Using Saha‐Boltzmann Plot to Diagnose Lightning Return Stroke Channel Temperature. Issue 8 (25th April 2019)

• Record Type: Journal Article
• Authors: Liu, Guorong; Yuan, Ping; An, Tingting; Sun, Duixiong; Cen, Jianyong; Wang, Xuejuan
• Is Part Of: Journal of geophysical research. Volume 124:Issue 8(2019)
• Page Start: 4689
• Page End: 4698
• Publication Date: 2019-04-25
• Subjects: Saha‐Boltzmann plot method -- lightning return stroke channel temperature; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2018JD028620
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Based on the high time‐resolved spectra of a cloud‐to‐ground lightning flash with seven return strokes captured by a high‐speed slitless spectrograph, this work was the first to use the Saha‐Boltzmann plot method for the determination of the lightning return stroke channel temperature. The channel temperatures of the seven return strokes ranged from 21370 to 26500 K. Compared with the traditional Boltzmann plot method, the Saha‐Boltzmann plot method can provide more reliable temperature estimation for lightning channel. Analysis of several strong return strokes along the channel showed that the temperature changed little and there was no obvious tendency with increasing height. In addition, it was found that the channel temperature in the late stage of a return stroke was only about 3000–4000 K lower than in the initial stage. This means the channel remains >20000 K during nearly the entire period of the return stroke. This sustained high temperature could be the main cause of lightning‐related disasters. Key Points: Lightning return stroke channel temperature was determined by the Saha‐Boltzmann plot method for the first time The channel temperature drops very slowly, and the channel retains >20000 K high temperatures after around 100 microseconds of peak current