摘要
叙述了国家自然科学基金重点项目“雷电物理及人工引发雷电研究”所取得的主要成果。项目发展了雷电的空中引发新技术,并在我国南、北方进行了人工引雷实验及综合观测,揭示了南北方人工引发雷电的特征及差异;建立了雷暴下空间电荷演化的数值模式,提出了雷电成功引发的空中电场判据;研究了雷电流及辐射电磁场的关系,提出了改进的地闪传输线模式;用高速摄像系统研究了人工引发雷电的发光特征,首次观测和证实了闪电通道发展中双向先导传输现象,光、电同步观测揭示了先导接地时的物理过程;与日本学者合作进行了高原雷电的综合观测,发现了云下部闪电放电起始于云内负电荷区;首次发现人工引发雷电有抑制冰雹、增加降水的作用,用积云动力和电数值模式解释了利用电催化原理进行强风暴人工影响的可能性。
In this paper, the main results of the project 'Study on lightning physics and artificial triggering of lightning' sponsored by NSFC are described. The experiments were conducted with traditional triggering techniques as well as newly developed one called 'altitude-triggering'.
The discharge processes of triggered lightning show great differences in Northern and Southern China. In order to increase the rate of success of lightning triggering, a numerical model has been established to simulate the evolution of space charge between cloud base and the ground. As a result, a criterion for successful triggering of lightning was put forward in terms of the magnitudes of ambient electric field. The relationship between return stroke current and radiation fields was studied, and an improved model of transmission line was derived.
The luminous characteristics of artificially triggered lightning flashes were studied by use of a high-speed digital camera system. Bi-directional propagation of leader in 'altitude-triggered' lightning has been observed and verified. The physical processes of downward leader approaching the ground were revealed by using high-speed camera and simultaneous measurements of current and electric field. The thunderstorms in the inland plateau of China were studied in cooperation with Japanese scientists. The results indicate that ground discharges in the area originate in the main negative charge region in the middle part of cloud and propagate towards the lower positive charge layer. In addition, there is evidence to show that triggered lightning may have effects on hail suppression and rain intensification. The possibility of modification of thunderstorm by triggered lightning was studied using a two dimensional, axisymmetric and time-dependent dynamic-electric cloud model.
出处
《中国科学基金》
CSCD
1999年第1期20-23,共4页
Bulletin of National Natural Science Foundation of China
基金
国家自然科学基金重点项目
批准号49235090
关键词
人工引发雷电
雷电物理
雷暴电结构
雷暴
artificially triggered lightning, lightning physics, electric structure of thunderstorm, modification of thunderstorm
