Transient luminous events above two mesoscale convective systems: Charge moment change analysis

[1] Charge moment change (DMQ) data were examined for 41 positive cloud‐to‐ground (+CG) lightning discharges that were parents of transient luminous events (TLEs; mainly sprites) over two different storms: 9 May (20 parents) and 20 June 2007 (21). Data were broken down by contributions from the impulse DMQ (iDMQ), within the first 2 ms of the return stroke, and the DMQ from the continuing current (CC), which can last tens of ms afterward. Three‐dimensional lightning mapping data provided positions for the in‐cloud components of the parent +CGs. Charge and charge density neutralized by the strokes were estimated. The 20 June parents were more impulsive than 9 May, with increased iDMQ and CC amplitude but reduced CC duration. Total DMQ values between the two storms were very similar, averaging ∼1800 C km. Estimated charge density on 20 June was nearly twice that on 9 May, consistent with the 20 June storm being more intense with a stronger electrical generator. Lightning metrics were analyzed for 9 high‐ iDMQ (>300 C km) +CGs that did not produce an observable TLE on 20 June, and compared to that day’s TLE parents. Non‐TLE +CGs had reduced CC magnitudes and duration, with less total DMQ. Photogrammetric estimates of TLE azimuthal swaths were positively correlated with similar metrics of the in‐cloud portions of the parent +CGs, as well with total DMQ. The implications of all these results for the DMQ theory of sprite initiation, and for the relationship between sprite development and in‐cloud discharging, are discussed.