Observations of Red Sprites Above Hurricane Matthew

Abstract

More than three dozen red sprites were captured above Hurricane Matthew on the nights of 1 and 2 October 2016 as it passed to the north of Venezuela after undergoing rapid intensification. Analyses using broadband magnetic fields indicate that all of the sprites were produced by positive cloud-to-ground (CG) strokes located within the outer rainbands as defined by relatively cold cloud top brightness temperatures (≤194 K). Negative CG strokes with impulse charge transfers exceeding the threshold of sprite production also existed, but the timescale of the charge transfer was not sufficiently long to develop streamers. The reported observations are contrary to the finding of the Imager of Sprites/Upper Atmospheric Lightning showing that sprites are preferentially produced by negative strokes in the same geographic region. Further ground-based observations are desired to obtain additional insights into the convective regimes associated with the dominance of negative sprites in many oceanic and coastal thunderstorms.