Anomalous electric field changes and high flash rate beneath a thunderstorm in northeast India |
| |
Authors: | S D Pawar P Murugavel V Gopalakrishnan |
| |
Institution: | (1) Indian Institute of Tropical Meteorology, Pune, 411 008, India;(2) Department of Physics, Banaras Hindu University, Varanasi, 211 005, India;(3) Physics Department, Lucknow University, Lucknow, 226 007, India |
| |
Abstract: | 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. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|