Mapping the Lateral Development of Lightning Flashes From Orbit. Issue 17 (12th September 2018)

• Record Type: Journal Article
• Authors: Peterson, Michael; Rudlosky, Scott; Deierling, Wiebke
• Is Part Of: Journal of geophysical research. Volume 123:Issue 17(2018)
• Page Start: 9674
• Page End: 9687
• Publication Date: 2018-09-12
• Subjects: lightning -- LIS -- GLM -- TRMM -- atmospheric electricity -- thunderstorms; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2018JD028583
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Optical lightning measurements from the Lightning Imaging Sensor (LIS) are used to map the lateral development of lightning flashes and produce statistics that describe their motion through the electrified cloud. This is accomplished by monitoring the frame‐by‐frame (group‐level) evolution of the optical signals produced during each flash. While the optical flash properties recorded by LIS gravitate towards the most exceptional optical signals produced during the flash, group‐level data describe the evolution and lateral development of the flash resulting from physical lightning process that emits enough light out of the top of the cloud to be detected from orbit. The groups that comprise LIS flashes constitute examples of complex lateral flash structure that can extend 80 km in length with dozens to hundreds of visible branches. The lateral development of individual flashes is described in terms of its speed and direction of motion, whether the development extends the overall length of the flash or reilluminates an existing segment, and whether it is directed inbound or outbound with respect to the origin. Sixty‐five percent of propagating groups are directed outbound from the origin, 22% extend the length of the flash, and 3–5% reilluminate an existing branch. LIS flashes are commonly oriented from east to west and develop at speeds ranging from 10 4 to 10 6 m/s, consistent with large‐scale leader development. These results provide evidence that lightning imagers may be used in conjunction with Lightning Mapping Array systems to document physical lightning phenomena across global domains. Plain Language Summary: Lightning imagers on satellites measure all types of lightning flashes with a high probability of detection. They can also be used to document the evolution of individual lightning flashes and examine their lateral structure. This study uses Lightning Imaging Sensor measurements to identify what level of spatial and temporal development that can be detected by lightning imagers. We find that orbital lightning sensors observe lateral flash development that is consistent with physical lightning processes. These results suggest that lightning imagers can make viable lightning mappers that can be used to examine lightning physics in flashes across the globe. This is particularly important for remote regions such as the open ocean where flash development is not observed by other means. Key Points: Lightning imagers provide a 2‐D composite view of the horizontal development of lightning flashes Flash properties typically describe the most radiant group while group‐level data document flash evolution and structure Flash propagation encompasses velocity scales of 10 4 and 10 6 m/s, consistent with leader development