On the Series of +CG Lightning Strokes in Dancing Sprite Events

Abstract

In dancing sprite events, sprite entities and groups appear in rapid succession together with a corresponding series of parent lightning strokes. Dancing sprite events, including a case with possible sprite rebrightening, were recorded on video simultaneously from two observation sites above a mesoscale convective system in Central Europe on the night of 6 August 2013. Joint analysis of triangulated locations of sprite elements, position, type, and peak current of lightning strokes from the LINET lightning detection network database and current moment waveforms deduced at the Hylaty station, Poland, showed that subsequent sprite-parent lightning strokes occurred no further than 21 km from the closest preceding sprite entity in the cases analyzed in this study. Additionally, it was found that longer sprite delay times tend to correspond to larger sprite location offsets from the parent +CG stroke. These observations, the occurrence of +CG lightning stroke and sprite sequences, as well as sprite-sprite delay times and displacements can be explained if +CG strokes are part of one extended lightning flash. A corresponding production mechanism based on previous findings on the formation of sprite-producing and general +CG lightning discharges is suggested.Plain Language Summary In dancing sprite events, sprites appear in rapid succession together with a corresponding series of parent lightning strokes. Dancing sprite events were recorded on video simultaneously from two observation sites above an extended thunderstorm system in Central Europe on the night of 6 August 2013. Comparison of triangulated sprite locations and the locations of corresponding lightning activity revealed that subsequent sprite-parent lightning strokes occurred below or relatively near the location of the closest preceding sprite entity in the examined cases. In this paper, a mechanism is suggested for the development of lightning flashes that produce dancing sprites. The proposed mechanism accounts for prompt and delayed sprites relative to their parent lightning stroke, highlights the role of the variation of lightning current in sprite production, and can explain the observed closeness of the next +CG lightning stroke to the area of previous sprites.

Megaflashes: Just How Long Can a Lightning Discharge Get?

“…propagation between start and finish implies a negative leader propagation speed through positive charge layers of ~1.1 × 10 5 m s −1 , which is consistent with prior observations (Bór et al 2018;van der Velde et al 2014). The LMA time-height display of the megaflash (Fig.…”

“…After reaching its northern terminus, sporadic pulses of lightning were detected by the NLDN, LMA, and GLM at points along the initial channel. Such rebrightening of segments within horizontally extensive channels is common (Warner et al 2018;Bór et al 2018), and has been noted in LIS reconstructions of large flashes (Peterson et al 2017).…”

Origin of an Uncommon Multiple‐Stroke Positive Cloud‐to‐Ground Lightning Flash With Different Terminations

“…The development of a negative leader from the convective region to the stratiform region before a +RS, which usually transfers large quantities of positive charge to ground, has been reported previously (Lu et al, 2009). The reports about dancing sprites suggested that they were associated with a sequence of +CG strokes (Bór et al, 2018), and the lightning discharge process described here could shed a light on their conclusions. Several cases of upward lightning were triggered by the multiple‐stroke +CG flashes during our summer observation campaign, and related works will be continued.…”

“…Journal of Geophysical Research: Atmospheres +CG strokes (Bór et al, 2018), and the lightning discharge process described here could shed a light on their conclusions. Several cases of upward lightning were triggered by the multiple-stroke +CG flashes during our summer observation campaign, and related works will be continued.…”

The altitude of sprites observed over South Africa

“…However, the most probable production mechanism for sprites suggests that in fact there is a horizontal displacement in most of the cases (typically up to 21 km). 27,28 A shift of tens of kilometres is small in comparison to the camera-sprite distance of ~440-890 km in our data set, so the displacement effect is small and would affect only the calculations along the radial line of sight from the point of observation.…”