Dart‐Leader and K‐Leader Velocity From Initiation Site to Termination Time‐Resolved With 3D Interferometry

Abstract

Simultaneous data from two interferometers separated by 16 km and synchronized within 100 ns were collected for a thunderstorm near Langmuir Lab on October 23, 2018. Analysis via triangulation followed by a least squares fit to time of arrival across all six antennae produced a three‐dimensional interferometer (3DINTF) data set. Simultaneous Lightning Mapping Array data enabled an independent calculation of 3DINTF accuracy, yielding a median location uncertainty of 200 m. This is the most accurate verified result to date for a two‐station interferometer. The 3D data allowed profiling the velocity of multiple dart leaders and K leaders that followed the same channel. 3D velocities calculated from the in‐cloud initiation site to ground ranged from 3 × 106 to 20 × 106 m/s. Average velocity generally increased with subsequent leaders, consistent with increased conditioning of the channel. Also, all leaders showed a factor of 2–3 decrease in velocity as they proceeded over 15 km of channel. We speculate that the velocity decrease is consistent with energy lost in the reionization of the channel at the leader tip. This paper includes an appendix providing details of the triangulation technique used.

Timing Calibration and Windowing Technique Comparison for Lightning Mapping Arrays

“…Finally, and perhaps most critically, this work establishes two new post-processing techniques that can be applied to almost any lightning-mapping system, not just LMAs. This is especially important for multi-station lightning interferometers, which have proven to be very difficult to calibrate without this technique (Hare et al, 2018;Jensen et al, 2021).…”

Analysis of the Configuration Relationship Between the Morphological Characteristics of Lightning Channels and the Charge Structure Based on the Localization of VHF Radiation Sources

“…The leader velocity was calculated in a similar manner to Jensen et al (2021). The radiation sources of the leader channel were selected, and the velocity of the leader propagation was estimated using the sliding average method (see Text S1 in Supporting Information S1 for more details).…”

Time resolved 3D interferometric imaging of a section of a negative leader with LOFAR

“…The imaging of lightning in three dimensions using VHF-interferometric-based methods has a history dating back to the early work of [1], where 3D is reached by combining angular measurements from two different stations. This work was followed up by others, such as [2][3][4], and culminated recently in the work of [5] reaching a resolution of 200 m using six antennas.…”