Abstract The integrals of lightning current and its square over time, named as the electrical charge quantity and lightning current action integral, respectively, are indicative of the total charges and heat energy released by the lightning. The temperature of air molecules along the discharging path is thus increased and can be observed by a properly-configured ground-based microwave radiometer which is originally for atmospheric temperature remote sensing. Field experiments have been performed with a ground-based, MWP967KV type microwave radiometer, which is common for atmospheric temperature profile remote sensing but has been properly-configured in order to observe the artificially triggered lightning events in May–July in 2017 and 2018 at Guangzhou Field Experiment Site for Lightning research and test (GFESL). The brightness temperature (Tb) data from the radiometer and the lightning current data measured by a coaxial shunt have been processed. The results show that a relationship like Tbmax = a + b*exp.(c*It) may exist between the maximum pulse amplitude, Tbmax, in unit of K, observed in 30-50GHz band and the total current action integral, It, in unit of A2s, calculated from high temporal resolution lightning current records. The correlation coefficient is as high as 0.75 when taking the data of the two years as a whole (sample size = 16) while the coefficients a, b and c are equal to 21.53, 2.47 and 3.47, respectively. It is not evident that maximum pulse amplitude has a significant positive correlation with the total electrical charge quantity. In addition, it has been found that the variation trend of Tb pulse amplitude and lightning current integral values (i.e. current action integral and electrical charge quantity) in the lightning process are consistent.

中文翻译：

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地基微波辐射计观测亮温脉冲与雷电流积分值关系的初步研究

摘要 雷电流及其平方随时间的积分，分别称为电荷量和雷电流作用积分，表示闪电释放的总电荷和热能。沿着放电路径的空气分子的温度因此升高，并且可以通过适当配置的地基微波辐射计进行观测，该微波辐射计最初用于大气温度遥感。使用地面MWP967KV型微波辐射计进行了现场实验，该微波辐射计在大气温度廓线遥感中很常见，但为了观测2017年5-7月和2018年广州的人为触发闪电事件而进行了适当配置闪电研究和测试现场试验场 (GFESL)。对辐射计的亮温（Tb）数据和同轴分流器测得的雷电流数据进行了处理。结果表明，在30-50GHz频段观测到的最大脉冲幅度Tbmax（单位为K）与总电流作用积分It之间可能存在类似Tbmax = a + b*exp.(c*It)的关系，以 A2s 为单位，根据高时间分辨率的雷电流记录计算。将两年的数据作为一个整体（样本量=16），相关系数高达0.75，而系数a、b和c分别等于21.53、2.47和3.47。不明显的是，最大脉冲幅度与总电荷量呈显着正相关。此外，