Open Access Digital Repository of Ministry of Earth Sciences, Government of India

Anomalous electric field changes and high flash rate beneath a thunderstorm in northeast India

Pawar, SD and Murugavel, P and Gopalakrishnan, V (2010) Anomalous electric field changes and high flash rate beneath a thunderstorm in northeast India. Journal of Earth System Science, 119 (5). pp. 617-625.

2099.pdf - Published Version

Download (479kB) | Preview


In spite of many experimental and theoretical studies the relationships between storm dynamics, severe weather, and lightning activity have been least understood. Measurements of electric field made under a severe thunderstorm at a northeastern Indian station, Guwahati, India are reported. Lightning flash rate increases drastically to about 84 flashes per minute (fpm) during the active stage which lasted for about 7 minutes, from about 15 flashes per minute during the initial phase of thunderstorm. Sudden increase in lightning flash rate ('lightning jump') of about 65 fpm/min is also observed in the beginning of the active stage. The dissipating stage is marked by slow and steady decrease in lightning frequency. Despite very high flash rate during the active stage, no severe weather conditions are observed at the ground. It is proposed that the short duration of the active stage might be the reason for the non-observance of severe weather conditions at the ground. Analysis of Skew-t graph at Guwahati suggests that vertical distribution of Convective Available Potential Energy (CAPE) also may play some role in non-occurrence of severe weather at ground in spite of large lightning flash rate and lightning jump observed in this thunderstorm. Further, all electric field changes after a lightning discharge indicates the presence of strong Lower Positive Charge Centers (LPCC) in the active and dissipation stages. This suggests that LPCC plays an important role in initiation of lightning discharges in these stages.

Item Type: Article
Additional Information: Copyright of this article belongs to Indian academy of Science
Uncontrolled Keywords: atmospheric dynamics; atmospheric electricity; cloud to ground lightning; convective system; electric field; potential energy; severe weather; thunderstorm, Assam; Gauhati; India
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 28 May 2015 11:24
Last Modified: 28 May 2015 11:24

Actions (login required)

View Item View Item