ABOUT THE VARIATION IN THE CLOUD-TO-GROUND LIGHTNING RETURN STROKE PEAK CURRENT IN DIFFERENT REGIONS ON EARTH
The knowledge about the lightning peak current distribution at different regions is very important as a key parameter to revel possible changes in the thunderstorm electrical structure, as well as to improve the reliability of lightning protection schemes in many engineering applications. However, in spite of the large amount of information available on cloud-to-ground lightning peak current distribution, based on multiple different techniques, there is no a general agreement about its variation in different regions. The reasons for that is primarily related to limitations of the different techniques normally used to obtain lightning peak current values, which can basically be divided in two types: direct observations by instrumented towers, available in a few countries, and indirect observations based on lightning location systems, installed in more than 40 countries. Peak current values obtained by instrumented towers are limited by current reflections in the tower and by bias in the measured values due to dependence of attachment process on the peak current and on the relief. Peak current values estimated by lightning location systems, in turn, are limited by the propagation effect on the lightning electric and magnetic fields due to non perfect ground conductivity, which is dependent on the network configuration, and by the limited knowledge regarding the lightning current variation along the lightning channel. The above limitations preclude in most cases a direct comparison of peak current values obtained in different regions. In this article, a different approach is done to estimate this variation. The approach is based on physical nature of these variations in the lightning peak current. It is assumed that the lightning peak current is primarily a result of breakdown electric field intensity inside the thunderstorm, which in turn is dependent on the local atmospheric pressure and temperature. So, basically, any factor that can change these parameters can potentially change the peak current. The above ideas are used in conjunction with data obtained by lightning location systems operated by many years throughout the world to estimate the possible variations in the peak current on Earth.
lightning lightning peak current lightning location systems
O. Pinto Jr. I.R.C.A. Pinto
Atmospheric Electricity Group – ELAT Brazilian Institute of Space Research (INPE)
国际会议
第13届国际大气电学会议(The 13th International Conference on Atmospheric Electricity)
北京
英文
2007-08-13（万方平台首次上网日期，不代表论文的发表时间）