Observation of cloud-to-ground lightning channels with high-speed video camera

TL;DR

This study used high-speed video to observe and analyze the detailed behavior of cloud-to-ground lightning channels, including leader propagation and branching, during thunderstorms in France.

Contribution

It provides new detailed observations of lightning leader dynamics and branching behavior, comparing positive and negative flashes using high-speed imaging and detection network data.

Findings

Differences in characteristics between positive and negative leaders.

Estimated propagation velocities and their evolution during flashes.

Observed branching behavior during channel development.

Abstract

Between May and October 2013 (period of sustained thunderstorm activity in France), several cloud-to-ground lightning flashes have been observed in Paris area with a high-speed video camera (14000 frames per second). The localization and the polarity of the recorded cloud-to-ground flashes have been obtained from the French lightning detection network M{\'e}t{\'e}orage which is equipped with the same low frequency sensors used by the US NLDN. In this paper we focused on 7 events (3 positive cloud-to-ground lightning flashes and 4 negative cloud-to-ground lightning flashes). The propagation velocity of the leaders and its temporal evolution have been estimated; the evolution of branching of the negative leaders have been observed during the propagation of the channel which get connected to ground and initiate the first return stroke. One aim of this preliminary study is to emphasize the differences between the characteristics of the positive and of the negative leaders.