Seeking sprite-induced signatures in remotely sensed middle atmosphere NO2

The local chemical impact of sprites is investigated for the first time. This study is motivated by the current understanding of the streamer nature of sprites: streamers are known to produce NOx, thus sprites are expected to lead to a local enhancement of the background abundances, and possibly impact ozone. We adopted the following strategy: middle atmosphere MIPAS/GMTR NO2 satellite measurements were correlated with ground-based WWLLN detections of large tropospheric thunderstorms as a proxy for sprite activity. We found no evidence of any significant impact at a global scale, but an indication of a possible sprite induced NO2 enhancement of about 10% at 52 km height in correspondence with active thunderstorms. This local enhancement appears to increase with height from a few percent at 47 km to tens of percent at 60 km.