Energy coupling between atmosphere and inosphere via electrical descharge

为了研究中高层大气闪电放电发光事件的产生机制及其与雷暴活动的关系，我们利用一个由多台光学仪器和甚低频-极低频无线电波传感器组成的多点观测系统进行了一些观测活动和连续测量。通过对观测资料的详细分析和计算机模拟，阐明了以下几个问题：（1）冬季在日本周边产生雪碧的雷暴云可分为4种类型，雪碧的明显特征取决于地理位置。(2)在日本，产生冬季雪碧的云对地放电发生在雷暴云最活跃的对流区。(3)考虑到雪碧光辐射后在甚低频范围内出现的间歇性无线电波，认为云对地放电和云内放电的混合型放电与雪碧的产生有关。(4)子闪电中闪电柱的数目与母闪电的峰值电流有很好的相关性，而闪电柱的垂直长度与云对地闪电的电荷矩有很好的相关性。(5)雪碧晕的平均上下高度和水平范围分别为88 km、73 km和86 km。估计电子能量为6？23电子伏。(6)根据ELF的测量，一天的平均雪碧事件数估计为720。(7)闪电能量变化的时间周期为27.9天，这可能是由太阳活动引起的。(8)夜间中间层中O（D）的主要来源可能是雪碧和雪碧晕。

In order to investigate the generation mechanisms of luminous events in the middle and upper atmosphere induced by lightning discharge and their relationship to the parental thunderstorm activity, some observation campaigns and continuous measurements have been carried out using a multipoint observation system composed of several optical instruments and VLF-ELF radio wave sensors. Detail analysis and computer simulations based on the observation data clarified following issues : (1) Thunderclouds producing sprites around Japan in wintertime are classified into 4 types and the apparent feature of sprites depends on the geographic location. (2) Cloud to ground discharge generating winter sprites in Japan occurs in the most active convective region of the thundercloud. (3) Considering the appearance of intermittent radio wave in VLF range just after sprite optical emissions, it is suggested that hybrid type discharge consisting of cloud-to-ground and intra-cloud discharges is relating to sprite generation. (4) Number of columns in a sprite event well correlates to the peak current of the parent lightning while the vertical length of column shows good correlation with charge moment of the cloud to ground lightning. (5) The average upper and bottom heights and the horizontal extent of sprite halo are 88 km, 73 km and 86 km, respectively. The estimated electron energy is 6 ?23 eV. (6) The average number of sprite evens for a day is estimated to be 720 based on the ELF measurements. (7) The lightning energy shows variation with a time period of 27.9 days, which may be caused by solar activity. (8) Sprites and sprite halo could be major sources of O(D) in the nighttime mesosphere.