Electric Field Signatures in Wideband, 3 MHz and 30 MHz of Negative Ground Flashes Pertinent to Swedish Thunderstorms

Atmosphere

Mohd Muzafar Ismail²  Mahbubur Rahman²  Vernon Cooray²  Shriram Sharma¹  Pasan Hettiarachchi²  Dalina Johari² 

[1] Department of Physics, Amrit Science College, Tribhuvan University, Lainchaur, Kathmandu 001, Nepal;Ångström Laboratory, Division of Electricity, Department of Engineering Sciences, Uppsala University, Box 534, SE-75121, Sweden;

关键词: lightning;    negative ground flashes;    3 MHz and 30 MHz radiations;   

DOI  :  10.3390/atmos6121837

来源: mdpi

【 摘 要 】

In this study, the electric field signatures of negative ground flashes pertinent to the Swedish thunderstorms were recorded simultaneously during the summer of 2014 using wide (up to 100 MHz) and narrow (at 3 MHz and 30 MHz as central frequencies) bandwidth antenna systems. The electric field signatures were recorded for a time duration of 250 ms. In the analysis, the whole flash was considered and a total of 98 flashes were chosen where electric field signatures of all wideband, 3 MHz and 30 MHz signals were present. It is observed that preliminary breakdown pulses are stronger radiators at 3 and 30 MHz compared to the return strokes. A comparison of our results with those of the previous studies obtained from different geographical regions clearly shows that the strength of preliminary breakdown pulses is higher in the temperate region (Sweden for instance) and is a function of latitude.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.