title: Upward electrical discharges observed above Tropical Depression Dorian.
abstract: Observation of upward electrical discharges from thunderstorms has been sporadically reported in the scientific literature. According to their terminal altitudes, they are classified as starters (20-30 km), jets (40-50 km) and gigantic jets (70-90 km). They not only have a significant impact on the occupied atmospheric volumes but also electrically couple different atmospheric regions. However, as they are rare and unpredictable, our knowledge of them has been built on observations that typically record only one type of such discharges. Here we report a close-distance observation of seven upward discharges including one starter, two jets and four gigantic jets above Tropical Depression Dorian. Our optical and electromagnetic data indicate that all events are of negative polarity, suggesting they are initiated in the same thundercloud charge region. The data also indicate that the lightning-like discharge channel can extend above thunderclouds by about 30 km, but the discharge does not emit low-frequency electromagnetic radiation as normal lightning.
authors.affiliation: Department of Physics and Space Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, USA.
authors.forename: Ningyu
authors.initials: N
authors.lastname: Liu
authors.affiliation: Department of Physics and Space Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Spiva
authors.affiliation: Department of Physics and Space Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, USA.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Dwyer
authors.affiliation: Department of Physics and Space Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, USA.
authors.forename: Hamid K
authors.initials: HK
authors.lastname: Rassoul
authors.affiliation: Space Coast Intelligent Solutions, Melbourne, Florida 32934, USA.
authors.forename: Dwayne
authors.initials: D
authors.lastname: Free
authors.affiliation: Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Cummer