摘要
2003年夏季在青藏高原那曲地区进行了雷电综合观测试验，利用宽带干涉仪系统获取的闪电资料，根据辐射源定位结果和相应的电场变化对云闪放电起始阶段进行了分析，初步分析结果表明：雷暴过境时地面电场为正值的情况下，云闪放电多发生在中部负电荷区和下部正电荷区之间，上部正电荷区一般不参与放电。虽然不同的云闪会有不同的放电发展过程，但放电起始阶段具有相似的特征。云闪放电起始于中部负电荷区，在初始几十毫秒内，辐射源垂直向下发展，云内负流光向下发展速度约为1.14～1.72×10^5m／s。在下部正电荷区内，闪电通道可以垂直发展，也可以水平发展。且发生在正电荷区的放电过程比较复杂，正电荷区辐射点比负电荷区要多。
Radio frequency observations of intracloud lightning （IC） over the Qinghai-Xizang Plateau have been made using a broadband interferometer system in the summer of 2003. The spatial and temporal variations of radiation sources and electric field change of IC discharge have been analyzed in this paper. The result indicate that the IC discharges occur between the lower positive and upper negative charge regions when the polarity of surface electric field of thunderstorm passing is positive, but the upper positive charge doesn＇t participate in discharge. Although different flashes have differently very structures, the initial stage of discharge has the similar physical process. The IC discharge always initiates at the negative charge region, the channels of IC lightning propagate downward during initial stage within tens of milliseconds, and the downward speed of the lightning channel is about 1.14-1.72 10^5m/s. In the lower positive charge region, the channel of the flash can vertically propagate, and it also can levelly propagate. The radiation which occurred in the lower positive charge is very complicated. There are much more radiation points in the lower positive charge region than in the upper negative charge region.
出处
《高原气象》
CSCD
北大核心
2007年第1期55-61,共7页
Plateau Meteorology
基金
国家自然科学基金项目(40575002
40375004)资助
关键词
宽带干涉仪
云闪
辐射源
Broadband interferometer
Intracloud discharge
Radiation source
