On remote measurements of lightning return stroke peak currents
On remote measurements of lightning return stroke peak currents
复制标题
DOI：
10.1016/j.atmosres.2012.08.008
复制
发表时间：
2014
影响因子：
5.5
通讯作者：
S. Mallick;V. Rakov;D. Tsalikis;A. Nag;C. Biagi;D. Hill;D. Jordan;M. Uman;J. Cramer
中科院分区：
文献类型：
--
作者：
S. Mallick;V. Rakov;D. Tsalikis;A. Nag;C. Biagi;D. Hill;D. Jordan;M. Uman;J. Cramer
在大气电学研究的各个领域中，回波峰值电流是测量雷电强度的重要指标之一。可由相应的电或磁辐射场峰值估计。位于盖恩斯维尔的闪电观测站在距离闪电通道约45公里的地方记录下了在佛罗里达州布兰丁营地使用火箭和电线技术触发的89次闪电中的电场。根据Rakov et al.（1992）的经验公式和基于传输线模型的场电流转换方程（Uman and McLain, 1969），从测量到的电场峰值估计雷电回击峰值电流。这些估计以及美国国家闪电探测网络（NLDN）报告的峰值电流，与在闪电通道基地直接测量的地面真实数据进行了比较。经验公式基于肯尼迪航天中心（KSC）获得的28次触发雷击数据，倾向于高估峰值电流，而nldn报告的峰值电流平均低估。基于传输线模型的场电流转换方程与直接测量的峰值电流匹配最佳，回程行程速度在/2和2c/3之间（分别为1.5和2 × 108m/s）。根据经验公式得出的峰值电流估计值与实际数据存在差异的可能原因包括现场校准因子的误差、CB和KSC的典型回冲速度的差异（这里认为这是最可能的原因），以及有限的样本量，特别是对于KSC数据。根据CB触发的89次雷击数据，导出了一个新的经验公式I= - 0.66-0.028rE。
Return-stroke peak current is one of the most important measures of lightning intensity needed in different areas of atmospheric electricity research. It can be estimated from the corresponding electric or magnetic radiation field peak. Electric fields of 89 strokes in lightning flashes triggered using the rocket-and-wire technique at Camp Blanding (CB), Florida, were recorded at the Lightning Observatory in Gainesville, about 45 km from the lightning channel. Lightning return-stroke peak currents were estimated from the measured electric field peaks using the empirical formula of Rakov et al. (1992) and the field-to-current conversion equation based on the transmission line model (Uman and McLain, 1969). These estimates, along with peak currents reported by the U.S. National Lightning Detection Network (NLDN), were compared with the ground-truth data, currents directly measured at the lightning channel base. The empirical formula, based on data for 28 triggered-lightning strokes acquired at the Kennedy Space Center (KSC), tends to overestimate peak currents, whereas the NLDN-reported peak currents are on average underestimates. The field-to-current conversion equation based on the transmission line model gives the best match with directly measured peak currents for return-stroke speeds betweenc/2 and 2c/3 (1.5 and 2 × 108m/s, respectively). Possible reasons for the discrepancy in the peak current estimates from the empirical formula and the ground-truth data include an error in the field calibration factor, difference in the typical return-stroke speeds at CB and at the KSC (considered here to be the most likely reason), and limited sample sizes, particularly for the KSC data. A new empirical formula,I= − 0.66–0.028rE, based on data for 89 strokes in lightning flashes triggered at CB, is derived.