Dark Lightning

点击翻译按钮获取中文摘要

One of the biggest mysteries in lightning science is the Narrow Bipolar Event (NBE), a rapid intracloud charge transfer. Its physics remains enigmatic, because the NBE: (a) lacks readily detectable light output, unlike all other known lightning of comparable current; (b) lacks any detectable channel-preparation (leader) process, again unlike all other known lightning strokes; and (c) radiates the most powerful High-Frequency (HF) and Very-High-Frequency (VHF) emissions compared with those of any lightning.Intellectual merit. This study will investigate the properties of NBEs using both satellite- and ground-based observational data. In particular, the project involves analyzing polarization and spectral information in the data by studying all VHF events. The research will improve current understanding of the physics of NBEs, and may advance our knowledge on lightning initiation processes.Broader impacts. The remote sensing of lightning from space is an important proxy for monitoring convective weather processes. Detecting and understanding of intracloud charge transfer may improve prediction of severe weather. The research may also shed light on lightning initiation processes, terrestrial gamma ray flashes, or any other types of unusual discharges in the atmosphere. A graduate student will be trained in this subject area as well.