Differences of Electric Field Parameters for Lightning Strikes on Tall Towers and Nonelevated Objects

Abstract

In this article, we analyzed the far electric field parameters of cloud-to-ground (CG) lightning striking tall towers in Guangzhou at the distance of 20–70 km, and compared with lightning striking nonelevated objects from the same thunderstorm near the tall towers. By comparing the waveform characteristics, we found that the far-field waveform of tall tower exhibits the characteristics of early narrow undershoot, zero crossing, oscillation damping attenuation and there is a secondary peak after the opposite polarity peak, which is absent in the CG lightning. The GM values of 10%–90% rise time, fall time and zero-crossing time of lightning strikes on tall towers are 1.6, 2.0, and 8.4 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> s which are far less than 2.5 (1.8 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> s), 7.9 (6.4 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> s), and 28.1 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> s (28.7 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> s) of the first return stroke (subsequent return stroke) of CG lightning. In addition, the initial electric field peak, the ratio of the opposite polarity overshoot amplitude to the initial peak, and the time interval between initial electric field peak and second peak of the lightning striking on tall tower are larger than those of the CG lightning.