Observation of corona discharges and cloud microphysics at the top of thunderstorm cells in cyclone Fani

Different Types of Corona Discharges Associated With High‐Altitude Positive Narrow Bipolar Events Nearby Cloud Top

“…The total number of lightning events at the zoom region, shown in Figure 1d, started to increase around 15:00 UTC, then peaked at the time around 17:50 UTC when ASIM passed over. The BLUEs are accompanied by the highest concentration of IC and CG lightnings, which is consistent with previous studies (Chanrion et al., 2017; Husbjerg et al., 2022; Li, Neubert, et al., 2022). The geolocations (latitude and longitude) of the 16 BLUEs are based on the 337 nm images detected by MMIA.…”

“…The nature of NBEs, and their relation to the formation of the lightning leader is still poorly understood; however, it may provide further insight into the most important problem in lightning physics: the initiation of lightning inside thunderstorms (Rison et al., 2016). Recent observations connected NBEs with a new type of discharge, called fast breakdown (FB), suggesting that NBEs are produced by a system of streamer coronas without a conducting channel or hot leader involved (Lyu et al., 2019; Rison et al., 2016; Tilles et al., 2019), which is further supported by the recent studies of the NBEs‐associated BLUEs detected by Atmosphere‐Space Interactions Monitor (ASIM) (Li, Luque, Lehtinen, et al., 2022; Li, Neubert, et al., 2022; Li et al., 2021; F. Liu, Lu, et al., 2021; Soler et al., 2020).…”

“…In their study, Li, Neubert, et al. (2022) showed that most of the corona discharges are located close to high ice water content with a photon mean free path Λ ≈ 3 m measured by the Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation. However, note that both particle radius and the number density can be strongly affected by the deep convection inside the thunderstorm (Brunner & Bitzer, 2020; Li, Neubert, et al., 2022).…”

“…(2022) showed that most of the corona discharges are located close to high ice water content with a photon mean free path Λ ≈ 3 m measured by the Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation. However, note that both particle radius and the number density can be strongly affected by the deep convection inside the thunderstorm (Brunner & Bitzer, 2020; Li, Neubert, et al., 2022). To further investigate the cloud microphysics and its effect on the corona discharges, a more detailed light‐scattering model including a parameterization of cloud microphysics is required in future studies.…”

“…For the 5 BLUEs without the corresponding camera images, we use the meta data of 337 nm camera images to find their geolocations. Note that the final geolocations of all the BLUEs have been projected to the cloud top (about 18 km) with a horizontal uncertainty of less than 10 km (Bitzer et al., 2021; Husbjerg et al., 2022; Li, Neubert, et al., 2022).…”